- Scientific name: Spinachia spinachia
- Also know as: Fifteen-spined stickleback
- Size: Up to 20cm but typically 8 – 12cm
- UK minimum size: N/a
- UK shore caught record: 10 grams
- IUCN Status: LC (Least Concern)
- Distribution: All around UK and Ireland with range extending throughout European waters.
- Feeds on: Small invertebrates and marine worms.
- Description: Small fish with elongated scaleless body. Small square dorsal and anal fins are set quite far back on the body. The upper body usually bluish to grey in colour with a paler underside, which is sometimes yellowish in colour in males. The tail section is thin running towards the small tail fin. Usually fourteen to eighteen spines along the back, with the average number being fifteen – hence the alternative name fifteen spined stickleback.
The sea stickleback is a small fish species which is common all around the coasts of Britain and Ireland. They are a small, streamlined fish which is usually brown to dark green in colour with around fifteen small spines on their back. Sea sticklenbacks are generally found in shallow coastal waters in rock pools, weed beds, estuaries and other sheltered areas. This species feeds on any dead animal matter, small invertebrates or marine worms which it finds, although it may also prey on fish fry.
Sea stickleback can reproduce after around one year of life and will build a nest in a shallow area where the female will lay her eggs. After this she will soon die but the male will stay and, despite his small size, will attempt to defend the eggs from any predators which try to feed on them. A true mini-species the sea stickleback has one of the smallest shore caught records with the current record standing at just over a third of an ounce (5.6 drams, 10 grams) which was caught at Newton Shore, Ayr, Scotland in 1997 by V. Hendrie in 1997. It is therefore only caught by anglers who are specifically targeting tiny species such as this. Unsurprisingly the very small size of this species means that it has no commercial value. The sea stickleback is classed as a species of Least Concern with a stable population by the International Union for the Conservation of Nature (IUCN). This species is thought to be abundant along the coastlines of the UK and Ireland.