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efforts to make and distribute modified traditional baskets used for trapping fish are ongoing along the Kenyan coast. The baskets are proving a big help in reducing the impact of fishing on the East African country’s coastal reef system， while simultaneously boosting fishermen’s profits.
By using these modified gated traps， it has been demonstrated for the first time anywhere in Africa that catching targeted fish， without capturing the juveniles or unintended species， is indeed possible.
“We have been converting a trap fishery in Mombasa to gated traps. This process is moving along but not complete yet，” said Dr. Tim McCalanahan， head of the Wildlife Conservation Society （WCS） coral reef research and conservation program.
Discussions are ongoing about how to expand the use of the new traps in Tanzania and the Quirimba Islands in Mozambique.
To help create more interest in the modified traps， a pair of three-and-a-half minute films have been made in Swahili， under the title Lema la Kisasa， one of which is a cartoon. Both of the films can be viewed on Youtube.
A paper on the experimental study on the use of the modified basket trap appeared at the end of last year in the Fisheries Research publication.
The study was jointly conducted by the Kenya Marine and Fisheries Research Institute （KEMFRI） and the WCS.
Marine researchers have proved that by modifying the fish basket so that it has escape gaps， larger fish can be trapped， while allowing more undersized and non-target fish to escape. The research took six months， according to McClanahan and was conducted at the Mombasa Marine National Park， on the Kenyan coast.
“This is important in eliminating by-catch， which plays an important ecological role in the marine ecosystem，”explained McClanahan， who is also the study’s co-author.
Such innovations， he observes， can make a big difference in maintaining the ecology of vital coastal resources.
Emanuel Mbaru of KEMFRI explains that catching of coral reef fish， even at an artisanal scale， can lead to severe changes in the fisheries ecosystem.
“Continuous capture of ornamental species that are neither targeted by fishermen nor desirable as food can also reduce the number of ornamental fish in the water，” he said.
This can have a negative impact on ecotourism， “since many recreational divers consider species diversity a key attraction of coral reef dives，” said Mbaru.
Capturing unintended fish has long been a problem in Kenya， given that most of the fishing gear used by artisanal fishermen. These include spearguns， beach seines and monofilament gill nets， which are still in use， despite bans imposed on them by the State Department of Fisheries.
Although trap fishermen typically target high value fish such as groupers and snappers， traditional traps in use are not selective enough. They usually retain most fish that enter， resulting in the capture and mortality of many species.
Mbaru said high numbers of juvenile fish and nontarget species have consequently reached well over 50 percent of the total catches， even with relatively little fishing effort. Evidence from the study shows that the new trap has made a statistically measurable difference in minimizing by-catch， while maximizing the size of fish caught. The fishing basket is metal-framed with netting and a single， tube-shaped opening leading into the middle of the trap， with escape gaps measuring 12 inches by 1？ inches. The escape gaps are designed to allow undersized and non-target fish to exit while retaining commercially valuable adult fish.
The baskets are also cheap， costing a little over $1 per trap while increasing the fishermen’s income by 55 percent， as bigger fish bring in more profit.
By using these modified gated traps， it has been demonstrated for the first time anywhere in Africa that catching targeted fish， without capturing the juveniles or unintended species， is indeed possible.
“We have been converting a trap fishery in Mombasa to gated traps. This process is moving along but not complete yet，” said Dr. Tim McCalanahan， head of the Wildlife Conservation Society （WCS） coral reef research and conservation program.
Discussions are ongoing about how to expand the use of the new traps in Tanzania and the Quirimba Islands in Mozambique.
To help create more interest in the modified traps， a pair of three-and-a-half minute films have been made in Swahili， under the title Lema la Kisasa， one of which is a cartoon. Both of the films can be viewed on Youtube.
A paper on the experimental study on the use of the modified basket trap appeared at the end of last year in the Fisheries Research publication.
The study was jointly conducted by the Kenya Marine and Fisheries Research Institute （KEMFRI） and the WCS.
Marine researchers have proved that by modifying the fish basket so that it has escape gaps， larger fish can be trapped， while allowing more undersized and non-target fish to escape. The research took six months， according to McClanahan and was conducted at the Mombasa Marine National Park， on the Kenyan coast.
“This is important in eliminating by-catch， which plays an important ecological role in the marine ecosystem，”explained McClanahan， who is also the study’s co-author.
Such innovations， he observes， can make a big difference in maintaining the ecology of vital coastal resources.
Emanuel Mbaru of KEMFRI explains that catching of coral reef fish， even at an artisanal scale， can lead to severe changes in the fisheries ecosystem.
“Continuous capture of ornamental species that are neither targeted by fishermen nor desirable as food can also reduce the number of ornamental fish in the water，” he said.
This can have a negative impact on ecotourism， “since many recreational divers consider species diversity a key attraction of coral reef dives，” said Mbaru.
Capturing unintended fish has long been a problem in Kenya， given that most of the fishing gear used by artisanal fishermen. These include spearguns， beach seines and monofilament gill nets， which are still in use， despite bans imposed on them by the State Department of Fisheries.
Although trap fishermen typically target high value fish such as groupers and snappers， traditional traps in use are not selective enough. They usually retain most fish that enter， resulting in the capture and mortality of many species.
Mbaru said high numbers of juvenile fish and nontarget species have consequently reached well over 50 percent of the total catches， even with relatively little fishing effort. Evidence from the study shows that the new trap has made a statistically measurable difference in minimizing by-catch， while maximizing the size of fish caught. The fishing basket is metal-framed with netting and a single， tube-shaped opening leading into the middle of the trap， with escape gaps measuring 12 inches by 1？ inches. The escape gaps are designed to allow undersized and non-target fish to exit while retaining commercially valuable adult fish.
The baskets are also cheap， costing a little over $1 per trap while increasing the fishermen’s income by 55 percent， as bigger fish bring in more profit.