Many years of restraint and restrictive fishing quotas seem to finally have paid off. Within a decade the stocks of spawning cod have almost doubled

Though levels of cod in the North Sea are not yet what they were pre-crisis, a remarkable recovery is well under way and advancing. Along with cod and plaice stocks of herring, haddock, hake, Norway lobster, common dab and witch (Torbay sole) are also improving .

In an article just published in the open-access science journal PloS One, the first appearance of lionfish off the Brazilian coast has been reported.

The invasion of the northwestern Atlantic by the Indo-Pacific lionfish has developed extraordinarily fast, and is expected to cause one of the most negative ecological impacts among all marine invasions. Despite the anticipation that lionfish would eventually extend their range throughout most of the eastern coast of South America, it had not been recorded in Brazil until now.

According to study leader Dr Yuuki Watanabe of the National Institute of Polar Research, Japan, "The physiological mechanism of keeping heat in the body is well understood. But, more a fundamental question is, why this unique evolution occurred in the first place. In other words, what kind of advantages does the fish gain from being warm-bodied?"

Fishing is the primary source of diminished reef function globally, leading to widespread calls for additional marine reserves to recover fish biomass and restore key ecosystem functions.

Removing too many herbivorous and predatory fish species deprives coral reefs of critical ecosystem functions and the capacity to respond effectively to other disturbances. Knowing the right amount to leave behind can help local fisheries set clear limits on how many fish can be taken without threatening the ecosystem they rely on.

Pacific bluefin tuna are unique amongst bony fish as they are endothermic (warm bodied) and can raise their core body temperature to 20°C above that of the surrounding water.

These animals are also capable of diving to depths of more than 1000 meter where the water is frigid. This chills the heart because it receives blood directly from the gills which mirrors water temperature. During deep dives their body temperature stays warm but their heart temperature can fall by 15°C within minutes. In other animals, humans included, this would stop the heart.

Potato cod in Queensland are at risk and their placid and curious nature appears to be playing a major part. The Great Barrier Reef Marine Park Authority (GBRMPA) is investigating reports that illegal fishing and fish 'framing' are responsible for declining potato cod numbers at the Cod Hole, a popular dive site off Lizard Island.

In order to understand the rich genus diversity in Turkey, a group of researchers from Recep Tayyip Erdoğan University, Faculty of Fisheries collected samples from more than 200 localities throughout the country between 2004 and 2014. The resulting paper, published in the open access journal ZooKeys, focuses only on the Salmo species distributed in the Alakır Stream drainage, from where the new species was described. It as named Salmo kottelati after Maurice Kottelat, who contributed to the knowledge of the fish fauna of Europe and Asia.

Zebrafish suffering from chronic stress as a result of a genetic mutation showed signs of depression in behavioural tests.

Meanwhile, a doctoral thesis on stress response and frustration in fish by research fellow Marco Antonio Vindas at Norway's Environmental and Life Sciences University has also established that salmon have emotional responses, defined as more or less unconscious reactions in the brain triggered by consuming or positive situations.