denise
08-12-2008, 04:33 PM
Turtles are a diverse group of 300 plus reptiles whose body is shielded by a special bony shell. Even though turtles spend most their lives in or around the water, they are air breathers, and lay their eggs on land.
As divers, most our glimpses and interactions with turtles are with the marine turtles, and we can see up to five species or marine turtles in Florida. Divers regularly see Loggerheads, Hawksbills and Green turtles, Leatherbacks and Atlantic Ridleys are more rarely spotted around our coastlines.
http://www.scubadiver.cc/forums/gallery/files/4/5/1/robertturtle_1.jpg
Photo by Robert Palmer
Sea turtles spend most of their lives submerged but must breathe air for the oxygen needed to meet the demands of their vigorous activity. They quickly replace the air in their lungs with a single explosive exhalation and rapid inhalation on the surface. Their lungs are adapted to facilitate a rapid exchange of oxygen and carbon dioxide, and to prevent gases from being trapped during deep dives. The blood of sea turtles still delivers oxygen efficiently to body tissues even at the high pressures sometimes encountered during their dives.
Turtles can rest or sleep underwater for several hours at a time but their down time is much shorter while actively diving and swimming, when hunting for food, or trying to escape predators. Their breath-hold ability is affected by activity and stress, which is why turtles drown in nets and and other fishing gear within a relatively short time.
http://www.scubadiver.cc/fishid/Hawksbillturle5.jpg
Marine turtles are extremely sensitive to the Earth’s magnetic field and actually use it to navigate themselves around! Most turtles return to nest at the locations where they were born, and it is believed they do this by using the location's magnetic features. Females return to their "home" beach, and dig a small nest in the sand with their flippers. They lay up to 200 eggs in their nest, and then cover them up with sand. After she lays her eggs, she returns to the ocean.
Some of the eggs contain baby turtles, and the rest are unfertilized. These eggs incubate over the next few months, and amazingly, the temperature of the eggs determines the sex of the hatching turtles! Higher temperature eggs produce females, lower temps produce male turtles! When the baby turtles hatch from the eggs, the babies dig their way out of the sand and head towards the sea. this is the most dangerous time of their life, unfortunately mortality rates are high due to predators and less than 1% make it to the ocean!
Even if turtles make it this far, there are a range of threats that are currently threatening sea turtle populations worldwide including pollution, habitat degradation, over harvesting for food and souvenir trade, by catch in fisheries.
In fact, all species of marine turtles are now listed as endangered, primarily due to over-harversting, and also due to the loss of their nesting habitats.
Turtles are very important in marine ecosystems. They are prey for a variety of fish, sharks and birds. They also control various prey species. In addition, marine turtles are economically important to humans. They are important as an ecotourism attraction, providing jobs and much needed revenue to many countries.
These beautiful creatures represent the delicate balance that exists within marine ecosystems, and how we can use our influence to reverse the downward trend we have witnessed in recent years.
http://www.scubadiver.cc/fishid/debbiebuck/turtledebbie.JPG
Photo by Debi Buck
Hawksbill Turtles Eretmochelys imbricata
Hawksbill sea turtles have elongated hooked, beak-like mouths, two visible claws on each front flipper and a serrated look on the back of their carapace.
http://www.dayo.com/fishid/hawksbillturtlerob_1.jpg
Close up of Hawksbill turtle, Lantana Beach, showing its distinctive beak
Photo by Robert Palmer
Adult hawksbill sea turtles usually live on and around tropical coral reefs. During the day they are often spotted resting in caves and ledges in the reefs. They omnivorous and their favorite food appears to be sea sponges (they are pretty particular about which sponges they eat), but also feed on sea jellies, fish and marine algae. They can grow up to three feet in length, and weigh in at about 100-175 lbs. Hawksbill turtles have a worldwide distribution, with an Atlantic and Pacific subspecies. Unfortunately both are endangered!
http://www.scubadiver.cc/fishid/hawkbillturtle2.jpg
Hawksbill turtle, Eretmochelys imbriocota, West Palm Beach
Hawksbill turtles, like all turtles, have a very hard shell that discourages most predators from trying to eat them! That said, they are still taken by humans, sharks, crocodiles, large fish, and octopus. Their nests are commonly pilfered by terrestrial predators such as humans, dogs, raccoons and rats.
http://www.scubadiver.cc/fishid/hawkbillturtle3.jpg
Hawksbill turtle chilling under a ledge
Hawksbill turtles are highly migratory, and are spotted in a wide range of habitats, from the open ocean to lagoons and even mangrove swamps in estuaries.
http://www.dayo.com/fishid/hawksbillturtlefederico_1.jpg
Back shot of a hawksbill turtle showing its beautiful carapace coloration
Photo by Federico Arismendi
Unfortunately this attractive shell is highly valued by many people, and they are slaughtered in the thousands for their shell which is used for decorative purposes.
