Study shows modifying gear size allows smaller fish to escape resulting in more profitable catches for poverty-stricken fisheries

Path towards fisheries success found in coastal Kenya

NEW YORK (May 7, 2012) – A new study by marine scientists from the Centre of Excellence for Coral Reef Studies at James Cook University, Australia and the Wildlife Conservation Society says that modifying the size of certain fishing gear results in more profitable fisheries by minimizing the harvest of juvenile fish, which are smaller and less profitable than adults.

The paper, published in the open access journal PLoS ONE, looked at trends in the lengths of the fifteen most common types of fish caught in the coastal fisheries of Kenya to find out whether these species were being fished at rates that reduce fisher’s potential incomes. The study found that most of the fifteen species were fished beyond levels that would achieve the maximum yields. However, the study applied a fisheries model to optimize the yield of these species and found that modifying nets so that juvenile fish could escape could rectify this problem, and result in significantly increased fisher income.

According to the study, an increase in the current minimum mesh size of fishing nets by only 2.5 cm would protect over 60 percent of the current catch from being harvested prematurely.

The authors have been studying Kenya’s fisheries for close to 20 years to find ways to reduce the poverty around these fisheries. Some of the key questions they have been trying to answer include whether or not the catches and incomes of fishers could be increased if the rules were followed or changed. This study lends positive empirical evidence that this goal is indeed in reach.

The papers lead author Christina Hicks of the Centre of Excellence for Coral Reef Studies at James Cook University said: “Fishers often prefer management that controls or modifies the types of fishing gears, than the common alternative of banning fishing entirely, because they can continue fishing. However, it is pretty costly to keep checking if the rules about fishing gears are being followed.”

Unfortunately, some of the gears that were used to land the fifteen species had been banned by the Kenyan fisheries department, making it clear that current gear restrictions are not being universally followed, according to the study.

Co-author Dr. Tim McClanahan of the Wildlife Conservation Society, said: “The fisheries department is on the right track and with another set of modifications of restrictions focused on the mesh size, which we know to be more acceptable to fishers, and these species could recover and increase fishers incomes over the long term. The gears that are banned target the vulnerable species that grow slowly. Furthermore, the minimum legal mesh size on nets provides adequate protection to at least of the common species, the immature green parrotfish. This is promising news and should provide the impetus needed to step up fisheries monitoring and education to make sure these rules are followed”.

Hicks added: “These new net rules would have to be introduced gradually if they are to have any hope of success. But if successful, using larger mesh nets would lead to more fish in the sea and more money in fishers’ pockets.”

The full article, including a Kiswahili abstract, can be downloaded free from PLoS ONE: Hicks CC & McClanahan TR. Assessing gear modifications needed to optimize yields in a heavily exploited, multi-species, sea grass and coral reef fishery: http://dx.plos.org/10.1371/journal.pone.0036022

From Fiji to Kenya to Glover’s Reef, Dr. Tim McClanahan’s research examines the ecology, fisheries, climate change effects, and management of coral reefs at key sites throughout the world. This work has been supported in part by the John D. and Catherine T. MacArthur Foundation.