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Submitted by matt.ellis on Wed, 07/05/2017 - 15:06
Audio file
Podcast Transcript
Welcome to "On the Line", a NOAA Fisheries podcast.

[Music playing]

Host: It's Shark Week, and so today we have two shark experts on the line, and they each approach sharks from very different perspectives. One is a NOAA biologist, and the other is a commercial shark fisherman. But they do have the following very important trait in common: they both want shark populations to be healthy, and they're working together to help make that happen. Specifically, they're cooperating on a research project to find a way to increase the chances that a shark that's hooked inadvertently will survive.

John Carlson is a biologist working out of the NOAA Fisheries Lab in Panama City, Florida, where he does research on sharks, fins, and rays. Here, Carlson explains the situation using the dusky shark as an example. The population of dusky sharks is small and considered vulnerable, and for that reason catching them is prohibited.

John Carlson: It's prohibited. You can't land it commercially or recreationally anymore; however, it still is caught when fishermen are out there targeting other species, and the same holds with hammerheads. I mean hammerheads are not prohibited, but say, for example, the fisherman's quota has been reached. Fishermen are only allowed to land 30 – 33 coastal sharks, and say they've already gotten to a point where they're gonna land those 33 sharks and they still have gear to pull in and they have a hammerhead on the line. Well, they have to release him because they're no longer allowed to catch him. If that shark's already dead, well, what's the point?

Host: Carlson cited dusky sharks and hammerheads as examples, but sharks of any species can be caught inadvertently, so the idea is to increase the chances that a hooked shark will survive. To do, that scientists are comparing two different types of hook, a J-hook and a circle hook. To test out the hooks Carlson and his colleagues have recruited a bunch of shark fishermen to help with their research. Joe Klosterman is a commercial fisherman based out of Ft. Pierce on Florida's Atlantic coast. He fishes mainly for tilefish and for sharks, and he's one of the fishermen participating in this cooperative research project.

Joe Klosterman: A J-hook is your normal fishhook. Anybody would draw a picture of a fishhook, they would draw a J-hook. A circle hook, it curves around like you had taken, like, the bottom part of the "J" and you would bend it back to the shank. That would be a circle hook.

Host: Here's the scientist John Carlson again.

John Carlson: When a shark's hooked with a J-hook it is often gut-hooked, and if it's gut-hooked, it's gonna have some internal damage. With a circle hook, generally when they grab it and the line tenses, the hook will pull in and hook on the side of the mouth which will allow the animal to still swim around on the long line. It may still allow the animal to keep its mouth open and breathe, and it doesn't have a hook jammed down into its gullet.

Joe Klosterman: You know, mostly the hooks are hooked in the mouth and in the lip, so basically you've got a piercing, you know. Like, think about, you know, these kids that have all these piercings around their lips and stuff, so you got a shark with a hook hanging it out its mouth, which really hasn't impeded its life that much.

Host: Circle hooks have been around for a while, and they've been used mainly to protect sea turtles which also sometimes get hooked on long lines, and there's quite a bit of research to show that circle hooks do increase sea turtle survival, but there's very little data on how circle hooks affect sharks. So even though there's reason to think that circle hooks would help, there's no solid data to back that up, and even if they do help, there's still the question of how much. Before NOAA makes any circle hook regulations in the shark fishery, they've gotta do some research to figure out the costs and benefits and see how those balance out.

So, the research—here's how it works. NOAA has contracted with a bunch of commercial shark fishermen to go out fishing for sharks just like they normally do, but they use half circle hooks and half J-hooks. They also bring an observer along who collects scientific data and assesses the condition of the sharks that they catch. All the sharks that are alive on the hook, they set free.

Joe Klosterman: I’m supposed to make a set that lasts for eight hours, and I put 50 percent circle hooks and 50 percent J-hooks, one after each other. And each one of those has a timer on it, so when you get a bite on that hook, it'll trip that timer and tell you how long that fish is on there, and if the fish is still alive then you can judge its condition for the time it is on that hook.

