At low tide along Tanzania’s coast, the ocean retreats just enough to reveal what lies beneath the surface. Thin lines stretch across the shallow water, anchored carefully in place. Farmers step into the sea, moving slowly and deliberately as they tend to the seaweed tied along each rope.

This is daily life in parts of Bagamoyo and Kilwa.

For decades, seaweed farming has been a steady source of income for coastal communities, particularly for women who make up the majority of farmers. It is work shaped by the rhythm of the tides, requiring patience, consistency, and an intimate understanding of the ocean. What appears simple from a distance is, in reality, deeply connected to both livelihoods and the health of marine ecosystems.

Seaweed is one of the few resources that offers both.

As it grows, it absorbs nutrients from the water and captures carbon, contributing in small but meaningful ways to healthier marine environments. At the same time, it provides income in regions where options can be limited, helping households meet daily needs and adapt to changes in traditional livelihoods such as fishing.

But along this coastline, the conditions that support this work are shifting.

Rising ocean temperatures are affecting yields. In some areas, unsuitable farming locations and unsustainable practices have placed pressure on ecosystems like seagrass meadows. Beyond the water, challenges continue after harvest. Much of the seaweed is sold in its raw form, with limited processing or value addition, meaning that farmers often earn only a fraction of its potential market value.

These challenges are not isolated. They are part of a broader system.

Seaweed farming is connected to a wider value chain that includes production, processing, transport, markets, and policy. Weakness in any part of this chain can limit the benefits for those at the very beginning of it. Improving outcomes therefore requires more than changes in farming techniques. It calls for a deeper understanding of how the entire system functions.

In Tanzania, efforts are underway to build that understanding.

In Bagamoyo and Kilwa, a growing focus is being placed on strengthening seaweed farming through a more coordinated and inclusive approach. This includes examining how seaweed moves from farm to market, identifying gaps in productivity, quality, pricing, and access to finance, and exploring how different actors within the sector can work more closely together.

At the centre of this work are the people who depend on it.

Women remain the backbone of the sector, yet access to resources, finance, and decision making opportunities is not always equal. Young people and persons with disabilities are also often excluded from participating fully in the value chain. Addressing these gaps is not only a matter of equity, but also of strengthening the sector as a whole.

There is also a growing recognition that sustainability must extend beyond production.

Seaweed farming has the potential to support climate resilience and improve marine ecosystems, but only when practices are aligned with environmental realities. Strengthening site selection, reducing pressure on sensitive habitats, and promoting better harvesting and post-harvest practices are all part of ensuring that the benefits of seaweed farming can be sustained over time.

Knowledge plays a critical role in this transition.

Research and field experience are being translated into practical tools designed for different audiences. Policy-oriented insights are helping shape national conversations around investment and regulation, while accessible guidance is being developed to support farmers in improving day to day practices.

Along the coast, however, much of this change remains quiet.

The tide still comes in and out. Farmers return to the water each day. Seaweed is tied, checked, harvested, and laid out to dry under the sun. These routines continue, largely unchanged on the surface.

But within them, something is shifting.

A more connected understanding of seaweed farming is taking shape. One that recognises it not just as an activity in the water, but as part of a larger system linking people, ecosystems, and economies.

And in that space, between the pull of the tide and the resilience of the communities who depend on it, lies the potential for something more enduring.

Not just survival, but a pathway toward a more sustainable coastal future.