Stingrays on video


This video says about itself:

17 March 2017

Jonathan visits the world-famous “Stingray City” in Grand Cayman with world-renown marine artist Dr. Guy Harvey to learn about Dr. Harvey’s research on Stingrays and how they cope with massive numbers of tourists.

JONATHAN BIRD‘S BLUE WORLD is an Emmy Award-winning underwater science/adventure program that airs on public television in the United States.

Sailfish video


This 17 May 2017 video says about itself:

Sailfish Are Master Hunters – Planet Earth – BBC Earth

Stunning footage of Sailfish three metres long closing in on prey. Ever the resourceful hunter, they will only use just enough energy to make their kill, never wasting a fin stroke. What is more remarkable is how they can change colour to warn their companions or confuse their prey.

Beavers save salmon from climate change


This video from the USA says about itself:

26 March 2013

Presenter Dr. Jimmy Taylor shares information about Oregon‘s state animal – the beaver – and how we benefit from their activity. Taylor is a supervisory research wildlife biologist and field station leader for the National Wildlife Research Center in Corvallis, Oregon. His research project focuses on understanding human-wildlife conflicts and improving management strategies to reduce damage by forest and aquatic mammals, with an emphasis on non-lethal tools and techniques.

North America’s largest rodent, the beaver, was once the most widely distributed mammal but virtually trapped to extinction in the early 1800’s for its pelt. A decline in demand for its fur and proper wildlife management helped beaver to become reestablished in much of their former range. While beaver foraging and building activities can cause flooding, damaging private property; beaver ponds and dams are also good for Oregon’s native fish and other wildlife. Beaver activities can also benefit private landowners by controlling downstream flooding and creating wetlands which improve water quality and facilitate ground water recharge. If managed correctly, conflict with beaver can be minimized.

From PLOS ONE:

Alteration of stream temperature by natural and artificial beaver dams

May 17, 2017

Abstract

Beavers are an integral component of hydrologic, geomorphic, and biotic processes within North American stream systems, and their propensity to build dams alters stream and riparian structure and function[s] to the benefit of many aquatic and terrestrial species.

Recognizing this, beaver relocation efforts and/or application of structures designed to mimic the function of beaver dams are increasingly being utilized as effective and cost-efficient stream and riparian restoration approaches. Despite these verities, the notion that beaver dams negatively impact stream habitat remains common, specifically the assumption that beaver dams increase stream temperatures during summer to the detriment of sensitive biota such as salmonids.

In this study, we tracked beaver dam distributions and monitored water temperature throughout 34 km of stream for an eight-year period between 2007 and 2014. During this time the number of natural beaver dams within the study area increased by an order of magnitude, and an additional 4 km of stream were subject to a restoration manipulation that included installing a high-density of Beaver Dam Analog (BDA) structures designed to mimic the function of natural beaver dams.

Our observations reveal several mechanisms by which beaver dam development may influence stream temperature regimes; including longitudinal buffering of diel summer temperature extrema at the reach scale due to increased surface water storage, and creation of cool—water channel scale temperature refugia through enhanced groundwater—surface water connectivity. Our results suggest that creation of natural and/or artificial beaver dams could be used to mitigate the impact of human induced thermal degradation that may threaten sensitive species.

In this way, beavers save sensitive species like salmon, which cannot live in warm water.

Interviewed by Dutch daily De Volkskrant on this today, Belgian Antwerp University beaver expert Kristijn Swinnen thinks that the European relatives of American beavers may in similar ways benefit European relatives of American salmon and other species threatened by climate change. European beavers came back in the Netherlands only recently after having been exterminated there in the nineteenth century.

New damselfish species discovery


This video says about itself:

18 May 2017

Evolutionary biologist Giacomo Bernardi describes how he and his graduate students discovered a new species of damselfish (Altrichthys alelia) in the Philippines. The parental care behavior of Altrichthys is unusual. Among the hundreds of species of damselfish, only a few protect and care for their young. Most coral reef fish produce large numbers of young that disperse into the ocean as larvae.

From the University of California – Santa Cruz in the USA:

New coral reef fish species shows rare parental care behavior

Among the hundreds of species of damselfish, only a few protect and care for their young; a newly discovered species raises the number from three to four

May 18, 2017

Summary: The vast majority of coral reef fish produce large numbers of young that disperse into the ocean as larvae, drifting with the currents before settling down on a reef. A few reef fish, however, keep their broods on the reef, protecting the young until they are big enough to fend for themselves. On a recent trip to the Philippines, researchers discovered a new species of damselfish that exhibits this unusual parental care behavior.

The vast majority of coral reef fish produce large numbers of young that disperse into the ocean as larvae, drifting with the currents before settling down on a reef. Giacomo Bernardi, a professor of ecology and evolutionary biology at UC Santa Cruz, studies reef fish that buck this trend and keep their broods on the reef, protecting the young until they are big enough to fend for themselves.

On a recent trip to the Philippines, Bernardi and his graduate students discovered a new species of damselfish that exhibits this unusual parental care behavior. Out of about 380 species of damselfish, only three brood-guarding species were known prior to this discovery. Bernardi’s team had gone to the Philippines to study two of them, both in the genus Altrichthys, that live in shallow water off the small island of Busuanga. On the last day of the trip, the researchers went snorkeling in a remote area on the other side of the island from their study site.

