The Trapdoor That Saves Sea Turtles From Shrimp Nets
Release Date: 10/14/2026
The Trapdoor That Saves Sea Turtles From Shrimp Nets
How To Protect The Ocean
A Kemp’s ridley sea turtle, the most endangered sea turtle on Earth, gets swept into a shrimp trawl. It hits a metal grid, slides out through a flap in the net, and swims away. That small trapdoor, the turtle excluder device, is one of the biggest success stories in fisheries management, and in late August 2026 a US federal appeals court upheld the rule extending it to skimmer trawl boats 40 feet and longer. In this episode, marine biologist Andrew Lewin walks through the bycatch fixes that are working and the fights still underway. You’ll hear why North Atlantic right whales get tangled...
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The Cod Came Back: What a Fishery Collapse Teaches Us About Overfishing
How To Protect The Ocean
Five centuries ago, explorers off Newfoundland described cod so plentiful that a weighted basket lowered into the sea came back full. By July 2, 1992, so few remained that Canada shut the northern cod fishery overnight. About 30,000 people lost their work in what became the largest single layoff in Canadian history. In this first episode of a week-long sustainable seafood series, Andrew tells the story of how the collapse happened and how slowly the cod came back. Andrew then breaks down the words that cause the most confusion in fisheries headlines: overfishing, overfished, depleted, and...
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How to Choose Sustainable Seafood
How To Protect The Ocean
You want to eat seafood the right way. Then you hit the seafood counter and face a wall of labels, a sign promising “sustainable practices,” and an employee who has no idea where the tuna came from. Add documentaries like Seaspiracy telling you to quit fish entirely, and it’s tempting to give up and buy whatever looks good. Unsustainable fishing is the biggest threat to marine biodiversity, so those choices carry real weight. In this episode, Andrew’s good friend Dr. David Shiffman joins the show to talk about his new book, Why Sustainable Seafood Matters. David spent two years on the...
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Slow Down for Whales: How Global Shipping Learned to Share the Ocean
How To Protect The Ocean
Blue whales can’t dodge ships. When scientists tracked blue whales alongside cargo ships off Southern California, the whales responded in just over half the encounters, and every response was the same: a slow, shallow dive. Not once did a whale move sideways out of the ship’s path. Models suggest ships kill around 18 blue whales a year off the U.S. West Coast, nearly eight times what the population can lose and still recover. The good news is in the data. Most blue whale strike deaths happen in a small slice of ocean, and that’s where ports, air quality agencies, marine sanctuaries, and...
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When Whale Food Moves: Climate Change, Crab Traps, and Pop-Up Gear
How To Protect The Ocean
In 2014, a patch of unusually warm water nicknamed "the blob" settled off the west coast of North America. The cold, food-rich water that normally stretches far offshore shrank into a narrow strip along the coast, and hungry humpback whales followed their food straight into the waters where Dungeness crabbers had set thousands of traps, each tied to a vertical rope. Entanglements jumped from about 10 a year to 53 in 2015 and 55 in 2016. In this episode, Andrew traces the line from warmer water to a specific whale in a specific rope. You'll learn why lunge-feeding whales depend on dense patches...
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The Whale Heart That Beats Twice a Minute
How To Protect The Ocean
Fill your hands with cold water, hold your breath, and press your face in. Your heart slows within seconds. That reflex lives in every whale in the ocean too, and in a blue whale it is pushed so far that the largest heart on Earth can drop to two beats a minute on a deep dive. In this episode, Andrew walks through the first heart rate recording from a wild blue whale, led by Jeremy Goldbogen's team at Stanford, and a study by Terrie Williams of UC Santa Cruz that tracked narwhals fleeing after release from nets in East Greenland. The narwhals swam as hard as they could while their hearts fell...
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The Biggest Mouthful: How Blue Whales Eat and Why Krill Matters
How To Protect The Ocean
A blue whale can swallow a volume of water bigger than its own body in a single gulp. That move, called lunge feeding, is one of the most extreme feats in the animal kingdom, and it only pays off when krill is packed into thick, dense swarms. In a thin patch, a blue whale gets back about six times the energy it spent. In a dense swarm, it gets back more than 200 times. In this first episode of the Age of Giants series, Andrew breaks down how rorqual whales feed, then follows the krill. In 2025, the Antarctic krill fishery hit its 620,000 tonne precautionary limit for the first time and closed...
