Large filter-feeding marine animals, like the whale shark and manta ray, are most commonly observed feeding near the ocean surface on blooms of zooplankton.  Recent techniques make it possible to determine the precise food sources of these animals, without relying on what can be limited observation.

Sharks are assumed to be carnivores, eating a high-protein diet of mammals, fish and other marine animals. 

A recent paper by Lopez-Martinez et al reports the frequent co-occurrence of whale sharks with cannonball jellyfish (Stomolophus meleagris) in the Gulf of California. 

The megamouth is one of the rarest sharks in the world.  Surprisingly for an animal that can reach 7 meters in length, it was described only in 1983, and only ~100 specimens have been found. 

Shark finning continues seemingly unabated, despite some gains in protection for threatened shark species. The scope of the trade is staggering, more than 70 million fins per year are thought to move globally. What species are targeted for these fins?

Eat a shark and you won’t get cancer, or the cancer you have will be cured. Many sharks are killed for the supposed curative powers of their cartilage, among other health claims. Sharks do, of course, get cancer, and numerous examples of shark cancer have been documented.

Multiple insults to shark populations - fisheries, habitat degradation, the fin trade, climate change - are believed to be interacting to cause steep declines in the numbers of many species.  It is difficult, however, to accurately estimate the population size of wide-ranging pelagic sharks.

Shark meat consumption is bad for sharks of course, millions of sharks are killed each year for the shark meat and fin trade, but it’s also bad for people. Shark meat has been shown to carry levels of toxic metals such as mercury that far exceed what is allowable for human consumption. 

We hear so much bad news about sharks – populations of many species have declined to historic lows, finning occurs in numerous countries, bycatch continues to threaten shark species, shark fishing tournaments are conducted for sport here in the U.S.  When a bit of good news about sharks comes along it seems natural to be encouraged that perhaps the situation is turning around.