Fish and animals of the sea
The western fjords were formed during the last ice age, about 10.000 years ago. They are often very deep, but with a shallow shelf at the mouth. Fresh water forms a lid on the fjord, while salt water from the ocean stays at the bottom. This reduces the circulation of the water, and reduces the amount of plankton in the Fjord. In spite of this all the kinds of fish that are common in the ocean outside of Norway exists in the Sognefjord.
Some years big schools of herring and mackerel appear in the Sognefjord. This attracts other kinds of fish, like pollack, coalfish and spiny dogfish. Packs of porpoise also come into the Sognefjord, and can be seen hunting the herring and mackarel near Balestrand.
Rarely the Sognefjord also gets a visit from killer whales.