A team of scientists, led by the Institute for Ocean Conservation Science at Stony Brook University, used video cameras to count Caribbean reef sharks (Carcharhinus perezi) inside and outside marine reserves on the Mesoamerican Barrier Reef in the Caribbean Sea. Using survey data collected from 200 baited remote underwater video (BRUV) cameras, nicknamed "chum cams," the scientists compared the relative abundance of these reef sharks in two marine reserves with those in two areas where fishing is allowed, and demonstrated that the sharks were more abundant in the reserves.

The research findings appear in the paper, "Reef sharks exhibit site-fidelity and higher relative abundance in marine reserves on the Mesoamerican Barrier Reef," published online March 8 in the journal PLoS ONE. The purpose of the study, conducted from 2005 through 2010, was to test the hypothesis that carcharhinid shark species, which include requiem and whaler sharks, are more abundant inside no-take marine reserves where fishing for sharks and their prey is prohibited. The authors tested the hypothesis by using BRUV surveys to determine the reef sharks' numbers, and combined these results with acoustic monitoring to measure their site fidelity (remaining within the same local area) in Glover's Reef Marine Reserve, Caye Caulker Marine Reserve, and two reefs where fishing is allowed, all located in Belize.

"Although we know that relatively sedentary reef fish and lobsters benefit from marine reserves, this study now presents visual proof that large, active sharks are also dramatically more abundant inside these protected areas too," said Mark Bond, lead author and doctoral student at Stony Brook University. "Nearly four times as many chum cam deployments in the marine reserves recorded reef sharks than on similar fished reefs. These areas provide the sharks and other coral reef species a respite from fishing, which means decreased fishing mortality for the sharks and more prey for them to eat."

The video cameras were enclosed in protective housing, and placed on the sea floor with small bait-filled cages positioned in front of them. Sharks, attracted by the smell of the bait, swam to the cameras, which allowed the research team to record, count, and compare shark populations in the marine reserves to those in the areas where fishing is permitted, at no stress to the sharks. In addition to the BRUV surveys, the scientists fitted 34 reef sharks with acoustic transmitters, and tracked their movements, using moored underwater listening stations. They found that the sharks, both juveniles and adults, live year-round within the reserves.

"Scientists who study tigers or jaguars in the wild use camera traps to count them," said Dr. Demian Chapman, assistant professor in the School of Marine & Atmospheric Science at Stony Brook, leader of the research team and assistant director of science of the Institute for Ocean Conservation Science. "It is just as difficult to count sharks in the ocean, so we took a page from the big cat researchers' playbook and deployed baited video cameras to count the sharks. It's only fitting since these large apex predators are the 'big cats' of the sea, and like their feline counterparts, their continued existence on Earth is threatened."

Due to intense fishing, Caribbean reef sharks are listed as "Near Threatened" by the International Union for the Conservation of Nature (IUCN) but it is possible they will be upgraded to "Vulnerable" by IUCN as more data are collected. They live in the western Atlantic Ocean, ranging from Bermuda to southern Brazil, and are the only Atlantic requiem shark species that undergoes its entire life cycles within coral reef ecosystems.

"Caribbean reef sharks and other shark species around the world are threatened by overfishing," said Dr. Ellen K. Pikitch, a professor in the Stony Brook University School of Marine and Atmospheric Sciences, who co-authored the paper and is executive director of the Institute for Ocean Conservation Science. "Our study demonstrates that marine reserves can help protect shark species that live on coral reefs. Moreover, the use of underwater video monitoring provides us with an excellent tool to determine if populations are recovering and thriving inside these reserves."

"As the saying goes, a picture is worth a thousand words," said Bond. "As Caribbean nations and other countries consider developing marine reserves, chum cams can virtually transport policy makers and the public beneath the waves and show them the benefits of these protected areas."

Text and Photo by Stony Brook University

Probing the largely unexplored question of what characteristics make a leader among schooling fish, researchers have discovered that by mimicking nature, a robotic fish can transform into a leader of live ones.

Through a series of experiments, researchers from Polytechnic Institute of New York University (NYU-Poly) aimed to increase understanding of collective animal behavior, including learning how robots might someday steer fish away from environmental disasters. Nature is a growing source of inspiration for engineers, and the researchers were intrigued to find that their biomimetic robotic fish could not only infiltrate and be accepted by the swimmers, but actually assume a leadership role.

