Sustainable fisheries and coastal management: forecasting for the long term

In the video, Ebenezer Nyadjro showed how ocean forecasting helps coastal communities feed themselves, earn a living, and protect the ecosystems they depend on. This reading gathers those ideas: why fisheries matter so much, the pressures they face, how forecasting supports sustainable use, and how the same information guides aquaculture, coastal planning, and the blue economy. The thread throughout: forecasting helps us use the ocean well today without depleting it for the generations to come.

Why fisheries matter

For coastal Africa, fisheries are not a minor sector – they are the number-one source of dietary protein, a major employer, and a billion-dollar industry. And “fisheries” means far more than fish: it’s an entire ecosystem of livelihoods – the fishers who go to sea, the fishmongers (often women) who smoke and sell the catch, the fuel suppliers, and many others whose living depends on it.

Yet the industry is under strain. Fishers whose families have worked the sea for generations report that the ocean is warmer and rougher than it used to be, less productive, its fish smaller – and some species gone entirely. The pressures come from several directions:

• Overfishing – catching faster than fish can reproduce, worsened by small-mesh nets that take juveniles before they can grow
• Illegal, unreported and unregulated (IUU) fishing – including “ghost fishing” by gear lost at sea that keeps catching fish no one collects
• Climate variability – shifting conditions that reshape where and whether fish appear
• Habitat degradation – such as cutting down the coastal mangroves where many fish spawn and their young grow

These pressures need to be addressed with science, data, and technology – and ocean forecasting is part of the answer.

What sustainable fishing means, and how forecasting helps

Sustainable fishing means catching fish no faster than they can reproduce and restock. Take more than that, and the fishery collapses – leaving future generations with nothing.

Forecasting supports this because a handful of ocean variables largely determine where fish are: sea surface temperature, currents, salinity, chlorophyll, and nutrient availability. Fish go where the food and the right conditions are. As the ocean warms, many species migrate toward cooler, more productive waters – often the upwelling regions like the Canary, Guinea, and Benguela Currents, where cold, nutrient-rich water rises to the surface. The consequence for fishers is direct: as fish move, they spend more time and fuel to catch less.

By forecasting these variables, a service can:

• anticipate a poor season – warning fishers when conditions won’t favour a good catch, so they don’t waste money on fuel for fruitless trips
• identify productive fishing zones – concentrating effort where it pays
• reduce operational cost – letting fishers go out only when conditions are right

From forecast to policy: closed seasons and protected areas

Forecasting and data don’t just guide individual fishers – they inform policy. A powerful example comes from Ghana, where ocean data supported the introduction of a closed season. Scientists identified the spawning period (around the June upwelling season), and the government responded by closing the ocean to fishing for a month so fish could reproduce – the Minister of Fisheries symbolically “locking the ocean” at a fishing community. Despite early resistance – this is people’s livelihood – modest government support eased the impact, and the policy has been maintained since.

Crucially, such measures work best collaboratively. Because “fish don’t need a visa” to swim between countries, Ghana and Côte d’Ivoire sometimes align their closed seasons for far greater effect than any one country acting alone. Marine Protected Areas – zones where fishing is restricted to protect spawning grounds or endangered species – work on the same principle, and have been established in Ghana, South Africa, and Kenya.

Aquaculture, ecosystems, and coastal planning

Forecasting supports the wider coastal economy too:

Aquaculture. Forecasts help site fish farms – matching a location’s salinity and nutrient levels to the species being raised – and monitor water quality in enclosed ponds, where nutrient build-up can trigger harmful algal blooms. This helps prevent disease and protect stock.

Ecosystem services. Healthy coastal ecosystems provide food, coastal protection (the grasses and mangroves that bind soil and prevent erosion), carbon storage, biodiversity, and recreation. Forecast information helps monitor these systems – for instance, understanding the water quality and human pressures threatening the mangroves of Cameroon’s Wouri estuary.

Coastal planning. Where coasts are well planned, infrastructure isn’t placed at random. Marine spatial planning uses environmental conditions to decide where to site housing, ports, hotels, fish markets, or wind farms – checking whether the ground can hold a hotel, or whether a site has enough wind for a wind farm – through careful impact assessment.

The blue economy and food security

All of this underpins the blue economy – the economic value drawn from the sea. Africa derives billions of dollars from the ocean and is home to over a hundred ports, all exposed to sea-level rise and wave activity. As coastal populations grow, economic activity must be undertaken in ways that don’t degrade the ocean environment.

It also underpins food security. Beyond fish, communities harvest ocean plants: in East Africa (Kenya, Tanzania), mariculture grows not just fish but seaweed exported for valuable foreign currency. Forecasting supports these industries – fisheries, coastal tourism, renewable energy – and the food and livelihoods that depend on them.

Key takeaways

• Fisheries are central to African food security, employment, and the economy – and are under pressure from overfishing, IUU fishing, climate change, and habitat loss
• Sustainable fishing means not catching faster than fish can restock – and forecasting variables like SST, currents, chlorophyll, and nutrients helps identify productive grounds and anticipate poor seasons
• Forecasts and data inform policy – closed seasons and Marine Protected Areas – most effectively when neighbours collaborate
• The same information supports aquaculture, ecosystem monitoring, and marine spatial planning
• Together, these sustain the blue economy and food security for current and future generations