Niches and interspecific association of major shrimp and crab species in Pishan waters of Zhejiang Province, China.

ABSTRACT

Based on the fishery resource investigation data in Pishan waters of Zhejiang coastal area in November of 2015 (autumn), February (winter), May (spring) and August (summer) of 2016, we analyzed the spatio-temporal niche characteristics and interspecific association of the domi-nant shrimp and crab species using the methods of niche test, variance ratio, chi-square test, Spearman test and redundancy analysis. A total of 34 shrimp and crab species belonging to 14 families and 20 genera were identified. Among them, 10 species were collected in all the four seasons. Dominant species were Parapenaeopsis hardwickii, Exopalaemon carinicauda and Portunus trituberculatus. The temporal, spatial and spatio-temporal niche breadths of the major shrimp and crab species ranged from 0.03-1.34, 2.07-3.63 and 0.08-4.64, respectively. The cluster analysis of niche breadths suggested that all the species could be divided into narrow, medium and wide niche breadth groups under the 90% similarity level. In addition, the spatio-temporal niche overlap values of the major species in Pishan Sea were mainly at low level (68.9% of the species's Qik<0.3), implying little interspecific competition for resource utilization. The analysis of variance ratio showed that the major shrimp and crab species were mainly positively correlated, with 11.1% of the species showing significantly positive association. The JI index, OI index and Spearman test all showed the relationship between major shrimp and crab species tended to be positive correlation as a whole. Redundancy analysis showed that surface temperature, bottom temperature, and surface salinity were the main environmental factors affecting the distribution of shrimp and crab species in Pishan waters.