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Whales Are Sprinters: What a Blue Whale's Heart Does When It Lunge Feeds
How To Protect The Ocean
What happens to the heart of the largest animal on Earth when it charges into a swarm of krill? Dr. Ashley Blawas, a postdoctoral scholar in Jeremy Goldbogen's lab at Stanford's Hopkins Marine Station, joins Andrew to unpack new research published in PNAS that measured the heart rates of lunge-feeding blue whales and humpback whales using suction-cup ECG tags. Ashley explains the three phases of lunge feeding (accelerate, engulf, filter) and why these giants behave a lot like human sprinters. Their heart rates stay high after each lunge, then gradually recover while they glide and filter,...
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The Pollution That Breeds: How the Great Lakes Stopped Invaders
How To Protect The Ocean
In 1988, someone found a striped mussel the size of a fingernail in Lake St. Clair. Within a few years, zebra mussels coated pipes, boats, and the bottom of the Great Lakes, and they became the poster child for "it's too late." Andrew closes Marine Pollution week with the pollutant that breaks every rule: a living one that reproduces instead of diluting. He follows two invaders. Zebra mussels rode in on ship ballast water, clogged power plant intakes, and stripped plankton from the base of the food web. Lionfish, likely released from home aquariums, spread from Florida across the Caribbean and...
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How Beach Cleanup Data Helped Canada Ban Plastic
How To Protect The Ocean
You rinse the yogurt tub, check the number on the bottom, and drop it in the blue bin. In Canada, only about 9% of plastic waste actually gets recycled, and the global rate is the same. Andrew breaks down why plastic is so hard to recycle, why microplastics are so hard to study, and what the controversy over plastic-in-the-brain headlines does and doesn't tell us. Then the story moves to a beach in Stanley Park in 1994, where Vancouver Aquarium staff and volunteers started picking up trash and writing down what they found. That cleanup grew into a national program, and its data fed into the...
info_outlineA Kemp’s ridley sea turtle, the most endangered sea turtle on Earth, gets swept into a shrimp trawl. It hits a metal grid, slides out through a flap in the net, and swims away. That small trapdoor, the turtle excluder device, is one of the biggest success stories in fisheries management, and in late August 2026 a US federal appeals court upheld the rule extending it to skimmer trawl boats 40 feet and longer.
In this episode, marine biologist Andrew Lewin walks through the bycatch fixes that are working and the fights still underway. You’ll hear why North Atlantic right whales get tangled in lobster and crab rope, how weak rope and ropeless gear could solve it, and why the US House just voted to extend a pause on new whale rules to 2035. Andrew also explains what the dolphin-safe label on canned tuna actually covers and why dolphin deaths in that fishery fell from hundreds of thousands a year to roughly a thousand.
Every number in this story depends on someone counting. Andrew draws on his own time as a marine mammal observer to explain why independent fisheries observers matter, the risks they face, and how electronic monitoring is changing the job. This episode is part of a week on sustainable seafood. Pre-order Dr. David Shiffman’s book Why Sustainable Seafood Matters using the link in the show notes.
Takeaways
- Turtle excluder devices must prove 97% effective at excluding sea turtles in testing, with little loss of shrimp
- A loophole for small skimmer trawl boats let turtles keep drowning; a 2019 rule requires TEDs on boats 40 feet and longer, and the Fifth Circuit upheld it in 2026
- Rope running from traps to surface buoys is the main entanglement risk for North Atlantic right whales, estimated at about 384 animals
- Weak rope and on-demand (ropeless) gear are the two leading fixes for lobster and crab fisheries
- Dolphin-safe means no nets were set on dolphins and none were killed or seriously injured in that set
- Pole-and-line, troll, and handline tuna carry the least bycatch
- When you choose the gear, you choose the bycatch
Pre-Order Dr. David Shiffman's book "Why Sustainable Seafood Matters"