SEA TURTLE BIOLOGY Photo courtesy of Burt Jones/Maurine Shimlock

What is a sea turtle? Class Reptilia General Characteristics Cold-Blooded Scales Egg-laying Three-chambered heart Photo courtesy of Turtle Trax, UKB General Characteristics Carapace/Plastron Non-retractable limbs Scutes/scales Lungs Adapted for Marine Environment Flippers Streamlined shell Salt excreting glands Sea turtles have been around for about 150 million years – they watched the dinosaurs come and go. They have flourished up until the last hundred years or so, at which time human interactions began wiping out population after population (get Fire In The Turtle House examples)

LOGGERHEAD Photos courtesy of Doug Perrine Named for unusually large head Diet consists of crustaceans/mollusks 57,242 nests on e. coast of Florida in 2002 Major threats are anthropogenic – incidental catch in shrimp trawl nets, over development of nesting habitat East Coast of Florida one of the most important nesting grounds in the world. The Archie Carr NWR (20.5 miles long) near Melbourne FL is the most productive nesting site of Loggerheads in the Western Hemisphere. They average 20,000 nests a year. Tend to nest in more subtropical and temperate areas, avoiding tropical beaches of Caribbean, South America, etc…

GREEN Herbivorous 2nd most common nester in Florida Heavily hunted for their meat Photo courtesy of Bill Keogh Green name comes from color of body fat Herbivorous – eats primarily sea grasses and algae Traditionally the most hunted turtle for it’s meat – individual populations were essentially wiped out due to human demand for turtle meat. In the 60’s and 70’s there was a tremendous demand for green sea turtle, the main ingredient in turtle soup. From 1963-1972, the amount of turtle meat taken (from Hawaii) jumped from 380 pounds to 25,583 pounds and this can be directly attributed to an increase in tourism and the desire of locals and foreign tourists to eat turtle meat.

Green Turtles Fibropapilloma tumors Photos courtesy of Turtle Trax, UKB FP, as it’s called, was first noted in the 1930’s, but over the last several years has reached epidemic proportions in parts of Florida and Hawaii. Scientists are still in the process of learning what causes it, but they believe it’s a virus. They can be all sizes – as large as a grapefruit, and covers any soft tissue area –flippers, head, eyes, mouth, even internal organs. Runs rampant in juveniles, though all ages seem to be susceptible. Tumored turtles have been in captivity with non-tumored turtles, without having ever spread the disease. Possibilities include pollutions, warming waters, food source is polluted (sea grasses) Predominantly found in greens, though records of it affecting loggerheads, hawksbills, olive ridleys and flatbacks.

LEATHERBACK Most extreme sea turtle Diet = Jellyfish Pacific populations facing extirpation Photo Courtesy of Matthew Godfrey Dive deeper, and swims in colder waters and travels farther than any other sea turtles. Adults have been known to dive to depths of 4,922 feet, and they have been recorded off the coast of Nova Scotia. Leatherbacks need to consume hundreds of pounds of jellyfish each day - it is thought that this is the reason they travel to colder waters, because this is where the larger jellyfish can be found in abundance. Pacific populations are declining due to commercial fishing practices, most likely. Between 1985 and 1995, the number of nests on a key nesting beach in Mexico dropped from 6,500 to less than 500. Ironically, the South American swordfish fishery expanded immensely during this same time period. Some scientists speculate the species may be threatened with actual extinction in the foreseeable future, others disagree. World population of leatherbacks is thought to be somewhere in the neighborhood of 30,000 to 40,000.

HAWKSBILL Photos courtesy of Doug Perrine Found primarily on reefs Sponges make up diet Hunted for shell Demise was due in large part to the trade of their shell – used in making jewelry, eyeglass rims, clips, combs, etc.. Shell trade is banned by and international treaty, but this is difficult to enforce, and shell products can still be found in marketplaces Consume large quantities of sponges, which can be poisonous, potentially tainting their meat, hence one reason they are not killed for their meat.

NESTING BIOLOGY Photo courtesy of Marilyn Kazmers Nest at night, except Kemp’s Ridley’s Nest from 2-9 times a season Usually take 2 or 3 years in between nesting seasons Photo courtesy of Doug Perrine Females don’t reach sexual maturity until anywhere from 20-50 years.

