An assessment of local fisheries in Diego-Suarez Bay, Madagascar

Identifying where the main fishing areas and areas of high fish biomass, species diversity, high numbers
of fish counted and coral cover within the bay provide information for possible management schemes, in
terms of implementing no-take zones.
4.3 Summary of possible conservation management methods
Restricting the use of seine nets to reduce coral damage (McClanahan et al., 1996) and regulating mesh
sizes to reduce juvenile mortality and by-catch could help to prevent the effects of overexploitation, by
increasing juvenile survivorship (Lindholm et al., 2001). The introduction of no-take zones in areas like
the eastern part of sector 4, the western part of sector 5, Nosy Koba and Nosy Langoro would encourage
long-term survival of fish stocks. This would in turn help protect the spawning stock of the exploited
populations, which could lead to the build up and replenishment of adjacent fishing grounds (McClanahan
& Mangi, 2000; Roberts et al., 2001). The introduction of no-take zones would have to be clearly
explained with examples given of how successful it can be given to the local fishermen. This is a very
important point, as clear explanation would help to reassure locals who are currently against having area
restricted to fishing.
Workshops with the local villages that use the bay would provide education on a number of important
issues that could improve the marine environment of the bay. Educating local fishermen on reducing
discarded fishing gear could minimise ghost fishing and coral damage. Using divers (e.g. Frontier
volunteers) to survey areas and systematically remove debris (Donohue et al, 2001) would improve the
reefs ecosystems and reduce the likelihood of ghost fishing. Informing fishermen that by-catch be
respected and returned to water would help to reduce the occurrence of unnecessary mortality and prevent
a reduction in species diversity. Providing information on the size or age at sexual maturity would help
fishermen understand the importance of not removing fish from the ecosystem before they have had the
opportunity to spawn. This could in turn allow the introduction of a minimum capture size to guarantee
that fishermen do not remove fish younger than spawning age. See Mangi & Roberts, 2006 for details on
length at sexual maturity for coral reef fish species.
With the increase in the local population of Diego-Suarez and other villages surrounding the bay plus an
increase in tourism, the sustainability of the fishery will need to be controlled and regulated. The
formation of a Diego-Suarez Bay fishery alliance including representatives from key stakeholders such as
fishermen from each village, business / hotel owners, local government officials from Diego-Suarez and
local conservation organisations such as Frontier, could form the basis for a local management strategy.
The formation of such a body would be able to help manage the bays resources, taking into account the
different needs of each key stakeholder, while incorporating local beliefs and fadys into management
plans.
4.4 Summary of topics for future study
Estimate total catch from the bay by assessing daily catch weights and species composition of catches.
Compare this value with an estimate of the fishery’s productivity to give a more accurate idea of
whether the fishery is currently sustainable or not. From this measures can be suggested to improve its
sustainability.
Assess the impacts of seine net fishing, to provide information on whether steps should be taken to
regulate current activities.
Assess how the growth of tourism in Ramena is affecting fishing pressure around the bay.
Investigate how to provide alternative sources of protein to help reduce fishing pressure.
Examine whether the current number of tourists visiting Ramena would be enough to support an
increased number of tour guides as a possible alternative to fishing.
Investigate the differences in fish size distributions between areas of high fishing pressure and areas of
low fishing pressure to identify if fishing has an impact or not. Other factors such as access to fishing
areas, reef quality and other environmental factors such as exposure and levels of sedimentation need
to be considered to correctly identify the cause of the current fish size distribution.
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