Sea Turtles, Pinnipeds & Cetaceans, Oh My!
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Sea Turtles, Pinnipeds & Cetaceans…Oh My!
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There are four species of sea turtles known to inhabit New York’s waters: (1) Kemp’s ridley sea turtle; (2) loggerhead sea turtle; (3) leatherback sea turtle; and (4) Atlantic green sea turtle. These four species of sea turtles may strand due to fishery interactions which include boat strikes, entanglement and hook ingestion. However, the NUMBER ONE reason for strandings in New York is cold stunning.
Even More About Sea Turtles...
Sea turtles are marine reptiles, which have evolved to live a completely aquatic life, with the exception of egg laying by females. Sea turtles have dry, scaly skin that is impermeable to water, and a tapered, streamlined shell. Their powerful paddle-shaped fore-flippers help them to move easily through the water, where they are capable of diving to great depths. Four different species of sea turtles are commonly found inhabiting Long Island waters during the summer months, where they feed on a variety of food, such as spider crabs, jellyfish, seaweed, and green crabs.
Kemp's Ridley Sea Turtles
Kemp’s ridleys are the most critically endangered of all the sea turtles, as well as the smallest. Adults may grow to lengths of .06 to .08 meters (2.0-2.5 feet), and can reach weights between 36-50 kg (80-100 lbs). Kemp’s ridleys have a heart shaped carapace (top shell) that ranges in color from olive, to gray, to black, while their plastron (underbelly) is white in color. These turtles feed on marine life such as crabs, fish, jellyfish, squid, snails, clams, sea stars, and some marine vegetation. Kemps Ridleys found in New York waters generally feed on a diet that consists mainly of spider crabs, rock crabs, and lady crabs. These turtles can dive for and average of 12-18 minutes, and can dive to depths up to 164 feet. Females begin to nest between April and August on one beach in Ranchos Nuevos, Mexico, although some evidence has been found of very small numbers nesting at other sites. Kemp’s ridleys are the only turtles that nest during the day, making their eggs and their young more vulnerable to predators. Adults can live to be up to 30 years old.
Green Sea Turtles
Green sea turtles are the largest of the hard-shelled sea turtles. Adults can reach lengths up to 1 meter (4 feet), and weigh up to 226 kg (500 lbs). Green sea turtles have a worldwide distribution, but concentrated populations can be found near Massachusetts in the summer and Argentina in the winter. These turtles have a unique starburst pattern to their carapace, with colors ranging from gray, to green, to brown, and black. Green sea turtles are not named for their carapace color, but rather for the color of their body fat. This body fat, called calipee, is pigmented green as a result of their largely herbivorous diet. Hatchling and juvenile green sea turtles are carnivores that feed on squid, bivalves, jellyfish, and crustaceans out in the open ocean. As these turtles mature and attain a length of 20-25 cm, they migrate to benthic (bottom) areas where they feed mainly on seagrass and algae. They are not exclusive herbivores, but plant matter makes up the majority of their diet as adults. Green sea turtles can dive to depths up to 110 meters (361 feet), and can stay submerged for up to 66 minutes. This species nests on tropical beaches in Florida, Puerto Rico, and the U.S. Virgin Islands between the months of March and October. Green sea turtles are a threatened species, with a life span of at least 60-70 years.
Leatherback Sea Turtles
Leatherback sea turtles are the largest living turtles, and are the only remaining representative of the Dermochelids. They are also an endangered species. Adult leatherbacks can reach lengths up to 2 meters (6 feet) and reach weights up to 590 kg (1300 lbs). The carapace of the leatherback sea turtle is covered with a black, leathery skin, which is what they are named for. This black skin is often spotted with white or pink on the underside of the head, limbs, and body. In addition, leatheracks have seven longitudinal ridtehs running along the length of the shell, and they have five along the underside of the shell. These turtles are the most pelagic of all sea turtles, capable of diving to 1300 meters (4,290 feet) to feed primarily on jellyfish, salps, and other gelatinous species. Leatherbacks tend to dive for less than 20 minutes per dive, but are capable of diving for up to 37 minutes. Unlike other reptilian species, leatherbacks have been known to inhabit waters with temperatures ranging from 0-15 degrees celsius, suggesting that they are capable of thermoregulation (controlling their internal body temperature). Studies done on leatherbacks suggest that their core body temperatures can average 8-10 degrees higher than the air temperature, and 2.5-5.1 degrees celsius higher than their surrounding water temperature. Scientists refer to this phenomenon as gigantothermy. Leatherback nesting occurs from April to November on beaches along the east coast of Florida and the Caribbean, and their lifespan is estimated to be more than 45 years.
