Rockpool Ramble at Prisk Cove

21st August 2012

The weather didn’t bode well for our Rockpool Ramble event at Prisk on Tuesday 21st August, with heavy showers hitting hard as we drove to our meeting point. However, by the time we all assembled at Mawnan Church car park the sun was shining and the afternoon turned out to be warm and beautiful. We were a small group with only three families from Helston, Truro and Perranporth, and a keen naturalist from Penzance who very kindly recorded our day’s findings for the Environmental Records Centre for Cornwall and Isles of Scilly. I was also joined by three enthusiastic members of the Helford Marine Conservation Group – Paul Garrard, Dave Thompson and Rhiannon Pipkin.

Once gathered, our select little group walked around the coast path to our destination – Prisk Cove. I love Prisk and it is highly regarded by many other marine ecologists as being one of the best rockpooling sites in the county (if not further afield!), but hush, it’s our little secret!! The walk around the coast path, particularly in the sunshine, builds the anticipation of what we might find with glimpses of the reef extending out to August buoy and Rosemullion Head in the background. As is often the case in this magical little corner of the Helford there was hardly anyone else around so we felt like we had the whole beach to ourselves.

Prisk is an incredibly bio-diverse spot and once again did not disappoint. We headed down to the low tide mark and started to rummage, the first stones turned revealing an abundance of life. We found numerous Cornish suckerfish (Lepadogaster lepadogaster), worm pipefish (Nerophis lubriciformis) many of which had distinct orange eggs under their bellies, and a butterfish (Pholis gunnellus). Crabs also abounded including the ‘body builder’ crab Xantho incises, velvet swimming crabs and broad clawed porcelain crabs (Porcellana platycheles) clinging to the undersides of most rocks. The beautifully coloured colonial seasquirts Botryllus schlosseri and Botrylloides leachi were also found on many undersurfaces at the very low tide. One of the biggest finds was made by one of our younger participants who found a large spiny starfish, Marthasterias glacialis, about 15cm across, and more commonly seen in deeper water when diving. Other highlights included green shore urchins (Psammechinus miliaris) camouflaged with pieces of shell stuck on their spines, squat lobsters (Galathea squamifera), and the ever comical hermit crabs.

Our two hour event on the shore flew by and no-one wanted to stop, but as the tide turned we called it a very successful day and headed back. Those new to Prisk Cove vowing to return to this amazingly rich but little known or disturbed haven.

Ruth Williams
HMCG event leader and Marine Conservation Manager for Cornwall Wildlife Trust.

Helford Conservation Cruise

1st July 2012

The 19th Annual Conservation cruise set off on a dry day with a few grey clouds and
a brisk westerly wind. The “Enterprise” boat skipper with his intimate knowledge of
the channels and mud banks took us high up into the creeks, the haunt of shelduck,
sandpiper, redshank, heron and little egret.

A peregrine falcon gave a stunning aerial display over Dennis Head, whilst a sparrowhawk
swooped along the woodland edge in the upper creeks where two pairs of shelduck with
grey downy chicks could be seen awaiting the fall of the tide.

Ancient oak woodland fringed much of the shoreline contrasting with the impressive Sea-
Core Fugro drilling platforms at Gweek.

Sea-water tanks on-board with National Trust volunteers, gave an opportunity to see
various shore species such as crabs and anemones at close quarters.

Whilst the 100 passengers were charmed by the beauty of the trees above the ruffled
water, they also enjoyed their tea or coffee as they learnt more about the birds, the fish
and fishing, management of the land and woods, geology, local history and industries and
most importantly the whole marine web of life.

Sailors and land-lubbers alike appreciated the timeless beauty of the secluded waters,
muddy creeks, woodland tapestry and rocky shores and the importance of protection for
this vulnerable sheltered arm of the sea.

Andrew Tompsett

What’s beneath your feet? (Dr Tegwyn Harris)

6th June 2012

Bar beach, Helford Passage

On a slightly blustery afternoon an intrepid group of Helford VMCA members headed out on to Bar Beach to explore the squidgy, muddy but intriguing world living beneath our feet. The event was planned to find, identify and learn a little more about some of the unusual critters to be found hidden in the muddy shores of the Helford River. We all see the mud shores, but to many of us they usually look muddy, flat and not terribly alive, so on this afternoon Tegwyn set out to prove just how much life was there, if only you open your eyes and look.

At the start of the event we promptly headed down to the bottom of the shore to begin our exploration. The first thing you notice is that the mud isn’t flat and barren – it is covered in holes, burrows, trails, mounds and strange little structures created by all of the critters living within it. With a few volunteers armed with spades, trowels and buckets it didn’t take long for us to start finding out what had made them. Tegwyn was brilliant, pitching information about the creatures we found at a level understandable by everyone from young children to marine scientists and featuring fantastic analogies including the equivalent of living on essence of fish and chips and body-snatching Hollywood aliens! We found masked crabs (Corystes cassivelaunus) which burrow into the sediment and breathe through a filtering snorkel formed from two antennae, common shore crabs (Carcinus maenas) whose body had been taken over by a parasitic barnacle which occupies its tissues and a range of bristle worms which, although often overlooked, are equally as beautiful and quirky as many of the other more familiar creatures.

Special thanks should go to Dr Tegwyn Harris for his wonderful, animated discussions on the lives of the creatures beneath our feet and for sharing some of his immense knowledge on this subject. Thanks also go to all the Helford VMCA volunteers who turned up, dug in and got muddy and to Matt Slater (Cornwall Wildlife Trust), Rhiannon Pipkin (Natural England), Pamela Tompsett and Dave Thomson (Helford VMCA) for organisation, logistics and making sure everything ran smoothly!

A full list of species found on the day can be found here.

Holly Latham

Coastal Ketches and Inside Barges (Andy Wyke)

14 January 2012

‘A sewn boat? What’s that?’ ‘Well, it was a way of constructing boats in the Bronze Age, about 2500 BC, before nails had been invented. With the tools available at the time, bronze axes and adzes, logs would be split and fashioned into planks, to be stitched edge-to-edge with fibres from yew branches. Moss was used for caulking.’

Our speaker, Andy Wyke, was well qualified to tell us. As Boat Collection Manager at the National Maritime Museum Cornwall, he has been one of the prime movers in a project which will use ancient tools to build a 60ft replica Bronze Age boat at the museum this summer (Apr – Sep), in an open workshop on view to the public. An example from the period was discovered in NE Yorkshire. Propelled by about 20 rowers it could have crossed the North Sea; and boats of this type may have been used to transport tin, which was a commodity traded with Europe during the Bronze Age. The Salcombe Hoard (over 300 items of copper, gold and tin discovered in 2009 and now in the British Museum) came from a sunken Bronze Age boat. Of similar age, the Sky Disc of Nebra, found in Germany, was a bronze disc with inlaid gold shapes representing the sun, moon and stars. The gold was traced to the old Carnon mine.

In Romano-British times, edge-butted planks were fastened onto ribs using iron nails; and the boat carried a square sail, Scandinavian-style. Gweek was a Roman trading port. By the 11th Century a distinction was developing between boat builders and ship builders. Boats were built ‘by eye’, from experience, using hewn planks and clinker (overlapping) construction. Ship building involved plan drawings, planks from saw mills and carvel (flush) construction.

Records indicate that since post-Medieval times, from about 1500 AD onwards, there have been around 39 quays in the Helford, Merthen being one of the oldest. They enabled river and sea-going trade in coal, spars, limestone, granite and a variety of other commodities, carried by ships and boats that were built at Helford or Gweek, or built elsewhere, such as Penryn and Fowey, and registered in the Helford. A table for 1786 to 1861 shows that their sizes ranged from 17 to 69 tons. Some of these vessels had long working lives. The Hobah, for instance, was a 70ft x 19ft, 56 ton ketch, built in 1879 on a creek near Mylor, which traded to the South Coast and France with cargos such as coal, manure and granite for lighthouses. It ended its activities in 1945. Ships’ masters, such as Capt. Will Lamey, were not required to have paper qualifications; they just had to be competent to do all the jobs on board. The captain’s proficiency in running his ship was the key factor in the success, or otherwise, of a trading vessel.

Diverse craft would have been seen in the Helford during the late 19th and early 20th Centuries, from the impressive 125ft x 25ft barquentine Waterwitch, which was built in 1871 and operated in the coal trade until 1948, to the more workaday 25 ton sailing barge Little Industry, which was built in Truro in the 1880s and traded from Porthallow. An evocative painting by local artist John Whale (who was in the audience) showed her resting on the mud at St Antony at low tide, offloading cargo into a horse-drawn cart alongside. Goods would be transferred to barges and lighters when deep-draught sea-going vessels were unable to dock at quays. A notable craft was the 1880’s brigantine Lady of Avenel. A photograph showed her loading granite at Porth Navas, where a quay had been constructed in 1830 to serve about 8 granite quarries in the Constantine-Mabe area and handle returning limestone. At times, piles of granite blocks on the quay would be 40-50ft high. The trade subsequently moved to Penryn and Lady of Avenel was sold to Frank Worsley, who famously was captain of the Endurance in 1916 and navigated the small boat in which Shackleton sailed for help to South Georgia after Endurance was crushed by Antarctic ice. In WWI Worsley commanded a Q-ship, a U-boat killer. In 1925 he took Lady of Avenel on an Arctic expedition. She returned to Bridlington, then Poole Harbour and ended her days in 1965 when she was towed out to sea, set alight and sunk.