In a paper published online in the Journal of the Royal Society Interface, Stefano Marras, at the time a postdoctoral fellow in mechanical engineering at NYU-Poly and currently a researcher at Italy's Institute for the Marine and Coastal Environment-National Research Council, and Maurizio Porfiri, NYU-Poly associate professor of mechanical engineering, found conditions that induced golden shiners to follow in the wake of the biomimetic robot fish, taking advantage of the energy savings generated by the robot.

The researchers designed their bio-inspired robotic fish to mimic the tail propulsion of a swimming fish, and conducted experiments at varying tail beat frequencies and flow speeds. In nature, fish positioned at the front of a school beat their tails with greater frequency, creating a wake in which their followers gather. The followers display a notably slower frequency of tail movement, leading researchers to believe that the followers are enjoying a hydrodynamic advantage from the leaders' efforts.

In an attempt to create a robotic leader, Marras and Porfiri placed their robot in a water tunnel with a golden shiner school. First, they allowed the robot to remain still, and unsurprisingly, the "dummy" fish attracted little attention. When the robot simulated the familiar tail movement of a leader fish, however, members of the school assumed the behavior patterns they exhibit in the wild, slowing their tails and following the robotic leader.

"These experiments may open up new channels for us to explore the possibilities for robotic interactions with live animals -- an area that is largely untapped," explained Porfiri. "By looking to nature to guide our design, and creating robots that tap into animals' natural cues, we may be able to influence collective animal behavior to aid environmental conservation and disaster recovery efforts."

The researchers posit that robotic leaders could help lead fish and other wildlife that behave collectively -- including birds -- away from toxic situations such as oil or chemical spills or human-made dangers such as dams. Other experimenters have found success in prompting wildlife to move using non-living attractants, but the researchers believe this is the first time that anyone has used biomimetics to such effect.

Text and Photo by Polytechnic Institute of New York University

Forming a unique part of the animal kingdom, corals have built the only living entity visible from space; the Great Barrier Reef. Scientists from the Australian Institute of Marine Science (AIMS) have recently discovered a previously unknown reproductive strategy in corals, adding another dimension to our understanding of their complex life cycles.

A study published in the journal Science shows for the first time that coral offspring have the unique ability to form genetic clones of themselves before they settle and develop into adult corals.

Coral 'offspring' are usually the result of sexual reproduction -- eggs are fertilized either before or after being released by the parent coral into the surrounding water. These fertilized eggs are carried by ocean currents before settling at new locations.

Coral "clones," on the other hand, are genetic replicas of the parent coral. For example, if waves generated in a storm break up a coral colony, the remnant parts may continue to survive as independent but genetically identical individuals; a faculty that most animals do not possess.

Dr Andrew Heyward and Dr Andrew Negri suspected that fertilized coral eggs (embryos) might also break up because, unlike most animal embryos, coral embryos lack a protective outer-layer or membrane; they are so called 'naked' embryos.

"As the early stage embryo develops it divides into a cluster of cells," explains Dr Heyward, "because this ball of cells lacks a protective outer-layer we wondered whether subjecting them to a little turbulence might cause them break up,"

It did, but what happened next was even more astonishing.

"To our surprise many of the fragmented coral embryos later began to develop and settle in just the same way as their siblings that had remained intact," continues Dr Heyward. "Interestingly, these fragmented embryos became smaller versions of baby corals than the complete embryos." The scientists were able to create these turbulent conditions in the laboratory simply by pouring embryos floating in seawater over a vertical distance of 30 cm.

"This effectively mimics the kind of wave height generated by moderate wind speeds where small breaking waves, commonly called whitecaps, occur. That sort of weather is often encountered during a night of coral spawning on the Great Barrier Reef," says Dr Negri. "So it's highly likely that this fragmentation occurs regularly on nights when corals release their eggs.

"It appears that the lack of protective membrane is no accident. Almost half of all these naked embryos fragmented in our experiments, suggesting that this has long been part of the corals' repertoire for maximizing the impact of their reproductive efforts."

