For a species to be successful, it must reproduce. Raising offspring is fraught with danger with many other animals finding fish eggs an easy and nutritious snack. Many fish species rely on safety in numbers, for both themselves and their eggs. By producing thousands of eggs at a time, the likelihood of a few hatching and surviving to adulthood is increased. However, eggs are costly to produce, so it pays to devise strategies to look after only a few eggs. Whilst some species, such as many of the African rift valley cichlids, go to lengths to create a depression in the substrate as a rudimentary nest and exhibit egg guarding, one fish takes nest building to the next level. The humble stickleback, in an almost bird-like fashion, constructs a physical structure using bits of debris, stones and algae in which to perform the spawning act and to shelter the developing eggs. Whilst the eggs mature, the male fish remains vigilant and ready to chase off any potential egg thieves to ensure the survival of his precious offspring.
Image credit: © Dwight Kuhn
Tagged in: Aquatic Adaptations