Posts tagged fish

The problem: Although scientists have been studying deep-sea animals since the 1860s, they still don’t know much about them. That’s in large part because the fish, octopuses and other creatures that thrive at the bottom of the ocean die quickly at the surface. In some cases, the lower pressure and higher temperature melt the lipids in their cell membranes. Even hardier animals, such as crabs, can survive at sea level for no more than a few weeks.

The solution: The AbyssBox can keep deep-sea fauna alive above sea level for months, and possibly much longer. Biologists from the Pierre and Marie Curie University in Paris and the French Research Institute for Exploitation of the Sea spent three years developing the 1,300-pound, four-gallon tank, which mimics the conditions found near deep-sea hydrothermal vents. (The actual vents on the ocean floor shoot hot water that attracts marine life.)

The team set the tank’s water to about 60°F and added a hot jet. A water pump raises the pressure to 3,000 pounds per square inch. Three-inch-thick steel walls withstand the pressure. The researchers feed the tank’s residents using an exchange tube with a pressure lock and watch them through a strong plastic porthole. Deep-sea-vent crabs and shrimp originally from the Lucky Strike hydrothermal field on the Mid-Atlantic Ridge are now living in two separate AbyssBoxes on display at the Océanopolis aquarium in Brest, France. They have survived since August.

(Source: futurenow321)

Bluefin tuna are some of the largest and fastest fish in the ocean—they’re powerful swimmers, built for endurance and speed. To help conserve energy on their long-distance journeys, tuna’s bodies are almost perfectly streamlined, reducing drag around their fins. And tuna can retract or fold those fins against the body so water flows more smoothly over their bodies. This makes them super-streamlined.

Unlike most fish, tuna are warm-blooded and can heat their bodies to 6° C (11° F) warmer than the surrounding water. This added warmth helps their muscles work faster and more efficiently. Tuna consume as much as 5% of their body weight daily and must continually swim with their mouths open to force water over their gills, supercharging their blood-rich muscles with oxygen.

Pacific bluefin tuna spawn off of Okinawa; between Taiwan and the Philippines; and in the Sea of Japan. They migrate over 6,000 nautical miles (11,112 km) to the eastern Pacific, eventually returning to their birth waters to spawn.

(Source: futurenow321)

In 2010, there were 32 reported sightings of the Asian tiger prawn in Gulf and Atlantic waters, according to Pam Fuller, the U.S. Geological Survey biologist who runs the agency’s Nonindigenous Aquatic Species database. In 2012, those reports jumped to 331.

“We can confirm there was nearly a tenfold jump in reports of Asian tiger shrimp in 2011,” Fuller said. “And they are probably even more prevalent than reports suggest because the more fisherman and other locals become accustomed to seeing them, the less likely they are to report them.”

Fuller said scientists aren’t sure why Asian tiger prawn sightings have suddenly increased so dramatically. It could be that shrimpers are more aware of the prawns and are reporting them in greater numbers. But it is more likely their population has increased.

The tiger prawn is native to the western Pacific and is farmed commercially across the globe, but there are no known aquaculture facilities for the prawn in the U.S. The shrimp may have come to the U.S. in ballast water from Asian ships, or arrived on ocean currents from wild populations in the Caribbean or other locations.

The Asian tiger prawn is visually striking, characterized by its distinct “tiger stripes” in bands of black and white.

They are also very large. Tiger prawns can grow up to 14 inches long and weigh as much as 23 ounces.

(Source: futurenow321)