In this research age composition, sex-ratio, growth, survival, mortality and exploitation rates were determined in the south-eastern Black Sea region of Turkey during the 2010–2011 fishing season. Anchovy in the age group 2 was the most abundant (64.06%), followed by age groups 1 (33.12%), 3 (1.80%) and 0 (1.02%). Mean length and weight of the total sample, males and females, were 11.63 ± 0.02 cm, 9.98 ± 0.04 g; 11.39 ± 0.03 cm, 9.40 ± 0.07 g; and 11.98 ± 0.02 cm, 10.73 ± 0.05 g, respectively. The mean condition factor was CF = 0.63 and the sex composition was 61.27% female, 34.40% male and 4.33% unidentified. Equations describing the relationship between length and weight, age and length, and age and weight were derived as W = 0.011 × L2.742, L(t) = 16.368*(1–e−0.425*(t +1.35)) and W(t) = 23.516*(1 –e–0.425*(t+1.35))2,747, respectively. The survival (S), instantaneous total mortality (Z), annual mortality (A), natural mortality (M) and fishing mortality (F) rates were found to be S = 5.8%, Z = 2.84 yr–1,, A = 94.2%, M = 0.66 yr−1, and F = 2.18 yr–1, respectively. The exploitation rate was calculated as 0.77, which is higher than the optimum exploitation level.
Summary The population parameters of stargazer (Uranoscopus scaber Linnaeus, 1758) were studied regarding age composition, sex ratio, growth, survival and mortality rates, and the exploitation rate in the southeastern Black Sea near the coast of Turkey during the 2011–2012 fishing season. According to ageing analysis of the samples, age group 1 is the most abundant (47.76%), followed by age 2 (41.04%), age 3 (9.33%), age 0 (1.12%) and age 4 (0.75%). Mean totals as well as total lengths and weights for males and females were 14.5 ± 0.22 cm and 12.9 ± 0.19 g, 16.6 ± 0.24 cm and 62.1 ± 2.76 g, and 37.2 ± 1.92 cm and 87.1 ± 3.88 g, respectively. The mean condition factor was K = 0.0167, while the sex ratio was 53.98% female, 38.75% male and 7.27% immature. Length‐weight, age‐length and age‐weight equations were W = 0.014 × L3.059, L(t)=44.5*[1−e−0.148*(t +1.242)] and W(t)=1544.4*[1−e−0.148*(t + 1.242)]3.059, respectively. The computed survival rate (S), instantaneous total mortality rate (Z), annual mortality rate (A), natural mortality rate (M) and fishing mortality rate (F) were S = 28.94%, Z = 1.24 year−1, A = 71.06%, M = 0.26 year−1 and F = 0.98 year−1, respectively. The exploitation rate was 0.79, which is above the optimum exploitation levels.
Relations between fish size and otolith size of stargazer (Uranoscopus scaber) were studied in this study. A total of 268 samples were obtained from the coastal shelf of Ordu Province (south-eastern Black Sea) by commercial trawling and gillnetting operations. It was found that there were high correlations between fish size and otolith size. It was concluded that all measurable body sizes could be effectively used to estimate otolith length, width and weight. Similarly, estimation of the age of fish from otolith length and weight was also possible with high significance. The results of this research will be useful for others working on this fish, being a first study in the field. The ages of stargazer were determined between 0+ and 4+. Relationships were determined as OW ¼ 0.001 × OW i 2.76 , OW ¼ 0.35 × 10 23 × OL 2.54 with high correlation coefficients of r ¼ 0.965 and r ¼ 0.949, respectively.
The veined rapa whelk is one of the most important invasive species in the Black Sea ecosystem since the 1940s. Following its introduction to the Black Sea, it destroyed most of the bivalve populations, mainly the Mediterranean mussel and oysters. However, the veined rapa whelk has commercial importance for the Black Sea fisheries as an alternative product. In this study, we aimed to determine some population parameters of the veined rapa whelk based on indirect ageing through length-frequency data by using the Bhattacharya method. We collected 1704 specimens by dredging along the coasts of Samsun Province in the Central Black Sea in 2011 from June to November. The age of the population varied from 0 to 6. Von Bertalanffy growth parameters were estimated as L 1 ¼ 112.35 mm, k ¼ 0.310, t 0 ¼ 20.486 and W 1 ¼ 243.94 g. Mean length and weight, length-weight relationship, mortality and exploitation rates were derived as L ¼ 56.80 + 0.36 mm, W ¼ 45.67 + 0.89 g, W ¼ 0.0006 L 2.719 , Z ¼ 0.96, M ¼ 0.57, F ¼ 0.39 and E ¼ 0.40, respectively.
ÖzetBu araştırmada Hatay, Adana, Mersin ve Antalya illeri Akdeniz sahil şeridi limanlarına kayıtlı balıkçı teknesi sahiplerinin örgütlenme ve sosyoekonomik yapıları değerlendirilmiştir. Hatay İl'inde 99, Adana'da 11, Mersin'de 53 ve Antalya'da 89 kişi olmak üzere sahil şeridinde tüm ilçe ve beldelerde faaliyette bulunan 253 adet balıkçı ile anket yapılmıştır. Yapılan değerlendirmeler sonucunda tekne sahiplerinin sosyoekonomik yönden önemli farklılıkları olmadığı görülmüş, sosyal güvencelerinin olmaması, gelir seviyelerinin düşük olması, bilinçsiz avlanmanın önüne geçilememesi ve denetimlerin yetersiz olması gibi sorunlar tespit edilmiştir.Anahtar kelimeler: Akdeniz, sosyoekonomik yapı, deniz balıkçılığı, Türkiye Socio-economic Structure of Pelagic Fishing in the Coastal Mediterranean Region AbstractIn this research, collective organization structure and the socio-economic conditions of the fishermen with fishing boats registered to the harbors in provinces of Hatay, Adana, Mersin and Antalya on the Mediterranean coast. A survey was carried out with the participation of 253 fishermen consisting of 99 fishermen from the province of Hatay, 11 from Adana, 53 from Mersin and 89 from Antalya all of whom work in various counties and districts of the given provinces.As a result of the evaluations, it was seen that the boat owners didn't vary significantly in terms of socio-economic parameters, furthermore; problems such as having no social securities, low incomes, not being able to prevent insensible fishing and lack of supervision were detected.Keywords: Mediterranean Sea, socio-economy, marine fisheries, Turkey *Bu çalışma yüksek lisans tezinden özetlenmiştir GİRİŞ Günümüzde, özellikle gelişmiş ülkelerde insanlar beslenmelerine çok dikkat etmektedir. Besleyici değeri oldukça yüksek, insan beslenmesi için son derece önemli bir gıda kaynağı olan, çoklu doymamış yağ asitleri yönünden zengin balık ve diğer su ürünleri beslenmede ilk sıralarda yer almaktadır.Akdeniz'in kıyı kesimi deniz balıkçılığı açısından Hatay, Adana, Mersin, Antalya illeriyle sınırlandırılmakta ve avlanan su ürünleri ile Türkiye ekonomisine katkı sağlamaktadır. Ayrıca bölge insanlarına geçim kaynağı sağlaması açısından da önemli bir yere sahiptir.Akdeniz Bölgesi Türkiye'nin toplam avlanan deniz ürünlerinin %4,6'sına, tekne sayısının da %12,7'sine sahiptir. Bu göstergeleri ile bölge deniz ürünleri avcılığında diğer 3 büyük denizin gerisinde kalmakla birlikte, bölgede tür çeşitliliği diğer bölgelerden daha fazladır (Taşdan vd., 2010).
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