Biological characteristics and spatial-temporal resource distribution of Asian moon scallop(Amusium pleuronectes) in the Beibu Gulf, South China Sea

Abstract

Through the commercial fishing independent trawlers catch sampling,a total of 794 individuals of Asian moon scallop,Amusium pleuronectes were collected quarterly from August 2010 to May 2011 in the Beibu Gulf,South China Sea.By biological measurement and resource statistics,the relationship of modality parameters and weight parameters,and the growth and the resource distribution were studied.Results showed that the partial correlation effects of four modality parameters on body weights and adductor weights were as follows in sequence: shell lengths shell widths shell heights hinge ling lengths.Shell lengths,shell widths and shell heights are the most important parameters.Moreover,the mollusk and adductor muscle accounted for almost half of the total body weight and mollusk weight respectively.In summer,the main growth was the shell.In spring,the mainly growth was the mollusk part.The resources are main distributed in the areas of 20°15′N-21°15′N,108°-109°′E,with the water depth ranging from 20 m to 50m and the bottom covered with mud and sand.The spatial distribution showed distinct regularity character.It progressively increased from the south to the north by the latitude,and increased firstly and then decreases from west to east by the longitude.Seasonal variations were also recorded with the peak in summer and the value from spring to winter was 8.72,13.93,9.82 and 5.90 kg/km2 respectively.Statistics demonstrated that sea surface temperature was the most important environmental factor and has a positive correlation with the average resources density(r=0.972),while salinity and plankton did not show linear correlations.