大海马昼夜活动节律与缠绕物偏好的观察

对大海马的昼夜活动规律及缠绕物偏好等行为进行了观察．大海马白天活动，晚上休息（Q≥3．59，P〈0．05）．成熟类群以游泳（S）或身体快速运动（Af）摄食，光弱时，游动少，仅头部运动（Ah）、身体缓慢摆动（As）或休息（R）；未成熟类群白天活动强烈，表现为2次摄食活动．大海马对细竹丝、聚乙烯绳、聚乙烯充气管等缠绕物类型偏好无差异（P〉0．05），与规格无关（P〉0．05）；较喜好垂直或倾斜的缠绕物，喜好程度相似（P〉0．05），而不喜水平放置缠绕物，也与规格无关（P〉0．05）；成熟个体喜欢在容器底部活动，未成熟个体以中上层活动为主（P〈0．01）．

Observation and Analysis of Daily Rhythm and Preferred Holdfast Behavior of the Seahorse, Hippocampus kuda

To improve culturing conditions and establish the protocols,daily rhythm behavior and holdfast preferences of the seahorse,Hippocampus kuda,are observed and analyzed.The results reveal that H.kuda are diurnally active,whereas during the night become immobile and spend more time attaching to the holdfast.In another group,the seahorse began to turn active with sunlight,and main action patterns include feeding (swimming behavior(S)for alive bait,fast action(Af)for frozen bait),greeting between mate spouses, swimming,etc.As the sunlight dims out,the swimming seahorses become inactive,and some individuals showed only head movement(Ah)and slow body movement(As).After sunset,almost all the seahorses take a rest(R)on holdfast or bottom.Generally,the subcategory of action appears similar between two groups. However,there were two instances of feeding behavior of immature seahorse during which experiment was in process,with the time duration being after sunrise(6:00-7:00)and before sunset(17:30-18:30).In terms of holdfast attachment materials,the seahorse prefers thin bamboo slices,polyethylene threads,and polyethylene aeration tubing.No behavioral difference was shown among the three types of materials,nor between the two groups.All the seahorses could rest on vertical or tilted holdfast attachment objects in any direction.The optimal water depth of the holdfast attachment depends on the size of the seahorses.The bigger ones prefer deeper area and smaller ones like shallower better.The above-mentioned behaviors of seahorses could be considered when designing strategies for rearing seahorses.