Fish

River Rhône in France

—Diving in the French river Rhône with European catfish

—Diving in the French river Rhône with European catfish

The Rhône is a large French river, which is 545km long. It flows from the Alps, across Lake Geneva and joins the Mediterranean Sea. Cloudy in appearance, as if to preserve her secrets, it is difficult to have strong views about this type of river

Seeking Eye Contact: Fish Gaze Reveals Self-Awareness

For many years, I held a weekly feeding session for the resident reef sharks and their visitors in the study area where I observed their behaviour. If I had enough shark food, I would scatter crumbs into the water for the fish after the sharks had left. The fish knew this, so they had to wait, and while they were waiting, they were excited.

Andrew A Shantz places an enclosure over corals on the sea floor at Florida Keys.

Selective fishing of larger parrotfish lets algae flourish

Scientists at Pennsylvania State University and the University of California, Santa Barbara have discovered that when fishermen selectively catch large and medium-sized parrotfish at coral reefs facing decline due to climate change, algae has a better chance of growing and overtaking the corals.

Nonetheless, according to the research, the reef’s biomass is maintained. This is because even with less of the large and medium-sized parrotfish, there would be many smaller parrotfish that would take their place.

The anemone fish's survival is at stake, due to climate change.

"Finding Nemo" clownfish won't survive climate change

A recent study by France’s National Centre for Scientific Research (CNRS), Woods Hole Oceanographic Institution (WHOI) and colleagues indicates that the anemonefish does not have the genetic ability to adapt swiftly enough to climate change.

The findings of the study were published in the November 27 issue of the Ecology Letters journal.

The research was conducted in the lagoons of Kimbe Bay, covering more than a decade. This area is a biodiversity hotspot in Papua New Guinea.

A cleaner wrasse interacts with its reflection in a mirror. A study, which suggests that fish might possess far higher cognitive powers than previously thought, has ignited an intense debate over how we assess the intelligence of animals

Do fish really possess higher cognitive powers?

Mirror self-recognition test

The standard method for testing whether an animal is self-aware is placing a mark on its body that cannot be viewed directly and then letting it have a look in a mirror. If the animal responds to its reflection and attempts to remove the mark it is considered evidence that the animal is self-aware.

Lake Trout (Salvelinus namaycush)
Lake Trout (Salvelinus namaycush)

Warmer waters in Ontario lakes messes with lake trout's diet

According to a new study, climate change is giving rise to changes in the diets of fishes in Ontario lakes, thereby altering the food webs there.

Researchers from the University of Guelph have discovered that the fish in Ontario lakes have been forced to forage in deeper waters due to the warmer average temperatures in the past decade. As a result, they consume prey species that are different from their normal diet, and this has led to a change in the flow of energy and nutrients in the lake.

A Matter of Sentience

Fish feel pain, or don’t they? Despite a growing body of sound evidence that fish do indeed feel pain and are sentient beings capable of all the types of cognition found in the “higher” mammals, with the possible sole exception of the ability to imitate, a group of critics seems to systematically seek to discredit this research. But for what reasons? Ila France Porcher takes a closer look at the stakes involved.

The Underrated Nurse Shark

Plentiful nurse sharks attended the sessions I held during my shark study in Tahiti. They are heavily-built animals with large, graceful fins, a long, pennant tail, and small eyes. They forage on the sea floor for a variety of foods at night and sleep in grottos in the coral during the days. Though these unusual sharks typically lie around on the sea floor, they are also capable of clambering.