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Recovery Strategy for Cultus Pygmy Sculpin

Executive Summary

The Cultus pygmy sculpin was first identified in 1934 and most of what is known about it comes from a single paper, published by Ricker in 1960.  It was described as a dwarf form of the coastrange sculpin, Cottus aleuticus.  The Cultus pygmy sculpin shares many physical features of the coastrange sculpin and of sculpins in general, but there are also important differences in morphology and ecology, most importantly small body size, retention of larval features, and a limnetic existence.  Observed diets of plankton corroborate the findings of limnetic life history, but other details of habitat use are not known.

There are large data gaps for this species including basic biology (e.g., life history, habitat use, reproduction), trends in abundance, and taxonomic status.  The most significant data gap for Cultus pygmy sculpin is its taxonomic status, since its legal status under SARA is dependent on its status as a designatable unit.  The species’ status will be reviewed by COSEWIC in 2008.

A variety of factors potentially threaten Cultus pygmy sculpin, but most are poorly understood.  The primary threats are introduction of exotic fish species and impacts associated with urbanization of the watershed.  Current and historic data are lacking for quantity and quality of Cultus pygmy sculpin habitat, so specific trends in habitat availability are unknown.  Comparisons of limnological information from 2001 with that collected in the 1930s and 1960s suggest that Cultus Lake limnetic habitat has changed little over the past 65 years, despite a considerable increase in public use of the lake and adjacent lands.

This recovery strategy focuses on the goal of ensuring the long-term viability of Cultus pygmy sculpin, and offers a variety of approaches to attain this goal.  The priority actions are to clarify taxonomic status, collect information on life-history and habitat associations, fill other data gaps that inhibit conservation of the species, delineate critical habitat in the wild, and reduce habitat impacts.  Activities aimed at protecting and enhancing habitats of other species of fish and wildlife (notably the endangered sockeye population in Cultus Lake) may benefit Cultus pygmy sculpin, although numeric enhancement of sockeye may negatively affect sculpins if the two species compete for plankton resources.