In 1848 around 200 boats operated from Gweek in the fish trade. Pilchards were the target catch, as they had been for about 400 years. The season ran from mid-summer to March and the fish were taken to cellars at Helford, Gweek, Durgan and Gillan, where they were cured on floors and then packed into hogsheads, containing 3000 fish and weighing 450lb, for export to Italy and other destinations. Over 50 million fish were caught annually, 63,000 hogsheads were noted for 1864 and the catch from 1815 to 1914 exceeded 1 billion tons. The boats were mainly luggers, such as the 35ft Ganges and the Mystery (a replica of which was used by Pete Goss and his family to sail to Australia a few years ago). Gig-type rowing boats could also be used for fishing. A lesser, but still important, trade was in oysters, associated with Porth Navas. These would be dredged from craft ranging from a 14ft rowboat to the 43ft Rob Roy, a fast sailing boat owned by the Tyacks of Merthen. Unusually this had a wet hold for transporting young oysters to the beds as well as containment for mature shellfish to market.

A perhaps unexpected part of shipping in the Helford over a century ago was linked to emigration. From 1815 to 1914, 50 million people from Europe, 10 million from Britain and ¼ million from Cornwall (a high proportion of the resident population) left in search of a better life in Australia and the Americas. The ‘Penny Emigrants Sheet’ advised them to take spades, shovels, etc, but ‘any clothes will do’. The West Briton advertised a sailing from Gweek to Philadelphia. Fares of £4 for an adult, £2 for a child, were administered by the mines, government agents and shipping agents. As cargos came in, people went out, packed into cramped holds where death and disease were commonplace.

What remains today of this past activity? Gweek has SeaCore and a boatyard, oysters are still farmed from Porth Navas, there is a small fishing fleet and commercial shipping has been replaced by leisure boating. Possibly the most enduring link is the ferry. Crossing from Helford Passage to Treath from about 1023 and Helford Passage to Helford from the 1880s, it has been owned at different times by the Godolphin family, the Duke of Leeds, the Grylls family and is now privately owned. It has been a continuing part of the Helford scene for over 1000 years.

The HMCG wishes to thank Andy Wyke very much for his wide-ranging and absorbing talk; and for editing the above report.

Paul Garrard

Leatherback turtles and their jellyfish prey (Dr Matt Witt)

31st March 2012

Of the 7 species of marine turtles, 3 are seen regularly in UK waters: the Leatherback, Loggerhead and Kemp’s Ridley turtles. However, Britain also has interests in overseas waters, such as the Caribbean, and so the work of the Marine Turtle Research Group of Exeter University, based at Tremough, encompasses the world’s oceans. For our speaker, Dr Matthew Witt, the principal study area has been the beaches of Gabon, West Africa. Secluded and little frequented, (although with oilfields offshore), these are the nesting grounds for the world’s largest population of Leatherback turtles. Hitherto this community has been one of the least studied, but by attaching transmitters to the turtles’ backs it has been possible to track their movements. The devices, which have a battery life of 180 days, transmit automatically to a satellite each time the animal surfaces. Combining the results for a 5-year period it is clear that the turtles from Gabon seek the food-rich areas along the west coast of Africa from Cape Town to the equator, then west along the Southern Equatorial Current, while some cross the relatively barren southern ocean to forage off south Brazil.

Turtles evolved from land reptiles which returned to the sea and had become fully adapted to the marine environment by the Cretaceous period (145 – 65 Ma), such that they are now cosmopolitan and occupy all marine habitats except polar. Belonging to the same taxonomic class as marine iguanas and sea snakes, they play key ecological roles, for example by having specialised diets or by grazing on sea grass. Hawksbill turtles eat mainly sponges, Leatherbacks eat jellyfish, while Loggerheads eat anything, such as fish discards, molluscs and crabs. Factors which cause their lives to be at risk include being caught in fishing nets and lines, degradation of breeding grounds and the harvesting of individuals and eggs. Turtles can live for 60 to 80 years. They are slow to mature, taking 20 to 25 years to reach adulthood, at which stage they migrate to their natal areas to breed. The male then returns to a foraging area while the female goes to the beach where it was born, scrapes a deep hole in the sand above high water mark, lays its eggs and then fills in the hole with sand. During adult life they breed every 1 to 4 years and in each nesting year multiple egg clutches are laid, perhaps 60 – 100 eggs every 2 weeks. After incubating for 50 to 70 days all the hatchlings from one clutch emerge together, at night, and rush for the sea, hoping to avoid gathered predators such as dogs, snakes, cats, lizards and birds. Their sex has been determined by the heat of the sand: temperatures above 260C favour the development of females, below that, males. Once in the sea, the hatchlings are distributed by coastal and ocean currents and begin their long period of maturing, although, because of natural predation, perhaps only one in a thousand will survive the 20 years to adulthood. By far the worst predator, however, is man, who kills turtles at their most vulnerable and most critical stage, when the females return to lay; and digs up their eggs.

Four species of marine turtle are rarely or never seen in UK waters. The Green turtle, which can be 4 ft (1.2 m) long and weigh 300-400 lb, is found around the globe within the tropics. It feeds on sea grass and has numerous nesting sites, such as Ascension Island, the Galapagos and NE Australia, but is in serious decline because of man’s exploitation for its flesh and eggs. Another tropical species is the Hawksbill, smaller than the Green turtle with a shell length of about 2 ft (60 cm). It frequents coral reefs where it feeds on sponges, crabs, molluscs and jellyfish. Its flesh is said to be unpalatable and may be poisonous, but the animal’s carapace is in demand as the source of “tortoiseshell”. The Olive Ridley turtle appears to be confined to the S. Atlantic. The Flatback is a rarity, found only in N. Australian waters.

The earliest record of a turtle in UK waters was in 1756, off Lands End. Since then, studies have shown that the principal distributor for Loggerhead and Kemp’s Ridley turtles is the North Atlantic Gyre, an ocean current which issues from the Gulf of Mexico and in a 7-year journey sweeps north past the Florida and Carolinas coasts (which contain the largest population of Loggerheads), then east towards Spain and back to the Gulf. A branch on the north side, the Gulf Stream, carries warm waters to Europe. These currents transport juvenile and immature turtles in their pelagic stages. Over the past 100 years there have been a few hundred UK sightings and strandings of Loggerheads, mostly 15-20 cm long but a few measuring more than 60 cm and perhaps representing a double circuit of the gyre. Full size animals can be 40 inches (1 m) long and weigh 300 lb. Sightings occurred throughout the year, but there were more in the winter months, which also saw a higher percentage of deaths, since smaller animals are more vulnerable to falling temperatures. The records for each decade since 1900 indicate very low numbers in the 1960s to 1980s, because of losses to fishing in the USA. Subsequently there has been a dramatic increase in UK Loggerheads, all recorded on the west and south coasts of Britain and Ireland.

The Kemp’s Ridley is a small turtle about 1 ft (30 cm) long which ranges from the eastern seaboard of the USA to W. Africa and W. Europe. Formerly numbering hundreds of thousands from its breeding ground off Rancho Nuevo in Mexico, by the late 1980s it was down to a few hundreds and heading for extinction. Its eggs had been taken for food and its skins for leather goods. Conservation and re-stocking have restored numbers to a few thousand. There have been several tens of sightings and strandings in UK waters over the last century, just a few each decade with none in the 1950s and 1980s. They occurred in winter months and most of the animals were 20-25 cm long, with a high proportion dead.

Leatherbacks are the largest of the sea turtles. They can grow to a length of 9 ft (2.7 m) with a flipper span of 9 ft and can weigh up to 1800 lb. Their carapace is made of hundreds of bony plates covered with leathery skin. All turtles are ectothermic, their body temperature controlled by the environment, but the huge body size of the Leatherback, combined with metabolic adaptations to conserve heat, gives it a wider global range than others into waters as cool as 100C. In the Atlantic it spreads from the tip of S. Africa to north of Scandinavia. Leatherbacks feed on jellyfish, salps and similar soft-bodied zooplankton and, being strong swimmers, they have no difficulty in following the areas of high food productivity as these move with the seasons. Satellites have tracked them from Venezuela to the Rockall Bank and from Trinidad and Tobago to the Flemish Cap region east of Newfoundland, thence to the Azores and to waters off Mauretania and Iberia. Unlike hard-shell turtles, which arrive in UK waters incidentally throughout the year in the Gulf Stream, Leatherbacks come with intent, seeking rich food areas during the warm summer months of June to October. More than 800 sightings and strandings have been recorded over the last century with a steeply increasing trend over the last 30 years. Predominantly they are on the west coasts of Britain and Ireland but some occur on the east coast.

Matthew made several points in summary. Increased sightings of the three species over the last few decades might be due to (a) better conservation, (b) climate change, (c) greater awareness. Climate change affects the distribution of jellyfish and hence Leatherbacks. Equally, over-fishing upsets the food chain allowing jellyfish numbers to increase. Hard-shell turtles are carried to the UK throughout the year by the Gulf Stream and suffer most mortality during winter months. Leatherbacks are seasonal, coming in the summer to eat. Sightings and strandings are concentrated on the west coasts of Britain and Ireland, but some Leatherbacks venture to the east coast. Most sightings in Cornwall are on the north coast and embayments appear to be important.

The HMCG is extremely grateful to Matthew for his informative and thoroughly fascinating talk and for amending the above report.

Paul Garrard

Rockpool Ramble

30 August 2007

Out at sea, yachts were heeIing in a brisk wind. Onshore, all eyes were directed downwards as Ruth Williams explained the mysteries and delights of the Rosemullion rockpools to 9 persons (and a dog). It must he admitted, since it was our dog, that the latter was more interested in splashing than learning: and his curiosity to discover why we were staring quietly and intently into the water was of no help in persuading timid creatures to emerge from their hiding places. That apart, it was an absorbing afternoon for all concerned, from grandparents to grandchildren, under ideal weather conditions, breezy but dry and warm. In the pools. snail-like creatures rocked gently to and fro as the grazed on the rock surface. Occasionally one would rise and scuttle off at speed – a hermit crab inside the shell! Ruth told us the difference between winkles and top shells: and between shrimps and prawns: and about the foraging habits of Iimpets which always return to the same place on the rock surface where they have created a depression matching the shell so that the can cling tightly and avoid dehydration when the tide is out. Mike, one of the party, had brought a magnifying jar which allowed us to see things in great detail. Particularly fascinating was the small cushion star which. when placed upside-down arched itself, extended minute tube feet to secure a grip and then rolled itself over. With Ruth’s expertise of knowing where to look and how to catch things were soon examining a sea urchin, and a pipe fish and a Cornish sucker fish, not forgetting the delightful little broad-clawed porcelain crab. The list didn’t stop there, because there was an array of seaweeds, from delicate fronds to robust fleshy types, in a great range of colours green – orange, red, brown and white. We even had a tasting session, sampling the bright green crinkly sea lettuce. One can spend hours just looking and marvelling at the variety of Iife in a rock pool and, had the tide not come in, we might still be there. Sincere thanks are due to Ruth for giving so freely of her time, enthusiasm and clear expert explanations.

