Fish

red hind (Epinephelus guttatus)
The red hind (Epinephelus guttatus), which is also known as the koon or lucky grouper in Caribbean vernacular, is found in the Western Atlantic.

Decoding Grouper Grunts Reveals Spawning Secrets

For the first time, scientists have decoded years of underwater “grunts” made by groupers to reveal how and when they spawn. The study, spanning more than a decade of recordings in the Gulf of Mexico and Western Atlantic, shows that fish sounds can provide vital clues for monitoring populations and detecting changes linked to climate and fishing pressure. 

A new study shows that anemonefish reduce their body size to cope with heatwaves and avoid conflict, improving survival.

Clownfish Shrink to Survive

Clown anemonefish, iconic residents of coral reefs, are now known to physically shrink to survive. A new study in Science Advances monitored 134 clownfish in Papua New Guinea during a 2023 marine heatwave and found that over 70 percent of individuals shrank at least once during the five-month event.

Live photos of the Hades' snake moray

Newly Described Species of Moray Eel Prefers Dark, Murky Environments

The Hades’ snake moray (Uropterygius hades) is a slender, dark brown eel which stands out for its unique adaptations to and preference for dim, turbid environments.

Unlike most of its marine relatives, which thrive in coral reefs, it is at home in estuarine habitats, a characteristic that is unusual among the 230 known species of moray eels. It is distributed across the Central Indo-Pacific, and has been found in southern Japan, Taiwan, the Philippines, southern Java, and Fiji.

The "fountain effect" can be seen when a marlin attacks a sardine shoal

Outsmarting the Predator: Sardines vs Marlin

In a recent study, researchers investigated how sardines that find themselves on a predator's radar collectively employ collective evasive manoeuvres and how their predators respond to outsmart them.

Using computational modelling and aerial video footage, the team from the Cluster of Excellence “Science of Intelligence” (SCIol), the Humboldt-Universität zu Berlin, the Leibniz Institute of Freshwater Ecology and Inland Fisheries, and Cambridge University focussed on the predator-prey behaviour of striped marlins and sardine shoals in the open ocean. 

Squaretail coral grouper (Plectropomus areolatus)
Squaretail coral grouper (Plectropomus areolatus)

Fishing Is Causing Fish To Flee When They Should Mate

Several times a year, squaretail groupers gather at spawning aggregation sites to mate, typically around the new and full moons between December and March. The males show up several days before to establish their territories, while the females arrive a day before the new moon. Then, both groups will attempt to pair and spawn in synchrony with the moon’s cycles.

For this species, these brief encounters are their only opportunities to reproduce.