Fish

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.

The Killer Fish

Whereas the beaks of the common needlefish were needle-sized and shaped, this one's mouth was similarly pointed, but 15 cm long and lined with large, sharp, interlocking teeth. As I crumbled some bits of food for the ever present lagoon fish, it accelerated forward to take a morsel and the small fish shot away, creating a dazzling, submarine firework exploding in silence. When it opened its pointed mouth to take a morsel it revealed a throat nearly the same diameter as its body--it was well equipped to catch and swallow large prey. It had two parallel scars on its right side.

Some fish 'farm' their food

Working on Palmyra atoll, around 1,000 miles south of Hawaii, a team of researchers from the University of California Santa Barbara became aware of the fish's farming habit when they noticed many bite marks in specific areas of algae growing on dead coral.

They followed these patches through time and found parrotfish were feeding heavily in each patch for a short period of time. Then, the fish would allow that exact location to recover before returning to harvest the algae again.

Infographic explaining why fish are expected to shrink.

Warmer weather shrinks fish

This is the findings of a new study in Global Change Biology by the University of British Columbia. The reason for this future decline in size stems from the fact that fish are cold-blooded animals, and are thus unable to regulate their body temperatures.

“When their waters get warmer, their metabolism accelerates and they need more oxygen to sustain their body functions,” said co-author William Cheung, associate professor at the Institute for the Ocean and Fisheries and director of science for the Nippon Foundation-UBC Nereus Program.