Helford River – Where The Land Meets The Sea

17 February 2007

A detailed look at this watery world and how we influence it gave a large audience (67) much food for thought as the issues of pollution, clean seas, farming and recreation were highlighted. This followed recent studies by scientists from the Environment Agency, University of Exeter, and the Farming and Wildlife Group as described by Dr Peter Jonas, Dr Julian Greaves and Annabel Keast.

HMCG Seashore Safari at Helford Passage

4th April 2008

Taking advantage of the extremely low tide and with dry, mild and slightly breci conditions, 40 persons, about half of them young children, assembled at Helford Passage to take part in the Seashore Safari run by Joana Doyle with two helpers from the Cornwall Wildlife Trust. All were enthusiastic, searching the shallow waters on the shore and carefully turning over small rocks to look beneath (and replacing them afterwards). Many creatures were found, to the delight and interest of all, enhanced by the keenness of Joana and her helpers in identifying the wildlife and explaining its habits. Goby and butterfish, sea slug and sea urchin, tube worms, sea-squirt, starfish, various sorts and sizes of crab, the list seemed endless. Mussels, barnacles and limpets festooned the rocky parts. Intriguing structures were produced by mounds of slipper limpets, by mussels attaching small stones and shell fragments to themselves as camouflage and by clusters of whelk eggs. A range of seaweeds and wracks added to the story. Many thanks are due to Joana and her assistants for giving freely of their time, knowledge and enthusiasm, ensuring the success of a very satisfying and informative outing.

Seashore Safari, Helford Passage with Ruth Williams

Monday, 18th April 2011

If shellfish, crabs and other marine creatures have an early warning system, it must have clicked on ‘Red Alert’ today as the Seashore Safari got underway.  But to no avail.  A horde of searchers, 30 adults and 45 children, with ages ranging from 2 to 80, was advancing over the rocks, armed with nets and buckets.  There was little chance of any creature remaining undetected as sharp eyes and quick hands and nets probed the rock pools and watery gullies; and soon treasured finds were being placed in the buckets and carried to Ruth for identification.

The weather conditions were ideal – a dry, warm, spring day and a slight breeze.  With one of the lowest tides of the year the water was receding fast, leaving the ferry immobile on the sand beside its jetty and allowing us to walk around grounded boats that an hour or so earlier had been riding to buoys.  Limpets, barnacles and mussels on the rocks of the upper shore had closed their shells for the drying out period and beadlet anemones in the small pools had retracted to jelly blobs.  There were topshells in a variety of colours, plus periwinkles, but the main quarry in the larger pools was creatures that moved – small fish including butterfish and different types and sizes of crabs: hermit, shore and velvet swimming crabs, among which was a soft-bodied one that had only recently moulted its outgrown shell.  Easier to capture were small common starfish.  An unusual find was a brown sea hare about 9cm long.

On the lower shore, now uncovered by the receding tide, were abundant sand-encrusted tubes and filigree tentacle umbrellas of the sand mason worm and smaller numbers of peacock worm tubes.  A few marooned scallops were trying to jerk themselves back into the water by slowly opening their shells and then snapping them shut.  Other shells, mostly empty, included native and Pacific oyster, razor shells, chiton, whelk, cockle and slipper limpets.  Gradually the party thinned as parents and children left for lunch, but not before they had thanked Ruth warmly for a very enjoyable and rewarding outing – and one mother took the opportunity to confirm that she had collected the right seaweed to add to her salad!

The HMCG wishes to express its appreciation to Ruth for leading an extremely successful trip.

British Divers Marine Life Rescue

19th March 2011 (following AGM)

It is always a lot to ask of a speaker to provide a presentation straight after an AGM, so the 45 people who attended on 19th March at Gweek Village Hall are particularly grateful to Dave Jarvis for agreeing to. He certainly gave us a very informative talk.

BDMLR is a fairly new charity, set up in 1988 by a group of divers who were concerned at their observations of the phocine distemper virus in Britain’s wild common seal populations. At the time, divers reported sick seals to the RSPCA.

Recognising their unusually close encounters with marine mammals, and with many divers having an obvious concern for environmental issues, BDMLR was born. It now forms part of an international network of similar organisations. Remaining true to its roots, virtually all funding raised goes straight towards buying new equipment or on training and virtually all activities are carried out by volunteers – there are only three paid staff members. Dave stressed that you don’t need to be a diver to be able to play a full role with BDMLR.

Dave then spent some time describing the details of BDMLR activity in each year from 2004. That year saw 31 call outs, including to nine cetaceans and 22 seals. Three profile-raising events and three medic-training events were held. Unusual species involved in 2004 were a minke whale and a harp seal, both extremely unusual in Cornish waters.

During 2005 call outs more than doubled to 67. These included a basking shark and two turtles. BDMLR was featured on a Radio 4 show – ‘How to rescue a dolphin’ – surely a pretty surreal event to conceive and execute through the medium of radio?!

2006 saw 75 call outs. One resulted in very high media coverage during the summer, when some CWT divers including Joana Doyle encountered a basking shark trapped in a fishing net off Newlyn. The divers put all their skill and training into action and managed not only to successfully cut the shark free but gathered some fantastic film of the process. I expect many people can remember this on the TV news.

2008 was an incredibly busy year. Of 129 call outs, 31 occurred in January alone. The year saw six turtles being rescued. Most of these have arrived from the Gulf of Mexico / Caribbean and go into a cold shock – like a coma – on reaching our shores. If found in time and given the right care, these can recover well enough to be repatriated back to their warmer climes.

Without doubt one of the highest profile BDMLR actions took place in June of 2008, when there was an unexplained mass stranding of common dolphins in various creeks of the Fal Estuary. The graphic TV images showed us bodies lined up on the shore – 26 died in total (24 prior to anyone discovering them) – but what we didn’t see so clearly was the excellent ‘pied piper’ work done by BDMLR volunteers, who managed to herd more than 50 animals into deeper water, and safety. This was achieved by tying 2 stranded animals to a pontoon of rigid inflatable boats, then slowly heading down river. These 2 animals were clicking, and the volunteers were convinced they were encouraging their friends to join the procession. This occurrence clearly demonstrated the depth and capacity of BDMLR and its ability to respond at a moment’s notice, involving as it did more than 50 medics.

Even closer to home, on 30th November 2008 volunteers were called to Frenchman’s Creek, where a mother and calf common dolphin had becoming stranded on the mud as the tide fell. Both animals were in good condition and so, given the right care, would be likely to survive. Dave said that dolphins can probably survive for 24 hours out of water if kept wet. Throughout the afternoon quite a number of people assisted in keeping the animals doused in water while a vet gave them fluids. As the tide would not be returning for some time – by when it would be dark – it was decided to lift the animals onto some inflatable lilos, carry them bodily up the access track – no mean feat – place them into a car and drive them to Porthallow at a very sedate speed, while all the while somebody lay beside them to ensure they stayed upright. A major risk facing large stranded marine animals is that they lose the essential body-support from the surrounding sea, and succumb to internal injuries caused by the weight of their own bodies Anyway, our story has a happy ending, as both mother and calf were successfully returned to the sea and the volunteers no doubt returned home tired but happy.

Dave reckons that about 4% of our Cornish seal population is affected to some degree by entanglements with fishing nets. Unfortunately it is not always possible to release animals, depending upon how serious the injuries are.

It is very clear that BDMLR is going from strength to strength. Dave has pondered over the increasing number of call outs each year and suspects it is partly a function of people being more in-tune with wildlife due to more TV programmes and partly due to Cornwall developing a more year-round tourist season, meaning that people are out on the cliffs more often. It is not possible to state that more animals are being trapped or injured now than before as a baseline does not really exist.

In response to a question at the end, Dave said he is convinced that dolphins at least know they are being helped – he has had frequent close eye contact to form this view! This must give the very dedicated volunteers a huge reward and sense of purpose when standing, kneeling or even lying in cold, wet conditions for hours on end.

Dave gave us a real insight into the hands-on nature of this organisation and the volunteers certainly deserve our support and respect. Anyone wanting to get involved or to find out more can look at the website www.bdmlr.org.uk.

Non-native Marine Invasive Species (Guy Baker)

Saturday, 26th February 2011

“You should clean your bottom every year”! Australians and New Zealanders are known for plain speaking, but this seemed unnecessarily rude. However, just to clarify, they were talking in this instance about the hull of your boat.  The point was quickly driven home by an underwater film, taken in N.France, which showed a hull so thickly coated with weeds and invertebrates that it looked like a sagging roll of shaggy carpet.  Boat fouling is a worldwide problem and marinas and harbours are important staging posts in the process, because hulls, piers and jetties provide numerous firm surfaces on which sessile plants and animals can gain a foothold.  It only takes a few weeks for a surface to be completely colonised.  Increasingly, however, it has been found that the plants and animals are not simply extensions of the local ecosystem, they include alien species which have invaded from different parts of the world.  Recognising that this was a problem, the Marine Biological Association (MBA) in Plymouth entered a consortium with the Scottish Association for Marine Science, the Natural History Museum and other research institutions to research the issue of Marine Aliens.

