Biodiversity & Conservation

Three-spined stickleback - Gasterosteus aculeatus

Gasterosteus aculeatus

Image Steve Trewhella - The three-spined stickleback, Gasterosteus aculeatus. Image width ca 9 cm
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Distribution map

Gasterosteus aculeatus recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

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Gasterosteus aculeatus is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Chordata Sea squirts, fish, reptiles, birds and mammals
Class Actinopterygii Ray-finned fish, e.g. sturgeon, eels, fin fish, gobies, blennies, and seahorses
Authority Linnaeus, 1758
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Common in estuaries and coastal lagoons around Britain and Ireland, and in fully marine conditions from the northern Irish Sea and North Sea northwards.
Habitat information icon Habitat information Found in shallow waters amongst seaweeds, seagrasses and pondweeds in freshwater, estuaries, rock pools and saline lagoons or coastal waters.
Text page icon Description A small torpedo-shaped fish with a slender tail and broad fan-like tail fin, usually 5-7 cm long but occasionally up to 10 cm in length. Two to four, usually three, sharp spines are born on its back in front of the dorsal fin. The first two spines are long and strong while the third is small. The pelvic fin is reduced to a single fin-ray and one sharp spine. The dorsal fin is longer than the anal fin. The sides bear a few bony plates, the number of plates increasing with increasing salinity. The body is greeny brown in colour, sometimes black dorsally and often bluish with silvery scales and belly in brackish waters.
Identifying features
  • Row of three sharp spines along the back.
  • Pelvic fin reduced to a single spine and one fin-ray.
  • Boney plates along the sides of the body.
Additional information icon Additional information The three-spined stickleback breeds in early spring and summer. In the breeding season the males develop a bright orange to red colouration on the throat. The males build hollow nests from seaweeds and aquatic plants, into which they drive females to lay eggs that the males then guard until they hatch and the young leave the nest (see Wheeler, 1969; Dipper, 2001).

This review can be cited as follows:

Dr Harvey Tyler-Walters 2003. Gasterosteus aculeatus. Three-spined stickleback. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/05/2013]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3377>