Seaweed farming poses threat to Philippine dugongs

June 16, 2016

Entanglement in fishing nets is a well-documented threat to dugongs; however, entanglement in ropes used to farm seaweed is less well-documented. A recent publication authored by our partners Community Centred Conservation (C3), documented cases of dugong entanglement in ropes used for seaweed farming in Busanga, Palawan, Philippines (see location here).

It appears that dugongs are not only susceptible to entanglement in set fishing nets but that static ropes associated with other anthropogenic marine activities can pose a significant threat.

Seaweed farming can be a significant source of income for coastal communities in the Philippines. Each kilometer of line can produce up to 1.6 tonnes of dry seaweed and resulting in income of up to $3,000 (FAO, 2013).

Seaweed farming in Philippines near mangrove forest

The Philippines is the second largest exporter of seaweed products globally. Only Indonesia outproduces it. Other major exporters include Tanzania, Malaysia, China, Solomon Islands, and India. The Philippines production stood at 1,750,000 metric tonnes in 2010 and Indonesia produced 3,400,000 metric tonnes, according to the FAO report cited above. Together Indonesia and the Philippines account for more than 90% of the global production of seaweed.

Seaweed farming has been reported to have many environmental qualities – not least of which is to reduce the pressure on fish populations and sequester carbon. Other reported benefits include filtering water and providing a nursery ground for fish.

Given the potential economic and environmental benefits, seaweed farming has grown globally, partly because of promotional efforts by the FAO..  A report published in 2013 states that global production of seaweed products doubled from 10,000,000 (wet) metric tonnes in the year 2000 to 20,000,000 (wet) in 2010.

Many of the countries where seaweed farming has developed in the last few decades also are home to viable dugong populations, including many within the Dugong and Seagrass Conservation Project including Solomon Islands, Timor Leste, Malaysia, Indonesia, Madagascar and Mozambique.

Seaweed is being grown in exactly the same habitat – shallow, protected, estuaries – where dugong feed on seagrass. With the boom in seaweed farming, we are concerned that threats to dugongs is also increasing. We are also concerned that seaweed is being cultivated without regard for protecting seagrass meadows. All of which potentially, perhaps significantly, off-set the environmental benefits of seaweed cultivation.

We are not proposing the cessation of seaweed farming, but we are advocating the investigation of dugong moralities in seaweed farm operations, and the effect of seaweed farming on existing seagrass meadows. In addition, it may be important to investigate alternative technology for seaweed farming, as noted in the Community Centred Conservation article.

The threat of entanglement could potentially be reduced through the use of alternative seaweed farming methods that do not employ ropes.