On Tuesday June 26, the Barbados National Union of Fisherfolk Organizations (BARNUFO), as part of its 2018 week of activities, hosted a Fisheries Forum on the topic Sargassum Seaweed: From Problem to Profit.
Panellists were marine biologist and environmental activist Nikola Simpson, Dr. Shelly-Ann Cox of the University of the West Indies’ Centre for Resource Management and Environmental Studies, fishermen Roger Greaves and Wayne Rose, and Mark Hill of Biogen Biotechnologies Inc.
One of the overall objectives of the Forum was to shift perspectives on the sargassum seaweed that has been washing up on Caribbean beaches in massive amounts. The tendency is to see the sargassum invasion solely as a nuisance, but with appropriate management strategies in place, the seaweed can be a beneficial resource.
As Ms. Simpson explained, when floating at sea the sargassum mats can be important habitats for marine species. Floating sargassum can be, as one audience member described it, “the open ocean equivalent of mangroves”, acting as a nursery for fish and shell fish, and a shelter for juvenile sea turtles.
Fisherfolk on the panel and in the audience agreed with this. Mr Rose said that the sargassum mats are teeming with sealife, including miniscule crabs and shrimp. A fisherman in the audience informed that since the sargassum influx began this year, his catches of certain types of fish, most notably amberjack, have increased, suggesting that the seaweed has helped to replenish those fish stocks. However, this is not the case for all types of fish. Fishers have seen their flying fish catches decline considerably, and have observed that flying fish seem to actively avoid the sargassum and don’t like to lay their eggs in it.
Mr. Greaves suggested that this is because the sargassum we are seeing now is different from the sargassum that used to be found in Caribbean waters before. Based on his conversations with older fisherfolk, in past years the sargassum used to have a positive impact on flying fish stocks, but that is no longer the case.
In her presentation, Dr. Cox explained that previously sargassum seaweed most likely entered the Caribbean from the Sargasso Sea (after which the seaweed is named), but research suggests that the current influx, which may be a different species, originates in a zone referred to as the North Equatorial Recirculation Region, between the west coast of Africa and the north-eastern coast of Brazil.
Dr. Cox gave the audience an introduction to research that focuses on predicting the movement of the sargassum. The aim of this research is to enable scientists to give advance notice of where major blooms and beaching events are likely to occur. While considerable progress has been made in terms of predicting the movement of sargassum, more work is needed to ground-truth the model and improve its predictions, particularly when it comes to forecasting sargassum amounts. You can read more about this research at the University of South Florida’s Optical Oceanography Laboratory website.
If good predictions of sargassum locations and amounts can be made, then better arrangements can be put in place to harvest it. Mr. Hill gave the audience some ideas about the uses to which the harvested seaweed can be put: animal feed, fertilizer, mulch, production of alginate.
Mr. Hill’s company, Biogen Technologies, has been using the sargassum as a substrate to produce biofuels for the transport sector. One of the major challenges has been figuring out how to harvest the massive quantities of sargassum that are coming ashore, without damaging the beaches (especially in the case of turtle nesting beaches) or nearshore coral reefs. Cooperation between government and the private sector has resulted in some efficient solutions, bringing Barbados closer to being able to make effective use of the sargassum as a high value raw material.
[Sargassum photo: via rjsinenomine. Other photos © Green Antilles]