Gilbert Nakweya, SciDev Net (January 23, 2012)
Fitting traditional fish traps with 'escape gaps' dramatically reduces the catch of non-target fish while maintaining fishers' incomes, according to research in Kenya.
Key to protecting fisheries is increasing sustainability without sacrificing the size of fishers' catches, Emmanuel Mbaru a researcher with the Wildlife Conservation Society, which is conducting the research, told SciDev.Net.
Local fishermen built traditional basket traps and then added vertical rectangular gaps, 2–4 centimetres by 30 centimetres, to their sides. These gaps allow juvenile and narrow-bodied species to escape but retain larger target species.
The research was carried out in Bamburi, Nyali, Mkwiro and Kibuyuni on the Kenyan coast in a heavily fished coral reef lagoon. Researchers placed the traps at marked locations 5–10 metres deep and baited them with sea grass and algae — a common practice in Kenya
The new traps reduced the number of non-target fish by up to 80 per cent.
The gaps had no significant effect on the number of target, high-value species.
Reducing wasteful 'bycatch' — young or small fish that are not always sold — is a key aspect of increasing the sustainability of fisheries.
The innovation is already being adopted in several fishing areas on the Kenyan coast and Mbaru hopes these successful experiments will encourage others to take up the technique.
He said this low-cost, low-tech innovation can contribute to poverty reduction and increase the biodiversity of fishery ecosystems.
The programme won the grand prize of US$20,000 at the 'Solution Search: Turning the Tide for Coastal Fisheries' contest and it will receive the award at a ceremony in the United States next month (8 February), for its work in Kenya and Curaçao, in the Caribbean.
Edward Kimakwa, fisheries programme officer for the Coastal East Africa Initiative of the World Wide Fund for Nature (WWF), said: "Juveniles will be able to grow into mature adults and, depending on the species, fetch higher value on the market than smaller individuals".
Mature stock will also be able to breed and contribute to the recovery of the fisheries, he said.
But Kimakwa cautioned that mass production of the traps could lead to shortages of the materials for the trap, driving up prices and damaging the environment.