Judul: The Effect of Different in Twine Thickness of Gillnet on Size Selectivity and Catching Mechanism of Tilapia
Abstrak: Ketebalan benang jaring insang diketahui menjadi salah satu faktor yang mempengaruhi selektivitas. Informasi mengenai pengaruh perbedaan ketebalan benang jaring insang terhadap performa selektivitas ukuran dan tingkah laku ikan nila (Oreochromis niloticus) pada proses penangkapan masih sangat terbatas. Penelitian ini bertujuan menghitung pengaruh perbedaan ketebalan benang jaring terhadap performa selektivitas ukuran ikan nila serta mendeskripsikan proses tertangkap dan mekanisme pelolosan ikan nila melalui mata jaring insang berdasarkan kajian tingkah laku ikan. Pengambilan data dilakukan melalui serangkaian penangkapan eksperimental. Uji Kolmogorov-smirnov digunakan untuk mengetahui tingkat signifikansi antara dua distribusi ukuran panjang ikan nila yang tertangkap berdasarkan ketebalan benang jaring insang. Data diolah menggunakan model log-normal dengan metode maximum likelihood melalui fasilitas SOLVER pada software MS-Excel. Hasil penelitian menunjukkan bahwa sebanyak 70 ekor (55,24%) ikan nila tertangkap pada mata jaring dengan ketebalan benang 0,15 mm dan 64 ekor (47,76%) ikan nila tertangkap pada mata jaring dengan ketebalan benang 0,28 mm. Distribusi ukuran panjang total ikan nila yang tertangkap pada kedua ketebalan benang jaring, tidak berbeda nyata (P>0,05). Meskipun demikian, mata jaring dengan ketebalan 0,15 mm sedikit lebih selektif dari mata jaring 0,28 mm, ditunjukkan dengan tingkat efisiensi penangkapan dan peluang tertangkapnya ikan nila yang lebih tinggi. Mekanisme tertangkap dan pelolosan terjadi ketika ikan nila berhadapan dengan jaring., The twine thickness of the gillnets is one factor that affects selectivity. Information regarding the effect of differences in the twine thickness of gillnet on size selectivity performance and behavior of tilapia (Oreochromis niloticus) in the fishing process is still a little. This study aims to calculate the effect of differences in the twine thickness on the performance of tilapia size selectivity and to describe the catching process and the captured mechanism of tilapia in gillnets based on the fish behavior observation. Data collection was carried out by experimental fishing. The Kolmogorov-Smirnov test was used to determine the level of significance between the two length size distributions of tilapia caught based on the twine thickness of the net. The data was analyzed using a log-normal model with maximum likelihood method through the SOLVER facility on MS-Excel software. The results showed as many as 70 (52.24%) tilapia were caught in a 0.15 mm net twine thickness and 64 (47.76%) tilapia were caught in a 0.28 mm net twine thickness. The size distribution of the total length of tilapia caught in the two net twines was not significantly different (P>0.05). The 0.15 mm net twines were slightly more selective than the 0.28 mm net twines, showing a higher fishing efficiency and catching efficiency. The captured mechanism and escaping behavior occurred when tilapia faced the net.
Keyword: Ikan Nila/Tilapia, Ketebalan Benang/Twine Thickness, Log-normal/Log-normal, Mata Jaring Insang/Gillnet, Selektivitas Ukuran/Size Selectivity