Publication Abstract

Is tagged spurdog a record breaker?

(Article first published in Fishing News, 22 October 1999)

A tagged male spurdog which was captured west of Stanton Bank in late September 1999 was found to have been at large for almost 35 years when it was examined by scientists from Aberdeen’s Marine Laboratory – possibly a world record for a tagged fish.

When the records were checked it was discovered that the fish had been tagged and released on 30 October 1964 by scientists from the MAFF Laboratory, Lowestoft, working 10 miles north of Rona aboard the research vessel Ernest Holt.

The fish had grown from 66 cm to 78 cm in the 34 years and 11 months leading up to its capture by the fishing boat ASTRA (BF 524) – an average growth rate of one third of a centimetre per year.

This is not the first time that tagging experiments have shown that dogfish grow extremely slowly and live to a ripe old age. A male that was recaptured in 1997 – 34 years and 9 months after it had been tagged – had grown by only 10 cm.

Because spurdogs grow so slowly and give birth to only a few pups they are extremely vulnerable to overfishing.

Although the fish landed by the ASTRA was recaptured fairly close to where it had been released nothing is known about its movements during its period of freedom.