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The Caribbean context
With 33 species of cetaceans recorded out of the 90 known in the world, the Caribbean region is positioned as one of the biodiversity hotspots for these marine mammals. These waters, representing less than 1% of the surface of the seas and oceans, are home to an incredible diversity, ranging from resident coastal dolphins to migratory whales such as the majestic humpback whales. This richness is a testament to the ecological importance of the Caribbean, where varied habitats, such as coral reefs and deep pelagic zones, provide essential refuges for cetaceans. Such diversity makes the Caribbean a key region for the research and conservation of these fascinating species.
Of the 33 species of cetaceans recorded in the Caribbean region, 7 are Mysticetes, also known as baleen whales, including iconic species such as the humpback whale, the blue whale and the fin whale. The other 26 are Odontoceti, or toothed whales, such as the sperm whale, the bottlenose dolphin, the short-finned pilot whale and the orca. These cetaceans are divided between resident species, which remain in the region throughout the year, and migratory species, which come to the Caribbean during specific periods, particularly for breeding. This diversity highlights the importance of the Caribbean as a key area for the preservation of marine habitats, both for sedentary species and those making long migrations.
Caribbean : unique biodiversity under pressure
Despite exceptional biodiversity, the situation of cetaceans in the Caribbean remains worrying and insufficiently documented. Research efforts, still limited in the region, do not allow for a clear and complete status report for all the species present. While five species are already classified as threatened with extinction according to the IUCN Red List, the majority of other cetaceans remain in an uncertain situation, due to a lack of sufficient data. This lack of knowledge raises concerns that some populations could be threatened without this being detected, making any conservation action difficult.
Threatened
IUCN categories of conservation status of cetaceans in the Caribbean (The figure corresponds to the number of cetaceans belonging to the given category
With this in mind, the Caribbean Cetacean Society is committed to bringing together Caribbean countries and going beyond human boundaries to actively contribute to the conservation of cetaceans in the region. Its mission is based on a collaborative approach that combines scientific research, awareness-raising among local communities and cooperation among nations. The goal is to harmonize regulations and adopt responsible human practices in order to reduce the pressures and disturbances that threaten these species that are essential to marine ecosystems.
Why do we need to save cetaceans?
Cetaceans, like all species, play essential roles in marine ecosystems, contributing to their balance and overall functioning. These animals, whether baleen whales, toothed whales or dolphins, influence the structure of their environment through their complex ecological interactions.
At the heart of the carbon cycle
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Cetaceans, particularly whales, play a key role in the carbon cycle. The fin whale (Balaenoptera physalus), for example, is one of the largest animals that has ever existed on Earth. Due to its size and exceptional longevity, this cetacean can contribute to a significant accumulation of carbon. In particular, when they die naturally, these individuals sink to the bottom of the oceans and allow sustainable carbon sequestration: this phenomenon is called Whale Fall.
However, among the many existing threats, overexploitation due to commercial whaling has, on its own, drastically reduced this capacity, such that it is estimated that this activity would have reduced the biomass of large whales by 81%. While it was estimated that 11 million tonnes of CO2 were stored per year before the intensification of industrial fishing, this capacity would have increased to 2 million tonnes per year. This deficit would promote a greater quantity of CO2 in the environment.
Engineer species
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The term engineer species refers to species that are able to positively impact an environment in a way that promotes the growth of biodiversity. Cetaceans, as engineer species, play a key role in ocean fertilization, stimulating the productivity and dynamics of marine ecosystems.
Through their defecation, they release large quantities of essential and often limiting nutrients, including nitrogen, phosphorus and trace metals (e.g. iron). In the case of sperm whales (Physeter macrocephalus), the transport of these limiting nutrients from the depths of the ocean to the surface (also called Whale Pump) can enhance phytoplankton production in the photic zone.
The waste from these species thus acts as fertilizers that stimulate phytoplankton productivity. This creates a virtuous circle: the more cetaceans there are, the more nutrients are available for phytoplankton, which feeds zooplankton, animals located at the base of the food chain. For example, whales alone are estimated to increase global phytoplankton productivity by 1%. Thus, these animals are not only predators, but also active vectors of nutrients, highlighting their fundamental role in the global biological cycle and ocean productivity.
- Gilbert, L., Jeanniard-du-Dot, T., Authier, M. et al. The composition of global cetacean communities shapes their contribution to ocean nutrient cycling. Nat Commun 14 , 5823 (2023). https://doi.org/10.1038/s41467-023-41532-y
- Pearson, Heidi C., Matthew S. Savoca, Daniel P. Costa, Michael W. Lomas, Renato Molina, Andrew J. Pershing, Craig R. Smith, Juan Carlos Villaseñor-Derbez, Stephen R. Wing, and Joe Roman. 2023. “Whales in the carbon cycle: can recovery remove carbon dioxide?” Trends in Ecology & Evolution 38 (3): 238‑49. https://doi.org/10.1016/j.tree.2022.10.012.
- Stéphan Jacquet. A NEW ECOLOGICAL ROLE ATTRIBUTED TO WHALES. Subaqua (Marseille), 2022, 301, pp.68-69. ffhal-03770063f