ALİ ULAŞ, F. Ozan DÜZBASTILAR, ALTAN LÖK, Cengiz METİN

Yapay resiflerde balık örnekleme yöntemlerinin etkinliğinin belirlenmesi üzerine bir ön çalışma

Bu çalışma, Ege Denizi’nin doğusunda yer alan, Ürkmez ve Gümüldür beldelerinin kıyı şeridinde oluşturulan yapay resif alanında yürütülmüştür. Çalışmada tahrip eden ve etmeyen örnekleme yöntemleri kullanılarak, bu bölgedeki balık tür ve sayısının belirlenmesi amaçlanmıştır. Tahrip edici örnekleme yöntemi olarak; kombine uzatma ağı ve olta, tahrip edici olmayan yöntem olarak görsel sayım tekniği kullanılmıştır. Çalışma sonunda; 40 balık türüne ait 2241 birey tespit edilmiştir. Kombine uzatma ağı ile yapılan örneklemede 27 türe ait 392 birey yakalanmıştır. Olta örneklemesinde 6 türe ait 102 birey yakalanmıştır. Görsel sayım tekniği ile yapılan örneklemede 27 türe ait 1747 birey kaydedilmiştir. 5 tür her üç yöntemle de belirlenmiştir. En fazla birey sayısı (450 adet) görsel sayım tekniği ile belirlenen Chromis chromis (Lin. 1758) türüne aittir. En az örneklenebilen türler 1’er adetle Balistes carolinensis (Gmelin, 1789), Lophius piscatorius (Lin. 1758) (kombine uzama ağı), Conger conger (Lin. 1758) ve Symphodus doderleini (Jordan, 1891) (görsel sayım tekniği) olarak belirlenmiştir. Bölgede yapılan üç örnekleme yöntemi içinde kombine uzatma ağı ve görsel sayım tekniği tür çeşitliliği açısından daha etkin yöntemler olarak belirlenmiştir. Görsel sayım yöntemi yapay resif alanında birey sayısının belirlenmesinde en verimli yöntemdir. Ayrıca resif bölgesinde Symphodus doderleini (Jordan, 1891), Parablennius rouxi (Cocco, 1833) gibi bazı kriptik türlerin belirlenmesinde daha etkin olmuştur. Olta örneklemesi ise hem tür hem birey sayısı açısından verimli olmamasına rağmen, seçici bir yöntem olması nedeniyle destekleyici olarak örnekleme çalışmalarında yer almalıdır. İstatistiksel analiz (spss, kruskall-wallis) sonucunda örnekleme yöntemleri içinde birey sayısı temel alındığında görsel sayım yöntemi diğer iki yönteme göre farklılık göstermektedir (p < 0,05). Yapay habitat bölgelerinde yapılan örnekleme çalışmalarında tahrip edici yöntemler canlı kütle tahmini yapmak için daha kesin boy-ağırlık verisine ulaşma olanağı verdiğinden (ağ, olta, sepet vb.) görsel sayım tekniğini destekleyecek şekilde kullanılmalıdır. Ancak küçük ölçekli yapay habitat bölgelerinde tahrip edici yöntemlerin yoğun ve sık kullanımı bölgesel balık popülasyonunda azalmaya neden olabilir.

Anahtar Kelimeler:

türler, Ege Denizi, tuzak ağlar

A pre-study for determining of efficiency of fish sampling methods on artificial reefs

A pre-study for determining of efficiency of fish sampling methods on artificial reefs. This study was carried out at the artificial reef site in Ürkmez and Gümüldür on the east of Aegean Sea. Destructive and non-destructive sampling methods were used to determine fish species and number in the site in this study. As destructive sampling methods, both combined gill net-trammel net and hand line, and visual census method as a non-destructive method were used. At the end of the study 2241 individuals belonging 60 fish species were determined. 392 individuals belonging 27 fish species were caught using combined gill net-trammel net. 102 fishes belonging 6 species were caught with hand line. 1747 fishes of 27 fish species were visually censused in experiments. 5 species were sampled by each sampling methods. The most determined fish with the number of 450 using visual census technique is Chromis chromis (Lin. 1758). Balistes carolinensis (Gmelin, 1789), Lophius piscatorius (Lin., 1758) (sampled combined gill net-trammel net), Conger conger (Lin. 1758) and Symphodus doderleini (Jordan, 1891) (visual census technique) have only 1 individual able to sampled. Among the 3 sampling methods, combined gill net-trammel net and visual census technique were more effective methods so as to evaluate fish diversity in the site. Visual census technique is the most efficient method to estimate number of fishes in the artificial reef site. In addition, it was more effective in order to determine some cryptic fishes such as Symphodus doderleini (Jordan, 1891) and Parablennius rouxi (Cocco, 1833) in the reef site. Although sampling of hand line is not efficiently, it should be used as a supportive method in sampling experiments because of having high selectivity. When the results were evaluated statistically using spss, kruskall-wallis analysis, according to number of individuals sampled, visual census technique is different from the other 2 methods (p < 0.05). Due to destructive methods (fishing net, fishing line, pots etc.) give possibility to reach data accurately in order to estimate biomass in artificial reef sites, these should be used to support visual census method. But, use of destructive methods intensively and enormously at artificial habitats with small scale may cause decreasing of local fish population.

Keywords:

species, Aegean Sea, nets,

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