ELEVATED SUMMER TEMPERATURE EFFECTS ON MEGALOPAL AND EARLY JUVENILE DEVELOPMENT IN THE DUNGENESS CRAB, CANCER-MAGISTER

Commercial fishery stocks of the Dungeness crab, Cancer magister, are absent in regions of the middle Georgia Strait, Canada, where suitable benthic habitat occurs and where a plentiful supply of post-larval me galopae is present in nearby waters. This has led to speculation that high summertime temperatures in the region may result in lack of settl ement or high juvenile mortality. The present study determined surviva l, time to metamorphosis, and growth of megalopae exposed to temperatu res of 14, 18, and 22 degrees C. Newly metamorphosed juveniles were su bjected to the same temperature treatments through the fourth crab ins tar. Although megalopal survival was not affected by temperature, juve nile crabs showed reduction in growth rate and high mortality in 22 de grees C. Results support the hypothesis that commercial crab fishery s tacks in the region are absent because of high mortality of newly sett led juveniles where summer water temperatures exceed 18 degrees C.