Le crabe girafe Ranina ranina, aux Seychelles: biologie et exploitation

Commercial catches of the crabe girafe, Ranina ranina in the Seychelles are analyses. Male crabs are dominant in the catch (65\_310= male to 35\_310= female) Large individuals present in the catch (exceeding 115mm) are all males. The size at first maturity for female crabs is 89.5mm. One spawning season is observed annually, around December Von Bertalanffy growth estimates obtained from length frequency data using the Hasselblad method to separate the modes followed by modal progressions, are as follows: Males: L oo = 160mm, k = 0.24 per year: Females: L oo = 137mm, k = 0.12 per year. Alternative estimates are also given using the Von, Bertalanffy equation assuming seasonally oscillating growth. The total mortality which corresponds to the natural mortality is estimated as 0.8 for females and 1.0 for males. The crabe girafe fishery in Seychelles waters is described: catch rates seem to be seasonal averaging 0.5 kg/tangle net or 180 kg per fishing day. 18 tonnes of crab were captured from December 1986to March 1988. The relationship between catches and lunar variations is described