Laegdsgaard P, Johnson C
Department of Zoology, University of Queensland, QLD 4072, St. Lucia, Australia
J Exp Mar Biol Ecol. 2001 Mar 15;257(2):229-253. doi: 10.1016/s0022-0981(00)00331-2.
Three hypotheses to discern the strong positive association between juvenile fish and mangrove habitat were tested with field and laboratory experiments. Artificial mangrove structure in the field attracted slightly more juvenile fish than areas without structure. Artificial structure left to accumulate fouling algae attracted four-times the total number of juvenile fish than areas without structure or areas with clean structure. Community composition of fish attracted to structure with fouling algae was different when compared with areas with no structure or clean structure; five species were attracted by structure with fouling algae whilst two species were associated with structure regardless of fouling algae. Algae were linked to increased food availability and it is suggested that this is an important selection criteria for some species. Other species were apparently attracted to structure for different reasons, and provision of shelter appears to be important. Predation pressure influenced habitat choice in small juvenile fish in laboratory experiments. In the absence of predators, small juveniles of four out of five species avoided shelter but when predators were introduced all species actively sought shelter. Large fish were apparently less vulnerable to predators and did not seek shelter when predators were added to their tank. Feeding rate was increased in the mangrove habitat for small and medium-sized fish compared with seagrass beds and mudflats indicating increased food availability or foraging efficiency within this habitat. Larger fish fed more effectively on the mudflats with an increased feeding rate in this habitat compared with adjacent habitats. The most important aspect of the mangrove habitat for small juvenile fish is the complex structure that provides maximum food availability and minimises the incidence of predation. As fish grow a shift in habitat from mangroves to mudflat is a response to changes in diet, foraging efficiency and vulnerability to predators.
通过野外和实验室实验，对辨别幼鱼与红树林栖息地之间强烈正相关关系的三种假说进行了检验。野外的人工红树林结构比没有结构的区域吸引的幼鱼略多。留有污损藻类积累的人工结构吸引的幼鱼总数是没有结构或结构清洁区域的四倍。与没有结构或结构清洁的区域相比，被有污损藻类的结构吸引的鱼类群落组成有所不同；有污损藻类的结构吸引了5种鱼类，而有两种鱼类与有无污损藻类的结构都有关联。藻类与食物供应增加有关，有人认为这是某些物种的重要选择标准。其他物种显然因不同原因被结构所吸引，提供庇护所似乎很重要。在实验室实验中，捕食压力影响了小型幼鱼的栖息地选择。在没有捕食者的情况下，五种鱼类中有四种的小型幼鱼避开庇护所，但引入捕食者后，所有物种都积极寻找庇护所。大型鱼类显然对捕食者的抵抗力较弱，当在其水箱中添加捕食者时，它们不会寻找庇护所。与海草草床和泥滩相比，红树林栖息地中小型鱼类的摄食率有所提高，这表明该栖息地内食物供应增加或觅食效率提高。与相邻栖息地相比，较大的鱼类在泥滩上觅食效率更高，该栖息地的摄食率有所增加。红树林栖息地对小型幼鱼最重要的方面是其复杂的结构，这种结构提供了最大的食物供应量，并将被捕食的几率降至最低。随着鱼类的生长，栖息地从红树林向泥滩的转变是对饮食、觅食效率和被捕食易感性变化的一种反应。
