No abstract

The b values in the length-weight relationship varied between 1.654 and 3.977, over 50% of which between 2.968 and 3.265 with a mean value of 2.949 (SE = ±0.05). The growth type was determined by t-test: 13 species (43%) showed positive allometries (b > 3; t-test, P < 0.05), 13 species (43%) isometric growth (b=3; t-test, P > 0.05) and the remaning 4 species (14%) negative allometries (b<3; t-test, P < 0.05). How to CiteAkalın, S., lhan, D., Özaydın, O. (2015): Length-weıght relatıonshıps for 30 demersal fısh specıes from Çandarlı Bay (North Aegean Sea, Turkey). CroaCroatian Journal of Fisheries, 73,[73][74][75][76]

Background. The knowledge of the age, growth, and feeding ecology of fish species is essential for conservation, monitoring, and management activities required for the sustainable use of fish stocks. The objective of this work was to describe the growth and feeding of Pagellus acarne from the Gulf of İzmir, central Aegean Sea. The information provided in this study contributes to the knowledge which is for sustainable management applications. Material and methods. The study was carried out to investigate the growth and feeding characteristics of axillary seabream, Pagellus acarne (Risso, 1827), in the Gulf of İzmir, the central Aegean Sea, from commercial trawl fishery between October 2012 and September 2013. Age and growth were determined by annuli counts of sagittal otoliths. Length-weight relation and the von Bertalanffy equation were used to evaluate the fish growth. Percentages by number, weight, and frequency of each food category were determined, and the index of relative importance (%IRI) was calculated to define the main food categories. A similarity of diet was also examined according to a season and fish size. Results. A total of 2036 specimens' were analysed. The lengths ranged from 7.5 to 22.0 cm and the weights ranged from 4.55 to 138.45 g. For the age determination, a total of 547 left sagittal otoliths were extracted. The age ranged from 0 to 4 years. Von Bertalanffy growth parameters were determined from mean lengths of age groups and the following parameters were obtained:

No abstract

This study investigates the age, growth and maturity of false scad (Caranx rhonchus Geoffroy Saint-Hilaire, 1817) in the İzmir Bay, the Central Aegean Sea. The total length of 392 fish varied between 12.8-36.0 cm and their weights were measured as 23.51-455.44 g. Sex ratio was 1:0.8 (F:M). Sagittal otoliths were used for age determination. Fish were between I-V age groups in the bay. The length-weight relationships were calculated as W= 0.0145*L2.8911 for females; W= 0.0168*L2.8425 for males, and W= 0.0132*L2.9259 for all fish. The von Bertalanffy growth parameters were found as L∞= 40.86 cm, K= 0.2181 years-1, to= -1.0584 years for females; L∞= 39.54 cm, K= 0.2156 years-1, to= -0.963 years for males; and L∞= 41.12 cm, K=0.2061 years-1, to= -1.0548 years for all fish, respectively. The growth performance index values (Φ) were 2.532 for females, 2.555 for males, and 2.542 for all fish. The length at first maturity was calculated as 18.53 cm for females, and 18.95 cm for males.

