An analysis of the taxonomic status of the Coregonus autumnalis species complex in North America, and An investigation of the life histories of whitefishes and ciscoes (Pisces; Coregoninae) in North America and Eurasia

• Main Author: Dillinger, Robert E.
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1989
• Subjects: Yukon; Mackenzie River; Beaufort Sea; Bering Land Bridge; Coregonus autumnalis; Mackenzie river; Yukon river
• Online Access: https://research.library.mun.ca/8592/; https://research.library.mun.ca/8592/1/Dillinger_RobertE.pdf

Aspects of the biology and taxonomy of the Coregonus autumnalis species complex were investigated in this study. The taxonomic and zoogeographic relationship of Coregonus autumnalis and C. laurettae was examined using morphometric, meristic, and distribution data. The morphometric data, a series of head and body measurements, was analyzed using a discriminant function analysis. The percentage of fish misclassified in the analysis was found to be higher than what would be expected for two distinct species, and was more indicative of subspecies, or stocks. The only meristic variable found to be significantly different was gill raker counts for the lower branch of the first gill arch. This character was originally used to separate the two species. An examination of the distribution of gill raker counts between the sample sites along the Beaufort Sea coast revealed a consistent percentage of the fish from the Mackenzie River with gill raker counts representative of the Yukon River species. This percentage was maintained in the hypothesized area of sympatry between the two species. It was concluded, from this analysis, that the original description was incorrect in the establishment of two reproductively isolated species with a single area of sympatry, based on gill raker counts. The actual situation is more likely that of two allopatric subspecies, with no area of sympatry. The distribution data were also analyzed to determine the support for the original zoogeographic hypothesis proposed to explain the separation of the two forms. It was concluded that the Bering Land Bridge was probably not responsible for this, as the present-day distribution of the two populations does not reflect ranges that could have been fragmented by the uplifting of the land bridge. An alternative hypothesis, which better fits the current distribution patterns of each form, involves known stream captures and headwater transfers between the Mackenzie and Yukon Rivers. Insufficient information is presently available to determine the ...