Sharks of the U.S. Caribbean

by Michelle T. Schärer, HJR Reefscaping, Puerto Rico November 15, 2018


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Gulper shark (Centrophorus sp.) watched at a depth that 868 meters (2,848 feet) inside the Inés María Mendoza Nature Reserve, additionally known as Punta Yeguas, throughout Dive 6 that the Océando Profundo 2018 expedition. Image courtesy the the rebab.net Office of s Exploration and also Research, trying out Deep-sea Habitats turn off Puerto Rico and the U.S. Virgin Islands.

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Predation is a solid driver of the ecology of maritime communities, and also sharks space the key predatory force in many marine ecosystems. The numerous years the sharks have occupied the planet’s ocean has led them come evolve right into a perfect predator, capable of eating most other maritime fauna, consisting of fishes, birds, reptiles, and also mammals. Sharks own fine-tuned sensory offal that have the right to detect fish vibrations from an excellent distances and also smell blood also if diluted in minute concentrations, and also sharks can learn come visit locations where methods for simple meals are recurrent.

These evolution advantages, coupled through the absence of a swimming bladder (a gas-filled sac because that buoyancy), big livers that aid digest a variety of food, a sleek hydrodynamic body design, and also a solid outer shield of denticle (toothlike) scales do sharks an extremely efficient predators. The evolution over millions of years has also led sharks to adapt to and thrive in a great variety of various marine habitats varying from shallow waters to the deep sea.

Historical records of Sharks in the U.S. Caribbean


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Unidentified shark seen at a depth that 638 meter (2,093 feet) in the Inés María Mendoza Nature Reserve throughout Dive 6 the the Océando Profundo 2018 expedition. Image courtesy the the rebab.net Office of ocean Exploration and also Research, exploring Deep-sea Habitats off Puerto Rico and also the U.S. Virgin Islands. Download photo (jpg, 1.0 MB).


Publications on the diversity that sharks in the U.S. Caribbean space greatly minimal when compared to various other U.S. Waters. One factor for this paucity of information is the scarcity of ahead studies focusing on this region, as well as the challenge in appropriately identifying sharks, which frequently times requires specimen collections to validate identification by taxonomic experts.

Recent enhancements in hereditary methods and also online databases have actually allowed an excellent advances in the to know of sharks, without the must sample entire specimens. We deserve to analyze the DNA of a very tiny piece that shark organization to recognize if that varieties has been previously described. These techniques have come to be a crucial tool to address taxonomic unpredictabilities within a an excellent variety of various organisms, and also sharks room no exception. For example, this methods aided disprove the hypothesis that the Atlantic six-gill shark no longer existed.

The earliest clinical reports the sharks in the U.S. Exclusive financial Zone bordering Puerto Rico and the U.S. Virgin Islands to be from the 1950s. Ten species of sharks in four family members (Carcharinidae, Squalidae, Mustelidae, and Isuridae) were recorded by Erdman in 1956. Added collections that shark specimens were made in the U.S. Caribbean during the 1980s by experimental fishing off large oceanographic vessels such together rebab.net delivery Oregon II and also rebab.net ship Delaware II, in addition to visual monitorings of sharks made from the Seward Johnson-Sea attach II manned submersible. This reports added varieties of the families Centrophoridae, Dalatidae, Etmopteridae, Hexanchidae, Scyliorhinidae, and also Triakidae to the list of sharks well-known from the U.S. Caribbean.

More recent research by various academic institutions has increased the depth and also geographic varieties of sharks well-known from U.S. Caribbean waters. In particular, work performed at the department of maritime Sciences the the college of Puerto Rico throughout the 1990s included important shark documents in the households Etmopteridae, Scyliorhinidae, Carcharhinidae, and Hexachidae.

