FADs must be constructed to prevent animals becoming entangled
Animals that are not targeted during tuna fishing but are inadvertently caught or entangled in fishing gear are known collectively as bycatch. The most commonly caught animals are juvenile bigeye and yellowfin tuna, some smaller species of tuna, seabirds, dolphins, whales, sharks, rays and turtles. Tuna fishing affects marine animals such as sharks, turtles, whales, dolphins, and seabirds when they are inadvertently caught (as bycatch) during normal fishing operations. As well, some kinds of tuna that are not desired in the catch end up as bycatch. They include juvenile bigeye and yellowfin tuna, and some smaller species of tuna.
Bycatch may be commercially valuable, or have no or little commercial value. Either way, bycatch generally results in economic losses from damaged fishing gear, lower catches of targeted species, and fishing restrictions being imposed.
Bycatch is also one of the biggest threats to marine biodiversity, with as much as 40% of all animals caught being discarded. Some estimate that about 300,000 small whales, dolphins, and porpoises, and hundreds of thousands of turtles, more than 3 million sharks, and 160,000 seabirds die every year after becoming entangled in fishing gear. By another estimate, every year, about 7.3 million tonnes of marine life is captured as bycatch from all fishing worldwide.
In the WCPO, two of the best practices in minimising harm to species not targeted by tuna vessels are:
- rules to enforce the use of non-entangling fish-aggregating devices (FADs)
- PNA rules that prohibit the use of FADS for three months a year.
PNA countries prohibit the use of FADs for three months a year
The member countries of the Parties to the Nauru Agreement prohibit the use of fish-aggregating devices (FADs) in PNA watersfor three months each year, from 1 July to 30 September.
A more detailed prohibition has also been agreed for the WCPO by the Western and Central Pacific Fisheries Commission.
WCPFC rules for bycatch-friendly FADs
Avoid using mesh
Under the new rules, FAD makers should avoid using mesh.
However, if they do use it, they must ensure that the mesh, when stretched, is no larger than 7 cm. It must be secured snugly to the raft, so it does not hang loose.
If used in the ‘tail’ that hangs beneath the raft, mesh must be securely tied in a sausage shape so that animals cannot get caught in it. Tails should be weighted so they hang vertically or almost vertically in the water.
A rope or a sheet of canvas are considered better options than mesh.
Need to reduce plastic waste in oceans
The promotion of natural materials is aimed at reducing the amount of plastic waste drifting in the oceans, and washing up on reefs and coasts. FADs and other lost fishing gear contribute to this pollution.
Parts of a FAD that has broken up washed up on a beach in New Caledonia. Photo: A. Durbano, Association HÃ´-Ã¼t, New Caledonia.
FADs are important in purse-seine fishing for tuna
Fish-aggregating devices are one of the most important methods used to catch tropical tuna. They exploit the habit of many kinds of fish, including tuna, of clustering around floating objects, whether natural (e.g. driftwood, dead whales) or artificial. Tuna will congregate around a FAD in schools numbering thousands.
Large FADs are used extensively in commercial purse-seine fishing because they increase the likelihood of successful fishing operations. Thousands of drifting FADs are put into the Western and Central Pacific Ocean every year.
They also cause the catch of juvenile tuna and loss of endangered animals
The widespread use of FADs has resulted in many problems. As well as catching the desired tuna, fishing fleets often also unintentionally take too many small juvenile tuna, which are part of the school but are too young to breed. They also take other fish that have no commercial value, as well as sharks and turtles.
Turtles and sharks, many of which are endangered, sometimes become tangled in the mesh used in FADs and die.
New FADs designed to reduce bycatch and plastic pollution
The WCPFC commissioned research on the best designs and materials for FADs to reduce bycatch. More research is needed, and the WCPFC will amend the rules for fishing in the western and central Pacific Ocean as better designs come on line.
Best practice in the design of biodegradable, non-entangling FADs. Image credit: ISSF.