A common argument used by sealers and politicians is that killing seals is needed to protect fish stocks, but this case is not supported by any scientific evidence.
The estimate of the amount of fish consumed by seals tells us nothing about the impact of seals on fish populations.
Ocean ecosystems are complex, and we cannot assume that the mass removal of one species will benefit another. In fact, mass culling of seals could have unintended and unpredictable results, and ultimately weaken the structure and functioning of ocean ecosystems. An analysis of the Cape fur seal cull in South Africa concluded that culling was not only unlikely to benefit fisheries, but was likely to be detrimental to them. The South African cull was called off.
As recently noted in a Scientific Advisory Report by Canada’s Department of Fisheries and Oceans : “Although widely practiced, the extent of seal population reduction and the response of targeted prey populations to culls have rarely been evaluated, such that their effectiveness is poorly understood. Further, results from other predator control programs indicate that unintended consequence in food webs, that will be difficult to predict, are nonetheless commonly observed.”
Despite the absence of scientific support, some governments continue to advocate mass culls of seals to benefit fish stocks.