THE ABC ISLANDS

The ABC Islands, consisting of Aruba, Bonaire, and Curaçao, located in the Southern Caribbean have long been a sought-after destination for tourists and nature enthusiasts alike. However, in recent years, these Caribbean jewels like many other Caribbean countries, have experienced recurring influxes of sargassum. Interestingly, despite their proximity, these islands have been receiving highly varied amounts of sargassum, with different associated impacts. Lac Bay and Lagun in Bonaire, Sint Joris Bay and Boca Ascencion in Curaçao and Boca Grandi and Boca Prins in Aruba are some of the sites most impacted by inundations.

Country / Region

Ongoing efforts

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Prioritising environmental and social well-being has been the imperative in the ABC islands. In these islands, an all of society approach is taken where the government, private sector, civil society groups, fisherfolk and members of the community all band together to remove sargassum in impacted regions. Notably, civil society groups are particularly active in sargassum management.

At the national level, Bonaire has a sargassum response plan which gives STINAPA, an non-governmental organization responsible for the management of the national parks, the authority to coordinate sargassum related activities. With a clear central focus on conservation efforts STINAPA is heavily invested in sargassum monitoring, removal, and disposal. STINAPA is also partners with Mangrove Maniacs, and together have been implementing measures to protect sensitive ecosystems. For instance, installing nets to prevent large quantities of sargassum from entering the mangrove ecosystems.

Sargassum in Aruba was seen as a “concern but not a threat”. Compared to Bonaire which receives a regular substantial influx requiring cleanup, Aruba is only severely impacted an average of once a year. Nonetheless, there are still protocols in place for letting nature take its course, allowing the sea to drag deposited sargassum from the beaches back into the water. During severe influxes, Public Works Aruba (DOW) spearheads the response of assessing the severity, and deciding on the appropriate removal methods.

In Curaçao The Ministry of Health, Environment, and Nature (GMN) is responsible for removing sargassum from impacted areas.

Wariruri Bay, Aruba. Source: Aruba News

Ascension inlet, Curaçao. Credit- Els Kroon

Barrier installed in Bonaire. Credit: Bonaire NU

St. Jorisbay, Curaçao. Credit: Els Kroon

Containment, collection and disposal

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Public Works Aruba (DOW) spearheads cleanup activities on the island. Once the DOW is notified of an influx, they first send personnel to assess the situation and evaluate whether sargassum should be left alone, cleaned up by hand, or if heavy machinery will be needed. On the windward shores, most times sargassum is carried back to sea without human intervention. Most cleanups are mainly prioritised on the Leeward coasts primarily along the tourist beaches to prevent any negative responses from the tourists. The DOW also consults with TurtugAruba regarding any possible impacts to sea turtle nesting sites. If removal is necessary, equipment is gathered and contractors, truck drivers, loaders, and rakers are sent to conduct the cleanup. The collected sargassum is taken to an old quarry site where it is sun-dried and buried with sand to minimize the smell. On the windward coasts sargassum is sometimes spread across the back of the beach, to mitigate erosion.

In Bonaire, Lac Bay and Lagun tend to receive large quantities of sargassum and clean up at these beaches are prioritised due to the extensive mangroves present. Efforts have been made to install floating barriers to strategically direct sargassum away from the ecologically sensitive areas. Foam barriers equipped with a mesh net underneath have proven to be successful. However, due to the strong waves and bathymetry of the coast, the barriers can only be positioned within the bay itself rather than at the entrance which would prevent sargassum from ever entering. Custom made excavator buckets are also used to remove large quantities of sargassum on the beach. Back in 2018, volunteers joined the fight to clear sargassum blanketed beaches using shovels and surfboards to collect the seaweed. It was reported that during a massive 2022 influx in Lac Bay, government commissioned the removal of 10-15 truckloads of sargassum every day for the 23 days the cleanup operations lasted. There has been some experimentation with an offshore sinking prototype using a recoverable net and weight system which proved moderately successful.

Similar to Aruba, most influxes in Curaçao are usually carried back to sea naturally. However, Boca Ascencion receives large amounts several times a year which fills the bay and threatens marine life. Unused oil booms are repurposed in Sint Joris Bay to guide sargassum into two designated areas on the north side, allowing the sargassum to gather and naturally decompose.

Regulations and legal instruments

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‘The Prevention and Clean-up of Sargassum in the Dutch Caribbean’ management brief developed by the Dutch Caribbean Nature Alliance and published in 2019, offers comprehensive guidance for effectively addressing the collection and utilization of sargassum in the ABC islands. Apart from this document, countries have made individual efforts to manage sargassum influxes.

In Aruba, official policy specifically dedicated to sargassum management is yet to be established. However, the Marine Park Management Plan completed in 2019, has recognized sargassum as a significant threat, necessitating further research, monitoring, and the potential development of strategies. The responsibility for sargassum response in Aruba falls under the jurisdiction of Public Works Aruba (DOW).

In Bonaire, in 2018 a draft Civil Service Checklist (Ambtelijk Bestuurlijke Checklist (ABC Card)) was developed for emergency services (fire department, police, Area Health Authority and Public Entity) and included a detailed work plan on how to assist STINAPA Bonaire during a sargassum disaster including responsibilities and contact details. Since then, a Sargassum Response Plan was developed which gives STINAPA the authority to organise and oversee various clean up and conduct monitoring activities.

In Curaçao, The Ministry of Health, Environment, and Nature (GMN) takes the lead in coordinating and executing sargassum cleanup activities. This centralized approach ensures that sargassum management is well-organized and efficiently carried out.