To date, at the very least 42 species belonging to 15 family members of sharks have actually been confirmed to exist in U.S. Caribbean waters based on specimen collections and DNA sequences. One of the many noteworthy current findings to be made by Grisel Rodríguez the the Puerto Rico department of Natural and also Environmental Resources, that investigated a big shark stranded top top the southwest coast of Puerto Rico and was may be to determine that it was a Megamouth Shark. This exploration was shown with a DNA sample and it came to be the an initial record of this varieties in the Northwestern Atlantic Ocean.

Recent Deep-sea Shark Records


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Scyliorhinus sp. Catshark observed eastern of Vieques Island at a depth the 479 meter (1,571 feet) during Dive 2 the the Océando Profundo 2018 expedition. Image courtesy that the rebab.net Office of s Exploration and also Research, trying out Deep-sea Habitats off Puerto Rico and the U.S. Virgin Islands. Download bigger version (jpg, 1.2 MB).


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Egg instance with live shark embryo observed west that Desecheo Island at a depth that 250 meter (820 feet) throughout Dive 15 the the Océando Profundo 2018 expedition. Image courtesy that the rebab.net Office of s Exploration and Research, trying out Deep-sea Habitats turn off Puerto Rico and the U.S. Virgin Islands. Download larger version (jpg, 740 KB).


The incidental record of sharks by fishers has actually added an important information top top the identity, as well as geographic and depth distribution, the sharks in deep waters (100 to 500 meters; 328 to 1,640 feet) surrounding the U.S. Caribbean. If these records have added important information, they are minimal to depth and geographic varieties where fishing takes place and do not administer much information about the herbal environments and also behaviors that sharks.

This is among the great advantages of the exploration methods offered by rebab.net ship Okeanos Explorer, together its remotely operated vehicles (ROVs) allow us to discover much deeper depths (up come 6,000 meter or 3.7 miles) that have remained mainly unexplored in the region as well regarding get high-resolution imagery and also environmental information of the habitats in i beg your pardon these varieties may occur. This information adds necessary evidence to understanding the simple biology and ecology of many deep-sea types including sharks.

For instance, a catshark in the genus Scyliorhinus to be observed swim in its herbal environment throughout both the 2015 and 2018 Okeanos Explorer expeditions to this this region. Back the varieties cannot it is in conclusively confirmed from video alone, this shark to be very similar to specimens the the genus Scyliorhinus collected by advertising fishers. This sharks room generally small (less than 50 centimeters or 20 customs in length) and also are connected with the seafloor, whereby they lay egg situations on corals and also sponges the contain your embryos. Us observed one such egg situation during Dive 15 the the Océano Profundo 2018 expedition.


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Hexanchus sp. It was observed at a depth the 672 meter (2,205 feet) in the Inés María Mendoza Nature Reserve, also known as Punta Yeguas, during Dive 6 of the Océando Profundo 2018 expedition. Image courtesy that the rebab.net Office of ocean Exploration and also Research, exploring Deep-sea Habitats off Puerto Rico and the U.S. Virgin Islands. Download larger version (jpg, 873 KB).


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View the the Hexanchus sp. Shark and ROV Deep Discoverer as seen from Seirios during Dive 6 of the expedition. Image courtesy the the rebab.net Office of ocean Exploration and Research, exploring Deep-sea Habitats off Puerto Rico and the U.S. Virgin Islands.

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Another group of sharks that is reasonably common in deep locations of the U.S. Caribbean is the household Hexanchidae, which consists of the six-gill and seven-gill sharks. The three species reported in the an ar are easily recognizable, because they only have one dorsal fin and have either 6 or seven gill slits on each side. One of these, the six-gill shark Hexanchus sp., to be recorded throughout Dive 6 the the Océando Profundo 2018 exploration swimming about ROV Deep Discoverer in ~ a depth of 672 meters (2,205 feet). Interestingly, us observed two added sharks during that same dive, including a Gulper shark (Centrophorus sp.) seen at a depth of 868 meter (2,848 feet) as well as an unidentified shark at a depth that 638 meters (2,093 feet). Collectively, the new observations of sharks from the Océando Profundo 2018 expedition add important insights right into the biology and ecology of these important yet still poorly understood deepwater sharks.