Guy Baker, the MBA’s Communications and Outreach Officer, gave us a comprehensive review of the subject.  What are marine invasives?  Why and how have they come here and where are they now?  One definition of invasive non-native species (sometimes shortened to INNS) is that they are plants or animals, introduced by humans, which have the ability to cause damage to the environment, the economy or our way of life or health.  A difficulty emerges with the term ‘non-native’.  The reference level is taken to be the 19th Century, when marine biology and taxonomy became established as sciences, but there is historical evidence that plants and animals were introduced by the Romans throughout Europe and progressively from the 1300s as world exploration took place.  Some of our familiar ‘native’ species must be classified as cryptogenic, of unknown origin.  Size is another factor.  Alien molluscs and crustacea, such as the Chinese mitten crab, are conspicuous invasives, but smaller forms are less obvious.  The European prawn had become well established in Chesapeake Bay before it was detected.  A graph showing exponential increase of macroalgae in the Mediterranean since 1900 prompted thoughts on possible causes:  multiple invasions?, global warming?, more recording?, changed human activity?

There are many reasons to be concerned about marine invasives.  While some forms can be welcomed, having arrived in small numbers and settled with native species, contributing to biodiversity, others have had dramatic impact, economic and social, upsetting the balance of the ecosystem.  They can be responsible for fouling marine vessels, installations and aquaculture, competition with native species, alteration of the substrate and water; and smothering of, or predation on, native species.  Many are resilient, fast-reproducing and unhindered, with no local predators.  They have arrived attached to the hulls of commercial or recreational vessels, or carried in ballast water, or as contaminants of shellfish or via seafood trade.  Figures indicate that global maritime transport accounts for 60% of the movement of invasives.  Particularly telling were data showing that invasives reaching Melbourne had come dominantly from the NE Atlantic, with lesser numbers from the Mediterranean and Pacific, a clear correlation with trade routes.

Information is vital in drawing up a strategy to deal with the invasive threat.  The GBNNSIP (Great Britain Non-Native Species Information Portal) has established an alerts system, whereby new arrivals in UK waters are reported to the Biological Records Centre, verified by experts and then notified to relevant authorities via websites such as MarLIN (Marine Life Information Network) and GBNNSIP.  The biological characteristics are important.  How does the species reproduce?, what are its migration patterns?  For example, sea squirt larvae do not feed and are relatively short lived and so the distance the organism can spread by larval means is limited.  Other species’ larvae can remain dormant for a long time in ballast water.  The Chinese mitten crab lives much of its life in fresh water and has now colonised northern rivers and the Thames as far as Didcot.  Preventing the spread of a species, if possible, is a better option than dealing with its presence and this may involve changes to working practices.  Moving a pontoon to another area, for instance, carries the risk of spreading an alien species.  New developments such as marinas and wind farms should ensure that biosecurity is built in at the planning stage, while existing developments should follow codes of practice, such as the Green Blue scheme backed by the Royal Yachting Association.  Clearly hull scrapings should be put in a skip, not dumped back in the sea, but what should be done with the wash water?  As pointed out by the RYA, small pieces of weed adhering to boat trailers or microscopic larvae or eggs surviving in damp ropes can transfer species from one body of water to another.

Leisure craft are the main vectors of secondary dispersal in UK waters.  A survey of boats in the 30-40 ft range in a Plymouth marina showed that over 80% of hulls carried the Pacific bryozoan Tricellariainopinata and Darwin’s barnacle Elminius modestus, while sites infected by the carpet sea squirt Didemnum vexillum are marinas on leisure craft routes, not ferry terminals.  Didemnum, an invasive colonial filter-feeder originally from Japan, forms sheets and rope-like masses which can smother mussel farms and so Holyhead marina began an eradication programme in late 2009, progressively wrapping the pontoons and mooring chains with plastic sheets and bags with calcium hypochlorite to cause death under anoxic conditions.  The first year of the programme has cost £200,000 and been largely successful, although reinfection did occur in places during the eradication attempt as larvae from untreated areas reached cleaned pontoons.  Unfortunately funding has now been withdrawn.

The Marine Aliens consortium focussed on monitoring dispersal pathways, classifying marinas and harbours for hull fouling potential and assessing the likely impact of control systems on native biodiversity.  A meeting was held in February at the Linnaean Society in London to mark the end of the present run of the project and review the findings of the consortium’s research.  Many of the presentations can be viewed on the Marlin website:www.marlin.ac.uk

Among other invasives present in South-West waters are the slipper limpet, Crepidula fornicata, which was introduced from the eastern USA in the 19th Century and is particularly successful at competing for food and territory with local oysters, and the leathery sea squirt, Styelaclava, a Far-Eastern species which arrived in Plymouth in 1953, possibly on boats returning from the Korean War.  It fouls mussel ropes, submerged gear and oyster beds.  The wireweed, Sargassum muticum, is a brown alga which is a vigorous coloniser of rock pools.  Wakame, Undaria pinnatifida, is another brown alga which was imported from the Far East to France as a food crop but subsequently escaped.  Another possible arrival is the veined rapa whelk, Rapana venosa, a competitor of the native whelk and predator of bivalves, which was confirmed in the North Sea in 2005.  The list goes on; and is increasing each year—— which underlines the need for a clean bottom!

The HMCG wishes to express sincere thanks to Guy Baker for his very detailed and informative talk and for suggestions which have been incorporated in this report.

The Fal-Helford Marine Special Area of Conservation (Kevan Cook)

Saturday, 15th January 2011

Because of its very special nature in terms of habitats, biodiversity, species, geology and scenery, the Helford River has long been recognised as worthy of protection at both European and national levels.  Fortunately our speaker, Kevan Cook, Lead Marine Adviser for Natural England, was able to guide us through some of the acronyms.  The Fal-Helford SAC (Special Area of Conservation), lying west of a line from St Anthony Head to Manacle Point and giving the highest level of protection, is a European designation relating to habitats and some species.  It identifies the range of environments in the Helford, from the rocky shores at Rosemullion and Gillan, buffeted by strong winds and tides, passing upstream to sand banks with seagrass and maerl and then to the highly productive intertidal muds with narrow saltmarsh fringe of Polwheveral, Frenchman’s Creek and Gweek.  Another European designation, though not present in the Helford, is an SPA (Special Protection Area) which safeguards the habitats of particular bird species.  At a national (UK) level, the intertidal zone of the Lower Fal and Helford is classified as an SSSI (Site of Special Scientific Interest) and this overlaps with the individual SSSIs of Merthen Woods and Rosemullion Head, the latter for geological interest.  Further UK designations are evolving and in course of discussion, namely MCZ (Marine Conservation Zone), MPA (Marine Protection Area) and MNR (Marine Nature Reserve).  In addition, the Helford lies in Cornwall AONB (Area of Outstanding Natural Beauty), in which the emphasis is on scenic character.  Through all of these, the Helford is afforded a  high degree of protection.  Damaging or destroying features for which a site is designated can incur considerable penalties and Natural England’s consent must be sought for a wide range of operations which might have impact, for example agricultural practice, drainage, shore work and dredging.

The Helford is blessed with a rich biodiversity.  The rocky shores at the mouth of the estuary, encrusted with limpets and barnacles, have a substrate of rock and shingle which supports a variety of seaweeds, such as bladder wrack and serrated wrack, passing seawards to kelp forest growing down to depths of 15 to 18m in the photic zone.  These in turn are home to invertebrates such as crabs, worms, sponges, sea urchins and bryozoa.  Up-river, with less active currents, the substrate changes to sand banks, sand with rocks, or sand with mud, providing environments for beds of seagrass  and small areas of maerl.  Seagrasses (largely eelgrass, Zostera spp) are seasonal, underwater, flowering grasses, spreading from sub-surface rhizomes which help to stabilise the sediment.  They are important protective habitats for juvenile bass and flatfish, plus sea horses.  However, they are sensitive to change and can be damaged by anchoring.  A current anxiety is the presence of Labyrinthula, a slime mould seen on the leaves as black spots, which inhibits photosynthesis and which has been implicated in widespread deaths of tropical seagrasses (as well as damage to golf courses!).  Maerl is a collective name for species of very slow-growing coralline red algae, which secrete a hard skeleton of calcium carbonate and grow as unattached round nodules or small, twig-like, knobbly branched shapes on the sea bed at depths down to 20m.  When the algae die, the skeletons build up as deposits of dead maerl with a thin layer of pink living maerl on top.  The Fal-Helford SAC contains the largest maerl beds in SW England, mainly on St Mawes Bank but with smaller areas such as off Durgan.  A 1978 licence from the Crown Estates Commissioners has allowed dead maerl to be dredged as a soil conditioner.  However, this is a non-renewable resource.  Thick deposits may have taken 8000 years to accumulate and it is a priority habitat.  Many creatures live on or burrow in the beds, including jewel anemones, fan worms and Couch’s goby, but it is a fragile and easily damaged environment.

The sandy sediments at Gillan, Treath and Helford Passage contain a diverse burrowing and surface fauna, among which are peacock worm, other polychaetes such as sand mason, hermit crabs, brittle star and cockles.  Shale shingle and mud from Helford Point to Frenchman’s Creek support sponges and tube worms.  Shore crabs, mussels and gastropods are common around Groyne Point.  The headwater creeks, such as Polwheveral and Gweek, are endowed with intertidal mudflats and sandflats which harbour amphipods, polychaete worms, sea cucumber and bivalve molluscs, creating rich feeding grounds for resident and migratory birds.

Why is protection necessary?  The pressures on habitats and species are numerous and real.  They include climate change, land-based pollution (agricultural and industrial), marine pollution (oils, litter), coastal development, aggregate extraction, renewable energy operations, fishing practices, aquaculture (over-stocked fish farms) and recreational use (moorings, slipways, etc).  A major difficulty, unfortunately, is that the effects are largely beneath the waves and mostly unseen.  For example, under climate change, sea level has risen 15cm over the last 90 years and is estimated to rise a further 1m by 2100, which will have impacts on biodiversity through altered temperatures and coastal squeeze.  Increased carbon dioxide in the atmosphere has led to a more acidic ocean, making it difficult for crabs and lobsters to produce their shells.  Slipper limpets, an invasive species introduced in the 1980s with no natural predators, have seen an explosive rise in population, competing with Fal oysters.  (Ben Wright commented later that 60 tons of them have had to be removed from the oyster farm).

