Dip Solungaç Ağlarında Afalina (Tursiops truncatus) Yunuslar İçin Kullanılan Yunus Kovucu Cihazların İncelenmesi ve Ekonomik Performansı

Bu çalışma Sinop liman bölgesinde Eylül 2015 ve Ocak 2017 periyodu içerisinde her ay cihaz kullanan ve kullanmayan balıkçılardan veriler alınarak, dip uzatma ağlarına yunus kovucu cihazlar (pinger) takılmasının akılcı bir uygulama olup olmadığını belirlemek amacıyla yapılmıştır. Balıkçıların kullandıkları fanyasız dip uzatma ağlarının göz açıklığı 34 mm, uzunlukları 1,1 km’dir. Cihazlı ağlarda kullanılan yunus kovucu cihazların frekansı 1-500 kHz olup, etkili mesafeleri 200m’dir. Cihazların şarj edilebilir ve total ömrünün 2-2,5 ay olması ayırt edilebilir özelliğidir. Cihazlı ağlarda (Eylül-Aralık 2015) ilk dört aylık dönemde ortalama 15,34±1,22 kg olan av miktarının ikinci (Ocak 2016-2017) dönem de yaklaşık %56 oranda azalarak 6,83±0,31 kg a düşmesi çalışmanın önemli bulguları arasında yer almaktadır. Her iki ağ grubuna ait diğer bulgulara göre birim çabada av miktarı cihazlı ağlarda 0,67±0,02 kgkms-1, kontrol ağlarda ise 0,63±0,02 kgkms-1 olarak gerçekleşmiştir. Avlanan balıklardan elde edilen toplam gelir cihazlı ağlarda 22.259,65 TL, kontrol ağlarda ise 20.880,90 TL olarak hesaplanmıştır. Ağlardaki hasar-donatım durumuna ve özellikle (2 adetx1500 TL) yunus kovucu cihaz alımına bağlı olarak değişiklik gösteren giderler; cihazlı ağlar için 6400 TL’na ulaşırken, kontrol ağlar için 4000 TL olarak hesaplanmıştır. Buna göre avlama yapılan periyodda cihazlı ağlardan elde edilen net gelirin 15.859,65 TL olduğu hesaplanırken, kontrol ağlardan elde edilen net gelirin bundan %6 daha fazla gerçekleşerek 16.879,90 TL olduğu belirlenmiştir. Sonuç olarak çalışmada kullanılan yunus kovucu cihazların bölgedeki balıkçı tarafından kullanılmasının önerilmesi mümkün görünmemektedir.

Anahtar Kelimeler:

Karadeniz, Dip solungaç ağı, Yunus kovucu cihaz, Etkileşim, Ekonomik performans

Investigation and Economic Performance of Acoustic Detterent Devices Used in Bottom Gillnets (Pingers) for Bottlenose Dolphin (Tursiops truncatus)

The study was performed in Sinop between September 2015-January 2017 to investigate whether it is a profitable application to attach pinger devices to bottom-gillnets used in coastal fisheries. Gear specifications of both fishermen group were same as follows; mesh size: 34 mm, length: app. 1,1km. The frequency range of the pinger device is 1–500 kHz and effective up to 200m. The most important distinctive feature of those devices is having a built-in rechargeable 1,6 Ah NiMH battery pack but limited up to 2-2,5 months (1000-1500h) total lifetime. In experimental group; average fish catch in the first periods (September-December 2015) was 15,34±1,22 kg and it decreased by 56% to 6,83±0,31 kg between January 2016–2017. According to results obtained from both control and experimental group, Catch Per Unit Effort (CPUE) was calculated as 0,63±0,02 kgkms-1 and 0,67±0,02 kgkms-1, respectively. Total incomes from the sale of fish were 20880,90 TL and 22259,65 TL for control and experimental groups. The fishermen in control group spent 4000 TL to repair nets damaged due to dolphin presence while other fishermen spent 3400 TL to repair nets. Considering the device expenses for the experimental group (2x1500 TL), total cost was calculated as 6400 TL for experimental group and 4000 TL for control group. Therefore, net income was calculated as 16879,90 TL in control group while it decreased to 15859,65 TL in experimental group, representing 6% decline.

Keywords:

Black Sea, Bottom gillnet, Pinger, Interaction, Economic performance,

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