Nearly all of the world’s seven sea turtle species are facing a high risk of extinction, in part because of illegal trade of their eggs and shells. Yet scientists still know very little about the lives of these turtles, making it difficult to accurately track their populations and choose successful conservation strategies. One of the most basic tools marine biologists lacked was a way to calculate a turtle’s age — until now. The solution has been right in front of them the whole time, on the backs of the turtles themselves.
The Marine Science Institute's monthly column, Science and the SeaTM, is an informative and entertaining article that explains many interesting features of the marine environment and the creatures that live there. Science and the SeaTM articles appear monthly in one of Texas' most widely read fishing magazines, Texas Saltwater Fishing, the Port Aransas South Jetty newspaper, the newsletter of the Texas Chapter of the American Shore & Beach Preservation Association , and the Heartland Of America online newspaper. Our article archive is available also on our website.
The hagfish is one of those animals that scientists aren’t quite sure how to classify. These bottom-feeders have a skull but no backbone. Like lampreys, they have no jaw, but then lampreys do have vertebrae. Hagfish look like eels, but with naked skin instead of scales. They can survive up to 36 hours without oxygen — while their hearts keep beating — and they’ve been around for more than 350 million years, long, long before the first dinosaurs ever walked the Earth.
Tiny marine creatures known as zooplankton feed on phytoplankton, which use photosynthesis to create their food. Since phytoplankton tend to hang out at the ocean’s surface to absorb the sun’s energy, zooplankton head there for their meals each night. But when morning arrives, zooplankton become targets for predators, so they move to deeper waters during the day.
Of more than 300 species of octopuses, a few outliers are bound to do things a little differently. Meet the sneaky — but surprisingly social — larger Pacific striped octopus, who has some unconventional ways of taking both his meals and his mates. While most octopus species seize their prey with all eight arms before the critter can escape, the Pacific striped octopus scrunches itself together and stealthily approaches its prey from behind. It then extends just one tentacle to tap the prey, such as a shrimp, on its far side.
Breeding season can be brutal — even bloody — for male elephant seals. These heavyweights take the competition for mates very seriously, with both vocal and physical threats to other males. Sometimes they rear up to show their height, and sometimes they slam their chests onto the sand to send intimidating vibrations into the ground. But despite all this posturing, actual physical fights occur less than five percent of the time in elephant seal colonies.
If a species on the brink of extinction could learn to clone itself, that nifty trick could improve its chances for survival. And that’s exactly what scientists have discovered some smalltooth sawfish are doing in Florida — reproducing without mating. This critically endangered species is one of five species of sawfish, creatures that look like a cross between a shark, a ray and a chainsaw blade. Sawfish have a long, flat snout with widely spaced teeth that protrude in a line on either side, an arrangement that is reminiscent of a saw.