Local governance of fishing resources in ten villages from the Sofia Region, Madagascar: The case of the mangrove crab, Scylla serrata.

The fishery for the mangrove crab (Scylla serrata) is a purely traditional fishing practice on which many fishing communities are completely dependent. Three main production areas for crabs have been identified as Boina region, Menabe region and Sofia region (inthe mangrove swamp of Sahamalaza (around Maromandia). Fishing productivity is estimated at about 2.5 mT/km²/year (Ralison, 1987).

Two main factors impact on the sustainability of the crab fishery:

1-    Madagascar’s mangrove swamps are showing alarming signs of degradation with a net loss of 13% from 1995 to 2018. Mangrove coverage in Madagascar has decreased from 310,452 ha (1995) to 236,402 ha (2018) (WWF 2019, unpublished). Mangrove area of Sahamalaza, excluding Rafaralahy Bay (5,900ha), is about 10,200 ha.

2-      The high international demand for mud crab has increased pressure on the stock. 75% of products are exported. Even with increased market demand, production has decreased in Sofia region in recent years as illustrated in the table below:

Source : SRPA Sofia, 2020

It is also apparent that under-sized individuals are sometimes harvested which are below the minimum size as required by regulation in order to ensure crab stock renewal, leading to a decrease in exploitable biomass. Only exported products are controlled and illegal products are marketed locally, due to the lack of application of the regulations.

Human population growth without the option of alternative livelihoods has led to an increase in pressure on mangroves and their resources over time. Without any concrete management actions linked to the creation of alternative income generating activities, and proper empowerment of communities in resource management, this sector may disappear entirely, causing significant ecological and economic losses.