Transcript: When Estimating Fish Populations, Seeing is Believing

Announcer: Welcome to On the Line, a NOAA Fisheries podcast.

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Rich Press: Somewhere off the Atlantic coast of Florida, a fishing boat bobs in the swell and people on deck are maneuvering the gear. They're fishing with fish traps. The traps are big metal cages shaped like giant arrowheads, and they're too heavy for one person to handle alone.

Nate Bacheler: We're able to sort of push them over with a couple of people. They're attached via a line to a couple of surface buoys, and they're retrieved just like on what you might see on the Deadliest Catch with a pot hauler off the side of the ship.

Rich Press: But this was no ordinary fish trap, and the guy you just heard from is no ordinary fisherman.

Nate Bacheler: Yeah, my name is Nate Bacheler, and I'm a research fisheries biologist with the National Marine Fisheries Service and located in Beaufort, North Carolina.

Rich Press: Bacheler and other scientists use fish traps as a tool for studying reef fish.

Nate Bacheler: So that's fish like red snapper, a variety of grouper species, black sea bass...

Rich Press: Gray trigger fish, red porgy, vermilion snapper, the list goes on and on. And many of these species are extremely important economically to coastal communities in the southeast. Bacheler and other scientists use the fish traps to estimate how many fish of each species are out there. That's one of the most basic pieces of information that scientists need to manage these fish sustainably, and for most species, the traps work well. But some species, like gag grouper, have a habit of avoiding the traps. So to catch those ones, scientists have attached two high-definition video cameras to each trap.

Nate Bacheler: So by attaching video cameras to fish traps, we can actually see and count gag grouper species and a variety of other species that we wouldn't really get as much information from the trap. So, the two used in combination actually work better than either gear separately.

Rich Press: Scientists aren't the only ones that are happy to have video data to help estimate fish populations. Fishermen are supporting the effort as well.

Jimmy Hull: There's an old saying is, who can count the fish in the sea? And, I mean, who can? You really can't.

Rich Press: That's Jimmy Hull, a fisherman from the town of Ponce Inlet in Florida.

Jimmy Hull: But we can certainly improve on our data collection, and that's why I'm involved because we need good solid data to make good decisions.

Rich Press: Hull and other fishermen are helping scientists by giving them the coordinates of their fishing spots. Reef fish live on hard-bottom habitat, but the continental shelf between North Carolina and Florida is mostly sand and mud. So, by giving scientists their fishing spots, fishermen are helping scientists to find good fish habitat. Then within those areas of hard-bottom habitat, scientists drop their traps at randomly selected points.

Nate Bacheler: We really tried to expand our sampling on hard-bottom habitats, really expand our knowledge of hard-bottom habitats, and the fishermen have helped us do that.

Rich Press: Now, fishermen are not exactly famous for giving up their favorite fishing spots, so I asked Hull what in the world he was thinking.

Jimmy Hull: [Laughs] Well, you know, we're trying to help in every way we can to get the best, accurate data so that we can have well-managed stocks. I mean, that's why, because I'm not in this to do anything except, you know, have sustainable fisheries for forever, for my children and for all the people in this country. And there's only one way we're gonna get that, and that's through good, solid science and data collection and decisions based on science.

Rich Press: I asked Bacheler if fishermen are going to be happy with the results of the video trap survey. I mean, what's the bottom line here? Will the new data show that fish are more abundant than we thought?

Nate Bacheler: Population trends might be increasing or decreasing, but what the results will show is that the uncertainty will be decreasing around those estimates, and that is really the name of the game. If uncertainty is reduced, then it benefits everyone. It benefits the scientists and it benefits the fishermen.

Rich Press: That's because when there's a lot of uncertainty around the population estimates, catch limits have to be more conservative, just in case the estimates are way off. But when uncertainty is reduced, all else being equal, catch limits tend to go up.

Scientists have been doing these video trap surveys for five years, and they now have a long enough time series for the data to be useful. For red snapper and gray trigger fish, two headline species in the southeast, scientists plan to use the new data in the next stock assessment. And for the people you heard from today, both scientists and fishermen, that's a big step in the right direction.

Jimmy Hull: We're helping all we can. Do we agree on everything? No. Will we ever agree on everything? No. But, we don’t have to be like other groups and bureaucracies that, just because they don't agree on everything, they don't get anything done. We're gonna get things done because there's so much that we do agree on and it's for the – you know, do the right things for the right reasons, you know. That's what we have to do.

Rich Press: In addition to being a commercial fisherman, Hull owns Hull's Seafood Market and Restaurant. That place has been in business for 34 years, and it supports 65 full-time employees. And that's just in the town of Ponce Inlet in Florida. But that same story is repeated in communities up and down the coast. A lot of people depend on the sustainable use of our fisheries, and that's why Nate Bacheler, Jimmy Hull, and a whole lot of other people are working so hard to get this thing right.

As always, you can get more information about this story on our website. That's www.fisheries.noaa.gov/podcasts. There you'll find a video from one of Bacheler's video traps, and it's a surprisingly beautiful view of reef fish habitat. Thanks for listening. Join us again next time for more stories about ocean life and ocean science. I'm Rich Press, and you're listening to "On the Line".

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You have been listening to the NOAA Fisheries’ podcast, "On the Line". Join us next time for a first-hand look at the people and the science behind managing our nation’s fisheries. For more information, visit NOAA Fisheries at www.fisheries.noaa.gov.

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