Life-history and systematics of Arctic char, Salvelinus alpinus (Linnaeus) in the Babbage River system, Yukon Territory

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Three populations of Arctic char (Salvelinus alpinus [Linnaeus]) in the Babbage River system, Yukon Territory, had meristic characters that corresponded to those of the Western Arctic-Bering Sea form of the Arctic char. These populations consisted of: 1. Self-perpetuating non-anadromous Arctic char isolated in the spring-fed headwaters of the Babbage River; 2. non-anadromous Arctic char below a waterfall on the Babbage River which are derived from the isolated population; 3. a dimorphic population (anadromous males and females and mature non-anadromous males) utilizing Fish Hole Creek, a spring-fed tributary to the Babbage River . Three life-history patterns occur among these populations: anadromy , self- perpetuating non-anadromy, and non-anadromy in which only mature males are present. The non-anadromous Arctic char are characterized by small size (maximum 395 mm), low growth rates and low fecundities (maximum 653 eggs). Mature fish were darkly pigmented and parr marks and spawning colouration were retained throughout life . The spawning season appears to be in the fall (mid-September to mid- October) with the possibility of earlier spawning (August) occurring in the spring channels in the upper Babbage River. The non-anadromous populations (including the mature nonnnadromous males in Fish Hole Creek) demonstrate inherent differences in growth rates, age at maturity, longevity, peak spawning activity and meristic characters. There are substantial differences between the anadromous and nonanadromous populations in growth rate, age at maturity, fecundity and food habits. The former are characterized by large size (maximum 629 mm), relatively fast growth rate, high fecundity (maximum 5151 eggs) and repeat spawning after maturity. Post-spawning mortality is not indicated and spawning colouration is seasonal. The spawning season appeared to be sometime between mid- September and late October, when the eggs of mature females averaged 4.4 mm in diameter. Some meristic characters (first arch gillraker and vertebral counts) varied significantly between the anadromous ATctic char and the self-perpetuating non-anadromous Arctic char in the upper and lower Babbage River. The available meristic and life-history data suggest that the non-anadromous Arctic char populations do not differ appreciably from other populations of Western Arctic char and do not warrant classification as a distinct species.
Bibliography: p. 138-154.
Bain, L. H. (1975). Life-history and systematics of Arctic char, Salvelinus alpinus (Linnaeus) in the Babbage River system, Yukon Territory (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from doi:10.11575/PRISM/18426