Natural England’s approach to assessing the state of the environment is evidence-based and grounded in good science.  It undertakes regular transects, mapping of habitats and monitoring of species, underwater studies being carried out by divers and by an ROV (Remotely Operated Vehicle).  The latter, as described in Newsletter No. 41, is a self-propelled robot with a video camera linked by cable to an onboard laptop.  Funded by Natural England, it has been used by the Cornwall Sea Fisheries Committee in conjunction with ground discrimination equipment to make detailed surveys of two candidate SACs, off the Lizard and Lands End.  These data sets are important bodies of information to be used in assessing proposals to create a South-West Marine Conservation Zone.  The process is well underway and involves collaborative discussion by a variety of groups, such as conservationists, industry and sea users, who will submit their report to Natural England and the JNCC for onward transmission to DEFRA.

An aim of Natural England is to raise public awareness and better appreciation of our environment and the issues facing it.  By engendering a sense of value and ‘ownership’ we could help to chart the way to a sustainable future.  Kevan commented that, with an audience of 45 turning out on a January evening, he was probably talking to the converted.  Subsequent questions, ranging over nitrates, oil spillage, bass nursery data and water quality, suggested that he was right.

The HMCG wishes to thank Kevan very much for his informative and wide-ranging talk.

Tales of a Wildlife Photographer (David Chapman)

Saturday, 11th December 2010

Is that a pin-tailed duck? No, it’s a long-tailed duck. Isn’t that a gannet? No, it’s a black-tailed godwit. We were trying to identify birds on David Chapman’s jumper, knitted by his mother who had produced separate jerseys for different talks. His outdoor gear depended on conditions, one photograph showing military-style camouflaged top and trousers, plus a back-pack to carry a tripod, camera and lenses and a chest-pack containing a portable hide. When erected, the last looked like a camouflaged igloo, just large enough to accommodate David and Adrian Langdon for several hours bird watching at the Walmsley Reserve. His account of that outing was returned by Adrian with the comment that the phrase “the mud came nearly to the top of our wellies” had a typographical error in the final word!

A couple of photographs followed, pin-sharp, beautifully composed, with no background clutter. One showed a house sparrow with a spray of pampas grass in its beak, the other was of a goldfinch clinging to the stem of a dandelion clock. One could sense that the audience was beginning to despair. How many years does it take to produce photographs like that? And is David blessed with an inordinate amount of luck? Then we learned of the preparation. Because the sparrows had kept darting from one clump of pampas grass to another, David had cut off all the sprays (with permission from his wife Sarah) and inserted one in a frame on a table, on which the camera was focussed. For the second photograph, the dandelion clock was fixed to a length of wire stuck in a block of turf resting on the table. Niger seeds had been scattered on the turf for a week to attract goldfinches. Incidentally, as the camera and tripod were inside the house, the kitchen window had to be removed for these shots.

Hides are important. Once he erected a hide on his garage roof to photograph a pied wagtail on the neighbour’s garage. Birds are not perturbed by motor cars and so these are good hides, as long as the occupants remain inside. For off-road locations, inaccessible to cars, David has experimented with a 3-wheeled, pedal-powered buggy with the tripod attached to the frame, all enclosed by a black mesh curtain. Another version, which folded up for carrying, had the drawback of a low seat which was unpleasant when the tide rose.

Depressing images of a dead common dolphin on Gunwalloe beach brought home the dangers faced by these animals. A close-up showed monofilament strands in its mouth, suggesting that it was a victim of fishing. Pair trawling for sea bass gives rise to one dolphin death per two trawls, on average, as dolphins follow the fish into the net, but in one horrifying incident 150 common dolphins died. The next image was of a grey seal pup, about a day old and with a cream-coloured coat. It would not be able to enter the water for two weeks, until its coat had become waterproof. Abandoned pups that have been rescued and cared for by the Seal Sanctuary are released at Godrevy and elsewhere when they have reached a weight of 50-55kg., although after weeks of being provided with daily fish some are reluctant to leave.

We were puzzled by the next photograph, a bush hat on the grass at Caerthillian Cove, until David explained that it alluded to the Rev. Charles A. Johns, a former teacher at Helston Grammar School and a highly regarded botanist with exceptional knowledge of the Lizard, who claimed that he could cover 8 species of clover with his hat. It appears that the underlying rock type, serpentine, creates only a thin layer of poor soil, but clovers can thrive on it because of their ability to fix atmospheric nitrogen. The cliff tops here, at Kynance and around the Lizard are haunts of the chough, which returned to the area about 10 years ago when a land management programme, including grazing by Shetland ponies, resulted in the short turf that they favour in searching for food. Currently four pairs are nesting and there are two males on the north coast, presumably hoping for mates. Choughs are best viewed around mid-June, when the young are being fed. Wildlife photography is not without its odd moments. On one occasion at Porth Joke David was questioned by police following a report that someone ‘was behaving suspiciously and appeared to have a ground-to-air missile launcher’.

A picture of a dormouse triggered “Aaghs” from the audience. They are not the easiest of subjects because they have a limited range, around the fringes of Bodmin Moor, with none west of Truro, and are a protected species. A licence is required to handle them and it is forbidden to look in a nest box if they may be present. During the long hibernation period from October to May (when their food starts to appear) their metabolic and heart rates become very slow, to the point that it takes the animal about two minutes to become mobile when disturbed. Another creature with wide appeal, the puffin, was photographed at Sanday in the Orkneys. David noticed that it stayed in one position in the water and, wading to it, found that its legs had been caught by fishing net. While he was freeing it, Sarah dutifully waded out carrying a camera and wide-angle lens, with a film in her mouth.

Some excursions give little return for a lot of effort, for example a rough 15 mile trudge on Westray in the Orkneys to a site where black guillenots should have been — but were not. Similarly, a £10 boat trip from St Ives to Seal Rock was fruitless, until the boat returned to Smeaton’s Pier where holidaymakers were enjoying the sight of a seal in the harbour.

A food lure can sometimes be an effective way of bringing a bird to the right place for a photograph. It was worth trying for the ravens nesting at Prussia Cove and so a dead rabbit was placed at a strategic point and David sat in his hide waiting. After 4 hours, with no sign of birds, he packed up and walked off. Glancing back he saw the ravens attacking the rabbit with gusto. The same thing happened the next day – a 4 hour wait and the ravens only appeared when he left. On the third day, working on the theory that birds cannot count, Sarah accompanied him into the hide and then walked away. The ravens were not fooled!

One of David’s long-held ambitions has been to take pictures of a buzzard swooping on prey and tearing it open. His early efforts involved a camera with wide-angle lens positioned on the ground close to a dead rabbit and triggered using a long cable release from a nearby bush hide. However, the framing was unpredictable and the slide film took days to process and come back. Subsequently, changing to a digital SLR, the results were immediately available, but in each case the bird’s wings were part-open on the verge of taking off. It had taken fright at the sound of the camera’s mirror flipping up a millisecond before the shutter opened. In the current arrangement the camera is partnered with a CCTV camera, both linked by long wires to David’s sitting room where he can view the action on a monitor screen and take pictures between sips of coffee!

The HMCG would like to thank David very much for an enthralling and stimulating evening.

Plankton on Parade

Saturday, 13th November 2010

The term ‘plankton’ comes from a Greek word meaning ‘wanderer’ or ‘made to wander’,an apt description for creatures which drift at the mercy of winds and currents. Some are large and easily seen – the Macroplankton, such as jellyfish and the Portuguese man-o’-war. Others are small – the Microplankton, which measure a millimetre or so across – or less – and are studied using a microscope. These are collected with a conical fine-mesh net swept or towed through the water and they include a great variety of plants and animals, in adult or larval stages. There is a third, even smaller, size category – the Nanoplankton, such as coccolithophores, which are just a few microns across and only seen with the aid of an electron microscope. Previously unsuspected, the existence of this group was deduced from studies of another marine creature, an early chordate which constructs a gelatinous ‘house’ in which to live and gathers its food by wafting water through ‘windows’ onto mucus-coated filters. It was observed that the openings in ‘grills’ over the windows were too small for microplankton to enter. Hence it was inferred that the water might contain even smaller creatures, in addition to ultrafine marine detritus which is also a food source.

Some planktonic creatures (a shorter term is planktont) can be regarded as ‘permanent’, in contrast to the ‘temporary’ group which are the larval stages of crustacea, molluscs, etc. Of those that live in surface waters, such as phytoplankton, diatoms and dinoflagellates, some are capable of making their own food, using carbon dioxide and releasing oxygen. Various mechanisms are used to enable planktonts to stay afloat without wasting energy. Some have constantly beating hairs (cilia) or flaps, e.g the pteropods. Others produce gas bubbles to give them positive buoyancy. An interesting example here is the Portuguese man-o’-war (Physalia), a large, colourful complex hydroid with a float bladder up to 12 inches long and 6 inches high beneath which is a mass of polyps having different functions, such as feeding tubes and reproductive organs, plus trailing tentacles up to 40 feet (12m) long armed with touch-sensitive stinging cells delivering a poison 75% as strong as a cobra’s venom. When prey, such as planktonic crustacea or small fish, is captured, the tentacles contract to draw it to the feeding tubes whose mouths expand sucker-like over the prey and secrete digestive juices. The float bladder can change buoyancy to counteract the weight of the prey. It also has the ability to deflate in storms and to immerse each side alternately in water to avoid drying. It is amazing to think that this colony with all its complex functions is derived from a single cell. Another example of positive buoyancy relates to a mollusc, Janthina, which floats at the surface attached to a raft of bubbles (gas enclosed by hardened saliva). When its eggs develop into larvae, these in turn develop their own bubble raft to float away.

