Atlantic herring  (Clupea harengus)

The biggest threat to this species is over-harvesting by the fishing fleets of many nations. Although the herring is still a relatively numerous species, it is now feared that there more are being caught by trawlers than can reproduce annually, particularly in European waters. Domestic pressure on governments to support their fishing industries has led to overfishing, and agreed quotas being exceeded, depleting populations of herring across much of its range.

The Atlantic herring is listed in the UK Biodiversity Grouped Action Plan for commercial marine fish. Being a species that is found in international waters, it has proved very difficult to impose restrictions on the number of fish that can be harvested from the sea without reducing fish stocks below the important Safe Biological Figure (SBF) limits.

During the 1960s, the herring population in parts of the north Atlantic collapsed catastrophically, virtually wiping out the Icelandic herring industry, and posting a warning sign about the fragility of the marine environment. The chief cause was overfishing and, following the creation of a management plan in 1975, the Icelandic herring industry became the first to be subject to a total allowable catch (TAC) restriction. Since then, in this part of the Atlantic, herring fish stocks have recovered to sustainable levels, and the experience should serve as a lesson as to what could happen to other commercially important species.

Whilst Atlantic populations of herring are currently considered to be above the SBF, those in the North Sea are giving cause for concern. Figures suggest that reproduction of many commercial fish species fell to an all-time low in the 1990s. Although populations now seem to be recovering, the herring is still covered in the part of the UK Grouped Action Plan specifically relating to North Sea fish stocks. However, it remains to be seen whether implementing the rules and recommendations in the current Common Fisheries Policy (CFP) will allow population levels to stabilise and recover. One effect of the CFP has been to remove the inefficient fishing boats from the fleets, allowing heavy overfishing by the 'factory' trawlers. This, coupled with the pressure on individual governments to support their country's own fishing fleets, has led to the harvesting of 'black fish', illegal catches above and beyond a country's legal quota, and this is still taking its toll on herring populations.