Author: A. Miletić
Bycatch refers to those species that were inadvertently caught during fishing activities and includes incidental catches of endangered species or discards of non-commercial and commercial marine organisms. It is one of the causes of the endangerment of many vulnerable groups of marine animals, such as marine mammals, sea turtles, cartilaginous fish, and seabirds.
Seabirds are most often caught on longline hooks (before the bait sinks) or entangled in nets. Bycatch is a missed opportunity for the fisherman and a fatal outcome for the bird. Therefore, several activities and measures are being implemented around the world to mitigate and/or reduce it. In countries where seabird bycatch during fishing is a big problem, fishermen are looking for solutions to reduce the loss of bait on hooks and to ensure targeted fish catches. Thus, for example, Greek fishermen who are fishing near large colonies of birds voluntarily began to set longlines at night, because then the activity of seabirds is reduced, like the possibility of mutual interaction.
Depending on whether they are related to the fishing activity itself or the fishing gear, seabird bycatch mitigation measures can be divided into two groups:
- modification or improvement of fishing practices,
- modification or improvement of fishing gear.
Group A includes measures that in some way change the fishing activity, and for their implementation, it is necessary to raise awareness of fishermen or introduce spatial-temporal regulation of fishing. These are the measures:
- night setting and minimization of lighting of longlines to reduce the visibility of the hooks and setting fishing activity at a time when seabirds are relatively inactive,
- offal and discard management i.e., avoid throwing fish waste when setting longlines or hauling nets, to avoid attracting large numbers of birds at this stage of fishing,
- avoiding fishing in areas where endangered seabirds feed and stay (seasonal or permanent).
Group B includes measures of using custom fishing gear that prevent accidental catch of seabirds. it is used to keep birds away from fishing gear, increase the speed of the sinking of baited hooks and make them less visible to the birds. These are the measures of use:
- streamer lines (tori lines, bird-scaring lines) – You can see how it works on the link,
- high contrast panels on gillnets,
- devices for scaring or distracting birds. They can be visual, acoustic, lighting, or have a combination of different effects (e.g., LED lights, artificial birds),
- additional weighting on demersal longlines, to increase the speed of sinking hooks and thus reduce the time of exposure of baits to seabirds,
- hook-shielding innovation, hookpod for pelagic longlines – You can see how it works on the link.
In order for measures to be effective and to ensure that they are implemented by fishermen, they should be simple, appropriate to the fishery type, cost-effective, practical, safe, and accompanied by economic or social incentives. In addition, it is important to raise the awareness of fishermen, and other key stakeholders, about seabird bycatch and their role in it.
Therefore, solutions to reduce seabird bycatch exist, and the efficiency is higher if different measures are combined at the same time.
In collaboration with fishermen from the islands of Vis, Korčula, and Lastovo, in 2022. modified fishing gear will be tested: LED lights for gillnets, additional weight for demersal longlines, and hookpods for releasing hooks of pelagic longlines under the sea.
Source: Udruga za prirodu, okoliš i održivi razvoj Sunce (2021): Izvješće o interakciji morskih ptica i ribolovnih aktivnosti te mjerama za smanjenje slučajnog ulova morskih ptica. Projekt: LIFE ARTINA – LIFE17 NAT/HR/000594 „Seabird Conservation Network in the Adriatic.
- Source 1: https://www.acap.aq/fr/latest-news/3703-bird-scaring-lines-and-night-setting-on-pelagic-longliners-save-albatrosses-from-drowning-on-hooks
- Source 2: https://marinemadness.blog/2019/12/18/using-led-lights-to-reduce-bycatch-in-gillnet-fisheries/
- Source 3: https://www.acap.aq/fr/actualites/dernieres-nouvelles/4191-new-trials-for-the-hookpod-mini-planned-for-south-africa-in-2022