Length-weight relationships were calculated for 48 fish species from İzmir Bay in the Aegean Sea, Turkey. A total of 3584 fish specimens were captured with beach seine, handline, fyke net, scoop net, castnet and trammel net in 2010–2014. The sample size ranged from three individuals for Squatina squatina to 140 for Mugil cephalus. R2 values varied between 0.95 for Pomatoschistus bathi and 0.99 for Argyrosomus regius, Chelon labrosus and Mugil cephalus. All regressions were highly significant (P < 0.001). Values of the exponent b in the length-weight regression (W = aLb) ranged from 2.750 for S. squatina to 3.514 for Syngnathus acus and the median value was 3.134 with 25–75% of the values ranging between 3.030 and 3.218.
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.
Abstract. The incidence of severe consecutive repetition of lordosis-kyphosis involving three flexions was reported in a specimen of the atherinid fish Atherina boyeri Risso. The values for the angles lay between the lines passing through the sides of the vertebral column and enclosing the curvatures, and the depth of the curvatures of the angles was obtained. Also, the ratio of the vertebral column to the fish total length of deformed and normal specimens of this species was calculated. Possible causes for these anomalies are discussed.
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.
Güllük lagoon is one of the six important lagoons (Güllük, Karina, Akköy, Köyceğiz, Enez and Homa) in where the active fisheries have been realizing. To the fishing activities carry out in the 250 hectares of Güllük Lagoon in Eastern Güllük Bay. Lagoon is leading jointly owned by the two Fishery Cooperatives. One of them is Güllük Fisheries Cooperative, founded in 1971 with 78 registered members and the other one is Kıyıkışlacık Fishery Cooperative, established in 1996 with 89 registered members. In this study, the current status of the two cooperatives managing the Güllük Lagoon, fishing gears and fishing methods in the lagoon were stated. Fishing gear types were studied by in situ observations. Socio-demographic characteristics of fishermen in Lagoon and problems concerning with managing of lagoon were obtained through surveys. Fishing cooperatives are following a pattern of sharing the fishing days of a week for fishing in the lagoon. Fishing has been performed with single type of gill net, fyke-net for eel with four fishing boats. According to manager of cooperatives the most important problems are discharging of waste water to the lagoon and increasingly shoaling area of lagoon, depending on the reduction of freshwater.Özet: Güllük dalyanı, Ege bölgesinde aktif balıkçılık yapılan altı önemli dalyandan (Güllük, Karina, Akköy, Köyceğiz, Enez ve Homa) biridir. Güllük dalyanı, Güllük Körfezi'nin doğusunda 250 hektarlık bir alanda faaliyet yapmaktadır. Dalyan, 1971 yılında kurulmuş 78 kayıtlı üye sayısına sahip S.S. Güllük Su Ürünleri Kooperatifi ve 89 kayıtlı üye sayısına sahip 1996 yılında kurulmuş S.S. Kıyıkışlacık Su Ürünleri Kooperatifi tarafından ortak olarak işletilmektedir. Bu çalışmada, dalyan işletmecisi olan bu iki kooperatifin güncel durumu, dalyan içerisindeki avcılık tipleri ile av araç ve yöntemleri ortaya konmuştur. Güllük Körfezi kıyı alanı içerisinde balıkçılıkta önemli bir yer tutan bu dalyanın av araçlarının teknik özellikleri yerinde gözlemlerle; dalyan balıkçılarının bazı sosyo-demografik özellikleri ile dalyan işletmesinde karşılaşılan sorunlar anketler yoluyla elde edilmiştir. Dalyanda balıkçılık, kooperatif ortaklarının haftanın belirli günlerini paylaşması ile gerçekleşmektedir. Avcılık tek tip uzatma ağı ve pinter kullanan dört tekne ile sürdürülmektedir. Dalyan işletmecilerine göre dalyanın en önemli sorunlarının başında bölgede bulunan fabrikaların atık sularını dalyana deşarj etmeleri ve tatlı su kaynaklarının azalmasına bağlı olarak dalyan alanının gittikçe küçülmesi gelmektedir.Anahtar kelimeler: Güllük Dalyanı, su ürünleri kooperatifi, av araçları, Ege Denizi
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