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2. Is net illumination a silver bullet for mitigating sea turtle bycatch in set net fisheries?Matic Jančič, Matteo Benussi, Sven Amančić, Peter Mackelworth, Draško Holcer, Bojan Lazar, 2025, izvirni znanstveni članek Opis: Fisheries bycatch is the main threat to sea turtle populations in marine habitats in the Mediterranean Sea. Bycatch in set nets accounts for 30,000 catches yearly, which combined with mortality rates of up to 82.6 %, makes it the deadliest fishing gear in the region. The Adriatic Sea is one of the most important foraging and developmental habitats for loggerhead sea turtles (Caretta caretta) in the Mediterranean. Bycatch in the Adriatic small-scale set net fishery is estimated at over 8900 individuals per year placing its mitigation among international conservation priorities. Use of light emitting diodes (LED lights) of different wavelengths as bycatch deterrents was proposed as an effective conservation tool, reducing bycatch levels by up to 93 %. In the present study we: (i) quantified the effects of net illumination on loggerhead sea turtle bycatch rates and (ii) demonstrate the importance of regional validation of conservation tools effectiveness prior to their widespread adoption. We assessed the effects of green LED lights on sea turtle bycatch rates in 390 net pairs with total length of 1278 km monitored nets. We found no significant change in sea turtle bycatch rates as a result of net illumination. A significant decrease of 35 % of primary target catch was observed in illuminated trammel nets. Possible explanations include fluctuating turbidity and an adapted LED light attachment method. Observed sea turtle bycatch rates in unilluminated nets were up to 84 times lower than in comparable gears in Northern Adriatic Sea. Understanding the drivers behind the differing bycatch rates would be necessary before conservation decisions are made. Our study showed that the net illumination is not necessarily a silver bullet for bycatch mitigation in set nets globally, and that regional testing is a key requirement before its introduction in fisheries as a conservation tool.
Ključne besede: marine megafauna, Caretta caretta, small scale fisheries, bottom set nets, bycatch hotspot, bycatch mitigation, visual deterrents
Objavljeno v RUP: 06.08.2025; Ogledov: 547; Prenosov: 6
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3. Zgodovina, sedanjost in prihodnost prilova v evropskem morskem ribištvu : zaključna nalogaMikel Gutiérrez Muto, 2018, diplomsko delo Ključne besede: bycatch, incidental catch, discards, sea turtles, sharks, Atlantic, North Sea, Mediterranean Sea
Objavljeno v RUP: 09.10.2018; Ogledov: 3711; Prenosov: 42
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5. Prioritizing fishery management for loggerhead turtle (Caretta caretta) conservation in the northern Adriatic Sea from reproductive value analysisBojan Lazar, Selina S. Heppell, 2009, objavljeni povzetek strokovnega prispevka na konferenci Opis: Fisheries bycatch often affects particular size classes of turtles. Because of the late age at maturity, the reproductive value (RV) of small juvenile, large juvenile and adult loggerheads vary by orders of magnitude. RV provides a relative measure of value for individuals, thereby allowing us to estimate the effects of different stressors based on the number of animals killed. Using RV as a comparative index, we assessed the relative impact of trawl and gillnet fi sheries operating in the northern Adriatic Sea on loggerhead populations. We tested several scenarios for bycatch in both fi sheries which signifi cantly differs in the size of captured animals and mortality. Despite high bycatch rates, bottom trawl fi sheries result in direct death of fewer loggerheads (156-260 vs. 346-486 in gill nets), but affect individuals that are older and hence have higher RVs. Because of data limitations for vital rates and bycatch estimates, we looked at a distribution of potential impact for each fi shery. Lessons learned include the need for relative impact assessment because of the sensitivity of adult RV to parameters such as clutch frequency, sex ratio and remigration interval. We anticipate that our analysis will help managers prioritize needs for regulation and mitigation among different fi sheries.
Ključne besede: sea turtles, bycatch, population modelling, reproductive values, marine conservation
Objavljeno v RUP: 15.10.2013; Ogledov: 6697; Prenosov: 98
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