Protected sharks can still be in trouble, because protection is drawn around places and sharks move between them. A whale shark at Ningaloo Reef in Western Australia swims in one of the most protected places on Earth, and a few weeks later it can be in Indonesian waters or out on the high seas, under very different rules. Marine biologist Andrew Lewin, host of Ocean Decoded and co-host of the Beyond Jaws podcast, breaks down a new University of Queensland study that tracked where Australia's migratory sharks and rays go, and what happens to them when they leave.
PhD candidate Diego Bezerra and Associate Professor Daniel Dunn pulled together 30 years of satellite tag, acoustic receiver and tag-recapture data on 29 shark and ray species listed under the UN Convention on the Conservation of Migratory Species. They found five species that regularly leave Australian waters: whale sharks, blue sharks, shortfin makos, school sharks and white sharks, travelling to Indonesia, Micronesia, New Zealand, South Africa and the high seas. They also found that 18 of the 29 species, or 62%, have no published movement data at all, and only eight had enough data to map a migration. Published in the journal Conservation Biology, the study shows why sharks are so hard to track and why one country's protections can only cover part of an animal's life.
Andrew then follows the sharks across the border. Indonesia caught more sharks than any other country between 2007 and 2017, averaging more than 110,000 tonnes a year, according to TRAFFIC, and blue and school sharks are often caught as bycatch on tuna and swordfish longlines. Oceanic sharks and rays have declined by about 71% worldwide since 1970. The High Seas Treaty came into force in January 2026 and Canada has ratified it, but high seas fishing is still managed by regional fisheries bodies. You'll leave with one question to ask of every "protected species" headline, protected where?, plus ways to help: support shark tracking programs like OCEARCH, ask your government how it will use the High Seas Treaty, and check how your seafood was caught with guides like Seafood Watch, Ocean Wise and the MSC label. Join Andrew live on Ocean Decoded Live, Monday to Thursday at 5 PM Eastern, and go deeper with Beyond Jaws, co-hosted with Dr. David Ebert, and How to Protect the Ocean.
Chapters:
0:00 - A Whale Shark at Ningaloo Reef
2:13 - A Quick Shark Tour
4:07 - Budgets, Boats and Fishing Communities
6:26 - The Corrected Picture
7:41 - Follow the Shark Across the Map
Takeaways:
Shark protection is drawn around places, and migratory sharks move between places with very different rules.
A University of Queensland study combined 30 years of tracking data on 29 migratory shark and ray species in Australian waters.
Five species regularly leave Australian waters: whale sharks, blue sharks, shortfin makos, school sharks and white sharks.
They travel to Indonesia, Micronesia, New Zealand, South Africa and the high seas.
18 of the 29 species (62%) have no published movement data, and only eight had enough to map a migration.
Sharks are hard to track because many rarely surface for satellite tags, acoustic receivers only detect sharks swimming nearby, and tagging programs are expensive.
Many neighbouring countries have less capacity to enforce strong protections, with smaller budgets, fewer patrol boats and coastal communities that rely on fishing.
Indonesia was the world's top shark-catching nation from 2007 to 2017, and blue and school sharks are often caught as longline bycatch.
Whale sharks and shortfin makos are Endangered, school sharks are Critically Endangered and white sharks are Vulnerable.
Oceanic sharks and rays have declined about 71% worldwide since 1970.
The High Seas Treaty is now in force and Canada has ratified it, but regional fisheries bodies still manage high seas fishing.
None of the five study species received new protection at the UN migratory species summit in Brazil in March 2026.
The same problem applies off Atlantic Canada, where white, blue and shortfin mako sharks move between Canadian, U.S. and open Atlantic waters.
When you see "protected species" in a headline, ask: protected where?
#OceanConservation #MarineBiology #SaveOurOceans #ProtectTheOcean #OceanAwareness #BluePlanet #ConservationMatters #ScienceForChange #SustainableOceans
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