Sea cucumbers are a highly valued resource in coastal communities of the Western Indian Ocean. There are, however, increasing indications that these fisheries are in trouble and slipping toward degradation.

While largely unknown in the English-speaking world, sea cucumber (trepang, bêche-de-mer or balate) fisheries are widespread around the world. In the Western Indian Ocean, the sea cucumber industry has existed for over a century and is an important livelihood source in many coastal households. However, it is an industry that is becoming increasingly brittle. The total sea cucumber catches have been declining over the last 10 years and fishers are catching smaller individuals and having to target lower-value sea cucumber species (since many high-value species have been depleted from the fishing grounds). These negative trends have been driven by an expansion of the industry that is fueled by the huge demands of, mainly, the Asian market.

In Kenya, these fisheries are poorly understood and the current management policies are woefully inadequate to confront the emerging challenges. A newly published study in Ocean & Coastal Management by Swedish and Kenyan researchers begins adressing critical knowledge gaps in Kenyan sea cucumber fisheries. They show that Kenyan sea cucumber stocks show several signs of over-harvesting.

- Commercially valuable species may be threatened with depletion if control measuresare not put in place urgently. Collection of the previously low-value species and small-size sea cucumbers is increasing due to high demand in the Asian market and the high profits from these sizes, says co-author Maricela de la Torre-Castro

Sea cucumbers sold in Chinese market. Photo courtesy of Max Troell/azote.se

One of the most alarming findings is that there are clear incentives to fish juvenile sea cucumbers, since the relative profits are higher when fishing juveniles contra adult individuals.

- About half of the interviewed fishermen pointed out that so far there is no regulation on the size of individualsea cucumbers harvested. This is an incentive for fishers to harvest what they feel among themselves is appropriate. Consequently, the fishing of small-size sea cucumbers is increasing and is likely to become a problem in future, especially if recruitment relies on local stocks, says de la Torre-Castro.

Improving management

A first step in improving the situation of sea cucumber stocks in the region would be to establish size limits for sea cucumbers that enter the market. Furthermore, reliable databases of trends in the sea cucumber fishery would provide better platforms on which to create sustainable management policies.

- It could be made mandatory for licensed owners of sea cucumber fishing vessels to provide data on catch and effort, the fishing ground where sea cucumbers have been caught and the number of fishers who have used the boat. Further, a special arrangement should be made with the sea cucumber exporters to provide accurate data on the quantity of each species exported, where they are exported to, and the price offered for each species, according to de la Torre-Castro