About us

Our ambition

Coast 4C is a social enterprise that aims to integrate the world’s largest supply of regenerative seaweed, benefiting Communities, Commerce, Conservation & Climate. We have established a network of suppliers in the Philippines that we plan to scale up and replicate into Indonesia in the next three years, and to integrate processing close to source that adds value and opens up new markets.

The opportunity

Restorative seaweed farming is increasingly recognised as being the key to the future of our ocean and climate.

We need to scale production fast – our ocean and climate cannot wait.

Large offshore commercial arrays are a thing of the future and will be important in time.

Small-scale fishers already farm seaweed today!

They produce the most cultivated seaweeds globally, despite a severe lack of access to essential services and largely exploitative value chains.

22 million small-scale fishers globally struggle to make a living from declining fish catches.

Unlocking restorative seaweed farming for small-scale fishers linked to community-based marine protected areas delivers benefits for people, planet and profit.

The challenge

Our ocean ecosystem is collapsing

Business as usual is not enough

Humanity depends on the ocean

Amongst countless services, the ocean provides 70% of our oxygen; 17% of animal protein, and; buffers us from anthropogenic climate change.

Yet the ocean is on the brink of collapse

Unsustainable exploitation, marine plastic pollution and climate change are compromising all of these critical ecosystem services.

22 million small-scale fishers are critical to food security yet are also under threat

Small-scale fishers produce more than 50% of the world’s seafood and provide 90% of fisheries employment. The majority live in impoverished coastal communities, limited by dysfunctional and exploitative value chains that drive unsustainable behaviours.

The rapid acceleration of the Ocean Economy is marginalising the most vulnerable people with highest dependence on the ocean

A recent report by the High Level Panel for a Sustainable Ocean Economy has highlighted the urgent need to focus on equity in the development of a sustainable ocean economy.

The Coast4C Plan

Our solution

Restorative seaweed farming and plastics recycling creates development opportunities for coastal communities and drives ocean and climate restoration.


The seaweed revolution is the key to regenerating our ocean and climate:

  • Provides habitat to replenish fish stocks
  • Mitigates coastal eutrophication
  • Draws down carbon
  • Integration with marine protected areas provides mutual benefits for biodiversity and seaweed farmers
  • A more efficient seedstock for bioplastics and biofuels that does not compete with space for food production or require fertilisers, pesticides or fresh water inputs

Small-scale fishers

22 million small-scale fishers need new opportunities:

  • Need viable alternatives to their current dependence on declining fish stocks
  • Already produce all of the world’s most cultivated seaweeds, despite the barriers they face
  • Are in the coastal zones where pressures are greatest
  • Need less investment and sub-sea infrastructure than offshore arrays

Coast 4C

Coast 4C is the missing link to catalyse change:

  • Provides a higher price through an inclusive and transparent value chain and value adding
  • Enhances seaweed productivity by providing access to new methods and strains
  • Aggregates coastal communities and sells to responsible global markets
  • Integrates seaweed farming with larger and more effective marine protected areas
  • Implements the systems, processes and vehicles for scale

How do we deliver?

Our history

Coast 4C is a social enterprise launched by ZSL in 2020 to drive ocean and climate restoration through inclusive value chains for regenerative seaweed and end-of-life fishing nets Coast 4C builds on the award-winning Net-Works project co-created by ZSL and Interface. Our first supply chain turned old fishing nets into carpet tiles, initially developed in the Philippines and with replicability successfully tested in both Cameroon and Indonesia.

The decision to expand Net-Works into Coast 4C was taken in order to accelerate scale-up now that prototyping and piloting has been completed, and to open up new partnerships that will facilitate scale-up and replication.


Our approach is informed by science

We believe in the imperative to take positive action based on the best available information, and to continually evaluate and improve. Here is a selection of research undertaken by team members that have informed our approach; research output from student projects we have hosted or supervised, and; peer reviewed publications resulting directly from our work. See more on the Research page.

Potential for Return on Investment in rehabilitation-oriented Blue Carbon projects
Duncan C, Primavera JH, Hill NAO, Wodehouse DCJ, Koldewey HJ. 2022. Frontiers in Forests and Global Change 4:775341. doi: 10.3389/ffgc.2021.775341
Read the case study
How do we help deliver systems-level sustainability innovation for responsible global brands?
Luqmani A, Leach M, Jesson D. 2017. Factors behind sustainable business innovation: the case of a global carpet manufacturing company. Environmental Innovation and Societal Transitions 24, 94-105
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The interaction between seaweed farming as an alternative occupation and fisher numbers in the central Philippines
Hill NAO, Rowcliffe JM, Koldewey HJ, Milner-Gulland EJ. 2012 Conservation Biology 26, 324-334
Read the case study