Hemolymph Ecdysone Concentration as a Function of Sexual Maturity in the Male Snow Crab (Chionoecetes opilio)

Abstract

Ecdysone concentrations in the hemolymph of juvenile and morphometrically mature male snow crab (Chionoecetes opilio) were determined by radioimmunoassay. A logarithmic transformation of the allometric relationship of the dry weight of the chelae versus the carapace width was used to identify morphometric maturity. Results indicate that concentrations of ecdysone found in the hemolymph of juvenile crab are higher than those found in morphometrically mature crab, thus providing a biochemical basis for the observation that the onset of sexual maturity seems to coincide with a terminal molt.

A novel morphometry-based method for assessing maturity in male Tanner crab, Chionoecetes bairdi

“…This consists of a terminal molt to a morphometrically mature state, characterized by a greater chela height (CH) to CW ratio (Somerton 1980;Conan and Comeau 1986;Keller et al 2016). Hemolymph molting hormone levels indicate that morphometrically mature males are effectively terminally molted, with limited or no potential for further molting (Cormier et al 1992;Tamone et al 2005Tamone et al , 2007. Following this terminal molt, males are hypothesized to possess a competitive mating advantage conferred by this increase in chela size, even against larger-bodied, small-clawed crabs (Sainte-Marie and Hazel 1992; Stevens et al 1993;Sainte-Marie et al 1997;Mayrand et al 1998).…”

Osmoregulation and salinity tolerance in zoeae and juveniles of the snow crabChionoecetes opilio

“…Female snow crab undergo a terminal molt to maturity between 47 and 95 mm cephalothoracic width (ctw) (Ito, 1963(Ito, , 1967Watson, 1969Watson, , 1970Somerton, 198 1). Males apparently also attain a terminal molt to morphometric maturity, within the range of 52-137 mm ctw (Conan and Comeau, 1986), although the existence of terminal molt in males is still controversial (Dawe et al, 1991;Cormier et al, 1992 ; Comeau and Conan, 1 992).…”