In this study, the population structure, growth and reproduction characteristics of 414 chub (Leuciscus cephalus L., 1758) from the _ Ikizcetepeler dam lake were investigated monthly between January and December 2000. Age groups ranged between I and VI for this species in the reservoir, with the second and third year-classes dominating. Sex ratio was 1 : 1.4 (M : F), corresponding to 58.4% males and 41.6% females. Females attained greater size and age than males. The largest female captured was 24.8 cm FL, the largest male was 24.1 cm FL, both age VI. The von Bertalanffy growth equations and length-weight relationships were found as: L t ¼ 28.89[1 ) e )0.224(t+1.55) ] for females, L t ¼ 26.71[1 ) e )0.259(t+1.55) ] for males; W t ¼ 347.386[1)e )0.224h (t+1.55) ] 2.86 for females, W t ¼ 286.48[1)e )0.259 (t+1.55) ] 2.92 for males; W ¼ 0.0227 · L 2.87 for females and W ¼ 0.0194 · L 2.92 for males. Significant statistical differences in condition factors between age classes and sexes were not found (P > 0.05, t-test). Spawning period of this species in the lake was between April and May. SPSS, STATISTICA STATISTICA for Windows V 11.0.
Results
Length-frequency distributionOf 414 specimens measured, FL of males ranging from 12.2 to 24.1 cm; the range (11.1-24.8 cm) for females was higher than
Morphometric and meristic analyses of chub mackerel Scomber japonicus were used to discriminate stocks throughout the Black, Marmara, Aegean, and northeastern Mediterranean Seas. Morphometric and meristic analyses showed a similar pattern of differentiation between S. japonicus stocks and revealed a clear discreteness of two groups, northeastern Mediterranean (Antalya Bay-Iskenderun Bay) and the northern group, including the Aegean, Marmara, and Black Seas. Univariate analysis of variance showed significant differences between means of the samples for most morphometric and meristic descriptors. The contribution of each variable in distinguishing between the stocks for the first discriminant function revealed high contribution from head size measurements for morphometrics, and first and second dorsal fin rays for meristics. Plotting all specimens on the first two discriminant functions accounted for 76% of total variance for morphometric and 69% of total variance for meristic analyses, and both plots resulted in two main groupings. The overall random assignment of individuals to their original group was higher in morphometric than in meristic analysis.
This paper presents 145 length-weight relationships gathered from the literature pertaining to 30 Turkish freshwater fish species belonging to six families. The value of the slope b ranged from 2.04 for Carassius carassius to 3.46 for Scardinus erythroptalmus. The mean value of b was 2.91 (SD ¼ 0.305), which did not differ significantly from 3.0 (t-test, P > 0.05). The median value of b was 2.95; 50% of the b values ranged from 2.68 to 3.14. The plot of log a vs b was used to detect outliers.
Summary
In order to determine the present benthic fish fauna in the Sea of Marmara, sampling was conducted at a total of 10 stations for 2 weeks in August 2009, using a commercial twin beam trawling vessel with 18 and 36 mm stretched mesh sizes at the cod‐end. In addition, some physicochemical parameters that play important roles, such as temperature, salinity, dissolved oxygen, and pH, were measured for each station. As a result, 31 fish species from 23 families were found at a total of 10 stations in depths of 30–1000 m. At each station, the Shannon–Weaver diversity index, Simpson dominance index, species richness index, and evenness index were estimated. This study reports on species composition of the demersal fish catches in the Sea of Marmara for a preliminary assessment of the status of these fish communities.
In August 2008 eight specimens of the hollowsnout grenadier, Coelorhynchus coelorhyncus, were caught by beam trawl off Barbaros in the Sea of Marmara, Turkey. The study represents the first record of this species in the Sea of Marmara.
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