The role of cephalopods in the Canadian Arctic – an examination of their distribution, biogeography and trophic interactions within the Canadian eastern Arctic
This thesis establishes baseline information on the distribution, biogeographical variability, habitat preference and trophic interactions for the most common Canadian Arctic cephalopod species: Gonatus fabricii, Rossia moelleri, R. palpebrosa, Bathypolypus species complex and Cirroteuthis muelleri. Records of Arctic cephalopods and their predators were compiled and areas of interest within the Canadian Arctic were identified. Morphometric analyses of G. fabricii and R. palpebrosa identified potential populations and described the key morphometric characters associated with each population. G. fabricii separated into four groupings: Hudson Strait, Ungava Bay, Baffin Bay/Greenland and Disko Bay, while St. Lawrence R. palpebrosa were distinguishable from Arctic samples. Principal component analysis (PCA) was the preferable multivariate method for population analyses. Stable isotope analyses of δ13C identified cephalopod habitat preferences and potential ontogenetic habitat shifts while stomach content analyses, δ15N values and mixing models provided trophic information, including the first descriptions of R. palpebrosa and C. muelleri prey items.