Distributional characteristics of chlorophyll a and relation to the fishing ground in the squid fishing ground of the northern Pacific Ocean

On the basis of the investigating results of chlorophylla,water temperature,salinity,phytoplankton and squid fishing in the squid fishing ground(39°~43°N,152°E~171°W)of the northern Pacific Ocean during June to August of 2001,The distributional characteristics of surface chlorophylla and relation to the environmental factors and squid fishing ground were mainly analyzed.The analyzing results show that the content of surface chlorophylla in the investigating area is between 0.03 and 0.32 mg/m³,mean value is 0.13 mg/m³.Among them,the content of surface chlorophylla in the middle part fishing ground is the biggest,the second is the in the eastern-part and the lowest is in the western-part.There is a good relationship of the distributions of surface chlorophylla contents with water temperature and salinity in the survey area.The high chlorophylla content is located in the region with high temperature,the content is the lowest in the cold eddy and the highest in the warm eddy.The chlorophylla content increases with increasing of salinity.The surface chlorophylla content has a positive relationship with the phytoplankton in the west,middle and east fishing grounds.The distribution of surface chlorophylla also exits a better relation with the middle part fishing ground of squid which mainly is located in the tongue part of 0.1 mg/m³ of isopleth and the maximum gradient belt.The values of the surface chlorophylla in the middle part fishing ground were more than 0.1 mg/m³.The relative analyses of distributional of chlorophylla with the environmental factors and fishing ground indicate that it may be as an important reference index in the study of squid fishing grounds.