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Aspects of the life history of Lycodopsis pacifica (Collett) 1879

University of British Columbia

Aspects of the life history of Lycodopsis pacifica (Collett) 1879 were studied during the period September 1965 to November 1966. Two areas in the Strait of Georgia, British Columbia, were investigated. Trawls were used as sampling devices. Sexually mature individuals were collected during the period September to January. Lycodopsis pacifica has a remarkably small complement of mature eggs (average complement 30.4), The mature eggs are large, with an average diameter of 5.0 mm. Sexual dimorphism is present. Males start to grow faster than females at approximately 170 mm in length. The older males are' larger than females. There is some evidence that parental care is involved in the reproductive behaviour of the species. Age was estimated by counting the annular rings on otoliths. Both males and females ranged up to five years of age. The age-length relationship for both sexes is presented. The length-weight relationship of the species is described. The food spectrum of Lycodopsis pacifica was determined. At outer Burrard Inlet, the species feeds primarily on infaunal invertebrates of the Phyla Mollusca and Annelida, and the Sub-phylum Crustacea, The place of L. pacifica in the bottom community is considered. The anatomy of structures associated with feeding are described. Visual and "chemical" senses are probably important in food-getting behaviour. The feeding adaptations and food of the species is discussed in relation to sediment type. L. pacifica is probably not specialized to remove infaunal food items from one type of sediment. It was assumed that Lycodopsis pacifica would aggregate where high concentrations of infaunal organisms suitable as food would be found. At outer Burrard Inlet, high numbers were caught on several sediment types, ranging from silt-sand to silt. At the Cape Lazo area, catches of L, pacifica were highest on a silt sediment. The species is likely capable of foraging on a range of sediment types. Some factors affecting the infauna are discussed, and the usefullness of simple mechanical analysis of sediments in benthic ecology is questioned.

Text

2011-08-06

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http://hdl.handle.net/2429/36540

Zoology

University of British Columbia

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