UBC Theses and Dissertations
The effect of structural complexity in eelgrass meadows on the predatory activity of the Dungeness crab Cancer magister Hollett, Lois Julia
The presence of natural and artificial eelgrass reduced predation by the Dungeness crab Cancer magister on three prey species: a bivalve, Macoma nasuta, a shrimp, Crangon franciscorum, and a fish, Gasterosteus aculeatus. Overall, when provided with a choice of the three prey species, crabs foraging in an eelgrass habitat consumed less total prey biomass than crabs preying in a bare habitat. The three species varied in their susceptibility to predation by Cancer magister and this variation generally reflected the microhabitat occupied by them. The epifaunal shrimp appeared to be most susceptible to predation, followed by the more motile fish and, finally, the infaunal clam.