UBC Theses and Dissertations
A study of the taxonomy and some aspects of the ecology of marine ostracods in the plankton of Indian Arm, British Columbia McHardy, Robert Alexander
In 1960 a program was carried out to study some aspects of the distribution of planktonic ostracods in Indian Arm, an inlet of the coast of British Columbia. As a result, Paradoxostoma striungulum Smith, Phllomedes sp., Conchoecia elegans Sars, and C. pseudohamata n.sp. were collected, described and illustrated. Of these species, C. elegans and C, pseudohamata were abundant in the plankton, and provided material for the diagnoses of growth stages and for the comparison of the adult stages with those collected from other British Columbia inlets and from the Ocean Weather Station ”P” (50° N., 145° W.) The distributions of Conehoecia elegans and C. pseudohamata were studied in relation to temperature, salinity, oxygen, and light. The species were seldom found in water above the thermocline and halocline. The general distributions of Conehoecia elegans and C. pseudohamata may have been partly influenced by the mixing between water long resident in Indian Arm and water entering by way of the mouth of the Inlet. . Both species generally inhabited waters having temperatures from 7 to 9° C, and salinities from 26 to 27°/₀₀. Both occurred at depths greater than the shallow sill at the mouth; the one living more deeply seems to have been more restricted to the inlet than the other. Diurnal vertical migration differed for the two species except within the shallower part of the water column, where both seem to have descended in the presence of light. The time of maximal breeding seems to have been in the early summer for Conchoecia elegans and from early summer to early autumn for C. pseudohamata. Examination of stomach contents shows that both species were omnivorous.
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