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Population structure, growth, mortality and estimated stock size of the introduced tench, Tinca tinca (L.), population in Lake Beyşehir, Turkey
Author(s) -
Balık İ.,
Çubuk H.,
Çınar Ş.,
Özkök R.
Publication year - 2009
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/j.1439-0426.2009.01213.x
Subject(s) - fishing , biology , fishery , population , zoology , stock assessment , stock (firearms) , mortality rate , fish measurement , body weight , veterinary medicine , fish <actinopterygii> , mathematics , demography , geography , archaeology , sociology , medicine , endocrinology
Summary Population structure, growth, length–weight relationship, mortality and stock size of tench, Tinca tinca (L.), was studied in Lake Beyşehir, Turkey in 2005. Totals of 3360 tench (1865 males; 1795 females) were captured with gill‐ and trammel‐nets of various mesh sizes. Male to female ratio was 1.04 : 1. The study covered length year classes. Fork lengths and total weights ranged from 9 to 37 cm and 13 to 815 g. For all individuals, the von Bertalanffy growth equation and length–weight relationship were L t = 54.2[1−exp(−0.1350( t + 1.0281)] and W = 0.0151 L 2.9993 , respectively. Growth performance index and mean condition factor of the tench population were 2.598 and 1.513, respectively. Mortality rates were Z = 1.97 year −1 , M = 0.29 year −1 and F = 1.68 year −1 for total, natural, and fishing mortality, respectively. The exploitation rate was E = 0.85, and the percentage of surviving fish was 13.9%. Tench stock was assessed as about 6–7 million individuals and 1450–1500 tonnes in biomass. It was determined that maximum sustainable yield could be obtained with an 80% level of the current fishing effort.