No abstract

Background. The red bandfi sh, Cepola macrophthalma (Linnaeus, 1758), is a benthic fi sh usually not exceeding 450 cm in length. It occurs in the eastern Atlantic from the British Isles to the north of Senegal and is also common throughout the Mediterranean Sea. The red bandfi sh has no commercial value and is often represented in the discarded catch. The knowledge of the feeding ecology, of non-commercial as well as commercial species, is essential for implementing a multispecies approach to fi shery management. Studies on red bandfi sh feeding biology have been rather scarce and the majority of them lacked taxonomical approach. The presently reported study constitutes the fi rst report on the diet of Cepola macrophthalma from two bays on the Turkish coast. Material and methods. The study was based on the specimens of Cepola macrophthalma collected in İzmir Bay and Sığacık Bay from May 2005 to June 2006. The following basic parameters were calculated, based on the data collected during the analysis of red bandfi sh diet: relative number of food items in the gut content, frequency of occurrence, and relative weight of total gut content. Principal food items were determined using the index of relative importance (%IRI). The differences in the diet composition were tested for length groups and seasons by using the Bray-Curtis similarity index for both areas studied. Results. A total of 380 stomachs were examined in two bays. According to the analyses a total of 18 different prey species belonging to nine major systematic groups were found, i.e., Anthomedusae, Siphonophora, Polychaeta, Crustacea, Mollusca, Chaetognatha, Appendicularia, Thaliacea, and Actinopterygii. Concerning overall diet composition, crustaceans (especially copepods) were the most important prey in terms of %IRI, %N, %F, and %W in all seasons. In this study, a total of 80 taxa were found and identifi ed. According to the Bray-Curtis similarity index, the diet of the red bandfi sh was similar within all seasons for both areas. Conclusion. Stomach content analysis of red bandfi sh showed that it is a zooplanktophagous species. In addition to bottom species it feeds also on pelagic organisms. This fact indicates ontogenetically based food preferences of the species.

The fish composition of five different stations in Çandarlı Bay (Aegean Sea) were studied by means of seasonal trawl surveys between March 2003 and August 2004. Samplings were carried out onboard R/V Egesuf by employing a conventional bottom trawl commercially used in Turkish waters during daylight hours. A total of 60 fish species of 49 bony and 11 cartilaginous fishes from 33 families were collected in the study area. The species of the group osteichthyes was the highest percentage in terms of number and weight. Mullus barbatus (% 15.63), Citharus linguatula (% 13.36), Diplodus annularis (% 13.27), Serranus hepatus (% 12.28) ve Merluccius merluccius (% 10.89) were determined dominant fish species during the studying period. While catched fishes's rate of among the whole prey was 89 %, following that cephalopods are 9.52 % and crustaceans are 1.42 %. successively Total 37 fishes species in station III and total 36 fishes species in station II and also total 35 fishes species in station IV were found. According to statistical analyses, species diversity, maximum species richness and Evenness Function were computed as H'=2.950, Hmax=4.17 and J'=0.715 respectively. Özet: Mart 2003 ve Ağustos 2004 tarihleri arasında beş farklı istasyonda mevsimsel olarak gerçekleştirilen trol örneklemeleri ile Çandarlı Körfezi'nin balık kompozisyonu ortaya konmuştur. Örneklemeler, Türkiye sularında ticari olarak kullanılan geleneksel bir dip trol ağının, araştırma gemisi Egesüf tarafından gündüz saatlerinde çekilmesi ile yapılmıştır. Çalışma bölgesinde 33 familyaya ait olarak 11 kıkırdaklı, 49 kemikli toplam 60 balık türü tespit edilmiştir. Kemikli balıklar grubundaki türler sayı ve ağırlık bakımından baskın olarak bulunmuştur. Mullus barbatus (% 15.63), Citharus linguatula (% 13.36), Diplodus annularis (% 13.27), Serranus hepatus (% 12.28) ve Merluccius merluccius (% 10.89) türleri tüm istasyonlarda ve tüm mevsimlerde dominant olarak yaklanan türlerdir. Tüm av içinde yakalanan balıkların oranı % 89.06 iken, bunu sırasıyla sefalopod % 9.52 ve krustase % 1.42 ile takip etmiştir. III nolu istasyonda toplam 37, II nolu istasyonda toplam 36 ve IV nolu istasyonda ise toplam 35 balık türü tespit edilmiştir. İstatiksel analizlere göre, tür çeşitliliği, maksimum tür zenginliği ve Evenness Fonksiyonu sırasıyla H'= 2.950, Hmax= 4,17 ve J'= 0.715. Anahtar kelimeler: Çandarlı Körfezi, dip trolü, balık kompozisyonu, tür çeşitliliği.