Selective fishing of larger parrotfish lets algae flourish

Although selective fishing of larger parrotfish does not affect the biomass of coral reefs, such practices allow algae to flourish and adversely affects the reef's ecosystem.

Ecology & Science

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.

"Finding Nemo" clownfish won't survive climate change

If the current pace of climate change persists, anemonefish (also known as "clownfish") will find it to be no laughing matter.

Ecology & Science

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.

Do fish really possess higher cognitive powers?

In this magazine, we have frequently pondered the intelligence, sentience and self-awareness of the creatures we encounter on our ventures into the aquatic environment and reported on various scientific findings and philosophical discussion held in that regard (see references at the end).

Ecology & Science

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.

 

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

The diet of lake trout has been affected by the warmer waters in Ontario lakes, and this may lead to significant changes in the food webs in the ecosystem.

Lake Trout (Salvelinus namaycush)
Ecology & Science

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.

X-RAY MAGAZINE FEATURE

The Remarkable Intelligence of Fish

Fish reveal such complex thinking in their daily lives that they could not possibly be as simple-minded as fishermen claim. They are capable of all the types of cognition found in primates (with the sole exception of the ability to imitate), and now an international team of scientists has established that the cleaner wrasse is one of the few animals able to pass the mirror self-recognition test (MSR), also called the “mark test.”1

Words:
Ila France Porcher
Images:
Download the full article as pdf ⬇︎
Ecology & Science

The MSR has been the classic test for self-awareness since it was developed by Gordon Gallup in the 1970s in his work on chimpanzees. In the years since, only monkeys, elephants, dolphins, magpies, and quite recently ants, have succeeded in passing it. As the animal looks into the mirror, recognises its reflection, begins to study it, and finally uses the mirror for grooming, scientists believe that it is showing awareness of itself as being an individual that is separate from others—it is self-aware.

X-RAY MAGAZINE FEATURE

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. They use their pectoral fins like paws to prop themselves up, while searching out food higher in the coral labyrinths.

Words:
Ila France Porcher
Images:
Download the full article as pdf ⬇︎
Ecology & Science

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. They use their pectoral fins like paws to prop themselves up, while searching out food higher in the coral labyrinths.

X-RAY MAGAZINE FEATURE

The Clowns of the Ocean: Anemonefishes of the Indo-Pacific

Anemonefish are aptly referred to as "clownfish" because of their swimming behavior. It is interesting to note that the different varieties of clownfish exhibit very different characteristics. Some are shy homebodies, some can be very aggressive, and some even share their host anemones with other species.

Words:
Steve Rosenberg
Images:
Download the full article as pdf ⬇︎
Ecology & Science

My observations of anemonefish have taken me to dive destinations all over the Indo-Pacific, including Australia, the Philippines, Indonesia, Micronesia and Fiji. In these areas, there are a wide variety of anemonefish to observe and photograph.

The Killer Fish

One evening during a systematic study of sharks in a lagoon near Tahiti, an extraordinary creature undulated near—a needlefish a metre long, as silver as a salmon. It turned its head first one way, then the other, to gaze at me from each huge eye, and did not approach.

Ecology & Science

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

Parrotfish ­strategically harvest their favourite food by rotating through algae patches, waiting for each patch to regrow before dining on it again. The fish also defend their feeding territory while the food patches recuperate sufficiently, a new study finds.

Ecology & Science

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.

X-RAY MAGAZINE FEATURE

The Incredible Australian Leafy Seadragon

Australia, the great brown land down under, is home to many iconic and often strange-looking creatures, both above and below the water. But few are as unique and visually spectacular as the leafy seadragon!

Words:
Don Silcock
Images:
Don Silcock
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Travel & Trips

Known colloquially as “leafies”, they are also known by the common name Glauert's seadragon. Leafy seadragons are endemic to the southern and western coasts of Australia, but are particularly synonymous with South Australia, where they have been adopted as the state’s marine emblem.

Timid creatures that grow to between 20 and 24cm in length, they use their ornate leaf-like appendages as very effective camouflage to blend in with their surroundings and become almost invisible to the untrained eye.

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