Coastrange Sculpin (Cottus aleuticus): residence description

1 Introduction

SARA states that

“No person shall damage or destroy the residence of one or more individuals of a wildlife species that is listed as an endangered species or a threatened species, or that is listed as an extirpated species if a recovery strategy has recommended the reintroduction of the species into the wild in Canada.” [section 33]

Also, SARA defines “residence” as:

“a dwelling-place, such as a den, nest or other similar area or place, that is occupied or habitually occupied by one or more individuals during all or part of their life cycles, including breeding, rearing, staging, wintering, feeding or hibernating.” [subsection 2(1)]

Sections 2 and 3 below provide a description of a residence for Coastrange Sculpin^{Footnote 1}. The information in these sections was adapted from the “Action Plan for the Cultus Pygmy Sculpin (Cottus aleuticus, Cultus Population) in Canada” (DFO 2017). The geographic distribution of the Coastrange Sculpin, Cultus population, is described in the action plan for this species (DFO 2017).

2 Structure, form and investment

It is generally assumed that female Coastrange Sculpin (Cottus aleuticus) lay egg masses under stones that are then guarded by males (National Recovery Team for Cultus Pygmy Sculpin 2007). This is supported by McPhail (2007), which states that C. aleuticus spawning behaviour has been observed in a laboratory, and is similar to that described for the Mottled Sculpin (C. bairdii). Savage (1963) summarized reported observations from the wild, where C. bairdii spawning occurred under rocks and in various other crevices with the eggs deposited on the roof of the nest to which they adhered. The females left the nest soon after spawning; the male remained with the eggs and were said to guard them until they had hatched and had left the nest (Savage 1963). In addition to guarding the nest, Goto (1982) also included fanning of the eggs by the males as a common reproductive behaviour of Cottids, with the fanning becoming more frequent as the eggs developed. The purpose of this fanning isn’t described, though it likely enhances oxygenation of the eggs, flushes away metabolic waste, and maintains the eggs free of any material that might inhibit water flow around the eggs.

3 Occupancy and life-cycle function

Based on frequency of observations of gravid (carrying eggs) females, Ricker (1960) suggests that most Coastrange Sculpin begin to breed in their third year, with spawning beginning in late May or early June, peaking in late June through July, and tapering until early September. Spawning behaviour and habitats are not known (Ricker 1960). It is difficult to determine these as the Coastrange Sculpin reside in the deep parts of Cultus Lake.

A nest of Coastrange Sculpin is considered a residence given Coastrange Sculpin spawning behaviour is similar to C. bairdii and Cottids generally where: there is a discrete dwelling place that has structural form and function similar to a den or nest; there is an investment in the modification of the dwelling place via removing material that might inhibit flow around the eggs; the dwelling place has the functional capacity to support successful spawning and hatching; and the dwelling-place is occupied during the life-stages of adult, egg and juvenile hatch. The nest is considered a residence during the time that it is occupied by the male through the spawning period, while the eggs are incubating and while the hatched juveniles occupy the nest.

4 References