Fish

First spotted in the Atlantic Ocean off Florida in the 1980s, they later spread across the Caribbean, reshuffling coral reefs and other ecosystems by feasting on fish unfamiliar with the voracious predator.

While ocean currents that flow north—such as the South Equatorial Current—and the freshwater plume created by the Amazon River hampered the spread of the invasive species, scientists predicted it was just a matter of time before it moved into Brazilian waters.

In this study, researchers discovered that fish larvae around the world used external cues like the sun, Earth’s magnetic field and sounds to find their way around in the open ocean. 

The fish larvae were able to control their destination and migrate by keeping a bearing. 

At the time of the spring tide (new moon and full moon), thousands of puffer fish around the world head for the coastlines to spawn. There, they gather at the water’s edge and vigorously tremble their bodies to spawn.

Scientists have long wondered how the puffer fish were able to synchronise their spawning with the lunar cycle.

A paper published in a recent issue of the Current Biology journal has the answers. 

Scientists have observed instances in which tuna rub themselves against the side of sharks. Apparently, they do this to dislodge painful parasites that cling to their head, eyes and gills.

“Shark skin is really smooth in one direction and it’s like sandpaper in the other,” said Chris Thompson, a Research Fellow at the University of Western Australia.

The 3.19 million barrels of crude oil that spilled into the Gulf of Mexico during the Deepwater Horizon in 2010 had a devastating impact to the natural environment, as well as the people and animals in the vicinity.

A study on the mahi-mahi in the nearby waters revisits the incident by studying how fish in the wild are being affected from the exposure to crude oil.

For more than a decade, some researchers in Australia have been monitoring coral reefs in the vicinity to see how rising ocean temperatures affect both the tropical and temperate reef fish communities.

The findings of their study was published in the Current Biology journal.

According to lead author Rick Stuart-Smith, a marine ecologist at the University of Tasmania, the team had focused on reef fishes as reefs provided many benefits to people and the fishes there helped maintain the natural ecological function of the reefs.