Canada's Fish Tale: Seals and Cod Stocks

Seals and fisheries: searching for scapegoats

Humans have a long history of blaming marine mammals, especially seals and whales, for eating 'their' fish. The reasons are obvious: it is always easier to point the finger at someone - or something - else, rather than take responsibility for the overexploitation and mismanagement of a resource.

In Canada, decisions involving the management of marine mammals are ultimately made by politicians, and of course, seals and whales don't vote. When the cod stocks collapsed off Eastern Canada in 1992 it was popular to blame seals, overfishing by Europeans, cold water, and a variety of other factors. But in 1994 two Department of Fisheries and Oceans scientists concluded that "the collapse of northern cod can be attributed solely to overexploitation [by humans]."

Seals are part of a much larger ecosystem

Marine ecosystems are complex, and we cannot assume that by removing one species another will benefit.  Harp seals eat a variety of fish and marine invertebrates, but many of them have no commercial value. Furthermore, there is no scientific evidence that culling harp seals will produce measurable benefits for any fish stock or commercial fishery.

In fact, in the case of seals, removing seals might have a negative effect on the recovery of Atlantic cod stocks since seals also eat predators of cod, such as squid. In this situation, a reduction in harp seals could lead to an increase in squid numbers, resulting in even greater predation on cod. Many scientists now believe that reducing the harp seal population might actually harm commercial fisheries.

The Eminent Panel on Sealing recently concluded that "the belief, expressed by some stakeholders, that reduction of seal numbers will rapidly restore fisheries is overly optimistic: even in 'normal' mortality regimes, the expectation is for very slow recovery." Whatever the future of Atlantic cod may be, culling seals is unlikely to bring back the fish in the near future.