“Immediately, as soon as we went in the water, we saw that this was a different species,” Bernardi said. “It’s very unusual to see a coral reef fish guarding its babies, so it’s really cool when you see it.”

Genetic tests on the specimens they collected confirmed that it is a new species, which the researchers named Altrichthys alelia (Alelia’s damselfish, derived from the names of Bernardi’s children, Alessio and Amalia, who helped with his field research). A paper on the new species was published May 18 in the journal ZooKeys.

Parental care dramatically improves the chances of survival for the offspring. According to Bernardi, less than one percent of larvae that disperse into the ocean survive to settle back on a reef, whereas survival rates can be as high as 35 percent for the offspring of the Altrichthys species. Yet the parental care strategy remains rare among reef fish.

“It’s a huge fitness advantage, so why don’t they all do that? There must also be a huge disadvantage,” Bernardi said.

One big disadvantage is that the young are unable to colonize new sites far from the home reef of their parents. As a result, brood-guarding species (the technical term is “apelagic” species, because they don’t have a pelagic, ocean-going phase) tend to occur in highly restricted areas, which leaves them more vulnerable to extinction.

“I suspect that species evolve this strategy regularly, and they are successful until there is some change to the local habitat, and then the whole population gets wiped out,” Bernardi said. “These are very fragile species. The Banggai cardinalfish is one that was discovered just a few years ago in a small area in Indonesia, and it’s already on the endangered species list.”

Blenny fish, all venomous?


This video says about itself:

18 March 2016

Ewa Fang Blenny at home on a Hawaii reef.

From Science News:

Blennies have a lot of fang for such little fishes

Some are venomous, but others are just faking

By Susan Milius

10:00am, May 16, 2017

After a recent flurry of news that fang blennies mix an opioid in their venom, a question lingers: What do they need with fangs anyway? Most eat wimpy stuff that hardly justifies whopper canines.

Not that fang blennies are meek fishes.

“When they bite, they bite savagely,” says Bryan Fry of the University of Queensland in Brisbane, Australia. “If these little jobbies were 3 meters long, we’d be having to cage dive with them.” Real-world blennies, however, grow to only about the size of a cocktail sausage.

These little beasts probably got their big teeth before evolving venom, says Nicholas Casewell of the Liverpool School of Tropical Medicine in England. That’s jusssst backward, snakes might say, as they evolved their venom first. Yet when Casewell, Fry and colleagues put together an evolutionary family tree for the blennies, the one genus with both fangs and venom branched off amid four genera that are all fang and no toxins, Casewell, Fry and colleagues report in the April 24 Current Biology.

Those with venom aren’t that scary to humans. Fish venoms tend to cause excruciating pain, says Fry, who adds from personal experience that “sting” sounds deceptively benign for what a stingray delivers (SN: 4/29/17, p. 28). A venomous fang blenny has yet to nail him, but he hears that others have felt little more than a toothy nip.

“There’s no real reason for most of these fish to have fangs to help them feed,” Casewell says. Many prey on small invertebrates or even floating plankton, which is about as hard to subdue as chicken soup.

The fangs, however, are useful for fending off predators, Casewell suggests. Blennies have no spiky fins or spines, the more usual defensive weapons in fish. Male-versus-male competition may have been another force for fang evolution; males stab each other during breeding season.

When fangs evolved, whatever the reason, they became a useful conduit for venom, Casewell and Fry propose. Once some blennies evolved venom, “all these crazy selection pressures started coming in,” Fry says. Forces of natural selection nudged nonvenomous fang blennies toward colors and stripes similar enough to those of their venomous cousins to discourage attacks from an educated predator.

The mimics take advantage, often brazenly swimming up to bigger fish to bite off some scales and mucus for a snack. “These fish are little jerks,” Fry says. “They should be called jerk blennies.”

Dutch children raise much money for sharks


This 2015 video is called Shark asks several divers for help.

Translated from Dutch NOS TV:

Children raise over 600,000 euros for sharks

Today, 18:54

Children have collected 621,780 euros for shark protection. This happened in the context of the Zapp Your Planet action of the WWF and NPO Zapp, the public broadcaster’s children’s branch. The action was concluded with an action day at the Mediapark in Hilversum.

Every year, Zapp and the WNF have Dutch children raising money for an endangered species, but the amount has never been so high. About sharks the WNF says that every year 100 million are killed for their fins or their meat.

Thousands of children today brought the contributions they have collected over the past months. Some children had collected deposit bottles, others had sold lemonade or chocolate eggs.

The collected money will be used, inter alia, to make areas in the sea more shark-friendly. There is also a global campaign for people not to eat shark meat.

Great white shark video


This video says about itself:

Great White Shark Attack And Breach – Planet Earth – BBC Earth

3 May 2017

Epic footage of one of earth’s most feared predators, the Great White Shark. Each dawn, Cape Fur Seals leave their colony to go fishing. To reach the open sea they must cross a narrow strip of water which is patrolled by the largest predatory fish on the planet.