Guarding Against Coral Invaders: Protecting (Dutch) Caribbean Reefs from Unomia stolonifera

Recent reports highlight the concerning spread of the invasive soft coral, Unomia stolonifera, currently devastating Venezuela’s marine ecosystems and detected in Cuba. With the potential threat of its expansion to the (Dutch) Caribbean islands, urgent action and awareness are essential to safeguard marine biodiversity and local economies from possible catastrophic consequences. 

Invasive species are animals or plants from another region of the world that don’t belong in their new environment. These species can have major ecological effects by decimating native flora or fauna. They can also cause large economic losses and impact human health. Invasive species also pose a significant threat to marine ecosystems worldwide, including the Dutch Caribbean. Among these invaders is the octocoral species Unomia stolonifera or “Pulsing Xenia”, originally from the Indo-Pacific. With its rapid growth and lack of natural predators, this species can outcompete native species and disrupt fragile marine habitats such as seagrass beds and coral reefs.  

Unomia invasion Venezuela. Photo credit: Juan P Ruiz Allais – Unomia Project- all rights reserved

 

Background  

The invasive soft coral U. stolonifera was first identified in 2014, off the coast of Venezuela. It is believed to have been introduced via the illegal aquarium trade.  Since this species can reproduce sexually and asexually (or fragment), even small pieces can regenerate to spread.  Once introduced it quickly took over shallow reefs and hard substrate at depths of 0-50 meters, outcompeting local corals and seagrass for space.  Follow on surveys found that this coral species exhibited average percentage cover as high as 80%, vastly outcompeting native corals. In highly colonized areas, fish are disappearing due to loss of habitats.   

In 2022, during a survey conducted in Cuba by the University of Havana, an unknown octocoral was discovered which was later identified as the invasive Unomia stolonifera. It is suspected that the coral larvae arrived in ballast water from fossil fuel ships originating from Venezuela, as nearby sites adjacent to Venezuelan ports have been heavily affected by the invasion.

Unomia invasion Venezuela. Photo credit: Juan P Ruiz Allais – Unomia Project- all rights reserved

 

How to help  

Prevention through continuous monitoring, particularly in high-risk areas such as marine harbors and oil facilities, is paramount. Early detection plays a pivotal role in mitigating the threat posed by Unomia stolonifera. 

The public’s involvement and awareness are also vital. Local communities, recreational divers, tourists, and all stakeholders are urged to participate in early detection efforts by reporting sightings (photo, location and date) of this invasive coral to their respective Protected Area Management Organization (PMOs)- the Fundacion Parke Nacional Aruba (FPNA),STINAPA Bonaire, CARMABI Curaçao , Saba Conservation Foundation (SCF), Nature Foundation St. Maarten (NFSXM) and St. Eustatius National Parks (STENAPA). If an invaded area is confirmed, follow the recommendations by the local PMOs.  

Unomia invasion Venezuela. Photo credit:: Juan P Ruiz Allais – Unomia Project all rights reserved

 

Keys to Success 

Despite the challenges, prevention and early detection are key to mitigating the threat posed by Unomia stolonifera. With continued vigilance, research, and community engagement, there is hope for containing this potential issue before it becomes a major threat. 

Unomia invasion Venezuela. Photo credit: Juan P Ruiz Allais – Unomia Project- all rights reserved

 

 

DCNA 

The Dutch Caribbean Nature Alliance (DCNA) supports (science) communication and outreach in the Dutch Caribbean region by making nature related scientific information more widely available through amongst others the Dutch Caribbean Biodiversity Database, DCNA’s news platform BioNews and through the press. This article contains the results from several scientific studies but the studies themselves are not DCNA studies. No rights can be derived from the content. DCNA is not liable for the content and the in(direct) impacts resulting from publishing this article.     

 

Related Publications

GBIF.org. 2023. Unomia stolonifera (Gohar, 1938). Available at: https://www.gbif.org/species/11218892  (Accessed 19 February 2024).    

Sáez, J.E., Estrada-Estrada, R., Ruiz-Allais, J.P. (2023). The marine invasive species Unomia stolonifera (Gohar, 1938) (Octocorallia, Alcyonacea) in Cuba. Actions for its control and elimination. Revista de Investigaciones Marinas 43(1): 140-146. Article    

Ruiz-Allais, J.P., Benayahu, Y., Lasso-Alcala, O.M.  The invasive octocoral Unomia stolonifera (Alcyonacea, Xeniidae) is dominating the benthos in the Southeastern Caribbean Sea. Memoria de la Fundación La Salle de Ciencias Naturales, 2021, 79(187): 63-80. Article
 

Ruiz-Allais, J.P., Amaro, M.E., McFadden, C.S., Halasz, A. & Benayahu, Y. 2014. The first incidence of an alien soft coral of the family Xeniidae in the Caribbean, an invasion in eastern Venezuelan coral communities. Coral Reefs 33(2): 287–287. 

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