Loggerhead Sea Turtles
Loggerhead sea turtles can be identified by their reddish-brown colored carapace, and by their large, stout head and neck. Adult loggerheads may reach lengths up to 0.9m (3 feet), and can weigh as much as 136 kg (300 lbs). These turtles have a worldwide distribution, but populations may be especially concentrated around Newfoundland in the summer, and Argentina in the winter. Loggerheads can dive to depths up to 233 meters (764 ft) to feed on crabs, crustaceans, squid, bivalves, jellyfish, fish, and eelgrass. Average dives last between 17 and 30 minutes. This species nests in April through September on Atlantic coast beaches of the U.S. from New Jersey to Texas, but they prefer to nest in Florida. Loggerheads are considered to be a threatened species, with a lifespan of around at least 70-80 years.
Our Current Sea Turtle Residents!
There are five species of seals known to inhabit New York’s waters: (1) grey seals; (2) harp seals; (3) harbor seals; (4) ringed seals; and (5) hooded seals. The majority of the seals that strand in NY are either in the age class pups or yearling rarely do we provide rehab to adult individuals. These animals strand due to various issues which include; dehydration, injured flippers, infectious diseases, anorexia, and entanglement.
Even More About Pinnipeds...
Seals, sea lions, and walruses are all pinnipeds. Some scientists believe that pinnipeds belong to a separate order of mammals, while others believe that pinnipeds belong to the sub-order Pinnipedia within the order Carnivora. Pinnipeds have fur and blubber for thermoregulation, long whiskers, two sets of flippered limbs, reduced or lost earflaps, and nasal openings at the tip of the snout. Also, all pinnipeds molt their fur once per year. There are three families within the sub-order pinniped: Phocids, Otariids, and Odobenids. The Phocidae (also referred to as true or earless seals) are characterized by the following: The absence of external ear flaps, short foreflippers with hair and claws on each of the digits, hindflippers that are oriented posteriorly and cannot be rotated forward, beaded vibrissae (whiskers), a short muzzle, short fur, and dark skin. The Otariids (or eared seals) are comprised of the sea lions and fur seals. All otariids have external ear flaps called pinnae, and in all species of otariids the males are significantly larger than the females. These seals have long fore and hind flippers which lack claws, and they can use their flippers to sit upright and walk on land. The only living member of the Odobenid family is the walrus. Walruses can be recognized by their huge bodies, sparse hair, and their modified canine teeth, which form the long tusks that are their trademark. Walruses are able to rotate their hind flippers underneath their bodies and walk on them on ice or land. Walruses also do not have fur, and have no external ear flaps. The Riverhead Foundation for Marine Research and Preservation operates the New York State Marine Mammal and Sea Turtle Stranding Program. The program responds to an average of 200 animals per year, with the majority of the animals being seals. The seals that we see in the Long Island area are all true seals. The five species most commonly seen in Long Island waters are harbor seals, harp seals, gray seals, ginged seals, and hooded seals.
