Meeting Abstract

P1.63  Thursday, Jan. 3  Feeding during low salinity in the Dungeness crab, Cancer magister, is hormonally regulated CURTIS, D.L.*; MCGAW, I.J.; Univ. Nevada, Las Vegas and Bamfield Marine Sciences Centre; Univ. Nevada, Las Vegas and Bamfield Marine Sciences Centre curtisd4@unlv.nevada.edu

Despite being classed as a weak osmoregulator, adult Cancer magister often venture into estuaries, presumably to feed. Nevertheless acute low salinity exposure results in both a decrease in the likelihood of feeding and the amount of food consumed. We previously hypothesized that the reduced feeding activity may be the result of energetic limitation due to the concomitant demands associated with osmoregulation. However, there appeared to be no additional increase in metabolic rate when crabs digested during hyposaline exposure. Based on this data we hypothesized that feeding motivation and food consumption may be under hormonal control, rather than being energetically limited. Following eye stalk ablation (thereby removing the hormone producing sinus gland), the amount of food that crabs consumed in 50% SW was greater than that of intact crabs. Ablated crabs even attempted to feed in freshwater, whereas intact crabs would not feed in salinities below 40% SW. Eye stalk removal does not inhibit the crab�s ability to detect low salinity. This data then suggests that low salinity exposure may be a contributing factor in controlling the release of hormones that regulate the feeding response.