Preliminary study of catch composition and fishing technology of Dosidicus gigas in the high seas off Chile

Abstract:

The experiments on fishing technology of Dosidicus gigas were made by Chinese squid jigging boats during April and June of 2006 in the high seas off Chile.The results showed that the catch mainly comes from the hand jigging which accounts for about 98 percent of the total.The hook-off rate of eightangle hand jigger is from 6.5 to 19.5 percent,and the average is 13.2 percent.The average hook-off rate of hand-jigger in the low and the stern is higher than that in the middle-part of the boat.The hook-off rate of machine-jigger is from 20.7 to 46.2 percent,and the average is 32.9 percent.The experiment showed that the squid,Dosidicus gigas,has the selectivity to the color of jigger,and the highest fishing rate belongs to the fluorescent jigger, the next is the green jigger,and the lowest fishing rate comes from the orange jigger.When the gathering-fish metal halide lamp(180 lamps,2kW per lamp) is used,the fishing catch of eight-angle hand jigger is 0.5 times higher than the four-angle jigger,but when the high pressure sodium lamp(30 lamps,500W per lamp) is used during the local time 02:00 to 03:30,the fishing catch of fourangle jigger is 0.35 times higher than that of eight-angle jigger.