Growth and Morphometry of Four British Columbia Populations of Pygmy Whitefish (Prosopium coulteri)

Abstract

A comparison is made of the growth, morphometry, age at maturity, food, and depth distribution of pygmy whitefish (Prosopium coulteri) in four British Columbia lakes. In Tacheeda and Cluculz Lakes where the species is of the usual dwarfed variety, the fish exists sympatrically with two other whitefishes, the mountain whitefish (Prosopium williamsoni) and the lake whitefish (Coregonus clupeaformis). These slow-growing pygmy whitefish differ markedly in morphometry and depth distribution from the "giant" pygmy whitefish of McLeese and Maclure Lakes which live in the absence of other whitefishes. The possibility that differences in the populations might be due to interspecific competition is discussed.

Egg Development Timing for Riverine Spawning Pygmy Whitefish (Prosopium coulterii)

“…comm. ), Flathead Lake in western Montana (Weisel et al 1973) and four lakes studied in British Columbia by McCart (1965). Exotic warmwater and trout species have been introduced into most of the Washington lakes containing pygmy whitefish.…”

“…Pygmy whitefish are most commonly found in large, deep, unproductive lakes. However, they have been collected from small, shallow, more productive lakes in British Columbia (McCart 1965), western Montana (Weisel et al 1973) and Washington (Mongillo and Hallock 1995). In shallow lakes, they appear to be more vulnerable to predation from exotic fish species.…”

Phylogenetic and ecological relationship between "giant" pygmy whitefish (Prosopium spp.) and pygmy whitefish ( Prosopium coulteri) in North-Central British Columbia.

“…The dark area indicates approximate area where pygmy whitefish have been captured. Pygmy whitefish have been captured in the following systems; Yukon River, MacKenzie River, Copper River, Alsek River, Liard River, Skeena River, Peace River, Fraser River, Columbia River, Saskatchewan River, Naknek River, Amguem River, and Lake Superior (Scott & Crossman 1973;Heard & Hartman 1965;Lindsey & Franzin;McCart 1965;and Chereshnev & Skopets 1992) 0 5 y were thought to have come from the refugium in the Columbia River basin (Lindsey & Franzin 1972). The Lake Superior population was thought to come from the upper Mississippi River refugium (Lindsey & Franzin 1972) …”

“…According to McCart (1965), pygmy whitefish and rocky mountain whitefish avoid habitat overlap by utilizing different depths. That is, the lower limit of depth distribution for rocky mountain whitefish is above the upper limit for pygmy whitefish (McCart 1965).…”

“…Females also tend to live longer than males (Weisel et al 1973;Heard & Hartman 1965;McCart 1965). The oldest pygmy whitefish reported was a nine year old female fi-om Tyhee Lake (McCart 1965).…”