trammel net meaning in English

三层刺网
三重刺网
鱼网

The number of fishing boat from 1999 to 2002 is 159 , 100 , 107 and 116 , respectively . the number of different fishing boat and the species composition of different fishing gears were calculated also . furthermore , the structure of drift trammel net , set longline of baited hooks and jig and their fishing methods were described
1999 - 2002年各年的作业渔船数分别为159只， 100只， 107只和116只，并统计了各年使用不同渔具的渔船数目以及不同渔具的渔获物种类，另外还对三层流刺网、饵钓和滚钩等主要渔具的结构和渔法进行了描述。
( 2 ) the fishing gears in hejiang section were divided into drift trammel net , set longline and jig according to the fishery status in hejiang section . " number of fishing boat day " was selected as the unit of fishing effort . the annual catch of the four kinds of fishing gears was get from multiplying catch per unit effort ( cpue ) by fishing effort
( 2 )根据合江江段的渔业现状，将该江段的渔具分为三层流刺网、饵钓、滚钩和其它偶见渔具四类，以“船?天”作为捕捞努力量的单位，用单位捕捞努力量渔获量( cpue )乘以年捕捞努力量分别得到这四类渔具的年渔获量，并将这四类渔具的年渔获量相加估算出合江江段1999 - 2002年的渔获量分别为104563 . 464kg 、 65564 . 231kg 、 123684 . 966kg和107285 . 272kg 。