Captive Shark Ray Gives Birth to Septuplets
Sept. 5, 2012
-- Five rays and sharks are receiving priority attention at this week's IUCN World Conservation Congress held in Jeju, Republic of Korea. The congress is the world's largest conservation event. One of the five sharks is the porbeagle, shown here. Porbeagles are vulnerable globally, and are classified as critically endangered in the Northeast Atlantic. Their low reproductive capacity combined with over-fishing has led to severe population declines over several parts of its range. "Sharks and rays have traveled the Earth for more than 400 million years," said Dr. Cristián Samper, president and CEO of the Wildlife Conservation Society and keynote speaker at the Jeju congress. "Yet, in only recent decades, many of these species have become threatened from overfishing and, in some instances, have disappeared entirely from major portions of their range." He added, "The potential loss of one of only two groups of the world's living fishes is a crisis the world community must take decisive action to address. We are calling for governments around the world to vigorously support CITES international trade regulations and strengthen fisheries management and protection measures for shark and ray species. We cannot continue to allow the destruction of these wonders of evolution."
Manta Rays Fate Worse Than Sharks
The oceanic whitetip shark is critically endangered in the Northwest and Central Atlantic Ocean. It's frequently sought after for its fins, used to make shark fin soup. Usually the rest of the dead or dying shark is then tossed back into the sea. Andrew Brierley, a University of St. Andrews marine ecologist, told Discovery News that when sharks like this die off, the deaths can cause a domino effect of other ecosystem losses. Shellfish, for example, may go into decline because they are consumed more by predators that the sharks would normally prey upon. "The trophic cascade brought about by the increasing demand for shark fin soup has not only left once economically valuable bivalve fisheries in crisis, but has precipitated an ecological and culinary bankruptcy," explained Brierley.
Scalloped hammerhead sharks are endangered all around the globe. This tropical species forms large migratory schools at certain times of the year. The aggregating behavior, distinct from that of other sharks, makes the shark particularly vulnerable to fishing. "We estimate that many millions of sharks are killed annually through both legal and illegal, unregulated and unreported fishing for the trade in fins, the prime ingredient in shark fin soup," said Dr. Rachel Graham, director of WCS's Gulf and Caribbean Sharks and Rays Program. "The high price for fins has caused the global shark fishery to expand far beyond what is sustainable. The need for international regulation and enforcement has never been greater."
Shark Paradise Found
Many rays, such as these, are also in peril. The Wildlife Conservation Society and over 35 government agencies and NGO partners at the congress additionally highlighted population loss problems associated with so-called "devil rays," which feed on planktonic crustaceans. Small schooling fishes become trapped on their specialized gill rakers. Rays are frequently captured in target fisheries and as bycatch across much of their range. One reason is that the gill rakers are dried and exported for the Asian medicinal market.
Dr. Dwayne Meadows, NOAA/NMFS/OPR
The reef manta ray, shown here, is among the world's largest fishes. Both it and the giant manta ray can grow several feet across. They are slow growing, however, typically giving birth to only one pup every two to three years. They are migratory and occur in small, highly fragmented populations that are sparsely distributed across the world’s tropics. Manta rays are captured in targeted fisheries and incidentally as bycatch. In addition, manta rays are used for human consumption, shark bait, and -- as for devil rays -- are increasingly sought for their gill rakers. "The international trade in shark and ray products, including fins, meat, and other body parts, is driving shark and ray fisheries around the world, and most of these are unmanaged or only minimally managed," said Dr. John Robinson, WCS's executive vice president for Conservation and Science. "Lack of controls on fisheries and international trade puts species at risk, but also jeopardizes sustainable fisheries, ecosystems, and food security." The Convention on International Trade in Endangered Species of Wild Fauna and Flora will meet in Thailand in March 2013.
PHOTOS:Shark Teeth Weapons Reveal Surprises
One of the pups, a little female, did not survive, but the rest did. “Sweet Pea” — the shark ray mom — now has three female pups and three males. One can only imagine that Sweet Pea is relieved … and tired. The birthing process took an arduous five hours.
At birth, the pups’ weight ranged from 2.1 to 2.4 pounds. The longest was 1 foot, 7.3 inches, and the shortest was 1 foot, 6.4 inches.
Shark rays aren’t exactly welcoming of human nursing. Staff at the aquarium had therefore moved the pregnant Sweet Pea to an offsite facility in Northern Kentucky, where she was remotely monitored using three high-definition surveillance cameras.
General Curator Mark Dvornak first noticed the pups at around 5:20 a.m. while checking the live video feed on his tablet at home, according to the press release. He sent an alert out to the rest of the husbandry staff, and by 5:35 a.m. biologists were on site monitoring the six newborn pups.
“Seeing the live video feed of the small pups swimming around was a bit surreal this morning,” Dvornak said in a press release. “Racing into work, I felt a bit of trepidation too as I realized our seven-year dream of successfully breeding these wondrous creatures had become reality.”
Shark rays, also known as bowmouth guitarfish, are an endangered species that’s closely related to sharks as well as to skates. Their body resembles that of a shark while their head is more ray-like. They are native to the Indo-Pacific region, where they spend most of their days feeding on crabs and other shellfish near the coast and offshore reefs in tropical waters.
Sweet Pea and her pups, however, are part of Newport Aquarium’s Shark Ray Breeding Program, which now has 10 shark rays in total — the most in the world for one institution.
It sounds like the dad is either Spike or Scooter, two males at the aquarium. Spike just arrived last year and might be the one that resulted in the birth spike!
The births come on the heels of distressing recent reports about shark and ray populations. The International Union for Conservation of Nature (IUCN), for example, estimates that 25 percent of all shark and ray species are at risk of becoming extinct. In the wild, threats to them include habitat destruction, pollution, overfishing and the use of their fins for soup.
“It’s cool that Sweet Pea gave birth the same week as the IUCN reports,” said animal health specialist Jolene Hanna, who has been studying hormones in the shark rays. “It shows the world that Newport Aquarium can successfully breed shark rays and help this species.”
Sweet Pea and her new newborn pups will go on exhibit at Newport Aquarium on separate to-be-determined dates.
Photo: Justin Cain, Newport Aquarium