TRACKS Tracks resemble tire tracks Photo courtesy of FWC Photo courtesy of Burt Jones/Maurine Shimlock Tracks resemble tire tracks Species can be identified based on appearance of track – Loggerhead – move limbs alternately Greens - move limbs simultaneously Often times turtles will false crawl - this is when the turtle begins to crawl up, decides she doesn’t like the spot, or is scared off by something (humans. Lights, noise, animals, etc..) and returns to the ocean. She will emerge later in the night or within the next day or so and try again. If this happens repeatedly, she may be forced to lay her eggs in an unsuitable area (ie – below the high tide line, where it can become inundated and drown the eggs)

NESTING Hatchling emergence – usually occurs at night; en masse, they scamper towards water Photo courtesy of George H.H. Huey Photo courtesy of CCC The temperature at which the eggs incubate also plays a key role in determining the sex of the turtles. Warmer temperatures produce females, cooler temps produce males. Each species has a pivotal temperature, which is the temperature at which the ratios between the sexes changed rapidly. For example, the pivotal temp for loggerheads is 29 – 30 degrees. Temps greater than 30 = females. Temps between 24-26 produce ~100% males.

PREDATORS Photo courtesy of George H. Huey Ghost crabs Raccoons Feral Dogs/Pigs Birds Fish Sharks

THREATS Fishing Practices Shrimp and gill nets Long lining Trade of meat & eggs; use of other parts Habitat loss/alteration Pollution

FISHING PRACTICES Turtles caught as bycatch, especially on shrimp boats Photo courtesy of Ian K. Workman

TED’s Photo courtesy of NMFS Reports have shown that TED’s are effective at excluding up to 97% of sea turtles with minimal loss of shrimp. Estimated that 55,000 turtles drown every year in American shrimp nets.

Photo courtesy of Karumbe Fotos 2002 Leatherback caught by a trawl fisherman

Long Line Fishing Non-selective Kills thousands of sea turtles, birds, sharks Long lining severely affects turtles, as well as many other species of animals. Long lining, sometimes called “land mines of the sea”, is predominately used to catch swordfish and tuna. Long lines consist of fishing line, up to 60 miles long, with as many as 3,000 hooks, and can remain in the water for up to 16 hours. Is non-selective, so it catches whatever bites the bait or gets entangled in the line. Estimated that 40,000 turtles are caught each year in long lining operations. Photo courtesy of Greenpeace

Photo courtesy of Chris Johnson 2002, www.floridaleatherbacks.com Note the hook lodged in this turtles throat. Could lead to death.

ILLEGAL TRADE Eggs Meat – turtle soup Shell trade Photo courtesy of Peter C.H. Pritchard

HABITAT LOSS/ALTERATION Beach Armoring Over-development Beach Renourishment Beach armoring – includes sea wall, jetties, sandbags, etc…Alters the natural erosion/accretion process and often times increases the rate of erosion. Obstacles may prevent the females from crawling high enough to nest successfully. If below high tide line, the nest will become inundated with water, resulting in loss of nest Over-development – the less suitable nesting habitat they have, the more likely they are to nest in an unsuitable place – in vegetation where roots can penetrate the eggs, below the high tide line, in poor sand, etc… Beach renourishment - sand may differ from what was originally there – too porous or too compact – may heat differently, altering natural sex ratios… if it’s too compact, the female may find it too difficult to dig, or the hatchlings won’t be able to get out of the nest. Most of the time now, renourishment projects can’t take place during nesting season. Photo courtesy of Marilyn Kazmers/Sharksong

POLLUTION Photo courtesy of CCC Photo courtesy of Lee County Photo courtesy of CCC Plastic bags, balloons, monofilament line, discarded nets, oil, etc…

POLLUTION Fishing line wrapped around it’s neck

CONSERVATION Global approach Photo courtesy of FWC Long-term solutions necessary Protection of feeding & nesting grounds Global – they are highly migratory animals; they need protection worldwide Long-term – instrument better fishing practices, and protect feeding and nesting grounds; limit development, reduce fishing in certain areas during certain times of the year when turtles are known to be migrating or feeding in that area…

SUMMARY Turtles have existed for over 100 million yrs. All species are threatened or endangered Anthropogenic causes of mortality Conservation efforts – global & long term