ZANZIBAR, Sept. 2 -- FOR generations, the sea has been central to life in Zanzibar, providing food, employment and income for thousands of families. Yet, despite years of government efforts to develop the marine sector, many fishers and seaweed farmers continue to face challenges that limit the benefits they derive from the ocean.

Illegal fishing remains a persistent concern, while many artisanal fishers lack the equipment and capacity needed to venture into deeper waters. Seaweed farmers, meanwhile, continue to struggle with low productivity, limited farming techniques and low market prices for their produce.

Now, a major World Bank-supported initiative is raising hopes that some of these long-standing challenges could gradually become...