Where the weary whelk?

Have whelks disappeared from Mull? Or, if they haven’t disappeared, they are playing a very good game of hide-and-seek – and for this they have good reason.

Whelks, not to be confused with winkles, live in the sublittoral zone and littoral fringe and cannot therefore survive the lower salinity of the intertidal zone – the best chance of seeing them is at the lowest tides. However, even when diving local wilderness shores I rarely spot one.

One theory is that Tributyltin (TBT), a chemical compound used around the world in ship hull paint, is killing them. For 40 years TBT was used as a biocide in marine anti-fouling paint (commonly known as bottom paint), which was applied to the hulls of ocean going vessels to reduce the growth of barnacles and other organic matter. It should be of no surprise therefore that it does what it says on the tin and the use of TBT negatively affects bio-diversity for that is its very purpose.

Bottom paint is a cheap way to stop barnacles, weeds and algae from growing on a ships hull as all of these can adversely affect a ships structure, hydro-dynamics and performance. The invention of the copper-bottom was introduced to British warships of the line with similar effect – indeed the phrase ‘copper-bottomed’, when used nowadays with reference to the reliability of a venture or investment, stands testament to the effectiveness of the process. Sir Humphrey Davy of the Royal Navy pioneered the lining of its wooden ship’s hulls, prone to fouling by barnacle growth, with copper plating during the 1880s. Britain was fighting the French, the Spanish and the Dutch navies at once and all three were heavily defeated – British ships were faster, more manoeuvrable and could stay out at sea for longer.

However, lining a ship with copper is expensive, never more so than today and so is painting a ship’s hull each year. So TBT was cheap and effective but the chemical leaches into the marine environment where it is highly toxic to a wide range of organisms and its pollution led to the collapse of whole populations of organisms.

The International Maritime Organisation now bans TBT compounds. These bans first started in the 1980s on boats less than 25 metres long and the use of biocide compounds in anti-fouling paint was completely banned in 2008 by the International Convention on the Control of Harmful Anti-fouling Systems on Ships. It states that ships cannot bear organotin compounds on their hulls or external parts or surfaces unless there is a coating that forms a barrier so that organotin compounds cannot leach out. TBT will most likely be present in the water column and sediment for up to twenty years because of its long half-life.

TBT anti-fouling paints are still being used in countries with poor regulation enforcement, such as in the Caribbean so I don’t expect Whelks are very happy over there. Over here the search for whelks continues.

How foraging became hoovering

The islands surrounding Staffa are as protected as can be. They are Sites of Special Scientific Interest (SSSI), Special Protection Areas (SPA) and Special Areas of Conservation (SAC) and visitors require permission if they so much as consider breaking wind. Yet, under the water’s surface, around Scotland’s most protected land, the dredging continues.

The Mull coastal economy (fishing, diving, boat and wildlife tours, kayaking, rambling and camping) benefits from a bountiful and sustainable intertidal and shallow water ecology. Even the creel fishers, who account for 75% of the Scottish inshore fishing fleet, benefit from working in beds undamaged by trawlers. However, the dredgers don’t have such a good record.

The remote islands of Staffa (with its world famous basalt columns and Fingal’s Cave) Little Colonsay, and the Treshnish Isles (Lunga, Fladda, Cairn na Burgh More, Cairn na Burgh Beg), The Dutchman’s Cap and Iona may seem like protected pristine wilderness to the passing eye, but the waters surrounding them have little protection – under the water line it’s a wild-west dredging frontier.

Eco desert

One of the largest environmental disasters in modern British times happened in the Clyde in the 1970s. The sustainable fisheries at Carradale and Girvan first fitted steam-powered engines to their trawlers and diesel followed enabling them to go further, for longer and with bigger nets. Then fish finding sonar was discovered ‘and soon fishing became hoovering’ as trawlers netted herring in numbers never seen before.

When the herring ran out the fishermen switched to saithe and when this ran out they switched to cod, then plaice and then sole and when there were no fish in the water column they started dredging scallops from the mud. The more fish were caught the more needy were fishermen to pay for their new televisions, microwaves, cars and expensive technology reliant fishing boats. Now there is nothing left.

Not many people know of this disaster of desertification of the Clyde because it occurred under water and beyond the ken of environmental nimbys preoccupied with the demands of questioning windmill aesthetics. Also because the Scottish fishing fleet is an influential political force of national employers and no organised pressure groups were around to question their decades long inept handling of fish stocks. However, all that is changing.

Dredging ban

West coast scallop stocks have declined since 2011 yet scallop production and yield is increasing at a dramatic rate with new and additional boats entering the fleet. Mull Aquaculture & Fisheries Association say Nethrops (‘shrimp’), brown crab and velvet crab are all over exploited around Treshnish.

Nethrops are getting smaller and competition for them is increasing. According to official government figures published in the Scotland Marine Atlas: south and west areas of Mull are ‘heavily exploited’, Demerol stock ‘a concern’, Sandeel stock ‘in decline’, Whiting stock ‘in decline’, Treshnish burrowing Sea Anemone ‘at risk’, Fan Mussels are rare’, Ocean Quahog ‘in decline’, Seapens and Megafauna ‘at risk’ at Gometra and Ulva and Fireworks Anemone ‘scarce’. Tall Seapens of Inch Kenneth and The Wilderness are of ‘global importance’ and the Maeri beds at Treshnish represent 95% of the global volume of the species.

Signs the fleet learnt lessons from history are few so, when they cried for ministerial help to continue dredging MPAs, Environment Minister Richard Lochhead retorted with a ban. Such is the public consciousness of the marine ecological environment that pressure from campaigning groups such as COAST has brought results. Indeed, the 30 MPAs themselves are a result of Hugh Fernley–Whitingstall‘s own campaign Fish Fight which revealed 50% of every UK fish catch is thrown overboard, dead.

Trawlers have had to widen the mesh in their nets to reduce bye catch, reduce their number of fishing days and provide escape hatches for fish. Nevertheless, 77 million Nethrops are discarded annually (with a 75% mortality rate) and up to 50% of the overall catch is discarded (a large proportion of this being juvenile cod). For every kilo of Nethrops caught in the Clyde 9kg of bye catch is discarded. Dr S Campbell, Community of Arran Seabed Trust, says, “These parameters suggest that in time the Nethrops fishery will collapse”.

Day-trippers to Staffa, in fear of the eco Stasi, ensure they don’t use colourful language in front of the puffins whilst we watch dredgers tear up the Treshnish Isles’ surrounding seabed.