Nature table: STICKLEBACKS

(Gasterosteus aculeatus)

There are two species of stickleback found in fresh water in Ireland - the three-spined stickleback and the nine-spined sickleback. The three-spined is much commoner and the number of spines along the back is the best way of telling them apart because there is considerable variation in the colour and markings. However three-spined sticklebacks often have four spines and the nine-spined (which is sometimes called the ten-spined) can have anything between eight and twelve. They are very small fish and are the commonest quarry of the child with the pinkeen net. They can live in salt or brackish water as well as in ponds, marshes, ditches, rivers and lakes. Both species have unusual breeding habits. The male builds a nest into which he attracts a female. However, once she has deposited her eggs he drives her off and looks after his brood until they are able to fend for themselves. Three-spined sticklebacks normally build a nest on the bottom while the nine-spined males suspend it in under water vegetation.