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Friday 11 July 2014

Fishermen 'scraping the barrel' in English Channel


Some basic questions need asking here. As there are no skate landed under current CFP policy there are no landings to compare in recent years - boats do not target this fish anymore, and many years ago there was a huge longlining fleet in Newlyn that did fish for ling and skate - not one boat remains lining as they have all moved on to gillnetting - a method of fishing that does not target skate and is far less effective at catching fish like ling.

There are alternative explanations that might just explain the changes in data - for instance, scallops, squid and cuttlefish are not subject to quotas - hence there are now many more boats fishing for these species as buying or leasing quota is hugely expensive.

Data and the resultant statistics based on landing are never going to reflect a true and accurate picture of stock state when taken in isolation and out of context.

Here is the article in full courtesy of the Telegraph with a few areas highlighted:


Fishermen are "scraping the bottom of the barrel" in the English Channel with stocks of cod and haddock fast running out, according to new research. The common skate, a large iconic fish, which existed in huge numbers has all but disappeared from the channel. Sharks, rays, and many other species at the head of the food chain are also at historic lows, with many having vanished from the sea altogether. An analyses of catches over the past 90 years shows top predators that once filled the nets have been replaced by increasing amounts of shellfish - at the bottom of the food chain - scraped of(f) the sea bed.
The phenomenon is known as 'fishing down the food web' and has been caused by decades of overfishing, reports the journal PLOS ONE.

The scientists used statistics from the International Council for the Exploration of the Seas to establish a 'mean trophic level' for catches, an average for how far up the food chain the fish are located. Decades of overfishing in the English Channel has resulted in the removal of many top predators from the sea and left fishermen 'scraping the barrel' for increasing amounts of shellfish to make up their catch. Sharks, rays, cod, haddock and many other species at the head of the food chain are at historic lows with many removed from the area completely. Marine biologist Professor Jason Hall-Spencer, of the University of Plymouth, said: "All around the UK we are scraping the bottom of the barrel, destructively dredging the seabed for scallops and prawns as fish have disappeared. "When destructive fishing practices are banned, marine life soon recovers. So we urgently need a network of recovery zones in the English Channel to allow marine life to bounce back."

He was inspired to carry out the study, the first of its kind in the English Channel, after researchers uncovered a similar picture in the Firth of Clyde. He said: "We used to have giant common skate in the English Channel. They were called 'common', because they were exactly that. Really common! Now they have entirely disappeared. It is an iconic, very large fish, very slow moving and has very few babies. "It used to hide on the seabed but then these huge trawlers began dredging them up, and now they don't exist. The same could happen to cod and haddock which are threatened by this destructive equipment. A parliamentary select committee has found the Government is dragging its heels over this issue. "Norway and Iceland has banned these big trawlers from their waters because they realised the damage they were doing. We must do the same. Don't get me wrong. I am from Plymouth, and I realise how important the industry is to the area. But it must be sustainable."

He added: "It is clear from our analyses that fishing pressure has caused significant changes to food webs of the English Channel over the past 90 years. "The mean Trophic Level of English Channel landings has fallen by 0.1 unit per decade, one of the fastest rates reported among other heavily fished regions of the world, providing yet more evidence that 'fishing down food webs' is a worldwide phenomenon." Today, the UK and France land around 150,000 tonnes of seabed fish and shellfish per year from the 75,000 square kilometre channel, a huge rise from the 9,000 tons recorded in 1920 and the 51,000 in 1950.

During that time, the composition of catches has altered dramatically, with sharks and rays falling from 34% in 1920 to just six percent in 2010. The contribution of 'cods, haddocks and hakes' similarly fell from 48% to just four percent over the same period. Spurdogs, tope sharks, thornback rays, Atlantic cod, ling and European hake show the most remarkable decline, while flounders, halibut and soles have changed relatively little.

The falling levels of finfish has been counterbalanced by increased landings of shellfish such as scallops, and of squid, octopus and cuttlefish. This has in turn raised concerns over long term sustainability, and the potential damage done to the marine environment as a result of dredging and trawling for these invertebrates.

Researcher Carlotta Molfese said: "Fisheries typically remove top predators first and as a result their direct competitors and prey are able to prosper, affecting the overall productivity and ecological stability of the ecosystem. Severe declines in the populations of major predator species have now been reported around the world."

Doug Beare, of conservatists WorldFish, said its research has shown a decline of finfish species has been followed by an increase in their invertebrate prey, and although new and economically viable fisheries have developed for these, alarm has been raised about their long term sustainability. He added: "We promote a sustainable approach to fisheries that will help to protect our natural resources and ensure fish stocks are available for future generations. Solid global and regional governance of these vital resources will ensure we can produce enough fish for everyone." The researchers say that far from being a modern phenomenon, overfishing can be traced as far back as the 19th century, with declining stocks reported in 1863. But geographic expansion into new fishing grounds and improved technology combined to maintain increased landings.

Read the full paper here http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0101506