The North Sea, west of Scotland and Irish Sea cod stocks are at their lowest ever recorded level and are in danger of collapse unless urgent action is taken, warn scientists from the Fisheries Research Services (FRS) Marine Laboratory in Aberdeen. Their conclusions are based on a report published today (25 October) by the International Council for the Exploration of the Sea (ICES).
Current research estimates the spawning stock biomass to be about 38,000 tonnes in the North Sea, which is over a third lower than in 2000. In 1988 the spawning stock biomass was about 100,000 tonnes. The figure needs to be nearer 150,000 tonnes to ensure the stock remains at the safe biological limit to ensure adequate recruitment of juveniles.
These figures come against the background of cod mortality from fishing pressure over the research period remaining at about the same level of the historic high and, except for the 1996 year class, recruitment has been below average in all years since 1987. The 1997 and 2000 year classes are estimated to be the poorest on record.
The prospects for the North Sea haddock stock are also poor. While, the 1999 year class is good and is contributing to the current spawning stock biomass, it is the only year class above the average size for a number of years. The 2001 year class is the lowest observed on record and the 2002 year class may well be below average. This means that the stock is likely to decline rapidly in a couple of years.
However, the report by ICES covers all fish stocks and some, including mackerel and herring, are in a reasonably healthy state.
"It is an inescapable conclusion that the cod stocks around the UK are seriously depleted and that continued fishing at current levels will lead to collapse," states Dr Robin Cook, FRS Chief Executive.
"Since cod is taken in mostly mixed demersal fisheries with haddock and whiting, it is clear that you can’t take one without the other, and this could have serious implications for next year’s haddock fishery," he adds.
The loss of cod, a major fish predator, and the depletion of haddock, may have serious knock-on effects on the marine ecosystem and result in adverse changes to other marine life.
As part of the programme of monitoring the marine ecosystem stocks, FRS’ two research vessels spent more than 500 days-at-sea taking samples. FRS observers were deployed on more than 120 commercial fishing trips to record total catch rates. In addition, over 2,200 separate landings by fishing vessels were sampled and more than 450,000 fish measured.
Data collected by FRS and scientists from other north east Atlantic nations are used by the Advisory Committee on Fishery Management (ACFM) – a committee of ICES – to provide advice on fish stock management.
Ends 25 October 2002
For more information, contact Laura Lamb, tel: 01224 876544.
The ACFM report is available from the ICES website, www.ices.dk
Definition of technical terms:
Spawning stock biomass: the total weight of fish of spawning age in the stock.
Fishing Mortalities: the rate at which fish are removed by fishing.
At present about 50-60% of the stock is removed each year by fishing.
Recruitment: the number of young fish produced by the stock each year. These are often called year ‘classes’.
Demersal: fish which live on or near the seabed. They include cod, haddock, whiting, plaice and sole.