Lights can act as a visual cue to alert non-target species of fishing gear. They are a practical, cost effective solution to help reduce bycatch in driftnet and static net fisheries. Simple and robust, LED lights are designed to be attached to fishing nets to increase visibility of the gear to a wide range of non-target species. By illuminating the net, non-target megafauna species are aware of its presence and therefore are less likely to become entangled – the net becomes more selective – subsequently reducing the time fishermen spend repairing their gear after damages caused by unintentional bycatch.
Different patented designs are available – such as the FishTek ‘NetLight’ and the Centro ‘Deep Water Power Light’ – both are as compact and lightweight as possible. The lights are LEDs, run on AA batteries and can provide illumination for 500-800 hours (in the case of Fishtek’s ‘NetLight’). Built with reinforced attachment points, the lights are held securely in place, increasing usability when setting and hauling. Both Fishtek’s light and Centro’s light are additionally designed with automatic immersion control so the light only switches on once the device is underwater.
A 2019 study on a small-scale Peruvian gillnet fishery reported that illuminated nets reduced bycatch by 71% for small cetaceans and 84% for seabirds when compared with the non-illuminated, control nets. Crucially, lights did not negatively affect the catch rates of target species. Another study on the demersal, set gillnet fishery of Constante, Peru reported an 85% decline in cormorant bycatch following the deployment of lights. Finally, a study on Ghana’s artisanal gillnet fishery found that green LED lights resulted in an average of 81% declines in sea turtle capture across three different species (olive ridley, leatherback and green).
Although emerging evidence suggests that net lights may be a feasible mitigation measure, a study in the Baltic Sea gillnet fishery found otherwise. Researchers found that the lights actually attracted the bycatch species (in this case, long-tailed ducks) and suggested that this may be due to the species’ different foraging strategies. It is therefore recommended that future developments of net lights as a bycatch reduction device should be species- and location-specific, taking into account the varying behaviours and visual capabilities of vulnerable non-target species, as well as that of target species. The colour of the light-emitting lures used in longline fisheries, and interplay with the lunar cycle, has also been found to affect rates of bycatch across different species and taxa (for example, turtles and sharks may be attracted to light intended to attract tuna), although more research is needed in this area.
In the UK, lights are currently undergoing trials in a Cornish net fishery (CCUK NSG member pers. comm.).
This page was last updated on 20.12.22.
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