Preliminary Study On Community Structure Of Fishery Resources In North Yellow Sea And Coastal Waters Of Southern Shandong Peninsular

Based on the bottom trawl surveys in the coastal waters of southern Shandong Peninsular and North Yellow Sea during summer and winter in 2006, spring and autumn in 2007, the community structure of fishery resources, seasonal variations of biodiversity and dominant species are analyzed preliminarily. Combined with geography and hydrography characteristics in investigation areas, relative connections with fishery resources are analyzed. Based on the survey data, the species richness R, Shannon-Weiner diversity index H'and evenness index J'are calculated respectively. Cluster analysis, analysis of similarity (ANOSIM) and similarity of percentage (SIMPER) show that fishery resources in this area are decreased compared with original data. The results show that the catches in the study area consist of juveniles of the commercial fishes, small low-value fishes, and commercial invertebrates. The fish sizes are generally small. The research provides a scientific basis on protection of fishery biology diversities and resources restoration in the coastal waters of southern Shandong Peninsular and North Yellow Sea.(1) Survey results indicate that there are 72 species found by all investigations in the coastal waters of southern Shandong Peninsular, including 47 fish species,19 crustacean species and 6 cephalopod species.(2) The mean catch rates are 18.1 kg/h,6.9 kg/h,1.3 kg/h and 10.3 kg/h in summer, winter, spring and autumn in the coastal waters of southern Shandong Peninsular. The seasonal variations of biomass in weight follow the order of summer > winter> autumn> spring.(3) The dominant species are Thryssa kammalensis, Saurida elongate, Rachypenaeus curvirostris and some invertebrates including Oratosquilla oratoria, Loligo edulis and Rachypenaeus curvirostris etc. in the coastal waters of southern Shandong Peninsular. Based on the taxonomic range of fish species in the coastal waters of Shandong Peninsular, most species belong to the orders Perciformes, Scorpaeniformes, Clupeiformes and Pleuronectiformes, and few species belong to the orders Aulopiformes, Anguilliformes, Tetraodontiformes, Lophiiformes and Syngnathiformes.(4) Survey results indicate that there are 88 species found by investigations in North Yellow Sea, including 20 crustacean species,59 fish species and 9 cephalopod species in four seasons. Because of the differences of bottom trawls and survey stations in summer and winter in 2006, in Chapter 4 of this paper, the community structure of fishery resources, seasonal variations of biodiversity and dominant species are analyzed only between spring and autumn in 2007. Based on the survey results of spring and autumn, there are 75 species found by investigations, including 17 crustacean species,50 fish species and 8 cephalopod species in North Yellow Sea.(5) The mean catch rates are 6.4 kg/h in spring and 25.8 kg/h in autumn in North Yellow Sea. The mean catch rate of fish in spring is 4.6 kg/h, crustacean is 1.3 kg/h and cephalopod is 0.5 kg/h. The mean catch rate of fish in autumn is 24.2 kg/h, crustacean is 0.8 kg/h and cephalopod is 0.8 kg/h. The seasonal variations of biomass in weight, especially the mean catch rate of fish, follow the order of autumn> spring.(6) The dominant species in spring and autumn are Lophius litulon, Pseudosciaena polyactis, Amblychaeturichthys hexanema and some invertebrates such as Crangon affinis etc. in North Yellow Sea. Based on the taxonomic range of fish species in North Yellow Sea, most species belong to the orders Perciformes, Scorpaeniformes, Pleuronectiformes and Clupeiformes, and few species belong to the orders Aulopiformes, Anguilliformes, Gadiformes, Tetraodontiformes, Lophiiformes Syngnathiformes and Rajiformes. Compared with survey results in the coastal waters of southern Shandong Peninsular, the number of species belonging to the order Pleuronectiformes in North Yellow Sea is larger, and fishery resources contain Gadiformes(Gadus macrocephalus) and Rajiformes(Raja porosa, Raja hollandi and Raja schmidti lshiyama). (7) The dominant species in the study area consist of small low-value fishes(such as Engraulis japanicus. Thryssa kammalensis. Enedrias fangi etc.), some invertebrates(such as Oratosquilla oraloria. Crangon affinis, Trachypenaeus curvirostris. Palaemon gravieri. Loligo edulis. Octopus ocellatus etc.) and juveniles of commercial fishes(such as Pseudosciaena polyactis). These dominant species appear by turns. They make up the most catches in the fishing seasons.