The reputation of The Bahamas as the shark capital of the world is certainly not unfounded. Just a quick scroll through our social media will show you that: tiger sharks cruising over seagrass flats, majestic great hammerheads silhouetted on the white sand flats, baby lemon sharks skulking around mangrove roots. These iconic species are what makes Bimini so enticing to tourists and scientists alike, but every so often, and usually when we least expect it, we encounter sharks and rays that are unusual guests. Let us introduce you to some of Bimini’s recent (un)usual suspects…
1. Silky shark (Carcharhinus falciformes)
Native to The Bahamas, silky sharks are rarely found in Bimini due to their preference for deeper waters at the edge of shelf habitats. Usually found between 18-500m, silky sharks mature between 215-245cm and give birth in shallower, coastal waters. In the summer of 2020, the Shark Lab team were lucky enough to encounter four of these sharks in the deeper waters on the edge of the Gulf Stream. Not only were they able to collect valuable DNA and stable isotope samples, but ultrasound of a large female indicated pregnancy, suggesting that the waters surrounding Bimini could play a role in supporting silky sharks during their gestation.
[Photo: Chelle Blais]
2. Smalltooth sawfish (Pristis pectinata)
One of the most endangered fish species in the world, the Smalltooth sawfish is an intertidal species that is often found in shallow creeks and around mangrove habitat, and can be an astonishing 4 meters in total length. Their large, ornate rostrum has made them the target of poaching, and as numbers continue to decline, The Bahamas remains one of the last strongholds for the western Atlantic population. While acoustic and capture data shows that the species uses the tidal creeks in Andros, individuals have been detected on Bimini’s acoustic array, and satellite telemetry has also shown them to move through Bimini on their way into Floridian waters. The Shark Lab has had sporadic encounters with sawfish over the past 20 years, including one capture, but the team was surprised this year when one was spotted sailing through the shallow water just less than a few hundred feet from the lab, making for some incredible drone footage.
[Photo: Sarah Dauphinee]
3. Night shark (Carcharhinus signatus)
An Atlantic species, the night shark is typically found in deeper water between 185 and 365 meters. Due to their depth range, they are rarely encountered by humans other than as bycatch by deep sea fishermen. Information on their population is lacking, but their declining occurrence in fisheries has caused them to be listed as vulnerable by the IUCN. In 2019, a fisherman contacted the lab about a shark he was unable to recognise, and when the team reached the 237cm shark, they were able to identify it as a night shark, which became the first we had tagged since 2017.
[Photo: Sophie Hart]
4. Manta ray
There are two species of manta ray, the smaller reef manta Mobula alfredi and the much larger oceanic manta, Mobula birostris. Both are easily recognisable for the large cephalic lobes that flank their mouths, assisting them in feeding by filtering zooplankton from the surrounding water. Once a semi-regular spot in Bimini, over the past 10 years mantas have become increasingly rare to encounter. In an exciting progression of events, an unsuccessful day attempting to tag bull sharks in the summer of 2019 brought the Shark Lab team into a marina, where a manta was spotted weaving through the docks. The large female was alone and relaxed, which allowed some of our volunteers to hop in and get the rare chance to swim alongside a manta ray in Bimini.
In the past, reports of a number of exciting species have been relayed to us including white sharks and whale sharks. So while we are always grateful and excited to work with our regulars, watch this space for more unusual encounters!
[Photo: Rosie Poirier]