Rocky Mountain Sculpin (Cottus sp.): residence description

1 Introduction

The Species at Risk At (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 Rocky Mountain Sculpin, Eastslope populations. The information in these sections was adapted from the “Recovery Strategy for the Rocky Mountain Sculpin (Cottus sp.), Eastslope populations, in Canada ” (DFO 2012). The geographic distribution of the Rocky Mountain Sculpin, Eastslope populations, is described in the recovery strategy for this species (DFO 2012).

2 Structure, form and investment

Rocky Mountain Sculpin (Cottus sp.; Eastslope populations) are largely sedentary and relatively uniform in distribution in Alberta streams where they exist, so nests can likely occur at any location in a stream channel where appropriate structure exists. It is thought that much of the spawning that occurs in the St. Mary and Milk river watersheds occurs on the underside of rocks, boulders or debris since usable riparian and instream vegetation is largely absent due to the dynamic and erosive nature of the watersheds. There is likely more opportunity for sculpin spawning to occur on riparian or instream vegetation or woody debris in Lee Creek.

Male sculpin construct nests on the underside of rocks, aquatic vegetation, wood or debris in which a female(s) may deposit clusters of adhesive pale yellow to orange eggs. When a male constructs a nest it will remain at the nest for up to several weeks, beginning prior to egg deposition by a female, and continuing during incubation and early embryo life stages (Peden 2000; Bailey 1952). The male will actively fan the nest post egg deposition to keep the eggs free of silt and may protect the eggs and fry from predators. It is possible that the male stays at the nest until the yolk sac is reabsorbed.

3 Occupancy and life-cycle function

In southern Alberta, Rocky Mountain Sculpin generally spawn between May and June when water temperatures reach 7 to 13°C (Bailey 1952; Watkinson, unpublished data). The nests created and used by Rocky Mountain Sculpin for spawning demonstrate that there is significant investment in creating and maintaining the nest by sculpin. Thus, nests are considered to be the residence of this fish. The residence is limited to the nest itself and the spawning time period during which the male sculpin maintains the nest structure. This time frame also corresponds to the period of time when eggs, alevins or fry are present in the nest.

4 References