UBC Theses and Dissertations
The chaetognaths of western Canadian coastal waters Lea, Helen Elizabeth
A study of the chaetognath population in the waters of western Canada was undertaken to discover what species were present and to determine their distribution. The plankton samples examined were collected by the Institute of Oceanography of the University of British Columbia in the summers of 1953 and 1954 from eleven representative areas along the entire coastline of western Canada. It was hoped that the distribution study would correlate with fundamental oceanographic data, and that the presence or absence of a given species of chaetognath might prove to be an indicator of oceanographic conditions. Four species of chaetognaths, representing two genera, were found to be present. One species, Sagitta elegans, was the most abundant and widely distributed species, occurring at least in small numbers in all the areas sampled. It was characteristic of the mixed coastal waters over the continental shelf and of the inland waters. Enkrohnia hamate, an oceanic form, occurred in most regions in small numbers as an immigrant, and was abundant toward the edge of the continental shelf. Sagitta lyra, strictly a deep sea species, was found only in the open waters along the outer coasts, and a few specimens of Sagitta decipiens, another oceanic form, were also taken in deep hauls from areas exposed to open ocean influence. It was found that the outer limit of Sagitta elegans corresponded with the inner limits of all three oceanic forms, though Eukrohnia hamata invaded the inland waters to some extent.
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