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    Age and Growth of European Hake, Merluccius merluccius in the Sea of Marmara
    (Çanakkale Onsekiz Mart Üniversitesi, 2019) Gül, Güzin; Murat Dalkara, Elif; Yüksek, Ahsen; Demirel, Nazlı
    Within this study, the most important species European hake which constitutes 50% of the Sea of Marmara demersal fisheries, has been subjected to estimate age, growth characteristics and natural mortality. Bottom trawl hauls were carried out in 19 stations representing the entire Marmara Sea. Sea surveys were performed in different time periods from 2009 to 2011 (September 2009, December 2009, December 2010 and December 2011). A total of 274 sagittal otoliths (117 females, 75 males and 82 unidentified individuals) were obtained from 2009, 2010 and 2011. Sex ratio was calculated 1:1.5 males to females. Age composition was 0+ to 4+ years, most observed age group was 2+ both for female and male (37%). Growth parameters determined by von Bertalanffy equation were found as L∞= 57.51 cm K=0.27 y-1 and t0=-0.57 y-1. Natural mortality was estimated 0.41 y-1. Our results obtained from the Marmara Sea strongly support the fast growth hypothesis of M. merluccius. Growth rates clearly differ between males and females in this sea which shows hake growth depends on sex.
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    Length-Frequency Distribution of European Hake, Merluccius merluccius from 1995 to 2016 in the Sea of Marmara
    (Çanakkale Onsekiz Mart Üniversitesi, 2019) Gül, Güzin; Yüksek, Ahsen; Murat Dalkara, Elif; Demirel, Nazlı
    In this study, European hake (Merluccius merluccius) is one of the most important demersal species of the Sea of Marmara, has been subjected to estimate variation in length and size distribution based on obtained data from Sea of Marmara. A total of 174 bottom trawl hauls were performed in 19 stations representing the entire Sea of Marmara from 1995 to 2016 (July and November 1995, March and October 1996, December 2009, December 2010, February 2011 and August 2016). The estimation of length-weight relationships (LWRs) and distribution of length frequency was estimated according to years and sexes. A total of 5453 speciemens were evaluated. Sex ratio was calculated as 1:1.2 males to females. Overall length-weight relations were estimated W=0.006L3.077 (r2=0.97) for females, W=0.008L2.97 (r2=0.95) for males. According to the length frequency results, observed changes were not significant in size distribution of the samples between 1995 to 1996 and from 2009 to 2011. However, the median value of the total lengths of the individuals obtained in the 90s is greater than the values obtained at the end of the 2000s. The size distributions of the samples obtained in the 1990s are in a wider range than the size range of samples in 2000s. Especially in 2009 and 2016, it was observed that the size distribution was very narrow, also very few large-sized individuals were obtained.