Efforts to eliminate the cruel practice of shark finning – slashing the fins off captured sharks for financial gain and sending the mutilated sharks to certain, slow death in the oceans – has been a long slog of slow progress, inadequate measures and outright failures. But several steps supporting shark finning bans, including significant measures in the U.S. Congress, offer hope for effective progress. A BILL THAT WOULD MAKE IT ILLEGAL TO BUY, SELL ORRead more
Grass-Eating Sharks. Really.
SHARKS’ REPUTATION AS FIERCE, MAN-EATING APEX PREDATORS of the oceans takes a hit when you consider the bonnethead shark (Sphyrna tiburo), a small variety of hammerhead found mostly in warm waters along the Atlantic and Gulf coastlines of North and South America. Along with their normal carnivorous diet, bonnetheads eat grass, as in seagrass. How much grass? It accounts for as much as 62 percent of its gut content in some juvenile populations. The bonnetheads’Read more
Even Sharks Are Endangered by the Cold
THE EXTREME COLD GRIPPING MUCH OF THE NATION at present is likely a factor in the deaths of three thresher sharks, whose bodies have washed ashore on Cape Cod in recent days. As northern waters cooled, the sharks were probably migrating south along the coast, got trapped in Cape Cod Bay and ended up at the shore near bay-side towns Wellfleet and Orleans, according to a news article about the freezing weather nationwide in theRead more
Shark Fin Trade Ban Before Congress
A BILL BANNING THE SHARK FIN TRADE IN THE UNITED STATES appears likely to be passed by Congress, based on a hearing earlier this month by a House subcommittee. BIPARTISAN SUPPORT With 200 co-sponsors, HR1456, the “Shark Fin Trade Elimination Act,” has strong bipartisan support in the House and a similar bill under consideration in the Senate has 19 co-sponsors. The hearing by a subgroup of the House Committee on Oversight and Government Reform was describedRead more
Sharks Are Likely Colorblind
A STUDY OF 17 SHARK SPECIES has determined that the animals have only one type of photoreceptor cells in their eyes, leading researchers to conclude that they are potentially completely color blind. The work by Dr. Nathan Scott Hart and colleagues at the University of Western Australia and the University of Queensland found that sharks have only a single long-wavelength-sensitive type of cone in their retinas. The findings were published in Springer’s online journal NaturwissenschaftenRead more
It’s Shark Week. Here Are Some Actual Facts.
KILLER SHARKS! MEGA SHARKS! SHARK DISASTERS! Shark Weeks on cable is great for people who don’t really care about or know about sharks. But…. AN ALTERNATIVE VIEW Here’s a link to a Vox.com article I like from 2015 on “Sharks as you won’t see them on Shark Week: Intelligent and remarkably social animals.” FACTS. AND MORE FACTS! And here are some facts from the University of Florida’s Florida Museum on the risks of being killed byRead more
In Freshwater, Sharks Can’t Control Buoyancy
ABOUT 40 PERCENT OF BONY FISHES live in freshwater but only five percent of sharks, rays and skates can do so. There a number of reasons cartilaginous fishes don’t do well in freshwater, including problems with dehydration and reproduction. SINK OR SWIM. MOSTLY SINK A team of American and Australian scientists have determined that another reason is an inability to maintain buoyancy control in freshwater. In short, in freshwater, sharks and their kin would tend to sink like newbie divers. NEEDED: LARGERRead more
Deep-Sea Sharks Have Better Than Average Buoyancy
UNLIKE BONY FISHES, SHARKS maintain buoyancy with oil-filled livers rather than bony fishes’ air bladders. Recently, it was revealed that doesn’t work well for them in freshwater, where they tend to have poor buoyancy (see “In Freshwater, Sharks Can’t Control Buoyancy“). DEEP-WATER SHARKS CAN Now a study has found that deepwater sharks, such as the bluntnose six gill shark, have better than average buoyancy at the depths they frequent. Science writer Chris Cesare describes the study in an AAAS ScienceShotRead more