A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.
From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.
Tune in to 88.1 WYPR every Tuesday at 5:45 p.m. as John brings to the surface important issues and fascinating discoveries making waves in the world today.
August 28, 2013: Surprising Sharks
John Racanelli: In your mind’s eye, picture a shark for a moment. Perhaps it’s 9 or 10 feet long, with a mouth full of razor-sharp teeth and a menacing look. Now, take that mental image…and forget it. Today, we’re going to talk about the sharks that people seldom consider, the hundreds of species of smaller shark that inhabit every ocean on our planet. With me today is Jackie Cooper, our Senior Assistant Dive Safety Officer Aquarist at the National Aquarium. Thanks for joining me, Jackie!
Jackie Cooper: Thanks for giving me the opportunity to talk about something I’m so passionate about.
JR: How are these smaller species of shark like their larger counterparts?
JC: Well, all sharks are cartilaginous fish; they’re all carnivores; all sharks have 5 to 7 gill slits on the sides of their heads; all sharks have pectoral fins that are not fused to their heads. But that’s about where their similarities end. There is such a broad diversity of body shape and body size of sharks that is just amazing!
JR: What sizes are we talking about?
JC: Well, the smallest shark is the dwarf lantern shark, which is only about 7.5 inches long. From there, they range up to the whale shark, which can be as large as 40 to 60 feet.
JR: So with these smaller sharks, it sounds like they really average to be relatively small compared to even humans.
JC: Probably half of all the known shark species are 5.5 feet or smaller, and of that, half of the overall shark species numbers are shorter than 3 feet.
JR: Tell me a little bit more about those smaller sharks and their role in the food chain.
JC: We tend to think of sharks as apex predators, being at the top of the food chain. But in fact, most of these sharks are a part of the food chain. They’re similarly important, but they don’t sit at the top of it. Another thing that people tend to forget is that people eat shark meat much more than you would consider.
We tend to think of sharks as only being consumed in shark fin soup, but if you’re in Europe and you’ve had fish and chips, it’s more than likely you were really eating a shark called the spiny dogfish. They grow to be 3.5 to 4 feet long. The females don’t reach sexual maturity until they’re about 21 years old and produce only small litters. And yet, this species is fished commercially and sold as “fish and chips.” It’s simply devastating to that population.
JR: I know that’s an important species along the Mid-Atlantic shoreline, too. Can you even find some of these species of shark being sold as food in places like Baltimore?
JC: Certainly. There are definitely grocery stores in the Baltimore metro area that sell shark. Sometimes under names that we would not necessarily recognize as shark.
JR: Why do you think it’s important to understand these smaller species of shark?
JC: I think the most important reason is that they’re also being threatened. It’s important to keep in mind that when you think about conservation, it’s often driven by money and the glamour, and big species of shark are very exciting to think about and talk about and look at pictures of. These smaller sharks frequently aren’t as glamorous and don’t tend to draw the same kind of funding, so they’ve been much less studied.
JR: Well, I know they contribute to healthy marine ecosystems, too. They’re obviously vital to our ocean habitats, right?
JC: Every spot in the food chain is critical to maintaining the entire chain in a healthy manner.
JR: Jackie, I want to thank you very much for coming in to talk to us. To learn more about some of the smaller species of shark that inhabit our waters and to see a live cam of the new Blacktip Reef exhibit, visit aqua.org/ablueview.