Grey seals might look cute, but they are predators and, if their numbers are excessive, can cause serious damage not only to fish stocks, but also to marine mammals such as porpoises. Marine birds, including gulls, are not safe either.
When two groups of predators compete for the same food supply, one group can benefit by reducing the size of the other. For the fish off Estonia’s coast, harvested by both grey seals (Halichoerus grypus) and fishermen, this is exactly the proposed plan: a cull of the seal herds. Seals not only eat fish that swim free, but more detrimental to fishermen, they also eat fish in fishermen’s nets, damaging gear in the process. Seals also often take just a bite out of a fish, and the injury to the fish can cause parasite infection, threatening other fish within a population. Baltic fisheries are already in peril, according to ICES, with stocks of cod and other important species continuing their long-run decline. The grey seal population, on the other hand, is thriving, with an estimated growth rate of 5-6% annually and a Baltic population of about 30,000 animals. Within Estonian waters, researchers counted a 20-year high of 6,000 grey seals in the most recent aerial survey, according to the fisheries department of Estonia’s Ministry of Environment.
An annual quota for grey seal hunting is already in place in Estonia, set at one percent of population size, or currently 55 animals. But because the quota is not currently being met (the quota has been 25-50% filled in recent years), simply increasing the quota would be ineffective. A managed cull, perhaps with incentives, might produce more results. The possible opinion of the seals with respect to the proposed idea is expressed by many, including an expert on seal biology who argues that seals are blamed too quickly for the gear damage. More study of the fishing industry is urged, to possibly identify problems in the industry itself instead of blaming seals, cormorants, and other wildlife that feed on fish in fixed nets.
Other opponents of a simple cull include experts sympathetic to the fishermen’s plight. One suggestion is a cull limited to immediate areas of fishermen’s nets, because it is believed that a minority of the seals are responsible for the gear damage — “the smart ones,” in the words of an expert, i.e., the ones who know where the easy fish are.