Gray seals can be easily recognized by their horse-shaped snout and long head. Males are usually dark with light markings on their coat, while females are lighter, with dark markings. Pups are born with a long and thick lanugo coat, which they shed around two to four weeks of age for a less speckled version of the adult pelage. Pups gain approximately 3 pounds per day when they are nursing, because the fat content of their mother’s milk increases sharply during lactation from 40% to as high as 60%. Gray seal pups are usually weaned by 3 weeks of age. Adult females can reach up to 2 meters (6 ft, 7 inches) in length, and weights up to 200 kg (440 lbs). Adult males can be up to three times the size of some females, reaching lengths of 2.6m (8ft, 6inches) and weighing in at up to 350 kg (770 lbs). These seals live to be between 30 and 50, and are found only in the waters of the western North Atlantic. Populations are concentrated in eastern Canada, but extend southward to southern New England and eastern Long Island. Gray seals feed primarily on schooling fish such as herring, mackerel, flounder, cod, and salmon, as well as squid, octopus, crustaceans, and even seabirds. Major predators of this species include sharks, humans, and possibly killer whales. Worldwide population estimates are around 200,000-300,000. Gray seals are gregarious, and are also polygynous, meaning they will mate with more than one individual. Female gray seals reach sexual maturity between 3 and 5 years of age, and males reach sexual maturity between the ages of 4 and 8.
The Harp seal is the most abundant pinniped in the Northern Hemisphere, and it gets its name from the distinctive harp shaped saddle on the backs of the adults. Harp seal pups are born with a yellow coat, which is stained by the amniotic fluid. This coat is bleached white by the sun after approximately 3 days, giving them the nickname “whitecoats”. At around four weeks of age, the pups molt and develop a spotted silvery-black coat. Newborn harp seals are typically up to 85 cm (33 inches) in length, and weigh in around 11 kg (24 lbs). Adult females can reach lengths up to 1.8 meters (5 feet, 11 inches) and weigh up to 130 kg (290 lbs), while adult males are slightly larger, reaching 1.9 meters (6 feet, 3 inches) in length, and weights up to 140 kg (310 lbs). These seals can live to be up to 30 years old, and are distributed primarily in the pack ice of the North Atlantic Ocean, from Newfoundland to Northern Russia. Harp seals may travel up to 2,500 km (1,600 miles) during their migrations, moving northward to feed in the spring and summer, but some are found as far south as Virgina. These seals feed mainly on schooling fish such as herring and cod, and crustaceans. Major predators of harp seals include polar bears, walruses, sharks, and humans. Their total worldwide population is estimated to be between 4 and 6 million, with the largest population in western North Atlantic.
Harbor seals are highly social animals, and are known to haul out on sandy or rocky areas. Hauled out seals often exhibit a banana-shaped position that is characteristic of healthy seals. Their coats are usually tannish or black on the back, with their bellies being lighter in color, and scattered dark spots throughout the coat. When first born, harbor seal pups weigh approximately 8-12 kg (18-26 lbs) and are around 70-100 cm (28-40 inches) in length. Pups born early in the season may have a wooly, grayish coat called a lanugo coat, while others born later may shed this coat in the womb. Juveniles grow very quickly, and adult males can grow to be up to 1.9 meters (6 ft 3 inches) in length, and can weigh up to 170 kg (370 lbs). Adult females are slightly smaller, reaching 1.7 meters (5 ft 7 inches) in length, and weighing in at up to 130 kg (290 lbs). These seals can live to be between 25 and 35 years old. Harbor seals range widely in coastal areas of the North Pacific and North Atlantic, and are commonly found in Maine and eastern Canada during the spring and summer. In the wintertime, they have been found to migrate as far south as Long Island. These seals feed primarily on schooling fish such as bunker or herring, and also on squid, octopus, and crustaceans. Their major predators include large sharks, killer whales, northern sea lions, polar bears, and humans, and their worldwide population is estimated to number between 400,000-500,000, with at least four subspecies being recognized. Harbor Seals are usually very wary and shy on land, and are easily frightened into the water when they feel they are threatened.
Ringed seals are the smallest and most commonly found seals in the Arctic Ocean, with large populations also concentrated in the Hudson Bay, and Baltic and Bering Seas. It is rare to see these seals in Long Island waters, but vagrants have been spotted as far south as Portugal in the Atlantic Ocean. Ringed seals can be recognized by their small, plump body, and their pelage, which is light on their bellies and dark on their back, with scattered irregular rings throughout. Pups have a white, wooly lanugo coat that they shed around six to eight weeks of age for a pelage that is dark on top and light on the bottom. Only after their first molt do they begin to develop the characteristic irregular ringed pattern. Ringed seal adults can reach lengths of 1.6 meters (5 ft, 3 inches) and weights up to 110 kg (240 lbs), and live to be about 25 to 30 years old. This species is known for excavating birth lairs under the ice and snow to protect themselves and their young from predators such as polar bears and humans. They are the only species known to do this, as all other pinnipeds give birth on exposed surfaces, beaches, or occasionally in caves. Ringed seals feed mainly on polar cod, and their worldwide population has never been surveyed, but may surpass 4 million.
