Behavioural Ecology Study On Megalopae And First Juvenile Of Mud Crab, Scylla Serrata (Forsk(?)l)

From a behavioral ecological perspective and considering practical problems in rearing, this research uses experimental ecological methods to explore the habitat choice, foraging behavior and agonistic behavior (fighting and cannibalism) of megalopae and first juvenile of mud crab (Scylla serrata, Forsk?l 1775). The research results have enriched the arena of crustacean studies and provided new perspectives for solving practical problems in production rearing. The main results are as fellows:1. Habitat choice of S. serrata megalopae and juvenile1.1 Experiments on substrata, illuminance and shelter preference of megalopae and juvenile indicate that the preference of S. serrata megalopae and juvenile for mud or mud/sand substratum is much higher than sand substrata of three granular sizes (0.2～2mm,60～200μm,<60μm), possibly caused by the fact that the physical stability of mud or mud/sand is higher than that of sand in the current. The preferential illuminance of S. serrata megalopae is higher than juvenile. The ratio of megalopae selecting illuminance higher than 1,000 lux under conditions of brightness adaptation, darkness adaptation (movement), and darkness adaptation (rest) is 52.3%,54.4% and 47.5% respectively. The ratio of juvenile selecting illuminance lower than 500 lux is respectively 68.8%,52.1% and 58.6%, indicating that juvenile is more adaptable to low illuminance circumstances than megalopae.1.2 The settlement mode of S. serrata megalopae and juvenile is studied through observing the frequency of burrowing in or settling on the surface of substrata respectively. Burrowing preference and relative burrowing rate show that during the daytime, settlement mode of megalopae, especially the ratio of burrowing in substrata, is significantly higher than juvenile and also higher than itself during the nighttime; but it does not show significant difference between megalopae and juvenile during the...