Cod comes top in annual Cefas lottery

It may have taken a while, but at last a cod tag has been pulled out of the hat in the annual lottery for returned fish tags. A Danish fisherman, Søren Anderson, was this year’s winner, bagging the £1,000 (€1,400) top prize.

Scientists at the Centre for Environment, Fisheries & Aquaculture Science (Cefas) have been running the annual lottery since the end of the last century. It all began as a way of raising awareness of data storage tags (DSTs) on fish and to maximize their return rate. Tim Oliver, editor of Fishing News, pulled the very first lottery tag in 1998 and performed the honour again this year.

The first batch of DSTs was attached to plaice to study their migration patterns. Subsequently cod and rays have also been tagged. Cod tags now outnumber those for plaice and rays by 3:1, but it was only this year that a cod tag was pulled from the hat. Cefas scientists are pleased with the very high return rates of fish: 51% of tagged rays and 31% of plaice though cod still lag behind at around 20%.

The scientists are keen to gain as much informa t ion as possibl e about the condition of the fish , so return of the carcass is especially valued. They are able to reconstruct the lifetime movements of the fish using ear- stone (otolith) microchemistry. Combined with the data on the DSTs, the scientists can build up a wider picture of fish movements and behaviour.

Ewan Hunter of Cefas says: ‘The data returned are incredibly valuable. They have provided important insights into the migration, distribution and spatial dynamics of these species, including a relatively complex population structure in North Sea plaice and seasonal migration patterns in Thames rays. This sort of information isn’t always apparent from conventional tagging programmes.’

A poster campaign in the four principal North Sea languages (English, French, Dutch and German) has been used to target the main North Sea fishing ports. It advertises the rewards associated with the tagging programme. For every tag, returnees are awarded £25 (€35) in cash plus the market value of the fish. Returnees also receive a specially designed T-shirt or, for repeat tag returns, insulated mugs or beanie hats. Those who return the fish carcass are guaranteed a further £25 (€35). The ultimate reward, however, is the £1,000 (€1,400) top prize for the winner of the randomly chosen DST in the annual lottery.