Meeting Abstract

P3.91  Wednesday, Jan. 6  Relationship between gonadosomatic index and shell condition of male snow crab Chionoecetes opilio from the Bering Sea ZALESKI, M.A.F.*; TAMONE, S.L.; Univ. of Alaska Fairbanks, School of Fisheries and Ocean Sciences; Univ. of Alaska Southeast mfox30@alaska.edu

Research concerning the reproductive biology of snow crabs Chionoecetes opilio from the Bering Sea is predominantly focused on females, with little known about male physiology. While male crabs may reach reproductive maturity prior to the terminal molt, it is unclear whether reproduction is compromised by molting physiology. Male snow crabs can be distinguished in two groups by a change in chela allometry: terminally molted males are classified as “large-claw” (LC) whereas non-terminally molted males are classified as “small-claw” (SC). Shell condition is a relative measure that differentiates crabs having recently molted (new-shell) from those that have not molted for months to years (old-shell).Crustacean molting, mating, and behavior are regulated by hormones, among those ecdysteroids (molting), and methyl farnesoate (MF, reproduction). Literature supports a relationship of significantly higher MF in reproductively active male crabs; we propose that MF levels will be lower in post molt crabs. We sampled hemolymph from snow crabs to quantify ecdysteroids and MF. Circulating ecdysteroids differ between the two morphotypes; a SC male still has the potential to molt while a LC male stops molting. We measured gonadosomatic index (GSI) as a proxy for reproductive capacity. We measured male gonad weight versus total wet weight of 185 snow crabs. GSI was significantly lower in new-shell males compared to old-shell males (ANOVA, p<0.05). New-shell males are targeted for their visual commercial appeal over old-shell males. With lower GSI, recently molted crabs may be harvested before contributing reproductively and thus genetically to the population.