Monitoring, modeling and early warnings systems

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The ABC islands have made use of sentinel data and monitoring systems such as CLS SAMTool. During a trial period in 2020, over 50 end-users representing the Caribbean including Aruba, Bonaire and Curaçao received credentials to test the SAMtool web platform for free. Also during the trial, several dedicated analyses were provided to the end-users in the form of situation bulletins. The Department of Nature and Environment and the Meteorological Department participated from Aruba, STINAPA and the Port Authority participated from Bonaire and the Meteorological Agency participated from Curaçao.

Apart from satellite detection software, less formal monitoring methods have been conducted. Since Bonaire is always the first in line to receive incoming sargassum, their posts on social media platforms regarding the severity of the influx give the successive islands a heads up. Citizen science has also been incorporated in monitoring efforts. Fishers and windsurfers have been working with STINAPA, informing them of sargassum sightings. Pilots flying between the 3 countries have also sharing information about their observations of sargassum.

Socioeconomic and environmental impacts

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The ABC Islands provide a compelling illustration of the dynamic nature of sargassum distribution in the Caribbean. These islands, though in close proximity to each other, experience highly varied amounts of sargassum influxes. The positioning of the islands in succession along the route of winds and currents plays a role in the exposure and severity of sargassum influxes. Bonaire, on the front line of any southern-based sargassum trajectory, acts as a shield for Curaçao and Aruba. As such, Bonaire is most severely impacted followed by Curaçao and Aruba respectively. Aruba has fortunately escaped much the severe impacts. Patterns of human activity also vary between the islands. Both Bonaire and Curaçao have more visited regions of the windward coast making sargassum influxes more impactful on human and economic activity. Contrarily, Aruba’s windward side is especially desolate.

Fisherfolk in Bonaire, especially those that use the method of surface trawling, have been severely impacted by sargassum influxes. Fishers operating from northern edge of Lac Bay, reported clogged fishing nets, entangled motors and impeded access to vessels as bays become inundated. Fortunately, sargassum hasn’t crippled their entire fishing operations; instead, it is generally regarded as a significant nuisance that can be managed with sufficient effort. Fishing and aquaculture in Curaçao have also been impacted, though to a lesser degree. In Aruba, fishers have been spared the brunt of the impacts. On occasions when sargassum washes up on Aruban shores, it is only on the windward coast where fishers rarely go due to the rough conditions and large waves. In fact, fishers have been making the most of smaller patches of sargassum offshore. They consider these generally very productive areas, attracting all types of “large fish”.

Sensitive coastal ecosystems in Bonaire had been significantly impacted by sargassum influxes. Most prominently, the protected area of Lac Bay is directly in line with the wind and current directions, making it particularly prone to influxes. Sargassum in the nearshore can reportedly reach 2 meters in depth, creating hypoxic conditions that kill surrounding flora and fauna including seagrasses, mangroves, and various types of fish and crab species.

In 2018, the March sargassum influxed filled the Lagun, Washikemba, and Lac Bay in Bonaire, resulting in massive fish kills and the die-off of critical seagrass patches and several hectares of mangroves. At the same time Boka Ascencion in Curaçao faced similar devastating ecological impacts. The nauseating gases released from decomposing sargassum has also threatened the health of workers and volunteers who must occasionally stop removal operations to safeguard their well-being.

Potential uses

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There has been interest in developing products from sargassum and research is underway in exploring potential safe uses in the ABC islands. Last year in 2022, studies conducted by STINAPA in partnership with WWF-Mexico revealed high concentrations of heavy metals including arsenic and cadmium in sargassum-enriched fertilizer. It was advised that until its health effects are more widely understood, it would be wise to limit sargassum use to non-consumable options.

This has left the door open to the exploration of other uses. In 2022, the TNO Netherlands Water Partnership, in collaboration with various public and private sector partners in Curaçao hosted a workshop which explored means of turning sargassum into a business opportunity.

Research continues in 2023 and the TNO Energy and Materials Transition Unit, based in the Netherlands launched the TNO Living Lab project in collaboration with partners in Curaçao. The project intends to explore applications such as bioenergy, biorefinery and pharmaceuticals in Curaçao. Currently a proposal is being developed to further build out the project.

Sources

Written by R. Speede

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Balutowski, D. 2022. Thesis: Brown Tides: Assessing the Past, Present, & Future State of Sargassum in Aruba Through a Mixed Methods Approach. University of Utretch. https://www.dcbd.nl/sites/default/files/documents/Thesis.pdf

Caribisch Netwerk. 2018. Everyone does what they can against Sargassum on Bonaire. https://caribischnetwerk.ntr.nl/2018/03/07/iedereen-doet-wat-hij-kan-tegen-sargassum-op-bonaire/

Collecte Localisation Satellites (CLS). 2020. Sargassum Monitoring Service Final Report. https://eo4society.esa.int/wp-content/uploads/2020/11/CLS-ESASARGA-20-0415-FR-public.pdf

Dutch Caribbean Nature Alliance (DCNA). 2019. Prevention and clean-up of Sargassum in the Dutch Caribbean. DCNA, Bonaire, Dutch Caribbean

López-Contreras, A. M., M. van der Geest, B. Deetman, S. W. K. van den Burg, G .M. H. Brust and G. J. de Vrije. 2021 Opportunities for Valorisation of Pelagic Sargassum in the Dutch Caribbean. WUR report 2137, DOI: 10.18174/543797.

Netherlands Water Partnership. 2020. Sargassum in Curaçao, Turning a Challenge into an Opportunity. https://www.netherlandswaterpartnership.com/calendar/sargassum-curacao-turning-challenge-opportunity