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    Age, Growth and Mortality of Garfish, Belone euxini Gunther, 1866 in the Central Black Sea, Turkey
    (Zoological Soc Pakistan, 2019) Ceyhan, Tevfik; Samsun, Osman; Akyol, Okan
    A total of 986 garfish were collected from commercial fisheries, using encircling nets between October 2016 and December 2017 in Sinop, Central Black Sea. The length and weight distribution of all garfish samples ranged from 28.8 to 51.6 cm TL and from 26.6 to 177.2 g, respectively. Female: male ratio was 0.3:1. The LWR parameters (a, b, r(2)) were computed as 0.0009 +/- 0.50, 3.040 +/- 0.32 and 0.902 +/- 0.40, respectively. The age of garfish was between 1 and 4 years. The estimated von Bertalanffy growth parameters with standard errors were L-infinity = 55.74 +/- 26.75 cm, K = 0.28 +/- 0.42, and t(0) = -1.68 +/- 2.02. Natural, fishing and total mortality of the garfish were 0.47, 0.69 and 1.16, respectively. The current study revealed that about 68% of the fish caught were of size smaller than the first maturity length. In addition, exploitation rate was found to be higher than optimum. On the other words, there is a fishing pressure on the garfish stock in the Black Sea due to absence of minimum landing size (MLS) of the garfish. Apart from direct fishing control measures aiming to reduce fishing mortality, the establishment of a MLS of 38cm that coincides with the length at first maturity would be also beneficial for the stock. Our results suggest that the garfish stock undergoes high levels of fishing pressure and the adoption of management measures is necessary.
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    Öğe
    Age, growth, reproduction and mortality of Red Mullet (Mullus barbatus ponticus Essipov, 1927) from the Turkish coasts of the Black Sea
    (Ege Univ, Fac Fisheries, 2019) Yilmaz, Bulent; Samsun, Osman; Akyol, Okan; Erdem, Yakup; Ceyhan, Tevfik
    A total of 989 red mullets, Mullus barbatus ponticus, from the Black Sea were monthly collected from commercial gill/trammel net and bottom trawl fisheries, especially landed at Sinop Fishing Port, between December 2015 and December 2016. Total lengths and weights of red mullet specimens were ranged from 9.2 cm to 19.2 cm (average: 13.3 +/- 1.3 cm) and from 8.2 g to 68.6 g (average: 25.7 +/- 8.0 g), respectively. The samples were grouped densely between 13 and 15 cm. Minimum landing size (MLS) is 13 cm for Mullus barbatus according to Turkish Fisheries Regulation Circular. Thus, 39% of all samples in this study are under legal size. The LWR equation calculated was W = 0.0137 x TL2.902 (r(2)= 0.92). Age groups of red mullets in the Black Sea were ranged from I to IV. The mean lengths according to age groups (I, II, III, and IV) were 11.43 +/- 0.04 cm, 13.22 +/- 0.04 cm, 15.24 +/- 0.06 cm, and 18.44 +/- 0.29 cm, respectively. According to GSI values, reproduction of red mullets is between May and July with the peaks of June-July. The estimated von Bertalanffy growth parameters with standard errors were L-infinity = 17.64 +/- 1.43 cm, k = 0.43 +/- 0.13, and t(0) = -1.33 +/- 0.37. The mortality rates (M, F, and Z), and exploitation rate (E) of M. barbatus ponticus were 0.91 year(-1), 0.52 year(-1), 1.43 year(-1), and 0.36, respectively.
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    Öğe
    Length-weight relationships for 11 fish species from the Central Black Sea, Turkey
    (Ege Univ, 2017) Samsun, Osman; Akyol, Okan; Ceyhan, Tevfik; Erdem, Yakup
    This study reports length-weight relationships (LWRs) of the 11 fish species in the Central Black Sea. The values of b ranged from 2.523 (+/- 0.62) for Liza aurata to 3.445 (+/- 0.56) for Sarda sarda. The median value of b was 2.933. The information about the length-weight relationships of fish species in the Black Sea is still very scarce and incomplete. The LWR for Sparus aurata was not recorded before for the Black Sea. Consequently, this paper contributes the LWR of some Black Sea fishes, especially with S. aurata and Diplodus annularis, which are given for the first time.