Sea turtles and climate change


This video from Mexico says about itself:

6 March 2010

Baby leatherback turtles emerged from their eggs and nests this morning and made their painstaking way to the Sea of Cortez.

From Science News:

Hot nests, not vanishing males, are bigger sea turtle threat

Climate change killing nestlings with heat could be worse than sex ratios going too female

By Susan Milius

7:05pm, February 7, 2017

Worries about climate change threatening sea turtles may have been misdirected.

Warming that could lead to far more female hatchlings than males isn’t the most immediate danger from climate shifts. Lethally overheated beach nests are more important, researchers argue February 8 in Proceedings of the Royal Society B.

Climate change can meddle with sex ratios of the seven species of sea turtles because their embryos start life without a genetically fixed sex. Nest temperatures greater than roughly 29° Celsius tip the ratio toward more female hatchlings, explains marine ecologist Graeme Hays of Deakin University in Warrnambool, Australia.

Warm the nesting beaches enough, and sea turtle populations with few to no male mates might get feminized to extinction, biologists have warned. Yet records from 75 sea turtle nesting sites around the world suggest that many still-abundant populations are skewed to extreme female bias. “That’s not really the No. 1 concern,” Hays says. “A few male turtles already go a long way.” Instead, youngsters dying in overheated nests appears to be a more serious problem and needs a worldwide effort at data collection, Hays and colleagues say.

One reason heavily female turtle populations haven’t crashed yet is the difference between male and female breeding frequency, the researchers say. A male shows up to mate in the waters off the nesting beach roughly twice as frequently as a female does, perhaps every two years instead of every four, Hays says.

Disproportionately higher death rates among female hatchlings also could temper the female bias generated by upward creeping nest temperatures. Warmer spots in nesting beaches that are more likely to make embryos turn female are also more likely to cook them.

At extreme temperatures, however, everybody loses. Should a nest reach 35° C, a group of 100 eggs would yield on average only five living female hatchlings plus a ghost of a fraction of a male, mathematical simulations predict.

Vincent Saba has seen hatchling losses firsthand at the leatherback turtle nesting site he studied in Costa Rica. There, computer simulations suggest that as the beach overheats the dwindling survival of young turtles could nearly wipe out the population within a century, says Saba, a biological oceanographer with the National Oceanic and Atmospheric Administration’s Northeast Fisheries Science Center at Princeton University.

Just how much a beach heats up depends largely on rainfall, which in turn depends on how the climate changes, says Saba. Sorting out the effects on sea turtle populations is going to take science done “beach by beach.”

Rare olive ridley turtle beaches in Wales


This video says about itself:

7 Wonders of India: Olive Ridley Sea Turtles

6 February 2009

Found in the Indian Ocean along the Bay of Bengal is Orissa. Average weight of the turtles is just over 100 lb (up to 50 kgs). They have a high-domed shell, with a carapace length of only 30 inches (70 cms). Olive Ridleys are omnivorous, feeding on crabs, shrimp, rock lobsters, sea grasses, snails, fish, sessile or pelagic tunocates and small invertebrates.

The Orissa coast is one of the three sites worldwide where mass nesting of the Olive Ridley Turtle occurs. This sea turtle is especially known for its mass nesting when several thousand turtles migrate to the breeding ground to mate and nest simultaneously. Hindu mythology worships sea turtles as an incarnation of one of their gods. Over the past five years, sea turtles have suffered mass mortality along the Orissa coast due to death by drowning as incidental catch in trawl – fishing nets. About 5,000 to 10,000 dead turtles have been washed ashore each year, a total of over 100,000 in the last 10 years.

By Peter Frost in Britain:

A rare visitor washes up on Britain’s shores

Friday 3rd February 2017

Sea turtles are coming ashore in increasing numbers. But we’ve now had a rare visitor, writes PETER FROST

AN OVER two-foot long rare olive ridley sea turtle (Lepidochelys olivacea) came ashore on an Anglesey beach last November.