The hooded seal is named for the inflatable nose and extrudable nasal sac of the adult males, which can be inflated to attract a mate or to ward of potential predators. The color pattern of adult hooded seals can be described as a light background with scattered dark splotches, and a dark head. The pups are often referred to as “blue-backs”, because they shed their lanugo coat in-utero, and are born with bluish- gray backs and faces, and lighter underbellies. Hooded seal pups have the shortest lactation period known of any mammal – they are only nursed by their mother for four days. The mother’s milk consists of 60% fat, which allows the pups to gain around 16 pounds per 24 hour period while they are nursing. Adult females weigh in around 300 kg (600 lbs) and reach lengths up to 2.4 meters (7 ft, 10 inches), while adult males reach lengths of 3 meters (10 ft) and weights up to 400 kg (880 lbs). The breeding range of these seals is limited to the central and western North Atlantic, where they stay mostly along the edge of pack ice. Adult male hooded seals are monogamous, but the mating system of the hooded seal is polygynous. Breeding season lasts for around 2 to 2.5 weeks, with adults not feeding at all during this time. Juveniles have been known to wander surprisingly far during the non- breeding season. Hooded seals feed on a variety of schooling fish, as well as squid, shrimp, octopus, and crustaceans. Their major predators include polar bears, sharks, killer whales, and humans. Worldwide population estimates range from 250,000 to 300,000.
There are over 10 species of cetaceans that are observed in New York waters and NYMRC is responsible for providing in-field response and treatment to small cetaceans including dolphins, porpoises and small toothed whales. These animals may strand for a number of different reasons including to entanglement, anorexia, infectious diseases, and internal/external injuries.
Even More About Cetaceans...
The name Cetacean refers to any whale, dolphin, or porpoise of any species. There are two different groups of whales that exist: Suborder Mysticeti (baleen whales) and the Suborder Odontoceti (toothed whales). There are 76 known species of toothed whales, and 11 species of baleen whales. Baleen whales are named for the keratinous plates of baleen, which hang from their upper jaw. These plates can be thick and bushy, or can be long and coarse, and are used to filter out and capture large amounts of shrimp-like crustaceans or small fish from the water. Examples of baleen whales are the blue whale, fin whale, and humpback whale. Toothed whales have regular teeth, and include the narwhal, beluga whale, all dolphins, porpoises, Sperm whales, and beaked whales. Toothed whales feed on fish, squid, and marine mammals. Cetaceans are mammals that spend their entire lives in the water. They share five common characteristics with all other mammals: They are warm blooded, they have hair or fur, they breathe air, and they give birth to live young, whom they nurse with milk. Cetaceans have also developed a blubber layer to insulate themselves from the cold waters, and they have streamlined bodies for more aerodynamic and efficient movement through the water. New York is home to many species of cetaceans throughout different times of the year. All of these species are protected under The Marine Mammal Protection Act (MMPA) of 1972, and some are protected under the Endangered Species Act as well. Information about some of the species of cetaceans that have been rescued off of Long Island is presented below.
The common dolphin is one of the most commonly seen cetaceans – hence its name. These toothed whales can be found around Long Island and worldwide in tropical and warm offshore waters. Common dolphins can reach a length of 5-8 feet, and can weigh between 165-300 pounds, with common dolphin males being slightly larger than females. These dolphins have a dark, V- shaped saddle just below their dorsal fin on either side, and they have light gray or yellowish patches on their sides just forward of the dorsal fin. Their dorsal fin is tall and dark, often with a grayish or whitish area in the center, a dark stripe extending from the eye to the corner of the mouth, and completely white bellies. There are two recognized species of common dolphins: (1) short beaked; and (2) long beaked; with the major morphological difference being the length of their rostrum. Common dolphins have between 80-120 small, sharply pointed teeth in each jaw, allowing them to feed on anchovies, deep sea smelt, lanternfish, and squid, among other things. These dolphins are the most gregarious of all cetaceans, and are commonly found in pods of 100-1,000 individuals. Female common dolphins give birth to one calf each year, and their gestation period is around 11 months. These animals can live for 25-30 years, with sharks and humans being their biggest threats. Common dolphins are protected in the U.S. under the Marine Mammal Protection Act of 1972.