Host: So that's the first thing they want to know: how does a circle hook affect the chances of a shark still being alive when it's brought out of the water But they also want to know if the fish is alive and gets released back into the water what are the chances of it surviving after being released.

John Carlson: We have an observer onboard, or a scientist will be onboard the vessel. He's recording all the information as the animal is brought onboard, where is it caught, and you know, where is the hook location. Is it a circle versus "J"? And what's the condition of the animal? We kind of came up with a qualitative ranking being "5" very good, and "1" it's dead.

For the animals that are in moderate to good condition, even though they're in very good condition, it may be somewhat deceiving because once they're released they may swim, you know, 100 yards and then sink to the bottom and die. We don't know that, so what we're doing with some of these animals, we're outfitting them with satellite tags which will continuously record data once they swim off and out of our view, and once we get that data back we can analyze the data to see if actually they did swim off and die later.

Host: The final thing they're looking at is the effect on catchability: are circle hooks less effective for catching sharks? That question gets at how much lost income or extra work circle hooks would mean for fishermen.

Joe Klosterman: Now myself I'd like to keep J-hooks because that's what I've always fished with, and I've always had the best results.

Host: I asked John Carlson if he had a sense yet which way the research was going. He said that he didn't know yet. It's still too early in the research. I was like, "Come on. You gotta have some sense which direction things are headed."

John Carlson: No, because I mean we're still collecting data. We really haven't gotten into that analysis mode yet, so I don't really want to make big speculations on where it's going.

Host: All right. Spoken like a true scientist. Well, we'll update you in six months or so when the results are in. In the meantime though this cooperative research is already paying off.

John Carlson: Well, it involves the fishermen with the research, so when, for example, when they do attend – some fishermen do attend our stock assessment meetings – or when they attend public hearings, if they're part of the research they have a general idea, in some cases they may have a very specific of idea, of how NMFS got the answer that we did, especially if they're involved in it. And I think in my opinion in – in some cases they may feel more comfortable with the answers or the information that we give them because they're involved in the process.

Host: I asked Klosterman why he's participating in the cooperative research, bringing scientists and fishery observers on his boat. He said he wants scientists to see what he sees, and he hopes that that will help improve the science.

Joe Klosterman: Providing good science. Providing good science and catching fish, showing them that the fish are out there it'll change the science. Of course when I first started out I felt like they were there to put me out of my job. After working with the people for a while and getting other people – I actually got, you know, some guys on there and actually some girls that were, you know, down to earth and had been on raised on farms or had been in – their parents had been shrimpers or some kinda commercial fishing, so they had knowledge that – that we weren't the worst people in the world trying to destroy the ocean. You know, I thought it'd be a good thing that if every fishery's manager had to spend like a hundred days a year on the water.

Host: A hundred days a year might not be possible for a lot of fishery managers, but that's one of the reasons we do cooperative research, to get that understanding about fish in the ocean that only someone who's been on the water for decades can provide. Joe Klosterman, he started commercial fishing in 1972, and he wants, as much as anybody, that shark populations remain healthy. With his help and the work of scientists like John Carlson, hopefully they will.

As always you can get background information and photos about this story on our website. That's You'll also find links there to all of our Shark Week coverage, including a really cool and really disgusting video of what scientists call a "gut analysis". They're cutting open the stomach of a 1,300 pound Mako shark. You'll be surprised what's in there. The scientist sure was.

"On the Line" is a new podcast. This shark story was only our seventh episode so far. If you enjoyed it and you have a chance, give us a rating or a review in iTunes. That'll help get the word out and help us keep bringing you new stories about ocean life and ocean science.

Thanks for listening. I'm Rich Press, and this is "On the Line."

[Music playing]

You have been listening to the NOAA Fisheries podcast, "On the Line." Join us next time for a firsthand look at the people and the science behind managing our nation's fisheries. For more information, visit NOAA Fisheries at

"On the Line" is a production of the NOAA Fisheries Office of Communications.