The Influence of the Moon Phase on the CPUEs of Swordfish Gillnet Fishery in the Aegean Sea, Turkey

Year 2013, Volume: 13 Issue: 2, - , 01.04.2013

Okan Akyol

https://doi.org/10.4194/1303-2712-v13_2_18

Abstract

This paper provides the analysis the moon phase’s on CPUE (Catch per Unit Effort) related to Turkish Aegean swordfish (Xiphias gladius) gillnet fishery during 2009-2010 fishing seasons. Mean CPUE (kg/km) was 47.0 ±14.5 during the dark period, against 24.1 ±3.8 in light period in 2009. Besides, mean CPUE was 56.3 ±10.2 during the dark period, whereas 45.1 ±7.8 in light period in 2010. In the two years periods (2009-2010) examined, the mean CPUE was 50.5 ±9.7 during the dark period, while 32.8 ±4.1 in light period. All the CPUE peaks were clearly close to each new moon phase and the highest peak (300 kg/km) was computed in May 2009 during the dark period. The results obviously indicate the increasing of the swordfish landings during the dark periods.

Keywords

Swordfish, Xiphias gladius, CPUE, moon phases, Aegean Sea.

The Influence of the Moon Phase on the CPUEs of Swordfish Gillnet Fishery in the Aegean Sea, Turkey

Abstract

Bu çalışma 2009–2010 balıkçılık sezonunda Ege Denizi kılıçbalığı (Xiphias gladius) solungaç ağları balıkçılığıyla ilgili CPUE (birim çaba başına av) üzerine ayın evrelerinin analizini vermektedir. 2009 yılında ortalama CPUE (kg/km) karanlık dönem boyunca 47,0 ±14,5, aydınlık dönem boyunca ise 24,1 ±3,8 idi. Buna karşılık, 2010 yılında karanlık dönem boyunca 56,3 ±10,2; aydınlık dönem boyunca 45,1 ±7,8 idi. İncelenmiş iki yıllık (2009–2010) dönemde ise, karanlık dönem 50,5 ±9,7 iken, aydınlık dönem 32,8 ±4,1 idi. Tüm CPUE pikleri belirgin olarak hep karanlık fazdaydı ve en yüksek pik (300 kg/km) Mayıs 2009’da hesaplanmıştır. Sonuçlar açıkça karanlık dönemler boyunca kılıç avının arttığını göstermektedir.

Keywords

Kılıç balığı, Xiphias gladius, ayın evreleri, Ege Denizi.

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