The bottlenose dolphin is one of the most well known species of marine mammals. There are two morphotypes of the bottlenose dolphin. There are coastal and offshore bottlenose dolphins. They have a robust body and a short, thick rostrum. The coastal morphotype are typically light gray with lighter belly, while the offshore morphotype is much darker in color, but also has a lighter belly. They range in length from 6-12 feet and can weigh 300-1400 pounds. They are commonly found in groups of 2-15 individuals, but offshore groups can consist of hundreds. They feed on species endemic to their habitat and use high frequency echolocation to local prey cooperatively. While the offshore morphotype usually feed on squid and fish, the coastal morphotype typically feed on benthic invertebrates and fish. The lifespan is very long and bottlenose dolphins as old as 45 years have been known to give birth. Threats to the species include accidental injury due to fishing gear, marine debris and biotoxins, morbillivirus outbreaks, and direct harvest in Taiwan and Japan. In 2006, NMFS implemented the Bottlenose Dolphin Take Reduction Plan (BDTRP) to reduce serious injury and mortality of bottlenose dolphins. In addition, bottlenose dolphins are protected under MMPA.
Harbor porpoises are one of the smallest species of cetaceans found around Long Island. The harbor porpoise reaches lengths of only 4-6feet when full grown, and weights of 99-110 pounds. These animals are small and chunky, with a minimal forehead and snout. Harbor porpoises can be identified by their rounded fore flippers, and a triangular dorsal fin. Harbor porpoises are dark brown or gray in color, with a white belly and dark appendages. They have 44-56 spade shaped teeth in each jaw, and feed mainly on cephalopods, benthic invertebrates, capelin, hake, cod, and schooling fish such as herring or mackerel. Harbor porpoises are widely distributed, and can be found in coastal waters of the Northern Hemisphere. They usually travel in groups of 50 or more but can be encountered singly, in pairs, or in smaller groups of 5-10 individuals. Harbor porpoises are capable of breaching and porpoising fully out of the water, but they rarely display these behaviors. Females give birth every year to a single calf, with the gestation period lasting for 11 months. These animals can live for up to 15 years, and their main predators include Great White Sharks and Killer Whales. Harbor porpoises are listed as a species of concern in New York State.
The Atlantic white-sided dolphin is one of the most colorful species of all of the cetaceans. These dolphins can be recognized by their bold, well-defined white and yellowish-tan patches on their sides, as well as their short, inconspicuous beaks, and their robust body shape. White-sided dolphins are gregarious and very playful, and are known also as “lags” or “jumpers”, as it is common to see these dolphins breach fully out of the water. White-sided dolphins have moderately tall falcate dorsal fins, and have a very thick and keeled caudal peduncle. These animals have 29-40 teeth in each jaw, which allow them to catch and feed on herring, hake, squid, mackerel, and various benthic fish. The Atlantic white-dided dolphin is found only in waters of the temperate North Atlantic, where it prefers shelf waters and deep slope and canyon waters, but these animals may tend to move inshore in summer months and offshore in winter months. Adults can reach lengths up to 9.5 feet, and can weigh more than 510 pounds, with males being slightly larger than females. These dolphins can live to be at least 17 years old, and major threats to their populations include humans and sharks.
Globicephala melas / Globicephala macrorhynchus
There are two species of pilot whale that make up the genus Globicephala, the long-finned pilot whale (G. melas) and the short-finned pilot whale (G. macrorhynchus). Pilot whales are one of the largest oceanic dolphins and one of the largest species that NYMRC responds to. These animals are characterized by a slender pointed flippers, a large found bulging forehead, and a short snout.