This blog demonstrates the crucial role science can play in the sustainable management of mud crabs in the Sundarban, Bangladesh. The case presented here draws on a five-day field trip facilitated by Mangroves for The Future, Bangladesh in which two researchers and 15 different stakeholders were interviewed, and a discussion between the author and his colleagues at IUCN Bangladesh Country Office.

Fishers in Sundarban

The gradual shift of demand and markets of Sundarban’s Mud Crab from local to global changed the scenario on the ground. Now, mud crab fishery is of enormous socioeconomic importance to small-scale fishermen. Sustainable management will make a critical difference to a large number of people here. Photo: Garth Cripps/ Blue Ventures


Setting the Scene

Small-scale subsistence fishing of mud crabs in the Sundarban has turned into a fast-growing industry, thanks to flourishing international demand. The marginal fishermen who live in-and-around the Sundarban usually make 8- to 12-day fishing trips, during which they collect as many crabs as possible from the creeks of this mangrove forest. Before being exported, the live crabs change hands several times; some are sent to be fattened until they attain the desired weight, whilst others are exported directly from the natural forest to foreign markets.

Interestingly, this process is not as simple as it appears. The scenario on-the-ground has evolved alongside the gradual shift of demand and markets from local to international spheres. So, what are we actually missing?


A Burgeoning, Demand-Driven Market for Wild Mud Crabs

As the market for mud crabs grew, the promise of quick-and-easy money attracted both permanent and seasonal middle-men at all levels, resulting in an intricate, tangled web of a supply-chain. Whilst the profits derived from exports circulated amongst a greater number of actors, the profit margin per actor increased less than those climbing aboard the gravy train had expected. Later, old stakeholders and businessmen—with their influence and understanding of the mud crab market—started investing more, and taking up multiple roles in order to secure a larger share of the profits.


Crab Depots in Mongla

The crab fishers sell their catch to depots installed by traders, middlemen, and exporters in small towns surrounding Sundarban. Previously the middlemen were independent, but the exporters are gradually taking up multiple roles now in order to secure a larger share of the profits. Even most the middlemen are financed or contracted by the exporters now. Photo: Garth Cripps/ Blue Ventures


As a consequence, the market became complicated and competitive; this, along with a rising demand from consumers, led to significant pressure being exerted on the mud crabs of the Sundarban, a fact that went unregistered in this frenzied marked. Additionally, since no alternative forms of supply (e.g. mud crab culture) have yet been established, the market continues to depend on upon a constant supply of mud crabs from the serpentine creeks of the Sundarban.


Socio-Economic Equity and Perspectives

The booming mud crab industry undoubtedly employs and supports thousands of families along the southwest coast of Bangladesh. However, little has changed for the marginal fishermen who collect crabs directly from the forest. Researchers assert that the main factors behind this prevailing societal and financial injustice are the ignorance of fishermen regarding the price at international markets, and the informal money-lending system (which lacks the requisite paperwork and authority). The current lack of governance is highlighted when Laxmipod Mondol from Kolbari, involved with  the mud crab fisheries for more than 16 years, reflects that “most of them (fishermen/crab collectors) have now turned opportunistic and cheater.” Mr. Mondol also adds that fishermen either take loans from middle-men or are given advances from them in return for an oral assurance that they (the fisherman) will sell all their catch to the creditor.


crab fishers in Sundarban

Resting between fishing trips, deep inside the Sundarban, in a creek of Arpangasia river. Stocks in norther Sundarban are apparently over-exploited. So fishers must make 5-10 days fishing trips to southern forests now. Buying permits, boats and gears, protection money, and stock up on food cost a lot. So a fishing trip is well beyond their means and they have to borrow money from the crab middlemen. This binds them to sell their catch to the middlemen with no negotiation. Photo: Sumon Kormokar/ Save Our Sea


However, according to multiple stakeholders, fishermen often do not honor these promises, leading to conflicts, one of which took place just before my most recent field trip. It is hard to conclusively determine who is culpable for the tensions that exist; however, a five-day field trip and 17 interviews (two with researchers, 15 with various actors within the supply chain) were enough to get a sense of the mutual distrust between these two actors. Almost all those interviewed agreed that these conflicts stem from the nature of the lending system, coupled with a lack of governance. On the other hand, the link between the financial injustice suffered by marginal fishermen and their ignorance of the price of mud crabs at international markets is tenuous, and more research is needed to establish whether an objective relationship exists.


How Can Science Help?

Since the Sundarban mud crab market and its associated social issues loom large in the public consciousness, the unregulated collection of wild mud crabs has recently caught the attention of researchers. Unfortunately, I found neither a reliable system to monitor the yearly catch, nor any peer-reviewed paper that attempted to calculate the total catch of mud crabs from the Sundarban. Data regarding the quantity of exported crabs can be retrieved from exporters at Dhaka; however, these data rarely represent the actual catch, not only because injured and dead crabs are removed from the supply chain, but also because of non-graded crabs—reared in captivity to increase their weight—frequently cannibalize one another.


Crab Fishing Boats in Sundarban

A large number of crab fishers in Sundarban are from some of the most marginalized communities in Bangladesh. The level of poverty is high among them, and they include Hindu and Christian minorities. Photo: Mohammad Arju/ Save Our Sea


With all these questions and uncertainties, it is difficult to predict if-and-when the mud crab population will face a drastic decline; such a collapse would not only be an ecological catastrophe for the mangrove forest but would cripple the mud crab industry and the thousands who depend on it.

In fact, the Sundarban might be on the verge of experiencing such a collapse, if exploitation has already surpassed the Maximum Sustainable Yield (MSY). An assessment of the MSY of mud crabs would tell us about the quantity of total harvest each year, and the fishing practices that are necessary to make an informed management choice. Establishing social justice/equity and market sustainability requires a change at the core of the respective systems; however, we will not be able to tackle such issues until we know the threshold which fisherman must not cross. Knowing this will help us understand both the maximum market size and the tipping point for the mud crabs collected from the natural forest, and enable us to devise a sustainable management strategy.


Concluding Note

The present situation, skewed heavily in favor of utilitarian values, neglects the fact that ensuring the persistence of a threshold population of mud crabs—often regarded as ecosystem engineers—is important not only to keep this unique ecosystem functioning but also for securing the long-term sustainability of the market. Translating MSY results into action could potentially help both conservation of mud crabs and local fishermen in the Sundarban. Finally, it is true that neither the mud crab fisheries nor the mangrove ecosystem have fallen apart yet, but why must we always act after the unwanted occurs, and never before?


Mahatub Khan Badhon teaches Zoology at the University of Dhaka and is affiliated with Save Our Sea as a Program Associate. He can be reached at