Typical umbrella-shaped jellyfish can ‘swim’ upwards by rhythmic pulsations of the bell and then open it to descend slowly while capturing small planktonic animals using their stinging tentacles. In a rather similar fashion some planktonts maintain their position in the water column and minimise the tendency to sink by increasing their surface area relative to body mass, analogous to a sky diver spreading his limbs to slow his descent. This explains the fantastic bizarre to beautiful shapes of many small planktonic creatures embellished with spines, spikes, bumps and dimples. Some even have the ability to extend or reduce the length of spines and arms to adjust for differences in water density between warm and cold seasons and estuarine and marine environments. Planktonts typically feed on other planktonts, including nanoplankton, diatoms and algae, and on marine detritus, using a variety of mechanisms. Food particles can be drawn to the mouth by cilia, as in the case of dog whelk larvae, or wafted by fine spines, as in baby copepods. Others filter food from the water using a sieving system. The large white jellyfish Rhizostoma is a filter feeder with thousands of mouths on ‘arms’beneath the bell. By contrast the arrow worm, Sagitta, is a carnivore which actively seeks its prey, armed with two fans of spines at the head which capture the victim and pull it to rasping jaws.

Planktonic creatures can display some remarkable behaviour. Some are known to move systematically between higher and lower levels over a 24-hour period to ‘graze’ the water column. Those which are the larvae of crustacea, molluscs, etc. must adapt from a floating to a benthonic or sedentary existence. For example, a barnacle larva develops into a minute drifting two-shelled form which searches for a suitable settling place guided by a protein secreted by adult barnacles. It then anchors itself by its head antennae, secretes a cement, sheds its larval skin and develops limy plates, which can open to allow the feathery ‘feet’ to gather food. The close clustering of barnacles, which results from this larval behaviour, enables the extendable male organ to fertilise the eggs of neighbours (they are hermaphrodite). The planktonic larvae of the ribbon worm and of starfish do not develop into adult forms: they are simply carriers of the growing adult.

Although some plankton can have harmful effects on marine life, as witnessed by ‘red tides’ and ‘white tides’, this is far outweighed by their immense importance as a food source for creatures ranging from herring to the blue whale. Plankton populations fluctuate seasonally and with pollution, but these microscopic forms reproduce rapidly and overall their numbers appear to be stable.

The HMCG wishes to thank Dr Harris sincerely for his thoroughly interesting and enlightening talk and for reviewing this account.

The National Trust around the Helford

Saturday, 16th October 2010

Justin Whitehouse, National Trust Area Warden for the Lizard, first became associated with the National Trust as a volunteer shortly after graduating as a botanist and moving to Cornwall in 1994. His daily journey to work involved rowing across the river from Porth Navas to the office at Helford. Subsequently came five years work at Trelissick and then a return permanently to the Lizard, back to the woodlands and creeks that he preferred.

He began his talk by taking us on a picture tour of the numerous Trust properties around the Helford, starting in the north-east at Rosemullion Head. Here, above the ever-popular shoreline with its magnificent rock pools, the cliff top is farmland, worked under restricted tenancies and with careful control of practices such that it is one of the few places in the country where one can find the very rare green-winged orchid (also present at another Trust property, Kynance Cove). Journeying westwards we passed Toll Point, where gun emplacements guarded the mouth of the Helford during WWII, thence to Durgan where the National Trust owns three-quarters of the houses, two of them holiday cottages and the remainder long-lets. The wondrous Glendurgan Gardens to the north were planted in the early 1800s by the Fox family, shipping agents and Quakers. On the south side of the river the Trust’s properties, Penarvon, Frenchman’s Creek, Kestle and Tremayne, are mainly woodland and creek-side. They are among the few places where the public can gain access to the south shore west of Helford. Tremayne Woods were originally part of the Trelowarren Estate. Tremayne Quay and its access track were built, or at least up-graded, for an anticipated visit by Queen Victoria in 1846. She didn’t come, but the quay eventually received a royal visitor when the Prince of Wales, later Edward VIII, landed there in the 1920s. Farther east lies Frenchman’s Creek, a picturesque and wonderful wildlife habitat fringed with sessile oak woodlands, its intertidal muds attracting birds such as kingfishers and egrets. The name probably refers to a French sailing vessel not a person. Continuing eastwards, the Trust holds properties at Gillan Creek, Carne and Nare Point, the last mostly farmland managed for conservation. Nare Point was used as a decoy site during WWII to lure enemy bombers away from Falmouth Docks. The observation post that was part of an air-drop torpedo testing range is now occupied by Coastwatch.

The National Trust’s properties on the south side of the Helford are dominantly woodland, some of it ancient and some which has reverted from former farmland. Consequently most of its activities centre on woodland management, although time has to be found also to maintain about 10 miles of footpaths, collect beach litter and deal with the thankfully minor amounts of vandalism. A programme to eradicate the harmful Rhododendron ponticum has been running for about 30 years. A more recent problem, since c. 2007, has been the arrival of the fungus which causes Sudden Oak Death. This attacks a variety of species, such as rhododendron, laurel, larch, beech and bilberry, usually non-fatally, but they in turn become sources of spores which eventually kill oak. The potential impact here could be devastating and the situation is being monitored closely by DEFRA. There is also full awareness of invasive species such as Japanese knotweed, beech and Spanish bluebells.

In earlier years coppicing was an important activity, producing wood for charcoal and firewood and bark for tanning. The last commercial operations were pre-war, but the Trust has now re-introduced coppicing in Tremayne Woods, with the pleasing result that gaps and glades in the woodland have seen the return of bluebells and butterflies. When felling is necessary the trees are tagged and surveyed and the final stump is made jagged to provide a wildlife habitat. Much more could be done in the way of managed timber extraction, not just in Cornwall, which is the second least-wooded county, but throughout the UK to reduce the unnecessarily large quantity of timber imports. As well as caring for the health of its woodlands the Trust is recording and measuring large old trees as part of the Ancient Tree Forum. A prime example is a holly tree at Frenchman’s Creek, about 6m across and possibly 700-800 years old, with an old stone well beneath. Very likely this is one of the markers of an old routeway, the district name Meneage meaning Land of the Monks or Monks’ Way. Additionally there is a programme to monitor notable trees, such as old ones marking hedgerows and period plantings such as Monterey Pines from the 1920s. Nearly all the work in the woods is done by volunteers, many of them holidaymakers plus some more permanent local volunteers, in total amassing some 10,000 workdays a year.

The Trust’s properties are a haven for wildlife. Little egret, grey heron, kingfisher and great spotted woodpecker are among the birds that can be seen. Tremayne boathouse is shared by barn owls and greater horseshoe bats, the latter being vary rare in the UK. About 6 bat species occur in the surrounding woods. Lichens are common here, whereas in the UK as a whole 70% have become extinct since the Industrial Revolution. Fungi, indispensable to the health of woodland, proliferate. In addition to caring for the physical well-being of its properties, the Trust manages a number of holiday cottages ranging from simple buildings to the luxury Bosloe House and the eco-showpiece of ‘Powders’, with its solar panels, woodchip boiler and lambswool insulation.

The National Trust has recently adopted a new outlook, nationwide. No-one in the UK is more than half-an-hour’s journey from a Trust property, but these are under-utilised and the aim is for everyone to have at least some involvement by 2020, replacing the long-established image of a frozen heritage, older visitors, teashops and proscriptive signs with a friendly welcome and opportunities for young and old to learn, enjoy and participate. The Trust’s properties around the Helford and the Lizard provide almost unequalled potential for children, in particular, to take part in activities such as building dens, canoeing, coasteering and camping, as well as learning bushcraft and woodland crafts such as bodging, using a pole lathe, making charcoal and picket fencing. They can cut hazel and make their own boat or raft, erect a tree swing, play, learn to take risks, get dirty and wet, as children used to, whilst benefiting from supervision and instruction. It’s an exciting prospect.

The HMCG would like to thank Justin very much for his wide-ranging and absorbing talk.

Goongillings Exploration and Picnic

Sunday, 5th September 2010

“I waved goodbye to the couple I had just killed”. What an excellent quote to relate to Amanita phalloides, the Death Cap fungus. Pauline Penna had just dug one from the field adjacent to Scott’s Wood and she passed it round the group, pointing out that the gills were white, not grey-black as in a mushroom.

The morning had been unpromising, with heavy downpours. Fortunately after lunch the rain stopped and 25 hardy folk assembled for the Goongillings Exploration and Picnic (the latter component, by unspoken agreement, being abandoned). There was a wealth of expertise: Peter Ealey to deal with geology, Ian Bennallick (plants), Pauline Penna (fungi), Martin Rule (birds), Pamela Tompsett (shorelife), Sue Scott (ERCCIS) and Charles Pugh, Goongillings farmer / owner, who gave us an introductory talk about the farm’s history and current status. Early connections had been with the Trewardreva Estate. Scott had inherited the property through marriage in the early 1800s and built the track and quay on Polwheveral Creek to export granite from Constantine quarries via merchant schooners. Subsequently it was purchased by the Vyvyans of Trelowarren and then Mrs Hext of Trebah. Charles’ father had bought Goongillings about 50 years ago and for the past 30 years it has been farmed by Charles as an organic enterprise without fertilisers or chemicals and adopting a philosophy of ‘benign neglect’, allowing natural regeneration. In consequence, Goongillings has a species-rich fauna and flora and is justifiably part of the Countryside Stewardship scheme.

The track from Constantine to Scott’s Quay runs south along the watershed between two valley-creek systems: Nancenoy-Polpenwith on the west and Polwheveral on the east. From each side the road climbs very steeply to the farm, which is situated on the cusp of the watershed. Peter showed a geological map which demonstrated that there is a southward bulge of the Carnmenellis granite at this point, such that Nancenoy and Polwheveral valleys (and the remainder of the farm) are underlain by muddy rocks of the Mylor Slate Series while to the north of the farm the soils are markedly different, derived from the granite. Evidence of thermal metamorphism can be detected near the granite.

