Marine animals discoveries in Atlantic ocean


This video from the USA says about itself:

25 October 2017

Join NRDC senior oceans scientist Lisa Suatoni on an animated submersible tour of the weird, wonderful, and imperiled underwater world of the Northeast Canyons and Seamounts National Monument. The ocean floor off the east coast of the United States is carved with canyons deeper than the Grand Canyon, and, beyond those, extinct volcanoes. President Obama made almost 5,000 miles of this unique area a national monument, but the Trump administration is interested in revoking its monument status to open this pristine area with 4,000-year-old corals to industrial fishing, mining, and drilling. Not many people get to explore these incredible depths—but once you see what’s down there, you’ll never be the same!

Take action: here.

From the New England Aquarium in the USA:

Diverse and abundant megafauna documented at new Atlantic US Marine National Monument

Rare aerial survey of Northeast canyons and seamounts

May 16, 2018

Airborne marine biologists were dazzled by the diversity and abundance of large, unusual and sometimes endangered marine wildlife on a recent trip to the Northeast Canyons and Seamounts National Marine Monument, about 150 miles southeast of Cape Cod. Scientists with the Anderson Cabot Center for Ocean Life at the New England Aquarium observed dozens of dolphins mixing with schools of pilot whales plus more than a dozen of the very rarely seen and mysterious Sowerby’s beaked whales. The researchers, aboard a twin engine airplane, also spotted endangered, Moby Dick-like sperm whales as well as the second largest species of sharks in the world and the bizarre-looking giant ocean sunfish or Mola mola.

The Northeast Canyons marine monument is a critical hotspot of biodiversity on the edge of the continental shelf where the shallow seas off of New England drop sharply into the deep waters of the northwestern Atlantic. In 2016, President Obama designated three underwater canyons that are deeper than the Grand Canyon, and four seamounts as tall as the Rockies, as the first American marine national monument in Atlantic waters. However in 2017, Secretary of the Interior Ryan Zinke recommended to President Trump that the Northeast Canyons and Seamounts either be downsized or eliminated. The exact nature of the recommendation has yet to be specified.

Given the great distance offshore, documenting the marine life there is a challenge. During the 4.5-hour aerial survey, the team spotted 169 bottlenose dolphins, 57 pilot whales, 44 Risso’s dolphins, 13 rare Sowerby’s beaked whales, four sperm whales, and 44 other dolphins of various species. In two sightings, they saw a mixed group of up to 50 bottlenose dolphins and 30 pilot whales, but what intrigued the researchers most was that three groups of Sowerby’s beaked whales were spotted at the water’s surface, a rare occurrence given their marathon dive times.

This is “extraordinary for such a small area,” said Dr. Ester Quintana, the lead scientist on the Anderson Cabot Center aerial team, adding that they also observed basking sharks, the second largest species of shark in the world, and the strange, large, plankton-feeding Mola mola, or ocean sunfish.

The aerial sightings help researchers understand how the species are using the richly biodiverse monument waters and deep coral canyons at different times of year and for different purposes. “One of the reasons we do this work is that we are just discovering what’s going on out there,” said Dr. Scott Kraus of the Anderson Cabot Center. “This is an opportunity to see how animals use this habitat. No one has ever done this before.”

This was the third in a series of aerial surveys of the monument that began in summer 2017, and the number of sightings by the scientists during this survey was higher than any other, nearly double the number of animals observed last fall.

“These surveys continue to show the incredible abundance of marine life in the Northeast Canyons and Seamounts Marine National Monument,” said Kraus. “These sightings support the idea that this area is worthy of complete protection.”

“This area was declared protected because it is a fragile ecosystem with a wide diversity of corals, deep water fishes, and invertebrates around these pristine canyons and seamounts that support a vast array of whales, dolphins, and large fish”, Dr. Quintana said. “As new policies recommend opening more waters off the US coast to offshore drilling, it is incredibly important to have areas that remain protected.”

She said the Northeast Canyons monument area is about one-tenth of one percent of all US ocean territorial waters. “Yet, the wildlife diversity we are seeing out there highlights the importance of preserving its ecological value,” Dr. Quintana said.

‘A BETRAYAL OF THE AMERICAN PEOPLE’ EPA chief Scott Pruitt was lambasted by the Senate appropriations committee Wednesday for the myriad ethical scandals plaguing him, with Sen. Patrick Leahy (D-Vt.) accusing him of turning the department into “a laughingstock.” [HuffPost]

Advertisements

Zebra sharks off Oman, video


This video says about itself:

2 March 2018

Jonathan and cameraman Bill travel to the Daymaniat Islands in Oman in search of zebra sharks (also called leopard sharks in some parts of the world). The diving in Oman is fabulous! They encounter huge schools of fish, cuttlefish, sea turtles and finally…the elusive zebra shark. All while diving in 110° F heat!

