ABSTRACT

Coastal habitats are recognised for their role as nurseries for fish. However, there are conflicting results on whether fish are using mangrove habitats primarily for shelter or feeding grounds, making it challenging to generalise their ecological value for fish. The objective of this study was to investigate whether fish communities use mangroves in temperate climates as feeding grounds. Fyke nets were set during an outgoing tide to assess the fish communities found within mangrove creeks at high tide in the Austral spring and summer. Gut content analyses were conducted to assess diet, and samples were collected for prey availability (i.e. plankton, macroinvertebrates, and meiofauna). The mangrove creeks were used by small-bodied fish, including adults of small species or juveniles of larger species, which occurred in greater abundances in spring than summer. Feeding intensity (GFI) of fish was low, reflecting the low abundances of potential prey found in the mangrove creeks. This suggests that small-bodied fish may not use the mangrove creeks as potential feeding grounds. There is a possibility of fish using mangrove habitats at high tide for shelter while they rely on adjacent habitats (e.g. seagrass meadows) to feed, highlighting the relevance of habitat heterogeneity of tidal wetlands for ecosystem services.

摘要

沿海栖息地因其作为鱼类苗圃的作用而得到认可。然而，关于鱼类是否主要将红树林栖息地用作庇护所或觅食地，存在相互矛盾的结果，这使得概括它们对鱼类的生态价值具有挑战性。本研究的目的是调查鱼类群落是否使用温带气候中的红树林作为觅食地。Fyke 网是在退潮期间设置的，以评估在南方春季和夏季涨潮时在红树林小溪中发现的鱼类群落。进行肠道含量分析以评估饮食，并收集样本以了解猎物的可用性（即浮游生物、大型无脊椎动物和小型动物）。红树林小溪被小型鱼类使用，包括小型物种的成鱼或大型物种的幼鱼，春季发生的数量多于夏季。鱼的摄食强度 (GFI) 较低，反映出在红树林小溪中发现的潜在猎物丰度较低。这表明体型较小的鱼可能不会将红树林小溪作为潜在的觅食地。鱼类有可能在涨潮时利用红树林栖息地作为庇护所，同时依靠邻近的栖息地（例如海草草地）觅食，这凸显了潮汐湿地栖息地异质性与生态系统服务的相关性。