We moved south along the track, close to an Iron Age settlement and then to an open-fronted barn, formerly used by Charles’ father as a hangar for his light aeroplane, adjacent fields forming the runway. A barn owl is an occasional visitor, although it ignores the nest box. From this point there was a good view across Polwheveral Creek to Calamansack, producing discussion on the possible line of the iron lodes shown on the geological map. More obvious was the broad area of heathland on ground too steep for farm machines. Charles expressed his opinion that this uncommon habitat, an almost impenetrable mix of heather, bramble, gorse and coarse grass, probably represented natural recolonisation of land that had once been cultivated.

Passing into Scott’s Wood, Pauline was kept busy identifying the fungi discovered by the party, apart from a short diversion to a tree where a prisoner-of-war farm worker had carved his name and number. The air was still damp and the sky overcast. Insects and birds had so far been absent; and then a member of the party, at the edge of the creek with binoculars, spotted a stationary group of birds on the far bank. Martin identified them as six greenshank and a redshank, the former being larger, paler, with more distinct whitish underparts than the brown-tinged redshank. High tide precluding an examination of the shoreline, we continued along the side of the creek through mixed woodland containing oak, coppiced sweet chestnut, birch and beech. Then Peter decided that high water made it impractical for the party to visit the exposure of folded and frost-shattered Mylor Slates near Scott’s Quay and so the group headed off to a depression downslope from the Iron Age settlement where Charles has developed a freshwater pond.

A variety of wildlife was present here. Common blue damselfly and blue-tailed damselfly were seen in the reeds. Numerous small frogs were hopping in the grass around the pond, to the delight of the children. Meanwhile Ian and Pauline were speculating on a link between a fungus and the root system of an aspen tree several metres away. Martin heard the call of a great spotted woodpecker and eventually located it in nearby woods. Peter and another of the party branched off into the woods to seek the iron ore workings. On the return uphill to the farm Ian pointed out the large variety of ground plants, including black nightshade.

Overall, the poor weather had limited the chances of seeing many insects and birds, but there had been a positive side. The experts were all together and it was informative to listen to discussions which showed the interplay of their different disciplines. The HMCG wishes to express its thanks to all the leaders, to Charles for allowing us to come and to the members for supporting the event.

Rockpool Ramble, Prisk Cove

Saturday, 14th August 2010

Twenty adults and eight children was the tally for the Rockpool Ramble —- but age was irrelevant. Soon everyone, from youngster to pensioner, was in the same position, with bottoms up, eyes down and hands and nets probing the multitude of rock pools left by the ebbing tide. One intrepid man waded out up to his waist to the far rocks, amidst the Kelp and Thongweed, and came back with a hand-sized Velvet Swimming Crab. He was holding it very carefully, with good reason, for another crab had already scarred his finger and this one was furious, waving its large pincers in the air, its scarlet eyes glaring. In the pools there were crabs of all types and sizes – Shore Crabs of various colours, small Edible Crabs with their crimped, pasty-like shells, Hermit Crabs, often using Periwinkle or Top Shells as a house; and a type nick-named ‘Body-builder’ Crab (Xanthus) because its shell is textured like a muscular torso. Squat Lobster and Common Prawn were seen; and the collecting buckets soon contained specimens of Common Starfish, Cushion Star and Brittle Star. Ruth Williams was kept busy moving among the groups and identifying the finds. One, which looked like a small dark slug, turned out to be a polychaete worm with plate-like legs. Another type of worm – ‘Sand-armour’ – was deduced from the upright feeding tubes made of cemented sand and shell grains.

Carefully turning over a rock often caused a flurry of splashing as a fish darted for new cover. A Butterfish was found and several Cornish Clingfish, with two bright blue spots on the head looking like pseudo-eyes. Limpets, Barnacles, Top Shells and empty Mussel and Whelk shells were abundant, many carrying the white crusts of Coiled Tube Worm and Keelworm. Adding to the attractiveness of the rock pools were the multiple colours and textures of the seaweeds, ranging from yellow and pink encrustations of calcareous algae to bright green strings of Gutweed, olive fronds of Serrated Wrack, dark brown Fucus and floating bunches of Japweed.

Out at sea a host of yachts were taking advantage of the sunny day and stiff breeze, barely noticed by the party absorbed in the rock pools. Then two men in wetsuits emerged from the water. They had been snorkelling offshore and described to Ruth the big fish with striking blue markings that one had seen among the rocks. She said that it was likely to have been a Cuckoo Wrasse. The man’s spread-out hands were rather mobile (!), but we must conclude that it was BIG.

The HMCG would like to express its sincere thanks to Ruth for an extremely enjoyable and informative afternoon.

Helford Conservation Cruise

Sunday, 11th July 2010

Once again, the weather was kind, producing a warm, dry and wind-free day. With 95 passengers on board, plus tanks containing a variety of live fish, crabs and other creatures, the Enterprise boat headed to the mouth of the estuary and around into Gillan Creek, in sight of St Anthony church. The National Trust owns two small properties on the south bank, one containing Bronze Age barrows and an Iron Age cliff castle. Looking seaward there was a clear view of Nare Point and its observation post, now occupied by Coastwatch, but, during WWII, part of a testing range for air-drop torpedoes. Adjacent land had been used as a decoy site, with troughs of combustible material designed to delude enemy night bombers that they were hitting Falmouth Docks. The observation post sits on a raised beach. At a higher level is another and much more widespread plateau surface which forms the flat top of the Lizard Peninsula. This is a wave-cut platform, about 5 million years old. Uplift of the land, which raised it to its present elevation, caused the rivers to become incised, accounting for the steep sides of the Helford and other valleys.

The boat now re-entered the Helford and made its way up-river. The rocky shores on either side are made of shales, siltstones and sandstones, laid down on the bed of a deep sea about 380 million years ago. Subsequently, at about 300 million years, the rocks were compressed into E-W trends, which govern the line of the Helford, and intruded by mineralised granites. Very much later came the Ice Age. From about 600,000 years ago ice sheets dominated the northern continents, advancing and retreating four times with corresponding falling and rising of sea level. At maximum fall, sea level was 400 feet (120m) lower than today and when the ice finally withdrew, 17,000 to 7,000 years ago, sea level rose quickly, flooding the Cornish valleys to produce ‘rias’. The rivers and tributaries regraded to the new, higher base level, lost energy and dumped their sediment in their valleys. The Helford and its creeks are arms of the sea, stocked with marine, not freshwater, creatures. Penetrating far inland they provide sea-going routes for trade and leisure, whilst their muddy and sandy sediments are vital to marine and birdlife.

Heading up-river, David Muirhead mentioned the Durgan fish cellars, where pilchards had been salted and packed, and then told us about various fishing boats, interspersed among numerous leisure craft in the moorings between Helford and Helford Passage. At the height of the mackeral boom, hand-lining boats were landing 20,000 tons a week. Nowadays the fleet concentrates on net fishing , not trawling, for monkfish, turbot, ray and other species; and pot fishing for edible and spider crabs, crawfish and lobsters. Cornwall Sea Fisheries Committee administers regulations out to the 6 miles limit. Within the river, boat fishing for bass is not allowed from May to January, although shore fishing is permitted.

The fine weather had brought out canoeists and anglers and, perhaps for this reason, bird life had so far been in short supply. But in a quiet stretch near Mawgan Creek there was a treat as a flock of about 20 redshank wheeled away ahead of us and a pair of shelduck with 6 ducklings were seen. Andrew Tompsett discussed the Helford’s varied bird life and pointed out occasional egrets in trees and a pair of swans. Picking up the commentary, Abby Crosby explained the concept of the Your Shore project, a 3-year programme under the aegis of the Cornwall Wildlife Trust to enhance the activities of five Cornish VMCAs through education, school activities and volunteer involvement in marine conservation.

The boat had now reached Gweek and turned in front of the Seacore quay, where a large drilling platform was moored. Although now based in Falmouth, this international drilling contractor still uses its original Gweek base for some repairs and refitting. Pamela Tompsett noted that Gweek had long been a commercial port, with important boat building in the 1840s, several quays serving the hinterland and today a boatyard servicing leisure craft. Returning past the National Seal Sanctuary and a bed of Spartina grass, a favoured shelter for young bass, Ken McMullen told us about the National Trust property of Tremayne, which had been given to the Trust by the Trelowarren Estate. Much of the work involves managing the ancient woodlands, dominantly sessile oak, which are important habitats for bats and other species. The boathouse is occupied again this year by barn owls. Tremayne quay, a pleasant spot for a picnic, was built in 1846 in anticipation of a visit by Queen Victoria which didn’t materialise. Farther downstream is the National Trust’s property on the side of Frenchman’s Creek with, on the corner, the house built by ‘Powders’ Thorburn, a colourful character, artist, author and (alleged) gun smuggler.

We headed up Polwheveral Creek to the heronry, just south of Scott’s quay which had formerly been used to ship granite from Constantine quarries. There were a few herons in the trees and others flapping lazily overhead. More obvious were the startlingly white little egrets, about 20, which share the heronry although nesting later. Andrew explained that the egrets, moving north from Europe, had first nested in 1997 and are now established. This year’s count at the heronry gave 12 heron and 7 egret nests.

At the next location, the oyster farm in Porth Navas Creek, Abby told us that the Helford has been famous for oysters for centuries. Early leases were issued by the Bishop of Exeter. In more recent times the fishery was operated successively by four generations of the Hodges family and currently it is run by Ben Wright on a Duchy lease. Production is mainly of the native oyster, both from the Helford and brought in from the Fal for fattening and cleansing. Some quicker-maturing Pacific oysters are also reared. Oysters are vulnerable to predators such as starfish and crabs, and parasites, and last year were affected by the algal bloom which also caused problems for other species. Water quality is extremely important, since oysters are destined for human consumption, and Helford waters are very clean, category B and sometimes category A.