This is in stark contrast to how hawkbill turtles were viewed historically. There is evidence that humans and hawkbill turtles have interacted for at least the last 7,000 years. A wooden mask, dated 1200-1400 CE, was found recently in southwest Florida. It was made by natives in the area, and its face depicts a hawksbill turtle. This species of turtle was considered sacred to these native people, they witnessed its reproduction on local beaches, and they associated these turtles with fertility and promise of life to come.
Loggerhead Turtles Caretta caretta
Loggerhead turtles are distinguished by their huge, bulbous heads and large, slightly humped reddish brown shells.
Loggerhead turtles are commonly spotted Florida, especially from fall to springtime as they approach the Floridian coastline to mate and lay eggs.
Loggerhead turtles are the most common sea turtle to nest in the United States. In order to nest, loggerheads require soft sandy beaches, where there is little light pollution. The largest concentration of nests (91%) in the USA is in South Florida! In fact, Florida's beaches account for one third of the world's total population of loggerheads. However, since the late 1990's, the lowest nesting levels Florida has seen in 17 years were recorded, and they are still on the decline.
http://www.scubadiver.cc/fishid/loggerheadturtle_1.jpg
Loggerhead turtle heading back to the ocean after laying her eggs in the sand
Photo by Carol Bean (http://freelargephotos.com/)
This female loggerheads eggs will hatch in about 60 days, at night, when they have greater protection from predators. They instinctively follow the brightest light to the ocean's edge, usually the moon or star light out over the ocean. Often however, artificial lights from human activity can lead them astray. Once in the ocean they use ocean currents to travel to the Sargasso Sea using the Sargassum as protection for the next 10 or so years of their life.
Loggerhead turtles are able to hold their breath for long periods of time, but they must return to the surface to breathe periodically. Typical dives lasts only 4 to 5 minutes, but they can dive and swim around for up to 20 minutes, or rest on the bottom for hours without breathing.
http://www.dayo.com/fishid/turtlebob_1.jpg
Loggerhead turtle resting under a ledge at Boynton Beach
Photo courtesy of Bob Rosell
Loggerhead turtles are omnivorous, feeding mainly on bottom dwelling invertebrates such as crabs, shrimp and clams. Their strong beak-like jaws are adapted for crushing thick-shelled prey. They will also eat jellyfish obtained while swimming and resting near the surface. Loggerheads measure up to 4 feet in length when fully grown, and can weigh in at 300 lbs!
http://www.scubadiver.cc/fishid/Loggerheadturtle2.jpg
Photo by Bob Rosell
Loggerhead sea turtles have a worldwide range with exception of cold (polar) waters. They seem to prefer coastal habitats, but are often spotted hundreds of miles out at sea.
http://www.divetraining.net/pictures/2011_june_11/DSC01300.jpg
Green Turtles Chelonia mydas
Green turtles name does not come from their shell color, it derives from the green fat and flesh underneath their shell. The have brown or olive colored shells, sometimes they are mottled, and grows to up to 5 feet in length.
http://www.scubadiver.cc/fishid/Greenturtle.jpg
Green Turtle, Chelonia mydas, Boynton Beach
Photo courtesy of Bob Rosell
The range of the green sea turtle extends throughout tropical and subtropical seas around the world. Adult green sea turtles generally live in shallow, coastal waters in and around seagrass beds.
http://www.dayo.com/fishid/turtlerob_1.jpg
Green turtle, West Palm Beach
Photo by Robert Palmer
The green turtles diet changes significantly during its lifetime. Juveniles eat worms, young crustaceans, aquatic insects, grasses and algae. Once they grow to more than 10 inches in length, they mostly eat sea grass and algae, and they are the only sea turtle that is strictly herbivorous as an adult. They have finely serrated jaws which helps than to tear up vegetation.
