Scorching Amazonian lakes, killer whale cousins, and Vaquita calf sightings
Big Blue Bulletin #68
Welcome to the latest edition of the Big Blue Bulletin – things have changed just a little bit around here as featured stories will now focus on whales, dolphins, and porpoises, with a little bit of commentary from me thrown in as well. Still, you can expect good news, bad news, and a cute creature in your inbox every week.
Let’s dive in 🐬
Ocean news
🗞️ Big news of the week -
🌡️ Amazon lakes hit ‘unbearable’ temperatures amid mass die-offs of river dolphins
New research has revealed that shallow Amazonian lakes are reaching scorching temperatures of up to 41°C as heatwaves and droughts grip the region.
In one of the worst-hit areas, Lake Tefé, water became so hot it was “unbearable to touch”, researchers said, with the heat reaching all the way to the lakebed. The result was a mass die-off of fish and endangered pink river dolphins, with more than 200 carcasses surfacing across six weeks in September 2023.
Scientists say half the lakes studied exceeded 37°C at their peak which is a deadly threshold few aquatic species can survive.
🐬 West Coast mammal-eating killer whales are two distinct communities that rarely mix
A new study has confirmed that the mammal-eating killer whales of the North American West Coast aren’t one unified group, but two distinct communities that rarely interact.
Based on 2,200 encounters over 16 years, researchers identified clear differences between inner coast transients, who specialise in hunting inlets and bays, and outer coast transients, who navigate deeper offshore waters. The inner coast group are likened to city dwellers, skilled at weaving through complex waterways, while the outer group are adapted to life in the “backcountry” of the continental shelf.
The study, published in PLOS One, adds to growing evidence of orca social and ecological complexity, and suggests these two groups may be evolving along different paths.
🇮🇹 Dolphin seen near St Mark’s Square inspires Venetian rescue effort
A lone bottlenose dolphin, nicknamed Mimmo, has been drawing crowds in Venice’s busy lagoon.
First seen in June, Mimmo has become a regular near St Mark’s Square, leaping among the boat traffic but campaigners are now calling for the dolphin to be relocated, warning it risks injury or death from propellers in the heavily trafficked basin.
“This is not a tourist attraction,” said campaigner Cristina Romieri. “It is a wild animal that needs to be brought to a healthier environment.”
🇲🇽 Newly spotted Vaquita babies offer glimmer of hope for world’s rarest marine mammal
The world’s rarest marine mammal has shown signs of recovery, as between 7 and 10 vaquitas, including at least one or two calves , were spotted during a new survey in Mexico’s Gulf of California.
The critically endangered porpoise, once thought to be down to just 10 individuals, has been the focus of intense protection efforts. The sightings were made using acoustic detectors and long-range binoculars to avoid disturbing the shy animals.
It’s the first time calves have been seen since 2023 and is a small but encouraging step forward.
🫂 Rare footage shows fish gripping on to humpback whale – video
New footage captured by camera tags shows remora fish gripping, releasing and reattaching to a humpback whale.
The video offers a close look at the relationship between the suckerfish and their hosts, including how they feed on dead skin as the whales shed it.
Have a great weekend! 📸
Cover image by Gabrielle Therin-Weise/Getty Images.
Happy to hear of vaquita calf sightings.
Enjoyed all the links for keeping us aware of progress and challenges, especially the killer whales, since once upon a time I lived in the Puget Sound area and could occasionally seen them. No surprises there's a distinction between inner and outer coast populations, though I'd always assumed they all roamed everywhere. Learn something new every day!