JONATHAN BIRD‘S BLUE WORLD is an Emmy Award-winning underwater science/adventure series featuring underwater cinematographer/naturalist Jonathan Bird.

First silky sharks seen off Saba, Caribbean


This 2015 video is called Shark experts are surrounded by exceptionally large silky sharks in Cuban waters.

From BioNews:

First silky shark sightings by Saba Conservation Foundation!

Whilst nurse sharks and Caribbean reef sharks are regularly spotted on the Saba Bank, it’s not every day that you see silky sharks. During a routine visit to the Saba Bank, a research team from the Saba Conservation Foundation (SCF), Saba Bank Management Unit, made history a few weeks ago when Oceaware’s Guido Leurs spotted around 10 juvenile silky sharks (Carcharhinus falciformis). This was the first time that silky sharks had been reported from the Saba Bank.

Some of the defining characteristics of the silky shark include a small, rounded first dorsal fin that originates behind the end of the pectoral fins, a much smaller second dorsal fin with a free tip that is twice as long as the height of the fin together with long, slender pectoral fins that typically have dusky tips.

These slender oceanic sharks get their name from the smooth, silky texture of their skin which is caused by dermal denticles that are unusually densely packed. Silky sharks inhabit both deep oceans and shallow coastal waters and are highly migratory.

The silky shark population in the Western Atlantic follows the Gulf Stream as well as the movements of tuna and swordfish, their main food source. Their appetite for these schooling fish makes them extremely vulnerable to by-catch, and many silky sharks are caught and killed in pelagic longline fisheries or are trapped in purse seines targeting tuna and swordfish.

There are also targeted silky shark fisheries in operation in the Caribbean and Gulf of Mexico, where they are caught by longlines.

Silky sharks are ranked amongst the three most important sharks in the global shark fin trade – with up to 1.5 million fins being traded annually from this species. Population data for this species shows a worrying downwards trend since the early 1990s, especially in the northwest and western central Atlantic. The IUCN Red List status of the silky shark was adjusted in 2017 from “Near Threatened” to “Vulnerable” due to an estimated 47-54% decline of the global population over three generations.

Silky sharks are especially vulnerable to exploitation because of their life history characteristics: a long gestation period, a slow growth rate, small litters and a long reproductive period. Safeguarding the future of this highly migratory species will require a cooperative approach between all countries through which it migrates, and an increase in safe havens like the Yarari Sanctuary and the Saba Bank.

More information is here.

‘Cuckoo’ fish in Africa


This 2015 aquarium video is called A video of my Synodontis multipunctatus (cuckoo catfish) and my red empress spawning.

From the University of Konstanz in Germany:

Brood parasitism in fish

May 9, 2018

Summary: Biologists have demonstrated that ‘evolutionary experience’ as well as learning protects cichlid fish from the brood parasitism practiced by the African cuckoo catfish.

There are other animals besides the cuckoo who smuggle their offspring into another animal’s nest. The Synodontis multipunctatus, which occurs in Lake Tanganyika in Africa and is better known as cuckoo catfish, is just as cunning as the cuckoo is. Just like the bird, this savvy parasite manages to place its eggs among those of cichlids. To protect their eggs, cichlids carry them in their mouths. This can be fatal for the cichlids’ own offspring if cuckoo catfish eggs are among them. Professor Axel Meyer, an evolutionary biologist from the University of Konstanz, and a team of researchers from the Institute of Vertebrate Biology in Brno (Czech Republic) have carried out research into the evolutionary strategies employed by cuckoo catfish and various types of cichlids that occur in Lake Tanganyika and several other African lakes. Their study paints a fascinating picture of evolutionarily shaped and individually learned defence behaviour as well as the deception efforts employed by both species of fish — and the high price that cichlids pay for keeping the illegitimate offspring of the cuckoo catfish away from their own eggs. The research findings were published in the Science Advances issue published on 2 May 2018.

Lake Tanganyika in Africa is famous for its biodiversity. Many of its 250 endemic species of cichlids are mouthbreeders: To protect their offspring and prevent other fish from devouring it, cichlids carry and breed their eggs in their mouths. For several weeks after hatching and swimming by themselves, the young fish return to their mother’s mouth for protection.

