NOAA Fisheries conducts world-class science to support sustainable marine life and habitats. Our podcast, “Dive In with NOAA Fisheries,” is about the work we do and the people behind it.
Six different species of sea turtles swim in and out of U.S. waters. And each of them is listed as endangered or threatened under the Endangered Species Act. And why is that? You guessed it, people.
00:00:13:03 (Barbara Schroeder)
Sea turtles of course face a lot of threats, almost exclusively human caused.
00:00:18:04 (John Sheehan)
And one of those human-caused primary threats is bycatch. Bycatch is when fishermen, commercial or recreational, catch something that they’re not trying to catch. In this case, sea turtles. And in the case of protected sea turtles, bycatch can be deadly and a serious problem for the population. This is Dive In with NOAA Fisheries. I’m John Sheehan, and today we’re talking about sea turtles, bycatch, and the innovations and solutions getting implemented or developed thanks to some hard working scientists at NOAA Fisheries.
As I mentioned at the top, six of the seven global species of sea turtles swim in U.S. waters.
00:01:00:06 (Barbara Schroeder)
The Kemps Ridley, the Green Turtle, the Loggerhead, the Hawksbill, and the Leatherback Turtle. The sixth species is the Olive Ridley.
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This is my guest, Barbara Schroeder, the National Sea Turtle Coordinator in NOAA Fisheries Office of Protected Resources.
00:01:15:05 (Barbara Schroeder)
Sea turtles are found throughout the U.S. in the Atlantic, the Gulf of Mexico, and the Pacific.
00:01:20:02 (John Sheehan)
Basically, in all U.S. waters including the Pacific and Caribbean Islands and—
00:01:25:09 (Barbara Schroeder)
In our inshore waters. They’re very common in bays, sounds, and lagoons all way up through Cape Cod Bay and down through the southeast U.S. into the Gulf of Mexico.
00:01:37:01 (John Sheehan)
A little fun fact here, NOAA Fisheries shares responsibilities for sea turtles with the U.S. Fish and Wildlife Service.
00:01:42:06 (Barbara Schroeder)
They have primary jurisdiction on land, on nesting beaches. And we have primary jurisdiction in the water.
00:01:50:03 (John Sheehan)
And when we talk about bycatch, specifically commercial bycatch, there are four big categories of fishing gear that cause the problems: trawls, long lines, gillnets, and traps or pots. Trawls are the huge, usually cone-shaped nets dragged behind boats.
00:02:06:09 (Barbara Schroeder)
Things like shrimp trawl are the one that most commonly comes to mind and one that is a significant problem for sea turtles around the world.
00:02:15:08 (John Sheehan)
Long lines are just what they sound like.
00:02:17:07 (Barbara Schroeder)
Long lines can be miles in length from which hooks are set on perpendicular lines and dropped down into the water. And they’re fishing primarily for things like swordfish and tunas.
00:02:33:06 (John Sheehan)
Gill nets are another kind of net.
00:02:35:04 (Barbara Schroeder)
Its purpose is to capture fish as they swim into the net. I might describe them as sort of a curtain that’s hung in the water.
00:02:45:01 (John Sheehan)
And traps and pots refer to submerged cages.
00:02:48:02 (Barbara Schroeder)
Wooden or metal pots that sit on the bottom and attract things like crabs or lobster, these pots are generally tethered to a buoy line on the surface. And it’s that tether line that causes entanglement problems for turtles.
00:03:08:02 (John Sheehan)
Now sea turtles face another threat that is indirectly related to bycatch, and that’s climate change. And given that climate change is impacting everything in ways that we realize and don’t, is that creating any problems for sea turtle management or protection?
00:03:25:08 (Barbara Schroeder)
Yes, definitely. In the marine environment climate change can alter migratory patterns of fish and invertebrates or if it’s changing even slightly the migratory timing of sea turtles it could put them in an area that they would not have been in before. And now they may be exposed to a fishery that they had not been exposed to or exposed as much to before. So, it can effect things in as you said, ways that we don’t understand fully yet but that we certainly have concerns about in the marine environment. On the nesting beaches, the issues and the problems are even more profound. What is already happening with sea level rise is that sea turtles have a very narrow strip of beach that is suitable for laying their eggs. And so, we gradually are losing more and more suitable nesting habitat as we struggle with sea level rise.
The other very interesting thing about sea turtles and climate change is that the sex of sea turtle hatchlings is determined by temperature. And there is a threshold temperature over which a nest will be all female, and under which the nest will be all male. And so, what can happen if the temperature keeps rising, you push that what we call the sex ratio more towards females, less towards males. And then at some point temperatures become lethal to the developing eggs and they will die. So, this is going to be a growing problem, and one that does not have a lot of easy solutions.
00:05:07:09 (John Sheehan)
Yeah. Let’s talk about some solutions that can be addressed right now, at least with respect to bycatch. What are some innovations that are being used to prevent bycatch?
00:05:20:00 (Barbara Schroeder)
This is one of the positive things when we talk about bycatch is that there are solutions. For trawls, a very viable solution has been developed. And this came about primarily in the southeast U.S. shrimp trawl fishery. It is a relatively simple device. And these are what call TEDs, Turtle Excluder Devices. And they are really a simple grid, a very strong metal grid that fits down into the back of the trawl. When a turtle enters the trawl, it reaches the grid. And then the grid will sort of direct the turtle either up or down. And then the net will have an opening that the turtle can push through and escape. The beauty of TEDs is that while the turtle can escape, the target which is shrimp in this case, do not escape. So, this is really a win for turtles, and a win for the fishery to allow them to continue fishing.