It was the first ever example of this very rare species to be found alive on a British beach. Local people nicknamed the turtle Menai.

The animal was in poor condition, she was severely hypothermic when found stranded.

She was around 15,000 miles from her usual habitat, warm and tropical waters, primarily in the Pacific and Indian Oceans.

The stranded turtle was looked after at Anglesey Sea Zoo and then taken 400 miles by road to Hertfordshire’s Royal Veterinary College for a CAT scan and more sophisticated care.

The aim is to get her fit enough to be returned to the wild. The scans discovered Menai has gas inside her carapace, making it difficult for her to submerge and swim underwater. She is also suffering lung damage.

But experts who are caring for Menai called the results “good news.” “There are no huge worries,” Anglesey Sea Zoo director Frankie Hobro told us.

“We are happy now that we know what the problem is. We can now research what treatment she needs to recover. The next stage is to drain the gas and correct her buoyancy problems.”

Menai is the first olive ridley turtle to be sighted in Britain since records began in 1748. Now olive ridley turtle experts are planning her rehabilitation and hope to release her back into the wild.

The olive ridley is the second smallest sea turtle after the very closely related Kemp’s ridley. Olive ridleys weigh between 75-100 pounds and reach 2-2 ½ feet in length.

They are named for their pale green carapace or shell and are the most abundant of all sea turtle species.

Olive ridleys occur globally and are found mainly in tropical regions of the Pacific, Indian and southern Atlantic Oceans.

They are primarily pelagic, spending much of their life in the open ocean but may also inhabit bays and estuaries.

Some olive ridleys lay eggs on solitary beach sites but some come together for huge and spectacular beach invasions where thousands of females land on the same beach at the same time to lay their eggs. These spectacular mass-egg layings are called arribadas (“arrival” in Spanish).

Strangely there are only a few places in the world where olive ridley arribadas occur. In other parts of the world, they are solitary nesters.

Though arribadas are not well understood; the timing may coincide with weather events such as strong winds or cloudy days, or with moon and tide cycles.

The turtles congregate in large groups offshore of nesting beaches and then simultaneously come ashore to nest.

Females may remain offshore near nesting beaches throughout the nesting season.

These turtles eat a variety of prey including crabs, shrimp, lobster, urchins, jelly fish, algae and fish.

Despite their relative abundance in comparison to other sea turtles, olive ridleys are considered vulnerable by the International Union for Conservation of Nature’s Red List and are listed as threatened in the US.

Although they are still the most abundant species, their numbers have decreased by approximately half since the 1960s.

Historically, the olive ridley has been hunted for food, bait, oil, leather and fertiliser.

The meat is not considered a delicacy. The eggs however are said to be delicious and have always been a valuable commodity. Egg collection is illegal in most of the countries where olive ridleys nest, but these laws are rarely strictly enforced.

Legal egg harvesting has been allowed in several localities. Perhaps the biggest is in Ostional, Costa Rica, where villagers have been able to harvest and sell around three million eggs each year.

Over 27 million eggs are left un-harvested and villagers claim they play a large role in protecting these nests from predators, thereby increasing hatching success.

In most other regions, illegal poaching of eggs is considered a major threat to olive ridley populations and attracts much criticism from conservationists and sea turtle biologists.

As well as egg digging, other major threats to the turtle include degradation of nesting beaches, particularly in India where large commercial coastal developments threaten traditional turtles nesting sites.

Many of their nesting beaches have already been destroyed by coastal development and subsequent erosion.

Other threats include the direct harvest of turtles and eggs for human consumption and the accidental capture of turtles in commercial fishing gear.

It is estimated that more than 60,000 sea turtles, mainly olive ridleys, are caught and drowned in commercial shrimp trawl nets each year.

Over the last few years, winter storms have led to a steep rise in the number of turtles being washed up on our British beaches.

Last winter, a total of 16 warm-water turtles — some critically endangered — were found on the British shoreline, the highest total since 2008 according to environmental groups.

Most of the comatose turtles washed up are juveniles, less able to cope with strong waves, and they are usually starving and suffering from hypothermia.

