Also known as the Elephant Shark, Makrepe and the plownose chimaera, the Australian ghost shark is a species of chimaera ( a type of cartilaginous fish) found off of Southern Australia and parts of New Zealand. As its common name suggests the elephant shark has a long snout which resembles a trunk or a plow, this snout is used as a probe to aid the chimaera in finding small invertebrates and fish that are hidden in the sediment. Recently, the elephant shark genome has been proposed to be sequenced as a model species for the cartilaginous fish, as it has a small genome size and could help understand the evolution of early vertebrates.
Shark embryos cannibalize their littermates in the womb, with the largest embryo eating all but one of its siblings.
Now, researchers know why: It’s part of a struggle for paternity in utero, where babies of different fathers compete to be born.
The researchers, who detailed their findings today (April 30) in the journal Biology Letters, analyzed shark embryos found in sand tiger sharks (Carcharias taurus) at various stages of gestation and found that the later in pregnancy, the more likely the remaining shark embryos had just one father…
Over the course of nearly three years, researchers from Australia observed 39 mostly female gray reef sharks (Carcharhinus amblyrhynchos) living near coral reefs in Palau, Micronesia, east of the Philippines.
In the winter, the sharks stayed closer to the surface, at an average depth of 115 ft (35 m), where water was consistently warmer, the team found. Meanwhile, the sharks plunged deeper when seasonal temperatures started rising in the spring, averaging depths of 200 ft (60 m).
The sharks also changed their behavior in sync with the lunar cycle, diving deeper during the full moon but sticking to the shallows with the new moon. Previous tagging studies showed that other open-water predators — including swordfish, yellowfin and big eye tuna — also go to greater depths as the lunar cycle progresses. This suggests the moon’s brightness might sway the movements of many big fish…
Help Save the World’s Best Marine Reserve: Cabo Pulmo
Established in 1995, Mexico’s Cabo Pulmo Marine National Park is slightly more than 7,000 hectares of coastal waters in the Gulf of California, offshore from the small village of Cabo Pulmo. The park’s establishment followed a period of determined lobbying by the village’s 100 or so residents, who had become alarmed at overfishing and declines in the area’s marine life. The reserve is no more than 5 kilometers (3 miles) wide and measures just 14 kilometers (almost 9 miles) north to south. And yet its impact on the marine life within it, such as these Devil Rays, has been profound – so much so that researchers have dubbed it “the most successful marine reserve in the world.”…
You can help save one of the oldest living coral reefs in the world with a click of your mouse: http://bit.ly/178KBhG
For 20,000 years, the reef of Cabo Pulmo has provided sanctuary for whale sharks, Pacific manta rays, humpback whales, dolphins and sea turtles, but today this marine reserve and the thriving sea that surrounds it is still under threat from overdevelopment.
Urge North America’s environmental authorities to support strong enforcement and protect the coral reef. Send your message!
By Matt Jenkins, Nature Conservancy magazine Senior Editor
Twenty four hours after touching down on Palmyra Atoll— a profoundly remote spot 1,000 miles south of Hawaii, where the skies are rarely marred by even the contrail of a passing airliner — photographer Tim Calver and I were aboard the research boat Zenobia. That morning, a team of researchers had been catching Gray Reef Sharks and implanting tracking tags in them; now it was time for lunch. As Kydd Pollock steered the boat back to the research station, something in the distance caught his eye — a frothy eruption on the ocean’s surface, with a scrum of seabirds wheeling overhead…
…is a species of rough shark found throughout the eastern Atlantic, from Norway all the way down to South Africa. Unlike other rough sharks this species has ridges over its eyes, these ridges extend to knobs which are covered with scales. Angular roughsharks are usually found on muddy or algal bottoms of continental shelves where they feed on invertebrates like molluscs and arthropods.
Great White Sharks Gorge Together on Dead Whale Blubber
by Becky Oskin
Great white sharks feast together on dead whales, which are important food resources for the normally solitary predators, a new study finds.
