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BC Conservation Data Centre: Species Summary


Culaea inconstans
Brook Stickleback

 
Scientific Name: Culaea inconstans (Kirtland, 1840)
English Name: Brook Stickleback
 
Classification / Taxonomy
Scientific Name - Concept Reference: Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.
Classification Level: Species
Species Group: Vertebrate Animal
Species Code: F-CUIN
Kingdom Phylum Class Order Family
Animalia Craniata Actinopterygii Perciformes Gasterosteidae
   
Conservation Status / Legal Designation
Global Status: G5 (Aug 2015)
Provincial Status: S5 (Jul 2025)
BC List: Yellow
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status:
SARA Schedule:
General Status Canada: 4 - Secure (2005)
   
Ecology & Life History
General Description:
Global Reproduction Comments: Spawns spring and summer (about mid-May to mid-July in Manitoba, Moodie 1986). Females may spawn every few days when food is abundant. Eggs hatch in 7-11 days. Male tends eggs and fry. Sexually mature by age I, age II and III also are included in the breeding population (Becker 1983, Lee et al. 1980, Moodie 1986).
Global Ecology Comments: Population size varied greatly among years in a Manitoba lake; summer kill and winter kill common; recolonization via intermittent runoff streams (Moodie 1986).
Migration Characteristics:
(Global / Provincial)		 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant: 		N /
N /
N /
na /
Global Migration Comments: Migrationlike movements have been observed, (Becker 1983), but the context of the movements is not definitely known.
Habitats:
(Type / Subtype / Dependence)
Global Habitat Comments: This species generally occupies cool, clear, heavily weeded, spring-fed creeks, small rivers, lakes, and ponds, usually in shallow, quiet to flowing pools and backwaters over sand or mud (Lee et al. 1980, Page and Burr 2011). Sometimes it burrows into soft bottoms. Occasionally this fish can be found in brackish water. In a lake in Manitoba, adults were most abundant at the outer margin of emergent vegetation (Moodie 1986). Eggs are deposited in a nest made of plant material by the male just above the bottom in shallow water.
Food Habits: Herbivore: Adult, Immature
Invertivore: Adult, Immature
Piscivore: Adult, Immature
Global Food Habits Comments: Eats various aquatic invertebrates (including eggs and larvae), eggs and larvae of fishes, and algae. In a Manitoba lake, was opportunistic but heavily dependent on arthropods (Moodie 1986).
Global Phenology:
Provincial Phenology:
(1st half of month/
2nd half of month)
Colonial Breeder: N
Length(cm)/width(cm)/Weight(g): 8/ /
Elevation (m) (min / max): Global: 
Provincial: 
   
 
Distribution
Endemic: N
Global Range Comment: The range includes most of the southern half of Canada (Atlantic and Arctic drainages from Nova Scotia to Northwest Territories) and the northern part of the eastern United States, extending south in the Great Lakes-Mississippi River basins to Colorado (Woodling 1985), Nebraska, Illinois, Ohio, Pennsylvania. A population in the Canadian River system in northeastern New Mexico was regarded as probably introduced (through bait bucket or incidental to stocking of exotic salmonids) by Sublette et al. (1990) and Gach (1996), though the apparent native status in eastern Colorado (Woodling 1985) suggests that the New Mexico population could be native. Brook sticklebacks have been introduced in various places south of the native range, such as in Alabama, Kentucky, Tennessee, northwestern Colorado, northeastern Utah (Modde and Haines 1996, Great Basin Nat. 56:281), and California. Present distribution was influenced by postglacial dispersal from separate refugia in the Mississippi and Ohio river basins (Gach 1996).
 
Authors / Contributors
Global Information Author: Hammerson, G.
Last Updated: Nov 15, 2011
Provincial Information Author:
Last Updated:
   
References and Related Literature
Becker, G. C. 1983. Fishes of Wisconsin. University of Wisconsin Press, Madison. 1,052 pp.
Coad, B. W. 1981. A bibliography of the sticklebacks. Syllogeus 35:1-142.
Gach, M. H. 1996. Geographic variation in mitochondrial DNA and biogeography of Culaea inconstans (Gasterosteidae). Copeia 1996(3):563-575.
Lee, D. S., C. R. Gilbert, C. H. Hocutt, R. E. Jenkins, D. E. McAllister, and J. R. Stauffer, Jr. 1980. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, North Carolina. i-x + 854 pp.
McLennan, D. A. 1993. Phylogenetic relationships in the Gasterostidae: an updated tree based on behavioral characters with a discussion of homoplasy. Copeia 1993:318-326.
Moodie, G. E. E. 1986. The population biology of Culaea inconstans, the brook stickleback in a small prairie lake. Canadian Journal of Zoology 64:1701-1717.
Nelson, J. S. 1969. Geographic variation in the brook stickleback, Culaea inconstans, and notes on nomenclature and distribution. Journal of the Fisheries Research Board of Canada 26(9):2431-2447.
Page, L. M., and B. M. Burr. 1991. A field guide to freshwater fishes: North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts. 432 pp.
Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.
Scott, W. B., and E. J. Crossman. 1973. Freshwater fishes of Canada. Fisheries Research Board of Canada, Bulletin 184. 966 pp.
Sublette, J. E., M. D Hatch, and M. Sublette. 1990. The fishes of New Mexico. University New Mexico Press, Albuquerque, New Mexico. 393 pp.
Winn, H. E. 1960. Biology of the brook stickleback, Eucalia inconstans. American Midland Naturalist 63(2):424-440.
Woodling, J. 1985. Colorado's little fish: a guide to the minnows and other lesser known fishes in the state of Colorado. Colorado Division of Wildlife, Denver. 77 pp.
Wootton, R. J. 1984. A functional biology of sticklebacks. University of California Press, Berkeley, California. 265 pp.
 

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 2011. Species Summary: Culaea inconstans. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 4, 2026).