Gillnet Selectivity and Length at Maturity of Nile Tilapia （Oreochromis niloticus L.） in a Tropical Reservoir （Amerti： Ethiopia）  

作　　者：Mathewos Hailu 

机构地区：[1]Ziway Fisheries Resources Research Center, Ziway 229, Ethiopia

出　　处：《Journal of Agricultural Science and Technology(A)》2014年第2期135-140,共6页农业科学与技术（A）

摘　　要：The selectivity of gillnets for Oreochromis niloticus in Amerti reservoir （9°63′ N, 37°23′ E） was determined from gillnets with four mesh sizes （60, 80, 100 and 120 mm）. Four selectivity models （a normal model assuming fixed spread, a normal model assuming that spread is proportional to mesh size, a lognormal model and a gamma model） were fitted to the data by using the share each length＇s catch total （SELECT） method. A total of 657 specimens of Oreochromis niloticus were caught （12.0-35.5 cm total length, TD. The sizes at first sexual maturity were 21.5 cm TL and 18.9 cm TL, respectively, for male and female Oreochromis niloticus. The lognormal selectivity curve provided the best fit to the data according to model deviance estimates with optimum selectivity of 16.66, 22.26, 27.78 and 33.38 cm TL for the 60, 80, 100 and 120 mm mesh sizes, respectively.

关 键 词：GILLNET mesh selectivity Nile tilapia SELECT 

分 类 号：S965.125[农业科学—水产养殖] S972[农业科学—水产科学]