Selectivity of 40 mm Square and 90º turned mesh codend for the Eurpean hake Merluccius merluccius and Blue whiting (Micromesistius poutassou).

Öz

In this study, it was investigated that to determine the selectivity of 40 mm square (40S) and 90º turned mesh (40T90) codend for the European hake (Merluccius merluccius) and blue whiting (Micromesistius poutassou). Fishing experiments were conducted on the international waters of the Aegean Sea by using 1200 mesh tailored trawl. Codends have knotted polyethylene (PE) 380d/21 no rope thickness and 5 m in lengths. The hooped covered codend technique was employed for the estimated codend selectivity. The selectivity parameters were estimated by using SELNET software. The plots were made with R (v.4.0.3) based RStudio (v. 1.4.1106) software using the “ggplot2 (v.3.3.3)” package. Nineteen successful hauls, 11 with 40S and 8 with 40T90 codends, were performed. The mean L₅₀ values (50% retention length) of 40S and 40T90 were found to be a 13.23 cm and 12.55 cm total lengths for the European hake and 23.73 cm and 19.91 cm total lengths for the Blue whiting, respectively.

Anahtar Kelimeler

• Trawl
• Selectivity
• Aegean Sea
• Merluccius merluccius
• Micromesistius poutassou

Trol balıkçığında 40 mm göz açıklığındaki kare ve 90º döndürülmüş torbaların Bakalyaro (Merluccius merluccius, Linnaeus, 1758) ve Derinsu mezgiti (Micromesistius poutassou Risso, 1827) seçiciliği

Öz

Bu çalışmada, bakalyaro (Merluccius merluccius) ve derinsu mezgiti’nin (Micromesistius poutassou) 40 mm ağ göz açıklığına sahip kare (40S) ve döndürülmüş (40T90) torbalardaki seçicilik parametreleri araştırılmıştır. Denemeler 1200 gözlü dip trolü kullanarak Ege Denizi'nin uluslararası sularında gerçekleştirilmiştir. Torbalar düğümlü polietilen (PE) 380d/21 no ip kalınlığında ve 5 m uzunluğundadır. Torba seçiciliğinin ölçümünde çemberli örtü torba tekniğinden yararlanılmıştır. Boy seçiciliği analizi için SELNET programı kullanılmıştır. Grafikler, "ggplot2 (v.3.3.3)" paketi kullanılarak RStudio (v. 1.4.1106) yazılımı ile yapılmıştır. Toplam 19 geçerli çekim yapılmıştır. Bu çekimlerin 11’i 40S ve 8’i ise 40T90 ile gerçekleştirilmiştir. Bakalyaro için 40S ve 40T90 torbandan elde edilen, ortalama L₅₀ değerleri sırası ile 13,23 ve 12,55 cm’dir. Mezgit için L₅₀ değeri 40S torbada ortalama 23,73; 40T90 torbada ise 19,91 cm olarak bulunmuştur.

Anahtar Kelimeler

• Trol
• Seçicilik
• Ege Denizi
• Merluccius merluccius
• Micromesistius poutassou

Kaynakça

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