jellyfish

Thursday Trivia: Leatherback Sea Turtle

Posted Thu, Oct 13, 2011 by Meghan Bartels to jellyfish, leatherback sea turtle, marine turtles, protect sea turtles, reptiles

leatherback sea turtle

A leatherback sea turtle hatchling makes its way to the water. © Tim Calver

Leatherback sea turtles are the largest species of marine turtle and the only one to lack a hard shell made of scales.

Instead, these gentle giants have a softer shell made of bone and skin with seven ridges along their backs. Also unlike other sea turtles, leatherbacks do not have claws on their front flippers.

Even more unusual is that leatherbacks, unlike most reptiles, have some control over their body temperatures, making them warm-blooded. They have a thick layer of fat under their skin and a special blood supply system in their shoulders that can keep them warmer than the water around them, which means they can live both further away from the tropics and in deeper waters than other sea turtles.

Leatherback sea turtles eat mostly jellyfish, and are equipped with special spikes in their throats to keep the slimy creatures from escaping. Their jellyfish-heavy diet probably contributes to reports of leatherback turtle flesh sometimes being toxic to humans.

Like other sea turtles, leatherback turtles lay their eggs on sandy beaches, however, about 20% are “vanos,” or small, yolkless eggs that will never hatch. All the eggs in a clutch are either masculine or feminine—do you know what determines the gender of the eggs?  It’s this week’s trivia question on Twitter, so if you live in the US answer now for your chance to win!

Leatherback sea turtles are classified as critically endangered by the IUCN. Threats include being entangled in fishing gear; human collection of eggs and hunting of adult turtles for meat and shell; ingestion of plastic bags, which they mistake for jellyfish; and the effects of climate change on nesting behavior and success. Atlantic populations are considered slightly healthier than Pacific populations, which have seen several important collapses since scientists began tracking sea turtles.

Oceana’s sea turtle campaign focuses on preventing sea turtle bycatch, protecting habitat, and promoting legislation that keeps turtles safe.

You can learn more about leatherback sea turtles from Oceana’s marine wildlife encyclopedia.


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Guest Post: The Ocean’s Invisible Threat

Posted Wed, Jul 20, 2011 by Jon Bowermaster to chukchi sea, clownfish, jellyfish, jon bowermaster, ocean acidification, oysters

clownfish

Guest blogger Jon Bowermaster is a writer and filmmaker. In this post, Jon reports on the dangers of ocean acidification.

Of all the threats to the planet’s ocean, none may be more insidious or have longer-term impact than ocean acidification. It is also the least understood of all the potential harms.

Admittedly it is far easier to visualize plastic afloat on the surface of the Pacific or vast tracts of the Atlantic nearly devoid of fish than a chemical imbalance. But it is the change of acidity that may already be the ocean’s worst enemy.

Try this for a visualization, maybe it will help: 24 million tons of carbon dioxide created by the burning of fossil fuels – or the equivalent of 24 million Volkswagens – are dumped into the world’s ocean every single day.

On top of destroying coral reefs (the equivalent of wiping out rain forests on land) and killing off shellfish beds including mussels and oysters, a new report out of the U.K. suggests that the so-called “evil twin” of global warming is responsible for some fish losing their sense of smell and hearing.


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Day 25 + 26: Jellyfish and Canyons

Posted Tue, Sep 7, 2010 by Emily Fisher to jeff short, jellyfish, mapping the oil plume, oceana gulf expedition, oceana latitude, science experiment, toxic hydrocarbons, underwater canyons

Oceana's Cheryl Eldemar removes test strips from the line. © Oceana/Carlos Suarez

The crew aboard the Latitude has successfully completed the experiment to map the oil plume around the Deepwater Horizon. They successfully deployed 16 buoys up to 6,000 feet deep, and were able to retrieve 90% of the buoys and hundreds of sensors.

Oceana’s Pacific science director Dr. Jeff Short will now analyze the presence and concentration of toxic hydrocarbons surrounding BP's Deepwater Horizon wellhead, which noone has yet done.

Here’s Will’s final report, and stay tuned for the next leg of the expedition, in which the crew will use a deep-sea ROV to explore important habitat areas near the Deepwater Horizon.

Saturday, September 4, 2010

Another hard working day notched into the belt. After today the Oceana team can check three more moorings off the list. Today started in similar fashion as the last few days: wake up early, eat breakfast and hoist a mooring. What separated today from the others were jellyfish and canyons.

To this point the Oceana team has been relatively lucky in terms of accidents and painful encounters. Yet today after an “easy” first set, we went for another, and boy did we get a surprise. Everything was normal at first, and then it happened. Jellyfish started floating past the line. Minutes later, as the crew pulled the line through the winch, jelly slime began to pass through hands. Unnoticed at first, soon people began to squirm. 

Jellyfish sting their prey using nematocysts which are their stinging structures located in specialized cells called cindocytes. In our case the stinging structures of the jellies wrapped around the long line and in some cases stuck. As the crew pulled in the line the cindocytes transferred from the rope to the gloves of the team. Minutes later the fun ensued. When nematocysts pierce the skin they inject venom. The venom is very uncomfortable, and sometimes requires medical assistance. Luckily for us no such medical assistance was needed, but we all immediately washed off and changed clothes after the set.


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Fact of the Day: Box Jellyfish

Posted Thu, Jul 22, 2010 by MollyH to australia, box jellyfish, Fact of the Day, jellyfish

Today’s FOTD involves a short story. 

A few years ago, I was stung by a jellyfish while taking my first surfing lesson in Australia. It hurt so much that I could hardly walk!  We kept a close watch on my breathing while I was rushed to a pharmacy to get ice and some truly magical anti-sting medication.  (Thank goodness for that stuff!) After looking at my swollen and scarred legs, my instructor guessed that though I never saw my attacker, it was likely a young box jellyfish.   


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