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Za potrebe ovog rada uzorkovane su 94 jedinke jegulje (Anguilla anguilla). Svakog dana, mali uzorak živih jegulja je ubačen u testnu vršu, veličine oka 19,97 mm, koja je postavljena u posudu od 500 l ispunjenu morskom vodom. Nakon 24h, posuda bi se ispraznila, a jeguljama koje su pobjegle kroz oka testne vrše i jeguljama zadržanim unutar vrše izmjerena je ukupna duljina. Na temelju ovih podataka određeni su selektivna krivulja i selekcijski parametri L50 i SR testne vrše za lov jegulje. Mjerenjem opsega najvećeg presjeka jegulja uz pomoć morfometra, te provođenjem testa propadanja, kreiran je prediktivni model kojim je uspješno reproducirana selektivna krivulja testne vrše, te je ustanovljeno da kut otvora mrežnog oka na vrši ne igra nikakvu ulogu u selektivnosti, budući da ga jegulja snagom svog tijela može u potpunosti deformirati tijekom izlaska iz vrše. For the purpose of this thesis, 94 individuals of eel (Anguilla anguilla) were sampled. The eels were previously caught with commercial fyke nets. Each day, a small sample of live eels were transferred inside the test pot, made of 19.97 mm diamond mesh netting. The test pot was placed in a 500 l holding tank filled with seawater. After 24h, holding tank was emptied, eels escaped through the pot meshes and those retained inside the pot were collected and length measured to the nearest mm. Data collected was used to estimate eel pot selectivity. A logit curve was fitted to the experimental data, allowing the estimation of size selection parameters L50 and SR. Using the morphometer, we measured two cross sections with maximum circumference. The eels were then tested for their ability to pass through the range of mesh sizes from 14 mm to 40 mm, with mesh opening angles ranging from 15° to 90°. All this data was used to create predictive size selection model for eel pots. The prediction obtained using the model successfully recreated experimental size selection curve obtained for the test pot. |
