Three-spined Stickleback

The stickleback is the most common fish in the fjord. It lives mainly in bottom vegetation in shallow water. It is an important food for many species. Common- and Arctic tern often have more sticklebacks by their nest than they can eat.


The stickleback is an important food for common- and Arctic tern, etc.

These are fish which the male tern uses in courtship. The cormorants in the fjord also eat large quantities of sticklebacks. Poul Hald Mortensen’s study of cormorant cast showed that almost 10% (by weight) of cormorants’ food in Roskilde Fjord consists of sticklebacks.

Unfortunately we have very little knowledge about sticklebacks and other small fish that are not eaten by humans. There are, for example no statistics on population trends which can shed light on their importance for the species that live on these fish. In recent years though there seems to have been a growing interest in this subject.