Preliminary analysis on the fishing grounds of Cololabis saira in the North Pacific Ocean

Based on the production database of vessel" Zhongyuanyu 1"in the North Pacific Ocean during July-November 2004, the fishing grounds of Cololabis saira were analyzed. The results were summarized as follows: (1) According to the position the above-mentioned fishing grounds can be divided into the north and the south fishing grounds, the north grounds are around 44°-45°N,156°-158°E,and the south around 41°-42°N,150°-151°E, with the former being larger than the latter in the scope of distribution; (2) The maximum catch was in November, the average production per day was 22.7 t,and the highest production per day was 60.42 t. The minimum catch was the worst in August, with an average production of 29.5t per day, and in contrast with in August 2003, the average day production was 12.05t. The production varied greatly on account of the change of environmental factors in the fishing grounds ,and the central fishing grounds were on the Russian EEZ; (3)The average day setting number of stick-held net fishery was 7.6,with the highest day setting number of 16 and the highest production per net of 10.05 t; (4) The composition of catch was mainly medium-sized and small-sized fishes, which accounted for 80% of the total catch.There were few extra large-sized Cololabis saira except July; (5)The longer the fishing month, the smaller the size of Cololabis saira on the nearby fishing grounds.