Abstract
The behaviour, social interactions and mating system of the gobiid fish Amblyeleotris japonica, that utilize the burrows dug by the snapping shrimp Alpheus bellulus as a sheltering and nesting site, were investigated at two localities on the southern coast of Japan.The fish spent most of their time in the area near the entrance of the burrow in daytime.Movements were limited to an area of about three metres in radius from the entrance.Aggressive encounters occurred between adjacent individuals sometimes resulting in changes of occupation of burrows.Males were more active in pair formation, whereas females were rather passive.Paris were usually maintained for several days or more, but some of them broke up without spawning.All the males that successfully spawned were larger ones that were socially dominant, and they remained within the burrow for four to seven days after spawning to care for a clutch of eggs.Variation in social interactions and burrow-use was recognized between two study populations and was attributed to the differences in predation pressure and density of burrows.
