Exciting Rare Sighting in the Dutch Caribbean: the Antillean manatee
Exciting Rare Sighting in the Dutch Caribbean: theAntillean manatee
Last month STINAPA’s ranger Luigi Eybrecht was diving near Playa in Bonaire when he encountered a very rare marine mammal: the Antillean Manatee (Trichechus manatus manatus). This is the first confirmed record of an Antillean manatee in Bonaire.
Bonaire’s waters are part of the Yarari Marine Mammal and Shark Sanctuary. The YarariSanctuary, which encompasses Saba’s and Saba Banks’ waters and Bonaire’s Exclusive Economic Zone waters, does not only protect marine mammals such as whales, dolphins and manatees, but also sharks.
The Antillean Manatee is a subspecies of the West Indian manatee (Trichechus manatus)(Deutsch et al. 2008). The Antillean manatee is estimated at less than 2500 mature individuals sparsely distributed throughout the tropical and subtropical Western Atlantic Coastal Zone from the Bahamas to Brazil, including the Caribbean Sea and Gulf of Mexico (Deutsch et al. 2008). The declining manatee population is threatened by habitat degradation and loss, hunting, accidental fishing-related mortality, pollution, and human disturbanceand listed as Endangered on the IUCN Red list as it is predicted to decline by at least 20% over the coming 40 years (Self-Sullivan & Mignucci-Giannoni, 2008).
Manatees can inhabit waters with large changes in salinity concentrations and therefore are often found in shallow rivers and estuaries where they opportunistically feed on aquatic plants (Ortíz et al., 1998; Deutsch, 2008). They can grow up to 4.5 meter and weight up to 630 kg (U.S. Fish and Wildlife Service, 2018).
It is possible that the Dutch Leeward Islands (Aruba, Bonaire, Curaçao) prior or during the Holocene could have facilitated colonization and supported small populations of the manatee (Debrot et al., 2006). The geographic isolation of the islands and use of this defenseless species by the early Amerindian inhabitants explain why it is believed that this species could easily have been eradicated around these islands well prior to the European colonization (Debrot et al., 2006). Today, suitable habitat for manatees is clearly missing around the Dutch Leeward island (Debrot et al., 2017). However, the few manatees seen in the past years around the Dutch Leeward Islands suggest that they could still form part of the active range of this rare and elusive species (Debrot et al., 2006). A manatee spotted in January this year by Armand Cranen in Aruba may have been the same as the one seen in Bonaire by L. Eybrecht, passing by the Leeward islands and deriving from the population inhabiting the waters of Venezuela, Puerto Rico or Hispañola. Evidence from the Lesser Antilles suggests that in pre-Columbian times manatees could have occurred regularly in the Dutch Caribbean Windward Islands (Saba, St. Eustatius and St. Maarten) but are now regionally extinct around these islands (Debrot et al., 2006; Deutsch et al. 2008).
The recent sigthings show that manatees have the dispersal capacity to reach the Dutch Leeward Islands. The Yarari Marine Mammal and Shark Sanctuaryincludes habitats of former and potential future renewed importance for the endangered West Indian manatee (Debrot et al, 2011). It is hoped that together with other regional marine mammal protection initiatives this charamastic species could be saved from extinction.
Table 1: Overview of the West Indian manatee (Trichechus manatus) documentedin the Dutch Caribbean.