Two species of stickleback may be found in the streams and ponds of Britain: the Ten-Spined (Pungitius pungitius) and the more common Three-Spined (Gasterosteus aculeatus aculeatus). This column will focus on the Three-Spined (around 6cm in length) and the beauty of their spring colouring.
Each May, amorous male sticklebacks are busy cajoling females to lay their eggs, in specially built vegetation nests. These mound-shaped burrows are pressed carefully into place using their mouths, and stuck together using fluid from the male’s kidneys.
To attract the ladies, the males become brilliantly coloured during mating season, with bright red stomachs, and green backs. The three spines of the name can be located in front of the fish’s dorsal fin. These jewel-coloured fish are no fair-weather (fair-water?) fathers, and are attentive to their eggs and young, a behaviour unusual in most fish species. Eggs require plenty of oxygen to enable development, so the father fans waves of water over them with his tail. The eggs take between one week or a month to hatch, during which time the male will fiercely guard his nest against predators, chasing off anything with red colouring. Studies have shown that male sticklebacks will defend nests from cardboard fish painted red.
Sticklebacks are nocturnal hunters, and eat small creatures, such as worms, insect larvae, fish eggs and small fish. Aside from breeding season they can be found in loose shoals. To find these small fish in May, look in rock pools, streams and ponds for peacock-dazzling colours.
Find out how sticklebacks have helped scientists understand evolution.
All content ©2009 Lizzy Dening
site by sjward