海南典型热带海草床4种代表性鱼类的生长特征及其对海草资源量变化的响应

Growth characteristics of four representative fishes and their responses to seagrass resource changes in typical tropical seagrass beds of Hainan Island

文章以海南岛新村湾、黎安港和潭门港海草床为研究区域,选取褐篮子鱼(Siganus fuscessens)、点斑篮子鱼(Siganus guttatus)、四带牙鯻(Pelates quadrilineatus)和细鳞鯻(Terapon jarbua)4种代表性鱼类为研究对象,分析其体长与体质量的关系,并探讨4种鱼类对海草资源量变化的响应。结果表明,除栖息于潭门港海草床的4种鱼为负异速生长,其他区域海草床的鱼类均为正异速或等速生长;4种鱼的体质量生长速率(即异速生长因子b)和肥满度呈现黎安港>新村湾>潭门港的趋势,并与3个海草床的海草覆盖率、密度和生物量的变化趋势一致;推测海草资源量下降可能增加鱼类的被捕食压力和减少食物来源,从而导致生活于海草床的代表性鱼类生长速率下降。

The functions of seagrass beds to provide food and shelter in response to changes in seagrass coverage are still unclear.Xincun Bay,Li’an Port and Tanmen Port seagrass beds of Hainan Island were chosen as our research areas;and Siganus fuscessens,Siganus guttatus,Pelates quadrilineatus,and Terapon jarbua were selected for our research.The relationships between body length and body mass of these four representative fishes,and their responses to seagrass resource changes were addressed.The results showed that the four species inhabiting the Tanmen seagrass bed had negative allometric growth,and the ones in other seagrass beds had positive allometric or constant growth.The body mass growth rate(allometric growth factor b)and the fatness of these four fishes showed the trend of Li’an Port>Xincun Bay>Tanmen Port,which was consistent with the trend of seagrass coverage,density and biomass of the three seagrass beds.We speculate that the decreasing resources of seagrass increase the predation pressure of fish and reduce their food sources,and might consequently decrease growth rates of these representative fishes.Therefore,the protection of seagrass beds needs to be strengthened to promote the restoration of coastal fishery resources.