Stickleback

The sticklebacks are a family of ray-finned fishes, the Gasterosteidae which have a Holarctic distribution in fresh, brackish and marine waters. They were thought to be related to the pipefish and seahorses but are now thought to be more closely related to the eelpouts and sculpins. The stickleback family, Gasterosteidae, was first proposed as a family by the French zoologist Charles Lucien Bonaparte in 1831. It was long thought that the sticklebacks and their relatives made up a suborder, the Gasterosteoidei, of the order Gasterostiformes with the sea horses and pipefishes making up the suborder Syngnathoidei. More recent phylogenetic work has shown that the Gaterosteoidei is more closely related to the Zoarcoidei and the Cottoidei, which means that this taxon would belong in the order Scorpaeniformes. but in other phylogenetic classifications it is treated as the infraorder Gasterosteales within the suborder Cottoidei or as a sister clade to the Zoarcales in the order Zoarciformes. FishBase recognises 16 species in the family, grouped in five genera. However, several of the species have a number of recognised subspecies, and the taxonomy of the family is thought to be in need of revision. The family Gasterosteidae includes the following genera: Apeltes DeKay, 1842 Culaea Whitley, 1950 Gasterosteus Linnaeus, 1758 Pungitius d'Annone, 1760 Spinachia Cuvier, 1816 Sticklebacks are endemic to the temperate zone and are most commonly found in the ocean, but some can be found in fresh water. The freshwater taxa were trapped in Europe, Asia, and North America after the Ice Age 10,000–20,000 years ago, and have evolved features different from those of the marine species. Sticklebacks are carnivorous, feeding on small animals such as insects, crustaceans and fish larvae. Sticklebacks are characterised by the presence of strong and clearly isolated spines in their dorsal fins. An unusual feature of sticklebacks is that they have no scales, although some species have bony armour plates.