Moving out of the creek and back to Helford Passage, Abby noted the vessels of the Helford River Childrens’ Sailing Trust and talked about the various conservation designations which protect the Helford: AONB, SAC and SSSI. Particular mention was made of the eelgrass beds off Durgan, an environment ‘like an underwater meadow’ which is a haven for young bass. She expressed thanks to the captain and crew of Enterprise Boats, Nick Bailey for use of his pontoon, the National Trust and Derek Goodwin for tanks and live exhibits, the speakers and to the passengers for supporting the cruise and helping to make it a success.

Farming through the Ages

Sunday, 20th June 2010

Gear Farm, the home of the Hosking family since 1933, is the site of a large hillfort, dating back to perhaps 3000 BC, which was the subject of excavations and a TV programme by the BBC’s Time Team in 2001. For this event we had the benefit of two experts, James Gossip from the Cornwall Archaeological Unit (Cornwall Council) and Mary Combe from the Farming and Wildlife Advisory Group, each assisted by a member of the Hosking family. The group of 43 was divided into two parties, one going with James and the other with Mary and then, after a swap, our experts kindly repeated their tours for the other party.

James Gossip started his tour by taking us to a barn containing display cases which housed a host of artefacts discovered by Rex Hosking and his family over the years. Also on display were drawings and photographs prepared by the Time Team, who investigated the site using excavations and geophysical surveys. A few flint items might possibly have belonged to the nomadic hunter-gatherers of the Mesolithic period, 10,000 – 4,000 BC. The flint would likely have come from beach pebbles, the nearest rock source being Beer in Devon. Flint working was better developed in the subsequent Neolithic period (4000 – 2500 BC) and collected pieces included what might have been a scraping tool and a chisel-shaped arrow head.

Gear’s history probably started about 3000 BC (14C dating), but its main period was 150 BC – 300 AD, late Iron Age to Romano British. Artefacts from this time included a Cornish-style carved stone bowl, made from rock obtained from Gedonning(?) Hill; and pottery made from gabbroic clay. The clay is found in a small area of c.7 km2 near St Keverne but its use was widespread. About 90% of ceramics in Cornwall were made from it because it had the property of not disrupting when fired. Among other stone objects discovered were a saddle quern, a pounding stone and a rotary quern, the latter shaped like a thick discus with a central hole, probably made by an iron tool, for feeding corn to the grinding surface. It was thought to date from about 150 BC.

Some 2000 to 3000 Iron Age sites are known in Cornwall, over 30 of them in the Helford catchment. Mostly these were ‘rounds’, settlements surrounded by a bank and ditch, probably occupied throughout the year by people whose main activity was farming. A few sites were more substantial: hillforts and their coastal equivalents, cliff castles. Defended by deep ditches and earth or stone ramparts, these forts are thought to have been social and trading centres for the surrounding settlements. Gear was a large hillfort, enclosing an area of 15 acres (6 hectares). Only two others of comparable size are known in Cornwall. Interpretation of the geophysical data suggests the presence of about 16 round dwellings within the fort.

Leaving the barn, we walked around the fort along its defensive ditch. The adjoining rampart was impressive, a very steep bank of earth and stones about 16 feet (5m) high in places, now covered by woodland. In its time, however, it would have been relatively much higher, because the ditch had been partially filled in during the 19th Century as an attempt at landscaping by the Vyvyans of Trelowarren, anticipating a visit by Queen Victoria in 1846. The true bottom of the ditch, determined by the Time Team, was about 9 feet (3m) below us. About three-quarters of the way around there was a gap in the rampart, thought to have been the sole entrance to the hill fort. There is some evidence of an approach way and a zig-zag track to nearby Mawgan Creek.

We walked up-slope to the centre of the hillfort, now a large field of grass and clover. Queen Victoria, had she visited Trelowarren, would have been presented with a vista of ancient settlements at Gear, Caer Vallack and Bonallack, now not possible because of subsequent tree planting. Caer Vallack, a well-preserved round close to Gear, may have been a chieftain’s settlement. James expanded on life in the hillfort and settlements. The basic way of life probably changed little from the Iron Age through the Roman period. Romans had already been trading for tin prior to occupation and were apparently content to maintain that arrangement, without taking control of the mines. There are signs of increased trading, for example fragments of amphorae. For the Iron Age –Romano British people, salt was available from Coverack and Kynance, fishing was practised, suggested by holed stones possibly used to weight lines and by woven fish nets. Piles of cockle shells are known from Tremayne. Oak was used for construction and hearths, hazel for charcoal and coppiced roundwood for high temperature firing of furnaces. Spelt wheat, barley and oats were the principal crops, augmented by nuts and berries. Because of the acid soil, Cornwall has a poor record of animal bone remains, but there is evidence for cattle, pig/boar and Soay-type sheep. It is likely that the soil was ameliorated by manure and the spreading of seaweed.

The occupancy of Gear hillfort seems to have ended around 300 AD, for reasons unknown. The first written reference to it was in 1262. It had brief fame in 1643 as the Gear Rout, when 300 Royalist troops and 40 horse were pushed back by advancing Parliamentarians.

Very many thanks to James Gossip for his lively and thoroughly absorbing tour which brought an ancient hillfort back to life.

Mary Combe explained that the Farming and Wildlife Advisory Group is an independent organisation which exists to advise farmers on a wide range of topics, with the aim of improving productivity and profitability and reducing working costs, while at the same time benefitting the environment and conserving biodiversity. It provides practical information on diverse matters such as soils, water, nutrients, hedgerows, greenhouse gases and renewable energy, but couples these with advice on landscape, historical importance and wildlife habitats. Gear Farm is a superb example of the coordination of farming and environmental stewardship. In its early days it was part of the Trelowarren estate, the farmer, as tenant, renting the cows and profiting from the milk. It was bought from the estate in 1948, as a large farm of over 250 acres worked by 8 men. Subsequently it was divided among three brothers and is currently an 80 acre organic farm, famous, among other things, for producing the best pasties in the region, with all the ingredients coming from the farm. Walking from the car park towards Tremayne creek we stopped at a field containing rows of potatoes, swedes and onions. The farmer told us that the potatoes were early varieties, to crop before blight took hold. One, a Hungarian variety, was said to be blight resistant, though not drought resistant. Parts of the onion planting were thick with weeds, but these were soon to be cleared by machine hoe between the rows and then hand weeding. The farm doesn’t use herbicides. In the mean time the weeds provided a welcome habitat for ladybirds and other beetles.

Farther down the track, Mary sold us that a feature of the Cornish landscape was its age, many of the hedges being medieval, or at least 150-200 years old. Perusal of old maps was helpful in determining the age of a hedge, while an empirical method involved counting the number of woody species, such as blackthorn and sycamore, in a 30 metre stretch and reckoning 100 years for each species. Ancient hedges were often built curved, to give shelter from different wind directions. Crops such as corn, potatoes and hay, requiring transport, were planted near the farm house separated by ordinary hedges. Cattle, being mobile, could be grazed farther away and so hedges bordering lanes to pasture and water supply were often stone-faced to prevent cattle damaging them. Farm hedges were also a key timber source. For example, sycamore or ash logs would be laid on the ground and covered by a layer of bramble to make a base for hay and straw ricks. Because of their value, hedges used to be cut bare, whenever a farm changed hands, so that they could be properly assessed. However, this practice has been modified, following FWAG advice, because hedges are extremely important for wildlife, providing shelter, food, nesting places and corridors between habitats. Ideally they should be at least 1m tall and 1.5m thick, continuous, with a 1m herbaceous verge to protect the roots and the tops not trimmed until Nov-Feb, after berries have fruited.

Passing on, we came to the site of a former hedge. The soil here was poor, with few nutrients, but weeds and wild flowers were numerous, plus some small oak saplings perhaps indicating acorn dispersal by jays or squirrels. It is likely that brambles will follow, a plant extolled by Mary as good for birds and insects. Native species such as these, unlike imported plants, are in tune with the environment and capable of dealing with acid soils and a salty atmosphere. Alien species belong in gardens, not in the countryside. The next stop brought a view across the Helford to Merthen Woods, formerly coppiced to provide charcoal for the mines and containing a pack-horse track up which lime and seaweed were taken from the quay to farms, to counteract acid soils. In the foreground, grassy fields swept down to the National Trust woodlands flanking Tremayne Creek on our right. One section, too steep for vehicles, had been allowed to revert to woodland and showed a healthy development of sweet chestnut, birch, sycamore and ash.

Grasslands are valuable to the farm for hay and silage (cut in May), but are also important for wildlife, such as voles, spiders, butterflies and skylarks. The last need undisturbed conditions when nesting and may also find these in spring cornfields ( although these can be too dark) and in daffodil fields not yet cleared after flowering. One field in particular attracted attention. It was a favourite hunting ground for barn owls, possibly the ones which had nested in Tremayne boathouse last year, and its long grass would be deliberately left uncut until August, apart from a winding swathe of shorn grass over which voles might run (at their peril).

Discussion turned to the absence of honey bees and Mary said that there was a problem for insects generally. Availability of nectar at different times of the year was a key consideration. Blackthorn, gorse and hawthorn had largely finished flowering. Some clovers and creeping thistle were current sources. Umbellifers provided little. August was often a poor month, but nectar was available from ivy. Returning towards the car park, Mary opened the door of the camp-site shower cubicle to reveal an owl box, used for roosting by young barn owls (the shower as a consequence being out-of-bounds). In conjunction with another box in the barn and perching posts at either of the field, it epitomised Gear Farm’s sensitive consideration of wildlife in all its forms while at the same time running a very successful farm.

The HMCG would like to thank Mary Combe and Mr Hosking very much for an extremely informative and enjoyable afternoon.