Stickleback

**Sticklebacks** are fish of the **Gasterosteidae** family. FishBase currently recognises sixteen species in the family, grouped in five genera. Several of the species have a number of recognised subspecies, and the taxonomy of the family is thought to be in need of revision. They have a Holarctic distribution in fresh, brackish and marine waters.

An unusual features of sticklebacks is that they have no scales, although some species have bony armour plates. They were thought to be related to pipefish and seahorses, but recent studies have shown that they're now related to the eelpouts and sculpins.

Stickleback species are found in fresh water environments in Europe, Asia and North America. They feed on small crustaceans and fish larvae.

Sticklebacks have strong separated spines in the dorsal fin. All species show similar mating behaviour, with co-operation between the sexes, and protection of the eggs. The males construct a nest from vegetation held together by secretions from their kidneys. The males then attract females to the nest. The females lay their eggs inside, where the males fertilise them. The males then guards the eggs until they hatch.

## Taxonomy

The Gasterosteidae, was first proposed as a family by the French zoologist Charles Lucien Bonaparte in 1831. It has long been considered that the sticklebacks and others made up a suborder, the Gasterosteoidei, in the order Gasterosteiformes. Recent phylogenetic work has shown that the Gasterosteoidei is closely related to the Zoarcoidei and the Cottoidei. The taxon is now in the order Scorpaeniformes.

### Genera

The family Gasterosteidae includes the following genera:

- _Apeltes_ <small>DeKay, 1842</small>
- _Culaea_ <small>Whitley, 1950</small>
- _Gasterosteus_ <small>Linnaeus, 1758</small>
- _Pungitius_ <small>d'Annone, 1760</small>
- _Spinachia_ <small>Cuvier, 1816</small>

### Sizes

Sticklebacks have many sizes. _Spinachia spinachia_, the sea stickleback, is the largest of the sticklebacks and can grows to a length of 22 centimetres (8.7 in). The maximum size of the three-spined stickleback (_Gasterosteus aculeatus_), is about 4 inches, but few of them are more than 3 inches long.

Their body form varies with habitat: sticklebacks in shallow lakes have developed a deep body specialized to enable eating benthic invertebrates, whilst those in deep oligotrophic lakes love to feed on plankton and have a more slimlined body.

### Personality

Studies have shown that sticklebacks display distinct personality traits, specifically in the area of taking a risk, and can be considered bold or shy. Those traits were determined to have direct influence if they would lead and, if discouraged, attempt to lead again.

## Mating

Sticklebacks show similar, unusual mating behaviour:

### Mating choice

The sex with the greatest parental investment has the strongest mate preferences. These small, spiky fishes exhibit mutual mate choice in which both the male and female have strong mate preferences. That is most probably partly because of the strong parental investment on behalf of the male in guarding the eggs.

### Inbreeding avoidance

Female threespine sticklebacks adjust their courting behaviour to the risk of inbreeding. They prefer to mate with the non-sibling and avoid the disadvantages that accompany incest.

## Other websites

- View the _gasAcu1_ genome assembly in the UCSC Genome Browser.