It is this very particular brood care behaviour that the cuckoo catfish, also endemic to Lake Tanganyika, has learned to exploit: When the cichlids spawn, it simply places its own eggs among a cichlid’s clutch of eggs. If this goes unnoticed by the cichlid and if it cannot tell its own eggs apart from those of the catfish, it will carry and breed both its own and the catfish eggs in its mouth. However, the larvae of the cuckoo catfish hatch sooner, devouring the cichlid’s own offspring which the deceived mother cichlid believes to be safe. Often, the cichlid will believe the illegitimate offspring of the catfish to be her own even then, continuing to protect it.

But the cichlids are not entirely defenceless: They have learned to defend themselves against the cunning of the cuckoo catfish. When gathering their eggs into their mouth, they try to identify and exclude the smuggled eggs. Often, however, overcaution will lead them to reject some of their own eggs as well. A high price that the cichlids pay in return for their own “evolutionary fitness,” a price, however, they cannot avoid paying if their offspring is to survive.

“Evolutionary experience”

“Both species of fish have co-evolved for millions of years,” says Axel Meyer about their well-matched relationship of deception and defence. The behaviour of these two species is evidence of what the biologist calls “evolutionary experience”, which he was able to document in his joint study with his colleagues from Brno.

The scientists obtained eggs both from the cuckoo catfish and from the mouthbreeding cichlids that live in Lake Tanganyika and raised them in an aquarium. Then, they compared the captive cichlids’ capacity for distinguishing between their own eggs and those of the cuckoo catfish with that of other types of cichlid from other bodies of water where cuckoo catfish do not occur. The result: The deceptive strategy employed by the cuckoo catfish worked between three and eleven times better on the “evolutionarily naive” cichlids (from other bodies of water). Due to their “evolutionary experience,” the cichlids from Lake Tanganyika, who share an evolutionary history with the cuckoo catfish, were much more successful in identifying and rejecting the parasite’s eggs. By the term “evolutionary experience” the scientists mean natural selection in favour of the ability to discriminate smuggled eggs.

Individual learning works in co-evolved fish, but on “evolutionarily naïve” species

The study also revealed that cichlids lacking “evolutionary experience” are unable to learn to reject the eggs of the cuckoo catfish — in contrast to coevolved cichlids that increase their chances to see through the cuckoo catfish trick. This ability to adapt made the cichlids from Lake Tanganyika much more successful when coping with brood parasites. These findings suggest that is not the combination of “evolutionary experience” with individual experience and the ability to learn that help cichlids discriminate between their own and foreign eggs.

Unique among fish

Several bird species are known to practice brood parasitism, i.e. the smuggling of eggs into another bird’s nest. Among fish, the cuckoo catfish is the only known obligate brood parasite. None of the other 40 catfish species endemic to Lake Tanganyika are known to behave like this.

Great white shark research and conservation


This 2015 video is called Australia. The Great White Shark | Full Documentary.

From the Monterey Bay Aquarium in the USA:

White shark researchers tap data from electronic tags to gain insights into survival rates

May 9, 2018

Summary: Researchers have tagged juvenile white sharks for nearly two decades, tracking their movements in coastal waters of the Northeastern Pacific. Now they’ve tapped those data in a new way, gaining the first empirical estimate of annual survival rates for young white sharks and quantifying the role fishing plays in the rate of white shark deaths.

Tagging in Southern California and Mexico shows most shark deaths are due to unintentional capture in fishing gear, highlighting the value of best practices that support protected species’ recovery. The results are published today in the Journal of Applied Ecology.

Researchers in the United States and Mexico have tagged juvenile white sharks for nearly two decades, tracking their movements in coastal waters of the Northeastern Pacific. Now — drawing on methods used to study mountain lions, coyotes, moose and other terrestrial animals — they’ve tapped those data in a new way, gaining the first empirical estimate of annual survival rates for young white sharks and quantifying the role fishing plays in the rate of white shark deaths.

The study, “Juvenile survival, competing risks, and spatial variation in mortality risk of a marine apex predator,” published today in the Journal of Applied Ecology, confirms that unintentional capture in fishing gear (bycatch) is the greatest cause of death for young white sharks, a protected species in both Mexico and the United States.

More broadly, data from pop-up archival tags (PAT tags) — which have been used worldwide to track tens of thousands of individual ocean animals, including white sharks — represent “a widely-available, untapped data source that could dramatically increase our understanding of marine population ecology,” said lead author Dr. John Benson, an assistant professor at the University of Nebraska.

Benson, who primarily studies terrestrial predators, conducted the white shark study as a postdoctoral researcher at Monterey Bay Aquarium. The aquarium — together with colleagues at California State University, Long Beach; Aquatic Research Consultants in San Pedro, Calif.; and the Ensenada Center for Scientific Research and Higher Education (CICESE) in Baja California — has been tagging and tracking juvenile white sharks since 2002.

