M. Moriyasu et M. Comeau, GRASPING BEHAVIOR OF MALE SNOW CRAB CHIONOECETES-OPILIO (FABRICIUS,O., 1788) (DECAPODA, MAJIDAE), Crustaceana, 69, 1996, pp. 211-222
The grasping behavior of snow crab, Chionoecetes opilio, was observed
in 43 males when only male crabs were collectively held in an aquarium
. A larger male always grasped a smaller sized male which exhibited su
bmissive behavior similar to a mature female in a mating pair. This gr
asping behavior was observed in terminal molt larger sized males excep
t for one case observed for one intermolt juvenile male. During the ma
ting season, although a wide size range of morphometrically mature mal
es was present (51.0-131.0 mm in carapace width) in the wild populatio
n, mainly larger sized morphometrically mature males (72.1-128.4 mm in
carapace width) participated in the mating courtship. A small number
of solitary males was observed on the mating ground and their sizes we
re comparable to the males in mating pairs. Among the males in mating
pairs, the larger sized males tend to occupy favorable mating grounds
at greater depths, while the smaller sized males are found on less fav
orable grounds. The grasping behavior observed in the aquarium and in
the wild suggests that the male-male grasping behavior appears to be r
elated to the establishment of hierarchy among the mating males. Small
er sized morphometrically mature males appear to be eliminated before
the mating pairs are formed and appear on the mating ground. On the ma
ting ground, the second phase of competition among males occurs for fa
vorable mating grounds.