Is Bottom Trawling Always Bad? It Depends Where
How To Protect The Ocean
Off the south coast of England, about 100 kilometres out, sits Haig Fras, a granite reef covered in jewel anemones and cup corals. For years it was protected on paper, yet heavy fishing gear could still drag across it. In March 2024, that finally changed. In this episode, Andrew Lewin explains why where we fish matters as much as how much we fish, and what it takes to turn a line on a map into real protection. Andrew breaks down the difference between midwater and bottom trawls and puts the damage shown in the recent Ocean documentary into context. Bottom trawling lands about a quarter of the...
info_outline
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...
info_outline
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...
info_outline
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...
info_outline
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...
info_outline
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...
info_outline
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...
info_outline
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...
info_outline
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,...
info_outline
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...
info_outlineOff the south coast of England, about 100 kilometres out, sits Haig Fras, a granite reef covered in jewel anemones and cup corals. For years it was protected on paper, yet heavy fishing gear could still drag across it. In March 2024, that finally changed. In this episode, Andrew Lewin explains why where we fish matters as much as how much we fish, and what it takes to turn a line on a map into real protection.
Andrew breaks down the difference between midwater and bottom trawls and puts the damage shown in the recent Ocean documentary into context. Bottom trawling lands about a quarter of the world’s wild-caught seafood, and the impact depends heavily on where it happens. He walks through the research on paper parks, where trawling was more intense inside European marine protected areas than outside them, and the five features that make an MPA deliver results. He also explains how England used public consultations to ban bottom-towed gear over sensitive reefs, and why the same place-based logic applies to fish farms.
The episode closes with a simple action anyone can take. The next time your government proposes or reviews a marine protected area, submit a public comment supporting rules that keep bottom trawling off sensitive habitats. Consultations count comments, and the rules written there decide whether a park is real.
Takeaways
- Bottom trawling supplies about a quarter of wild-caught seafood, and its impact depends on the habitat being trawled.
- Regions where less than 10% of the seafloor was trawled almost always had sustainably fished stocks.
- In a study of 727 EU MPAs, 59% were commercially trawled, and trawling was 38% more intense inside them than outside.
- MPAs that are no-take, enforced, older than 10 years, larger than 100 km², and isolated deliver far more fish and sharks.
- England’s 2024 byelaw banned bottom-towed gear over reefs in 13 more offshore MPAs, including Haig Fras.
- Aquaculture now produces 51% of the world’s aquatic animals. Look for ASC or BAP labels and seafood guide ratings.
- Submitting a public comment during MPA consultations directly shapes the rules.
Pre-Order Dr. David Shiffman's book: "Why Sustainable Seafood Matter"
Support Independent Podcasts: https://www.speakupforblue.com/patreon
Need help with your ocean non-profit, company, or project? Get the help you need with Pisces Oceans Inc.: https://www.piscesoceans.ca
Connect with Speak Up For Blue
Website: https://bit.ly/3fOF3Wf
Instagram: https://bit.ly/3rIaJSG
TikTok: https://www.tiktok.com/@speakupforblue
Twitter: https://bit.ly/3rHZxpc
YouTube: www.speakupforblue.com/youtube