Research results at a glance

Data from 37 sharks tagged since 2002 revealed that:

  • The overall estimated annual survival rate for young white sharks was 63 percent. Though this study did not address broad trends in the white shark population in the Northeastern Pacific, the researchers note that protection of white sharks in 1994 has likely resulted in a reduction in fishing-related mortality. The increase in juvenile shark sightings over the last 15 years may be an early indication of a positive sign for population recovery.
  • Fisheries bycatch was the main source of mortality for juvenile white sharks in the region, highlighting the need to follow best practices related to incidental catch in coastal commercial and sport fisheries. Only two young white sharks tagged by researchers died of natural (non-fishing) causes.
  • Overall mortality risk for young white sharks was lower for larger animals, which could be attributed to smaller sharks being more abundant, or simply more susceptible to capture in gillnets.

According to Benson, the paper adds to scientific understanding of white sharks, and shows how models that estimate survival rates for top predators on land — data obtained from radio telemetry and tracking collars — can be applied to ocean species that carry PAT tags.

“We always learn things from adjacent fields,” said Dr. Salvador Jorgensen, principal white shark scientist at the Monterey Bay Aquarium and senior coauthor on the paper. “Before coming to the aquarium, John made his name studying mountain lions in Southern California. We were excited to see how the methodologies John was using for land-based predators could be applied in the ocean.”

Taking a new approach

Benson realized that data from PAT tags opened the door to a new approach to estimate survival rates for young sharks, using what are called known-fate models.

“Because the PAT tags record detailed data on temperature and diving, it is possible to reconstruct the fate of the shark in the final minutes of each track,” said Jorgensen.

The technique hinges on being able to determine the fate of individual animals — data that PAT tags provide. If a tagged shark was eaten by a predator, or if it died in a fishing net, the tag recorded those data.

By applying known-fate models to those data, researchers estimated survival and mortality rates for the population at large. They also determined that fisheries bycatch was the main source of mortality for juvenile white sharks in the Northeastern Pacific, and that juveniles were at significantly greater risk of mortality when in Mexican waters.

Protections are in place

In California, it is illegal to target and land white sharks, and coastal waters are permanently closed to all gillnets within three miles of shore. In Baja California and throughout Mexico, targeting and landing white sharks is prohibited all year. However, gillnet fishing in coastal waters is still permitted for other species. Data from the study show that juvenile white sharks are an estimated nine times less likely to get entangled in California compared with Baja.

“We are learning that the gillnet regulations in California, although originally designed to protect sport fishing interests, have done a lot to protect juvenile white sharks,” said Dr. Chris Lowe, director of the Shark Lab at CSU Long Beach and a coauthor of the paper.

The study also revealed that juvenile white shark mortality in gillnets is reduced when nets are checked by fishermen every 6 to 12 hours, so the young sharks can be released alive.

“In terms of reducing white shark mortality, avoiding setting nets close to shore and checking them frequently appear to be the best practices,” Lowe said.

Coauthor Oscar Sosa-Nishizaki, a professor at CICESE, stressed that engaging with local fishermen in Mexico is critical to reducing mortalities and improving recovery prospects for the Northeastern Pacific white shark population.

“It’s the best way to go,” he said. “Mexican fishing communities play a vital role in enabling this research as well as helping us solve any issues as they arise.”

CICESE doctoral student Emiliano García-Rodríguez, another coauthor, added: “It’s very important to work with the fishermen, because we want to know whenever they incidentally catch a white shark.”

“This research suggests the importance of a collaborative approach to management in California and Mexico, and opportunities to innovate on best practices that can support fishermen, research and protections for white sharks,” Jorgensen said.

Other co-authors on the study include John O’Sullivan, director of collections at Monterey Bay Aquarium; Chuck Winkler of Aquatic Research Consultants; and Connor F. White, white shark researcher with CSU Long Beach.

Additional information about this study and other white shark research is available on the aquarium’s Future of the Ocean blog (futureoftheocean.wordpress.com/).

Five ‘fish’ that aren’t fish


This 2018 video says about itself:

In this short video, underwater cinematographer Jonathan Bird explains what traits make a fish a fish, and 5 top animals often called fish that actually are not fish like the jellyfish, starfish, cuttlefish, crayfish and Swedish Fish!

Counting fish off Massachusetts, USA


This video from the USA says about itself:

Jonathan joins a group of volunteer divers as part of an international event called the Great Annual Fish Count to take a census of marine life across the globe. His mission: dive the chilly waters of Massachusetts with a pencil…and count fish!

JONATHAN BIRD‘S BLUE WORLD is an Emmy Award-winning underwater science/adventure program.