Weighing up at several hundred pounds, green turtles are among the largest sea turtles in the world. Their paddle like flippers make them graceful and effortless swimmers. Green turtles have a proportionally small non retractable head. Males are slightly larger than females and have a longer tail.
http://www.scubadiver.cc/fishid/greenseaturtle_1.jpg
Green sea turtle feeding in a sea grass bed
As divers, most our glimpses and interactions with turtles are with the marine turtles, and we can see up to five species or marine turtles in Florida. Divers regularly see Loggerheads, Hawksbills and Green turtles, Leatherbacks and Atlantic Ridleys are more rarely spotted around our coastlines.
http://www.scubadiver.cc/forums/gallery/files/4/5/1/robertturtle_1.jpg
Photo by Robert Palmer
Sea turtles spend most of their lives submerged but must breathe air for the oxygen needed to meet the demands of their vigorous activity. They quickly replace the air in their lungs with a single explosive exhalation and rapid inhalation on the surface. Their lungs are adapted to facilitate a rapid exchange of oxygen and carbon dioxide, and to prevent gases from being trapped during deep dives. The blood of sea turtles still delivers oxygen efficiently to body tissues even at the high pressures sometimes encountered during their dives.
Turtles can rest or sleep underwater for several hours at a time but their down time is much shorter while actively diving and swimming, when hunting for food, or trying to escape predators. Their breath-hold ability is affected by activity and stress, which is why turtles drown in nets and and other fishing gear within a relatively short time.
http://www.scubadiver.cc/fishid/Hawksbillturle5.jpg
Marine turtles are extremely sensitive to the Earth’s magnetic field and actually use it to navigate themselves around! Most turtles return to nest at the locations where they were born, and it is believed they do this by using the location's magnetic features. Females return to their "home" beach, and dig a small nest in the sand with their flippers. They lay up to 200 eggs in their nest, and then cover them up with sand. After she lays her eggs, she returns to the ocean.
Some of the eggs contain baby turtles, and the rest are unfertilized. These eggs incubate over the next few months, and amazingly, the temperature of the eggs determines the sex of the hatching turtles! Higher temperature eggs produce females, lower temps produce male turtles! When the baby turtles hatch from the eggs, the babies dig their way out of the sand and head towards the sea. this is the most dangerous time of their life, unfortunately mortality rates are high due to predators and less than 1% make it to the ocean!
Even if turtles make it this far, there are a range of threats that are currently threatening sea turtle populations worldwide including pollution, habitat degradation, over harvesting for food and souvenir trade, by catch in fisheries.
In fact, all species of marine turtles are now listed as endangered, primarily due to over-harversting, and also due to the loss of their nesting habitats.
Turtles are very important in marine ecosystems. They are prey for a variety of fish, sharks and birds. They also control various prey species. In addition, marine turtles are economically important to humans. They are important as an ecotourism attraction, providing jobs and much needed revenue to many countries.
These beautiful creatures represent the delicate balance that exists within marine ecosystems, and how we can use our influence to reverse the downward trend we have witnessed in recent years.
http://www.scubadiver.cc/fishid/debbiebuck/turtledebbie.JPG
Photo by Debi Buck
Hawksbill Turtles Eretmochelys imbricata
Hawksbill sea turtles have elongated hooked, beak-like mouths, two visible claws on each front flipper and a serrated look on the back of their carapace.
http://www.dayo.com/fishid/hawksbillturtlerob_1.jpg
Close up of Hawksbill turtle, Lantana Beach, showing its distinctive beak
Photo by Robert Palmer
Adult hawksbill sea turtles usually live on and around tropical coral reefs. During the day they are often spotted resting in caves and ledges in the reefs. They omnivorous and their favorite food appears to be sea sponges (they are pretty particular about which sponges they eat), but also feed on sea jellies, fish and marine algae. They can grow up to three feet in length, and weigh in at about 100-175 lbs. Hawksbill turtles have a worldwide distribution, with an Atlantic and Pacific subspecies. Unfortunately both are endangered!
http://www.scubadiver.cc/fishid/hawkbillturtle2.jpg
Hawksbill turtle, Eretmochelys imbriocota, West Palm Beach
Hawksbill turtles, like all turtles, have a very hard shell that discourages most predators from trying to eat them! That said, they are still taken by humans, sharks, crocodiles, large fish, and octopus. Their nests are commonly pilfered by terrestrial predators such as humans, dogs, raccoons and rats.
http://www.scubadiver.cc/fishid/hawkbillturtle3.jpg
Hawksbill turtle chilling under a ledge
Hawksbill turtles are highly migratory, and are spotted in a wide range of habitats, from the open ocean to lagoons and even mangrove swamps in estuaries.
http://www.dayo.com/fishid/hawksbillturtlefederico_1.jpg
Back shot of a hawksbill turtle showing its beautiful carapace coloration
Photo by Federico Arismendi
Unfortunately this attractive shell is highly valued by many people, and they are slaughtered in the thousands for their shell which is used for decorative purposes.
