Community Structure And Species Diversity Of Fishes In Zhongjieshan Islands Reef Waters

In this paper, we studied the fish species composition, quantitative distribution, ecological type,community structure, seasons changing, community diversity, community stability and the CPUE of Drift-net and Long-lining fishing of Zhongjieshan Islands reef waters area according to the Drift-net and Long-lining fishing data from November 2013 to October 2014.We captured 49 species of fishes in total, affiliated with 9 orders 28 families 42 genera, of which 25 species are the warm-water species and 24 are the warm-temperate species, the type of cold-water species being absent. there were 48 species of fish belonging to 9 orders 28 families 42 genera captured by Drift-net and 43 species of fish belonging to 9 orders 25 families 37 genera captured by Long-lining between them. Fish species number summer(36 species)≥autumn(36 species) >spring(29 species)>winter(25 species),only 5 species of fishes arised in all seasons, accounting for 10.20% of the total, and species number was on the rise from spring to summer, on the decline from summer to winter. The Index of Relative importance(IRI)showed that 11 species was dominant species in Drift-net fishing, of which 2 species are the ground fishes, 5 species are the near-ground fishes and 4 species are the Pelagic fishes, and only 6 species was dominant species in Long-lining fishing, of which both are the ground fishes and the near-ground fishes, the Pelagic fishes being absent, but Conger Myriaster and Muraenesox cinereus were more likely to be captured by the latter. Ecology type analysis showed that sedentary species for anniversary dependence, migratory fish reef waters for seasonal use of reef waters and occasional types of temporary stay together showed the ecological function of reef waters area.In Drift-net fishing, NMDS analysis showed that the two-dimensional scale sequence diagram had a certain meaning interpretation in Summer, a good sort in Spring, and they had the very good representative in Autumn and Winter. CLUSTER analysis showed that in the higher similarity level(63.48%, 81.31%, 77.07% and 62.52% in Spring, Summer, Autumn and Winter), Spring, Autumn and Winter three seasons could be divided into three different communities, Summer could be divided into two different communities; In Long-lining fishing, NMDS analysis showed that the two-dimensional scale sequence diagram had the very good representative in all seasons. CLUSTER analysis showed that in the higher similarity level(54.53%, 67.81%, 70.62% and 61.12% in Spring, Summer, Autumn and Winter), Spring, Summer and Winter three seasons could be divided into three different communities, Autumn could be divided into two different communities; SIMPER analysis showed that the community characteristic species and the community discriminating species in each season had larger similarity; the ANOSIM analysis results showed that there was no significant difference except community ACE between community BFGD in Summer in Drift-net fishing.Fish community stability studies focus on migration, resistance and interference three aspects. From migration, the alternate index winter > spring > summer > autumn, migration index winter > summer > spring > autumn, and migration index of autumn was equal to zero and suggests that fish communities tend to dynamic balance in this season. Resistance is usually use community diversity to evaluate. Community diversity analysis showed that: the mean value of Margalef richness index was lowest in February and increased with temperature warming from March to July, it was biggest in July and then declining from August. Monthly mean maximum of Shannon-Wiener diversity(H ’) index were in July and August, were about 2.80. And it was biggest in August, lowest in November. These two kinds of diversity index increased with temperature warming, go down with temperature declining. The evenness index had a fluctuant downward changes from December 2013 to May 2014, it was biggest in Judy and then declining. ABC curves showed that the W value were positive except February, but the W value were not large in each month, the fish community suffered secondary interference in some month. The W value is minus in February, and biomass advantage curve almost all under quantity advantage of curve.In this paper, the annual average catch rate and CPUE were 44.03 ind·(km)-1、13.43kg?(km)-1 in drift-net fishing,and 4.91 ind?(100 hooks)-1、1.67 kg?(100 hooks)-1 in long-lining.