Singing Seals
- Teachers' Notes
There are two species of seal in Scotland: Atlantic grey seals (grey) and harbour, or common seals (common). However, neither species are common world-wide, therefore national nature reserves, particularly Tentsmuir Point, are important breeding sites and we have a responsibility to protect the seals.
Atlantic grey seals are most easily told apart when in the water, by the shape of their head and position of their nostrils. The greys have a larger head with a straight Roman nose and sideways facing nostrils.
Some say they look as if they are wearing a top hat.
At Tentsmuir Point there is some seasonal fluctuation of grey seal numbers: peak numbers are about 2000.
They breed in summer and the pups must moult from white to a dark coat before they can swim, which happens several weeks after birth. Seal pups use the dune edge for shelter.
The common seals have a smaller, stepped profile to their face and forward facing nostrils - like a dog. Some say they look as if they would wear a flat cap.
Common seal
Common seals breed in autumn, and the single pups are able to swim and dive almost immediately. The seals are easily disturbed by dogs and people.
Seal hunting: Seals used to be hunted for their fur. Grey and common seals were both hunted in Shetland until recently. Seals are seen as a problem by fishermen, especially when their numbers start to increase.
At Tentsmuir for example, in the early 1990s around 800 seals were a common sight. A decade later, around 2000 seals may be seen on the sandbanks. They like to eat salmon, and individual seals have been known to cause problems at fishing stations - damaging nets and eating fish.
Seal culls: There is no doubt that seals eat a significant quantity of fish, and will eat whatever fish they catch - commercial and non-commercial. This makes them often unpopular with the fishing industry. They can be seen to compete with fishermen for the same prey species. The arguments for and against a cull of seals to improve fish stocks for the fishing industry are well-rehearsed.
However, the relationship between fish numbers and seal numbers is not fully understood. Rising numbers of seals are not necessarily responsible for declining fish stocks. The controls on fish stocks are complex and certainly as much to do with human exploitation and impacts such as pollution. Predation by mammals only has a marginal effect on total fish stocks.
Seabirds and porpoises together take more fish than seals. It does not follow that a cull of seals would increase the amount of fish available to fishermen.