By Samuel Stone, Marine Conservation Society Fisheries Officer

Photo courtesy of MCS

It’s true. The iconic European cod fishery which collapsed in the 1980s and has been ailing ever since, has finally increased above dangerously low levels and hauled itself off the Marine Conservation Society’s (MCS’s) Fish to Avoid list and is now rated 4 (Amber) at www.fishonline.org.

The latest stock assessment undertaken by the International Centre for the Exploration of the Sea (ICES) indicates that the spawning biomass (the adult population) has finally increased above the lower population reference point (The biomass limit or, ‘Blim’) and is in fact at its highest level since 1983. This recovery from very low levels is largely the result of significantly reduced quotas, fishing effort and cod avoidance measures, which Scotland has played a leading role in implementing, through the Conservation Credits Scheme.

Whilst this improvement is a real milestone, this needs to be sustained in order to increase the population above its next milestone (The precautionary biomass limit). And likewise, the proportion of the population that we’re removing through commercial fishing still needs to be reduced further to achieve a long-term healthy and sustainable fishery. For these reasons, the fishery is amber rated, and MCS still recommends better rated alternatives like green rated and Marine Stewardship Council (MSC) Certified haddock and hake. George Clark, (MSC UK Commercial Manager) says ‘If the North Sea fishery can make these improvements, there’s no reason why it couldn’t be certified in the not-too-distant future’.

Cod stocks not out of danger yet

The increase in population and move off the red list is clearly very good news for all concerned, not least the marine environment, where cod can once again start to resume its natural role in the food chain as a major predator and prey in the North Sea. This good news is however somewhat tainted by the many other ailing stocks (like Celtic Sea and West Baltic now both red rated) and the warnings that cod may never fully recover to levels seen in the 1970s. At its peak in 1971, the adult population was approximately 274,000t; at its lowest, just 44,000t in 2006. The combination of sustained overfishing which reduced the age and length at maturity of cod , and changes to environmental conditions – namely the warming of the northwest European shelf seas – have reduced the reproductive success of North Sea cod. As waters continue to warm, the slower and lower the recovery may be.

A key reason why conservationists lobby hard for the recovery of fish stocks as quickly as possible is to strengthen the resilience of the marine ecosystem so that it has the best chance of adapting to or tolerating other pressures like pollution and climate change. Where a system is already weakened, such changes may be enough to trigger irreversible change. Usually, where more vulnerable species (longer lived and slow to reproduce) are removed from a natural environment, more resilient species move in to fill their place and therefore reduce biodiversity and can alter the structure and function of the entire environment.  Such regime shifts have been observed for example in the West Atlantic where the collapse of Atlantic cod on the Eastern Scotian Shelf gave rise to an increase in small pelagic predators over large bottom dwelling ones and an increase in bottom dwelling crustaceans.

To keep encouraging and supporting well managed fisheries that are playing their part in improving the resilience and health of our shared seas, keep choosing seafood from the green end of the spectrum at www.fishonline.org.