This is in stark contrast to how hawkbill turtles were viewed historically. There is evidence that humans and hawkbill turtles have interacted for at least the last 7,000 years. A wooden mask, dated 1200-1400 CE, was found recently in southwest Florida. It was made by natives in the area, and its face depicts a hawksbill turtle. This species of turtle was considered sacred to these native people, they witnessed its reproduction on local beaches, and they associated these turtles with fertility and promise of life to come.
Loggerhead Turtles Caretta caretta
Loggerhead turtles are distinguished by their huge, bulbous heads and large, slightly humped reddish brown shells.
Loggerhead turtles are commonly spotted Florida, especially from fall to springtime as they approach the Floridian coastline to mate and lay eggs.
Loggerhead turtles are the most common sea turtle to nest in the United States. In order to nest, loggerheads require soft sandy beaches, where there is little light pollution. The largest concentration of nests (91%) in the USA is in South Florida! In fact, Florida's beaches account for one third of the world's total population of loggerheads. However, since the late 1990's, the lowest nesting levels Florida has seen in 17 years were recorded, and they are still on the decline.
http://www.scubadiver.cc/fishid/loggerheadturtle_1.jpg
Loggerhead turtle heading back to the ocean after laying her eggs in the sand
Photo by Carol Bean (http://freelargephotos.com/)
This female loggerheads eggs will hatch in about 60 days, at night, when they have greater protection from predators. They instinctively follow the brightest light to the ocean's edge, usually the moon or star light out over the ocean. Often however, artificial lights from human activity can lead them astray. Once in the ocean they use ocean currents to travel to the Sargasso Sea using the Sargassum as protection for the next 10 or so years of their life.
Loggerhead turtles are able to hold their breath for long periods of time, but they must return to the surface to breathe periodically. Typical dives lasts only 4 to 5 minutes, but they can dive and swim around for up to 20 minutes, or rest on the bottom for hours without breathing.
http://www.dayo.com/fishid/turtlebob_1.jpg
Loggerhead turtle resting under a ledge at Boynton Beach
Photo courtesy of Bob Rosell
Loggerhead turtles are omnivorous, feeding mainly on bottom dwelling invertebrates such as crabs, shrimp and clams. Their strong beak-like jaws are adapted for crushing thick-shelled prey. They will also eat jellyfish obtained while swimming and resting near the surface. Loggerheads measure up to 4 feet in length when fully grown, and can weigh in at 300 lbs!
http://www.scubadiver.cc/fishid/Loggerheadturtle2.jpg
Photo by Bob Rosell
Loggerhead sea turtles have a worldwide range with exception of cold (polar) waters. They seem to prefer coastal habitats, but are often spotted hundreds of miles out at sea.
http://www.divetraining.net/pictures/2011_june_11/DSC01300.jpg
Green Turtles Chelonia mydas
Green turtles name does not come from their shell color, it derives from the green fat and flesh underneath their shell. The have brown or olive colored shells, sometimes they are mottled, and grows to up to 5 feet in length.
http://www.scubadiver.cc/fishid/Greenturtle.jpg
Green Turtle, Chelonia mydas, Boynton Beach
Photo courtesy of Bob Rosell
The range of the green sea turtle extends throughout tropical and subtropical seas around the world. Adult green sea turtles generally live in shallow, coastal waters in and around seagrass beds.
http://www.dayo.com/fishid/turtlerob_1.jpg
Green turtle, West Palm Beach
Photo by Robert Palmer
The green turtles diet changes significantly during its lifetime. Juveniles eat worms, young crustaceans, aquatic insects, grasses and algae. Once they grow to more than 10 inches in length, they mostly eat sea grass and algae, and they are the only sea turtle that is strictly herbivorous as an adult. They have finely serrated jaws which helps than to tear up vegetation.
Weighing up at several hundred pounds, green turtles are among the largest sea turtles in the world. Their paddle like flippers make them graceful and effortless swimmers. Green turtles have a proportionally small non retractable head. Males are slightly larger than females and have a longer tail.
http://www.scubadiver.cc/fishid/greenseaturtle_1.jpg
Green sea turtle feeding in a sea grass bed