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Age and growth of round goby Neogobius melanostomus associated with depth and habitat in the western basin of Lake Erie
Author(s) -
Thompson H. A.,
Simon T. P.
Publication year - 2015
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/jfb.12576
Subject(s) - neogobius , round goby , biology , goby , habitat , population , catch per unit effort , fishery , ecology , sex ratio , predation , fishing , fish <actinopterygii> , demography , sociology
Round goby Neogobius melanostomus were examined from the Bass Islands area in the western basin of Lake Erie, U.S.A., to determine age and growth correlations. A total of 188 specimens were collected and examined during summer 2011 with 90 aged using scale analysis. Fish were grouped by sex, depth of habitat and habitat type (anthropogenically modified shallows, natural shallows and open lake deep water). Fish ranged from 17 to 117 mm total length ( L T ) and 0+ to 3+ years. Males dominated the population (1·94:1) and backcalculated age showed that both sexes grew exponentially, with male growth rate increasing faster than female. Males were significantly larger than females in L T and mass (both P < 0·001). The relative mass index ( W r ) was low for the sampled population (mean ± s.d . = 32·00 ± 26·87 g), implying that the health of the Bass Island area population is very poor when compared with the species throughout its range. This could be due to a lack of food resources related to population size or that the fish is not optimally utilizing the available food resources. In contradiction to these findings, regression slope coefficient ( b ), calculated using Fulton's condition factor ( K ) (mean ± s.d . =1·50 ± 0·20), was very low for each habitat, implying a healthy population throughout. This seemingly opposite effect may be due to more individuals per unit area in shallow waters, which would cause increased competition for resources. Poor condition may indicate that the Lake Erie population has reached saturation or may reflect indirect fitness costs associated with increasing anoxic or hypoxic hypolimnion conditions.