So fierce! Or so the movies would tell you. In fact, Carcharhinus plumbeus, or sandbar sharks (sometimes also called brown or thickskin sharks) are typically very calm. If you were to be in the water with them, they’d likely ignore you or more likely immediately swim away from you. In fact, that’s what pretty much all sharks would do. The largest of near coastal sharks, you’d commonly find sandbar sharks swimming in shallow tropical and temperate waters with muddy or sandy bottoms in the Gulf of Mexico, Atlantic, Mediterranean Sea, Indian Ocean and Pacific. So basically all over the world! You can distinguish them by their stocky bodies, high first dorsal fin, very long pectoral fins, irregularly shaped caudal fin with the longer top half, and short, round snouts. Unlike other sharks, small aggregations of same sex sharks are sometimes seen swimming together.
Since sharks are top predators, perfectly adapted to hunting prey, it’s easy to paint them as the villain. However, that could not be farther from the truth. Sharks, like the sandbar shark, have been part of marine ecosystems for more than 425 million years. Hundreds of other species have come and gone while sharks have stood the test of time. That means they’ve had a looooong time to become integral to the health of the oceans.
As top predators, they help keep the rest of the ocean in balance. If they were to go, then the abundance of their prey, say seals or large pelagic fish, would explode in number. The seals and fish would then deplete their own food source, medium sized fish and crabs, which would cause the seal and large fish population to then crash and die out. Meanwhile, the food of the medium sized fish, small fish and zooplankton, now released from above pressure because there are no more medium sized fish eating them, would explode in number. This cycle of population explosion, crashing and dying out would continue. This phenomena is referred to as cascading effects. One major change causes rampant other changes. And it’s a scary thought! Without sharks, who knows what the state of our oceans would be like? Not a reality I for one want to see happen.
However, with more than 100,000,000 sharks killed every year through finning, fishing, bycatch and loss of habitat, that might be a reality that comes true. 31% of sharks and their near relatives, rays, are on the IUCN Red List. This statistic includes the sandbar shark which is currently listed as threatened. Without better protections, more species will end up on the list. Or worse, they’ll end up in Category 8… extinct (see my previous post, Large and in Charge on the Endangered List, for more information on what the IUCN Redlist is).
Many people around the world are working very hard to change this reality though! Universities, not-for-profits, conservation groups, zoos, aquariums and local communities are fighting back on sharks’ behalf. More marine habitats are being protected, as GPS tracking studies identify key breeding and feeding areas. Eco-tourism is on the rise, as people begin to realize that living sharks can bring in more money year after year than dead sharks. More people are becoming educated every day on the importance of sharks to the health of marine ecosystems. There is hope! There is still so much more work to be done, many shark species are still in danger, but there is hope. And I will take all the hope I can get! Love sharks and what to know more about them? Drop your questions below!