And this technology has been introduced all around the world. NOAA Fisheries works very actively with other countries to expand the use of TEDs and has been very successful in doing that.
00:06:34:05 (John Sheehan)
And lets move to gillnets as another form of sort of net catching.
00:06:40:09 (Barbara Schroeder)
So, gillnets are a little more difficult. There isn’t a way to put a type of escape opening in like we talked about with trawls, but there are some innovative approaches that are being tested actively for gillnets. Those include putting lights on the gillnet to either alert or deter turtles from entering the net, from ever hitting the net and getting caught. And this seems to hold a lot of promise. The other approach that’s being tested and has shown some significant promise is to drop the top part. So, instead of the net, so, instead of having the net hang from the surface to the bottom, or the pretty far down in the water column, it’s sort of taking out that top panel and dropping that further down in the water. And the idea there is that turtles often are caught higher up in the water column.
And so, that may allow at least some of the turtles to not encounter those panels at all. Gillnets are, they are difficult. But there are some interesting and innovative potential solutions that are being tested now.
00:07:54:01 (John Sheehan)
Yeah. The lighted net struck me as particularly interesting just because it’s—it seemed completely out of the box that oh, right there are other variables that you can adjust to try and deter turtles rather than just necessarily focusing on the physical structure of the thing.
00:08:09:07 (Barbara Schroeder)
Yes. There’s been a lot of work on what we call sensory studies on how turtles see, or hear, or feed. And then thinking about if we look at these kinds of gears, are there ways that we can modify that gear that can change the way turtles perceive it. And that could potentially reduce their interactions with that gear.
00:08:31:09 (John Sheehan)
And how about long lines?
00:08:33:08 (Barbara Schroeder)
In the case of long lines, the focus has been on the hook and the bait, and how can we adjust those two things to potentially reduce bycatch. And what was found that was that circle hooks, hooks that the point wraps around towards the main shank of the hook as opposed to what we call a J-hook where the hook just comes up like you would draw a “J”. It doesn’t point back to that shank or the line of the “J”. Those type of hooks can catch more turtles than a circle hook where the hook is bent over, back. And they also found that using larger bait, especially finfish as bait instead of something like squid reduced the bycatch of turtles. And those kinds of things that we’ve looked at and have implemented by regulation in the U.S. long line fleets, those regulations have reduced the bycatch of turtles by extraordinary amounts: sixty, seventy percent less bycatch.
And even higher than that in certain areas depending on the nuances of the regulation while still allowing the target species to be caught.
00:09:49:01 (John Sheehan)
And how about, how about pots and traps?
00:09:52:00 (Barbara Schroeder)
That’s another one where there’s a lot of work ongoing. Many people may have heard about the issues with whale entanglement, especially the North Atlantic Right Whale. But Leatherback Turtles especially also get entangles in those pots and traps. So, there’s a lot of work ongoing now to look at ways to reduce whale entanglement. Those are things like stiffer lines or traps that don’t have lines but are remotely controlled and can be, you know, recovered that way. And so, all of those things will help turtles as well.
00:10:26:03 (John Sheehan)
Certainly, when you talk about success rates like sixty to seventy percent in reducing bycatch, that seems like a very successful use of the technology. How much of this are you developing with industry? And how are you coming by the research?
00:10:42:06 (Barbara Schroeder)
All of our bycatch work at one point or another closely involves working with industry. Industry may come up with a potential solution. And we will, you know, certainly work with stakeholders on exploring those solutions, potentially testing those potential solutions. We have a laboratory in Pascagoula, NOAA Fisheries Pascagoula Laboratory, that has a very exceptional group that focuses on a lot of the turtle bycatch reduction work. And also, in the northeast U.S. we have folks that focus on turtle bycatch reduction. And so, there’s a lot of back and forth with industry throughout the entire process from the earliest conceptual ideas to developing that to hopefully eventually become something that we fully implement in the fishery.
00:11:36:05 (John Sheehan)
And finally, what can, what can the public do to be more conscious of sea turtles and their safety?
00:11:43:05 (Barbara Schroeder)
Everybody can do something to help sea turtles. Even if you live in the middle of the country and you may rarely or never see the ocean, and you may never see a sea turtle there are always things you can do to help turtles. And one of the most important things we can all do is to become responsible seafood consumers. Find out where and how your seafood is caught. If you live near the water where turtles live, and that’s inshore areas: bays, lagoons, and also out in the oceans and you boat. Sea turtles have to breathe air. They come to the surface regularly. And they’re not easily seen until they’re at the surface. So, if you are a boater remember that they’re there. Boat strikes are another very serious threat to sea turtles. If you see them, slow down. Put your boat in neutral, steer around them.
And then of course if you’re a beach goer don’t leave any debris on the beach. Turtles might be coming up at night. Hatchlings might be emerging from their nests that evening. There’s something we can all do. And if we all do a little bit, it becomes a lot. And that’s what turtles need to survive and recover.
00:12:57:08 (John Sheehan)
Well Barbara Schroeder, thanks so much for talking with me.
00:13:00:08 (Barbara Schroeder)
Thank you very much for having me.
00:13:02:08 (John Sheehan)
Barbara Schroeder is the National Sea Turtle Coordinator in NOAA Fisheries Office of Protected Resources. And to piggyback on Barbara’s advice of being a conscientious seafood consumer, you can’t go wrong buying U.S. harvested seafood which is among the world’s safest and most sustainable. But don’t just take my word for it, learn more at fisheries.noaa.gov. I’m John Sheehan, and this has been Dive In with NOAA Fisheries.
00:13:33:08 (Podcast ends)