Diel and seasonal variation in fish communities in the Zhongjieshan marine island reef reserve

Abstract

Marine reserves are essential for the conservation of fishery resources. However, marine island reef as a natural reserve is poorly developed, mainly because the ecological patterns of fishes in such areas remain little known. Here, we attempt to uncover the diel and seasonal patterns of fish assemblage in the Zhongjieshan Archipelago, which is a typical marine island reef biotope, located at the junction of the Yangtze and Qiantang rivers in the East China Sea. Fish communities in this area are mainly composed of continental shelf demersal fishes, continental shelf benthopelagic fishes, and continental shelf pelagic-neritic fishes. Among them, continental shelf demersal fishes tend to occur in the daytime or during autumn, continental shelf benthopelagic fishes at night or during summer, and continental shelf pelagic-neritic fishes in the daytime or during spring. Seasonal migratory fishes are mainly observed during spring and summer. Moreover, alternate and migration indices showed the lowest stability of the community in the daytime and during winter, revealing that fishes prefer to occur around the island reef at night or in the day-night time. Such patterns are mainly affected by the seasonal shift, predominant communities, and diel alternation. These findings will greatly help develop the sustainable fishing strategy and construct the marine island reef reserve for the conservation of fishery resources.