Seals and humans
Seals and fishermen
Seals and fishermen are seldom the best of friends. Fishermen claim that seals damage their business by eating fish that they might catch. It is, however, not that simple. Many of the fish taken by seals are non-commercial species or not of the correct size and seals are not the only predators.
Seals are also host to a large number of parasites, such as codworm, which is passed from the seals to the fish and back again as the larvae develop. This affects not only the quality of the infected fish which are of lower value, but it also affects the growth and survival rates of the fish.
Salmon fishing is an important Scottish Industry, and seal damage to the nets and to the catch was once a serious problem. In recent years, stronger nets have been used, specially designed so that seals cannot chew through them and attack the fish inside. Fishermen are allowed by law to shoot any seals that are attacking the nets, but only very few seals are killed each year as a result of this activity.
In many sealochs, salmon are reared in net cages. Although seals seldom break into them, if they do, the result is disastrous. Besides the fish that the seal eats or injures while feeding, thousands more might escape. In 1989, one fish farmer reported that a single seal had attacked his fish and he had lost 13,000 salmon (at a market price of £20 per fish). Fish farms often have an extra layer of thick anti-predator netting around the cages to keep seals (and otters) out. Attempts have also been made to frighten seals away by using sound recordings of killer whales. But seals have excellent hearing, and seem to be able to tell the difference between a real whale and a recording. Instead of scaring the seals away, the tapes may instead tell the seals that food is available.
In the relationship between seals and fishermen, fishermen are not always the victims. Seals often become entangled in the sturdy nylon nets, and if they cannot reach the surface for air, they will drown. Occasionally nets are lost. These are known as ‘ghost nets’ and continue to catch or entangle seals, cetaceans, fish and birds long after fishermen have written off their loss.
Seals like to play, and pieces of brightly coloured nylon from broken nets are irresistible toys. Often these tough materials become wrapped around a seal’s body, and cut into it as the seal grows. They can also impede a seal’s swimming, reducing its chances of survival because it cannot hunt properly.
Seals and hunting
Their thick layer of blubber makes seals an attractive quarry. In Scotland, subsistence crofters and farmers killed seals until very recently for the oil that could be taken from the blubber. The oil was used in lamps, as medication, and for softening leather. For many years, sporrans were made from sealskins.
This small-scale hunting had very little impact on the local seal populations. There was a balance between local Scottish hunters and the seals, in the same way as there was between the peoples of the Arctic and the seals. However, in other parts of the world, the commercial hunting which started in the 16th century and continued until the 1970s put an end to this balance. Seals stocks from the Antarctic to the Arctic, and almost everywhere in between, began to decline dramatically.
Environmental pressure groups, such as Greenpeace, began a campaign called ‘Save the Seals’. The emotive sight of big-eyed, white coated harp seals being clubbed to death for their fur resulted in a public outcry.
As a result, the European Community issued a ban on harp and hooded seal fur in 1983, effectively destroying the fur trade. Neither grey seals nor common seals are endangered species.