Baja California

Baja California

Saves time, better quality

Illuminating gillnets with LED lights has been shown to reduce bycatch of sea turtles, small dolphins and porpoises and seabirds. The theory is net illumination provides a visual cue within the appropriate sensitivity range that selectively deters or alerts non-target species to the presence of nets. In addition there are further benefits in terms of easier working practices on board and opportunities to improve catch quality.

The Arizona State University team clipped Centro lights designed for longline fishing onto the float lines of the gillnets. The lights were powered by batteries that last for three to four weeks. The team found a 63% reduction in average total bycatch biomass and were surprised to discover that the nets almost eliminated bycatch of sharks, skates and rays, a group of animals that has been declining worldwide from bycatch and illegal fishing.

There were also some further interesting benefits.The time taken to retrieve a and clear the illuminated nets was 57% less than for the standard gear, providing possibilities for greater efficiency on board coastal fishing vessels. The team found that crews can save considerable time when fishing with illuminated nets, which can potentially improve the quality of their catch.

The Arizona State University team is continuing its gear trials in Baja California Sur. Image: Ryan Fitzgerald / El equipo de la Universidad Estatal de Arizona continúa con sus ensayos de artes de pesca en Baja California Sur. Foto: Ryan Fitzgerald

‘Illuminated nets reduced the time it took to retrieve and sort gillnets following their overnight soak,’ Jesse Senko said.

‘This is the first time that the operational efficiency of net illumination has been assessed. Increased efficiency likely resulted from fishers needing to remove fewer entangled bycatch and, to a lesser extent, reduced hydrodynamic drag stemming from less biomass in the net. Given that gillnet fishers in Pacific Mexico generally fish with 800 – 1000 metres of net, the reduced haulback time would be expected to save fishers an average of 55.5 to 70.6 minutes per trip.’

According to Jesse Senko, while there are intrinsic benefits associated with time saved, small-scale fisheries frequently lack adequate space and capital to ice their catches, which can quickly degrade in quality.

‘Assuming fishers fish with the same effort, the time saved from increased operational efficiency could help reduce catch waste and improve catch quality by allowing it to be offloaded and iced sooner,’ he said.

Hanging green lights to the corklines of gillnets has been shown to reduce bycatch rates, as well as providing further benefits / Se ha demostrado que colgar luces verdes en los corchos de las redes de enmalle reduce las tasas de capturas accidentales, además de proporcionar otros beneficios

‘Also, the retrieval of nets by hand is a common practice in many small-scale fisheries. The benefits of net illumination go beyond reduction of haulback time, as the physical exertion and nuisance associated with untangling massive quantities of by-caught animals from nets are also reduced.’

As well as more research to optimise the nets’ effectiveness, one of the biggest challenges is figuring out how to make the illuminated nets more cost-effective in order to encourage the fishing industry to use them.

At their current price point (~ 7-9 US$/light), the LED lights that were tested by Jesse Senko and his team remain costly, especially in developing nations, while ongoing operational costs may also be necessary. Other less expensive LED fishing lights (~ 1.5 US$/light) are available, but their efficacy in reducing bycatch and durability in gillnet fisheries has yet to be investigated.

The nets are currently being tested in Baja California Sur, Mexico with plans for future testing in Pacific Mexico and Trinidad and Tobago. The team has also developed solar-powered LED lights that can remain operational for several years without the need to change batteries. These can also double up as corkline floats.

It looks like a win-win – if these devices can make fishing gear more selective, reduce bycatch and improve the working practices of coastal fishermen.