Fish

Lionfish, which have spines that contain venom, are a well-known problem in Atlantic coral reefs. These invaders from the tropical parts of the Pacific and Indian oceans have no natural predators in the Atlantic Ocean. They are eradicating many fish populations in the shallow reefs that they have overtaken. Recently, the overwhelming problem has proven worse than originally thought.

New research conducted by Swedish researchers finds that anxiolytic drugs in surface waters alter animal behaviours that are known to have ecological and evolutionary consequences

Researchers from Umeå University in Sweden examined how perch behaved when exposed to oxazepam, a drug commonly used to treat anxiety disorders in humans.

The scientists exposed the fish to concentrations of the drug similar to those found in the waters near densely populated areas in Sweden.

Lionfish have no natural predators and are taking food and habitat from native fish that are important to the local ecology and economy. Lionfish are now found in waters from North Carolina south to Florida, the Caribbean, and all Gulf of Mexico states.

This new manual, Invasive Lionfish: A Guide to Control and Management includes the best available science and practices for controlling lionfish in marine protected areas, national parks, and other conservation areas.

Now, additional findings lends further credence to the notion that fish do indeed possess emotions and harbour thought processes. It turns out that fish growing up in the wild among predators use their left eye to look at novel objects, while their offspring raised in captivity use the right eye.
 

Pelvicachromis taeniatus is a dwarf cichlid from West Africa that is occasionally kept as an aquarium fish In this species, females seek to impress potential mates as well by fanning out their large, violet pelvic fin.
 
The results, published this month in BMC Evolutionary Biology, also suggest male choice can drive females to evolve exaggerated traits, a finding that disputes the traditional belief that sexual selection is a one-way road, allowing only females to affect male appearance.
 

Andrew Wendruff from the University of Alberta says his one-metre-long, forked-tailed coelacanth was an 'off-shoot' lineage that lived 240 million years ago.

In a study published in BMC Public Health, an open access journal, tilapia was introduced into abandoned fish ponds at an altitude of 1,880m and the effect measured over six months on the numbers of mosquito immatures.

For centuries, the Zoque people of southern Mexico would venture each year during the Easter season deep into the sulfuric cave Cueva del Azufre to implore their deities for a bountiful rain season.

As part of the annual ritual, they release into the cave's waters a distinctive, leaf-bound paste made of lime and the ground-up root of the barbasco plant, a natural fish toxin. Believing the cave's fish to be gifts from their gods, they scoop up their poisoned prey to feed upon until their crops are ready to harvest.

Small groups of sticklebacks (Gasterosteus aculeatus) reach consensus when choosing which of two replica fish to follow. As group size increases, the fish make more accurate decisions.

"It turned out that stickleback fish preferred to follow larger over smaller leaders," said Ashley Ward of Sydney University