For centuries, hagfish have been regarded as little more than deep-sea scavengers—primitive jawless fishes that spend their lives cleaning up dead animals on the ocean floor. But underwater video footage has revealed a very different story. Far from being passive scavengers, hagfish are active predators equipped with one of the most extraordinary attack and defence systems in the animal kingdom.

Divers using 406 MHz Personal Locator Beacons are being reminded that registration is now mandatory when the devices are carried aboard UK-flagged motorised vessels.

According to BSAC, the Maritime and Coastguard Agency has warned that it is now a criminal offence to carry an unregistered 406 MHz PLB on a UK-flagged vessel or mechanically propelled watercraft. The rule applies to both existing PLBs and newly purchased units.

For more than 30 years, one of Britain’s most enigmatic shipwrecks has challenged maritime archaeologists. Since its discovery off Salcombe, Devon, in 1995, the site has yielded more than 400 Moroccan gold coins, jewellery, ceramics, pewter objects and other artefacts, but the identity of the vessel remained uncertain.

Fanworms belong to a group of marine worms called polychaetes, relatives of the bristle worms that crawl through reefs and sediments. But unlike their wandering cousins, fanworms build protective tubes from mucus, sand, shell fragments, or calcium. Hidden inside these tubes, the worm’s soft body remains safely out of sight.

The seafloor is not a solid, impermeable barrier. Much of it is fractured and porous, allowing seawater to penetrate deep into the planet’s crust. Driven by heat from the interior, this water slowly circulates through networks of cracks and channels beneath the seabed. Some of these underground journeys may last thousands of years, and the water emerges altered by its passage, for it carries dissolved minerals and chemicals that influence the chemistry of the oceans above. Even below the floor of the sea, the ocean continues its hidden circulation.