Here is some advice for those taking winter walks on our beaches who may find a sea turtle washed up by recent gales.

The reptiles can’t stand the cold weather, which shuts them down and they eventually wash up on our shores.

When they wash up they are so moribund that, to the casual observer, they may appear to be dead but actually they may still be alive, and with expert care can be rescued and nurtured back to health to make a full recovery.

Under no circumstances should turtles be put back into the sea, as the thermal shock from the cold waters would certainly kill them.

You should immediately report any stranded animals to the RSPCA.

Cooter turtle in Florida, USA


This video from Florida in the USA says about itself:

20 January 2017

Turtle at perfect balance on a sunken tree log. This Peninsula Cooter Turtle is so at peace and one with Nature it totally ignored my presence and continued to dream of flying. This balancing act is pretty impressive and I believe the point is to expose as much of its body as possible to a sun bath to cleanse and heal in the suns rays. Oh to be a turtle…

Snakes, turtles, giraffes, other animals in 2016


This 2016 BBC video is called Giraffe DNA study identifies four distinct species.

From Science News:

Tales of creatures large and small made news this year

Snakes, giraffes, turtles and more were in the headlines in 2016

By Cassie Martin

7:00am, December 22, 2016

Scientists filled in the details of some famous evolutionary tales in 2016 — and discovered a few surprises about creatures large and small.

Venom repertoire

By studying a gene family important for toxin production, researchers found that modern rattlesnakes have pared down their venom arsenal over time (SN: 10/15/16, p. 9). Rattlers now have a smaller repertoire of toxins, perhaps more specialized to their prey.

Stepping forward

Small tweaks to a gene that makes a protein important for skeletal development may have led to the big toe and helped shape the human foot for bipedalism (SN: 2/6/16, p. 15).

Surprise absence

A gut microbe collected from chinchilla droppings appears to have no mitochondria, making it the first known complex life without the supposedly universal organelle (SN: 6/11/16, p. 14).

Turtle power

Studies of prototurtle fossils suggest that, instead of serving as natural armor, turtle shells might have got their start by aiding in burrowing (SN: 8/6/16, p. 15). The idea could help explain how turtle ancestors survived a mass extinction 252 million years ago.

Color change

Scientists pinned down the genetic changes that, in a famous example of natural selection, made peppered moths soot-colored (SN: 6/25/16, p. 6).

Tall beginnings

Giraffes should thank genes that regulate embryonic development for their long necks and strong hearts (SN: 6/11/16, p. 9).

Evolution at speed

A study of Darwin’s finches found that medium ground finches with smaller beaks survived better than big-beaked counterparts during a drought. The advantage was linked to a key gene, offering insight into the birds’ speedy evolution (SN: 5/28/16, p. 7).

Age record

Scientists have crowned a Greenland shark as the vertebrate with the longest known life span. Their analysis suggests the predator lived to an age of 392 years (SN: 9/17/16, p. 13).

Recovered loggerhead turtle back to sea


Loggerhead turtle Trident

From the Brevard Zoo in Florida in the USA on Twitter today:

Trident, a #loggerhead [turtle] who came to us in July, will be released on Wednesday at 4:45 p.m. at Lori Wilson Park in Cocoa Beach. See you there!

Sea turtles in Malaysia


This video says about itself:

28 October 2016

In Malaysia there is an island called Sipadan, famous for beautiful reefs, lots of fish and tons of sea turtles. But there is also a cave where sea turtles die. Jonathan and the team visit the cave in this spooky extra!

JONATHAN BIRD‘S BLUE WORLD is an Emmy Award-winning underwater science/adventure program that airs on public television in the United States.

Turtles in Florida, USA


This video from the USA says about itself:

1 December 2016

Florida Cooter (Pseudemys floridana) also called the Florida red-bellied cooter or Florida redbelly turtle is an attractive reptile that doesn’t get too excited about much of anything. It spends a great deal of time sunning on logs in swamps and canals. One of my favorite turtles.