Your monthly briefing on what’s happening in the world’s rivers and reefs.
June 2026: Dams Coming Down, Fisheries Recovering, New Coral Reef Discovered
Dams keep coming down, and the fish keep showing up. On the Klamath, the Snake, the Penobscot, and others, reconnecting rivers works faster than most people expected. Fish migration patterns are improving, which is good news becasue migratory freshwater fish populations have fallen over 80% since 1970. A new coral reef is discovered, meanwhile Florida reef scientists are spending the spring doing triage. Speaking of fish, see what happens when you give a wrasse a shrimp . . . and a mirror.
Coming in June on River & Reef: Is Your Vacation Rental in a Flood Hazard Area?/Reef Research & Recovery in the Florida Keys/What Does a Healthy Reef Look Like?
River
Open Access! Watershed-scale restoration of the Klamath River: Dam removal, restoration, and more (Society for Ecological Restoration, May 14, 2026). This webinar pulls together the science on Klamath dam removal, watershed restoration, and related work. Now that the dams are gone, this authoritative rundown explains what the restoration involves. For a background read on what happens in the river when the dam comes down, see Running Free: Re-establishing natural river processes through dam removal in the developed world
Why countries are tearing down hundreds of dams (CNN, May 27, 2026). Dam removal has gone global. The Klamath’s four-dam teardown (the largest in U.S. history) shows why countries worldwide are now pulling obsolete structures. The economics are as powerful as the ecology: aging dams are expensive liabilities, and removal is often the cheaper call. Europe is on board as well: Dam Removal Europe notes 603 dam removals in 2025 alone.
Migratory freshwater fish populations have fallen by 81% since 1970 (Mongabay). A landmark UN global assessment shows that migratory freshwater fish populations have fallen 81% since 1970. Why? Dams block migration routes, overfishing, and habitat loss. The report identifies 325 freshwater fish species in urgent need of transnational conservation. These species cross borders but receive almost none of the protections afforded to migratory birds or marine mammals. Only 23 freshwater fish species currently hold listings under the treaty that protects over a thousand other migratory animals. The Mekong River (home to 80 of the 325 species) and the Amazon basin are priority regions. Dam removal in Europe and North America are proof-of-concept that recovery is possible when full river corridors are managed cooperatively. (Mongabay)
World Fish Migration Day (NOAA Fisheries, May 21, 2026) NOAA spotlights the unglamorous mechanics of fish recovery: reconnecting tributaries and restoring habitat in the Snake River Basin so salmon and steelhead can complete one of the longest migrations in the U.S. Remember that river restoration is thousands of small passage fixes, as well as the more photogenic dam removals.
Reef
Racing to save Florida’s coral reefs before another bleaching crisis (Local 10 / WPLG Miami, May 28, 2026). With another hot summer in the forecast, South Florida coral scientists are racing to get heat-tolerant corals onto reefs. In the last crisis (2023), NOAA documented near-total bleaching on many reefs, with its coral program lead calling 100% bleaching seen then “absolutely crazy.” That baseline makes this year’s pre-summer push read more like triage than optimism.
One of the world’s largest deep-sea coral reefs discovered off Argentina (Mongabay, April 29, 2026). Two expeditions aboard the R/V Falkor mapped a previously unknown cold-water reef running 560 miles along Argentina’s territorial waters, roughly 1,000 meters down. This deep, cold reef hosts rich and rare biology. The team is already testing 3D-printed artificial corals to encourage new growth on the newly discovered system.
Novel strategies for coral restoration (University of Miami, April 20, 2026). A bottleneck in reef restoration is keeping nursery-raised coral alive long enough to matter. A University of Miami team found that growing young mountainous star coral on treated cement tiles raised survival fourfold. The tiles are cheap and reproducible, which is exactly what scaling restoration requires.
Sustainable Travel
Divers may think they protect reefs, but one unseen habit is taking a steady toll (Phys.org, May 26, 2026). A new study finds that 41% of diver-reef contacts cause observable harm. Wildlife encounters (often the highlight of any dive trip) may increase damaging contacts even more as divers reposition to get a better look. The study found that only a few divers accounted for a disproportionate share of reef damage. Not an argument against diving, but a clear case for pre-trip briefings and divers taking responsibility for their behavior. See our post on visiting reefs responsibly: The Tourism Trap: How to Enjoy Reefs Without Wrecking Them.
Wild Things
Cleaner wrasse show self-awareness in stunning mirror experiments (ScienceDaily/Osaka Metropolitan University, February 23, 2026) Cleaner wrasse, the small reef fish that run parasite-removal stations for larger fish, didn’t just recognize themselves in a mirror. They picked up a piece of shrimp and dropped it in front of the glass, watching how the falling food appeared in the reflection. That behavior, called “contingency testing”, was previously seen mainly with dolphins and other marine mammals. A fish the length of your finger, doing philosophy experiments with its lunch.
Video of the Month
The Rise of the River Herring (Trout Unlimited; video from National Fish and Wildlife Foundation). A short documentary following the return of river herring to the Penobscot after dam removal. See footage of fish doing what restoration promised they would do.
What did we miss? Share your news items for the month in the Comments and drop in any ideas for future posts or questions you’d like us to answer!