Drawn by wind-blown slicks of chemicals from decomposing flesh, great white sharks measuring up to 16 feet (5 meters) long gathered at floating carcasses near South Africa’s Seal Island, gorging on blubber, researchers found during observing trips in 2000-2010. These giant sharks rarely appear near the coast but may cruise nearby, waiting to pounce on dead or dying whales, the researchers said.
“These massive sharks come in pretty quickly — within less than 24 hours,” of a dead whale’s arrival, said study co-author Neil Hammerschlag, a marine ecologist at the University of Miami. “We hypothesize these animals are cruising the coastline to take advantage of these types of situations.”…
A whale shark (Rhincodon typus) opens its huge mouth as fish hitch a ride on its back in Azores, Portugal. As you probably already know, the whale shark is the largest species of “fish” currently in existence.
Gray reef sharks (Carcharhinus amblyrhynchos) are known for being active at night. They are considered Near Threatened by the IUCN Red List due to fishing and the loss of their coral reef habitat. The sinister animal, with its sleek body, can be quite aggressive when directly threatened.
Want to travel the oceans alongside great white sharks, but your busy schedule and fear of death always seem to get in the way? There’s an app for that.
Now anyone with an iPhone or an iPad (and $3.99 to spare) can follow along in near-real time with a dozen of the world’s most iconic predators with the app Expedition White Shark.
“We’re hoping it raises public awareness about white sharks, which helps our conservation efforts,” said marine biologist Michael Domeier, the man behind the app and president of the Marine Conservation Science Institute, a small, California-based nonprofit research organization.
Domeier has studied great white sharks for many years, and was one of the first people to ever outfit adult great white sharks with satellite tracking tags — the key to the new app. His adventures were chronicled on the National Geographic Channel program “Shark Men.”…
Great White Sharks Eat Far More Than Previously Thought
Great white sharks, the world’s largest predatory fish, eat three to four times more food than previously thought, an Australian study shows.
U.S. research from the 1980s estimated a 30-kilogram, or 66-pound meal of mammal blubber could sustain a one-ton shark for more than six weeks. That perpetuated assumptions that large sharks could survive long periods without eating.
However, a University of Tasmania-led study published this week in Scientific Reports on the nature.com website found that 30 kilos was only enough for 12-15 days. Researchers tagged a dozen great white sharks at Neptune Islands off South Australia and calculated their metabolic rate derived from swimming speeds.
They worked out how much energy the sharks burned and how much food they required. Senior research scientist Jayson Semmens, lead author on the study, said the amount of energy required by great white sharks was equivalent to eating a seal pup every three days…
In counter-illumination, the lanternsharks, like many deep-sea animals, light up their undersides in order to disguise their silhouette when seen from below. Brighter bellies blend in with the light filtering down from the surface.
Fishing the 2-ft-long (60-cm-long) lanternsharks up from Norwegian fjords and placing them in darkened aquarium tanks, the researchers noticed that not only do the sharks’ bellies glow, but they also had glowing regions on their backs…
CITES Ruling on Shark Protection - What Does it Mean?
Shark Trade to be Regulated to Curb Overfishing
by Megan Gannon
Conservationists voted today (March 11) to regulate the international trade of five species of sharks that are threatened by overfishing and targeted for their valuable fins.
Oceanic whitetip sharks, porbeagle sharks, scalloped hammerheads, great hammerheads, and smooth hammerheads — as well as two species of manta rays — are all set to get new protections after today’s votes at the meeting of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in Bangkok.
If the proposals are upheld at a plenary session later this week, all seven animals will be listed under Appendix II of the CITES Treaty, which includes species that may become threatened with extinction if they are traded unsustainably. So far, basking sharks and great white sharks are the only species of elasmobranch (a family that includes sharks, rays, and skates) listed on Appendix II…