Dr Heyward explains why discovery of this novel reproductive strategy is so significant. "This mixed breeding system means colonizing corals benefit simultaneously from the advantages of both sexual and asexual reproduction.

"Much like humans, it's important that the offspring of corals have genetically distinct parents, but these embryos also readily clone to form multiple versions of themselves, and helps to explain how coral maximize their chances of finding a suitable habitat in which to settle and survive.

In human terms this is the equivalent of giving birth to identical twins, triplets, quadruplets and so on.

"This is another example of the complexity of these incredible animals and suggests that there may be more to learn about the lives of corals and their interaction with the environment."

Text by Australian Institute of Marine Science Photo by Andrew Heyward and Andrew Negri

More than 99 percent of Antarctic blue whales were killed by commercial whalers during the 20th century, but the first circumpolar genetic study of these critically endangered whales has found a surprisingly high level of diversity among the surviving population of some 2,200 individuals.

That, says lead author Angela Sremba of Oregon State University, may bode well for their future recovery.

Results of the study have just been published in the open-access journal, PLoS ONE. As part of the study, the researchers examined 218 biopsy samples collected from living Antarctic blue whales throughout the Southern Ocean from 1990 to 2009, through a project coordinated by the International Whaling Commission.

The genetic survey revealed a "surprisingly high" level of diversity that may help the population slowly rebound from its catastrophic decimation by whalers.

"Fewer than 400 Antarctic blue whales were thought to have survived when this population was protected from commercial hunting in 1966," noted Sremba, who conducted the research as part of her master's degree with the Marine Mammal Institute at OSU's Hatfield Marine Science Center. "But the exploitation period, though intense, was brief in terms of years, so the whales' long lifespans and overlapping generations may have helped retain the diversity."

"In fact," she added, "some of the Antarctic blue whales that survived the genetic bottleneck may still be alive today."

Prior to whaling Antarctic blue whales were thought to number about 250,000 individuals -- a total that dwindled to fewer than 400 animals by 1972 when blue whales were last killed by illegal Soviet whaling. Blue whales are thought to be the largest animals ever to have lived on Earth, said OSU's Scott Baker, associate director of the Marine Mammal Institute and an author on the study -- and the Antarctic blue whales were even larger than their cousins in other oceans.

"These animals are very long-lived -- maybe 70 to 100 years -- and they can grow to a length of more than 100 feet and weigh more than 330,000 pounds," he said. "There is a jawbone in a museum in South Africa that takes up most of the lobby. This is one reason they were so intensively exploited; they were the most valuable whales to hunt."

Despite their history of exploitation, little is known about modern-day movements of Antarctic blue whales, which are considered a separate subspecies -- differing in size and habitat use -- from the smaller "pygmy" blue whales, which live in more temperate regions of the Southern Hemisphere.

Through "microsatellite genotyping," or DNA fingerprinting, the PLoS ONE study was able to track some of the movements of individual Antarctic blue whales.

"We documented one female that traveled from one side of Antarctica to the other -- a minimum distance of more than 6,650 kilometers over a period of four years," said Sremba, who is now continuing her studies as a Ph.D. student in the Department of Fisheries and Wildlife at OSU. "It is the first documentation of individual movements by Antarctic blue whales since the end of the commercial whaling era."

Baker said the long distance movement of a few individuals was "somewhat surprising" in comparison to the evidence for genetic differences between areas of the Southern Ocean. On one hand, it is apparent that individual Antarctic blue whales are capable of traveling enormous distances in search of food.

"On the other hand," Baker said, "there seems to be some fidelity to the same feeding grounds as a result of a calf's early experience with its mother. This 'maternally directed' fidelity to migratory destinations seems to be widespread among great whales."

There is much, however, which scientists still don't know about Antarctic blue whales, Baker pointed out.

"This is a poorly understood species of whales, despite its history of exploitation," Baker said. "Only now are we developing the technology to study such a small number of whales spread across such a vast habitat."

The biopsy samples were collected during more than two decades of research cruises supervised by the International Whaling Commission, and with international scientists joining research vessels from the Japanese Ministry of Fisheries.

Now that their population is slowly recovering, future studies may focus on Antarctic blue whales' migration patterns, and the locations of their breeding and calving grounds.

Text by Oregon State University Photo by Paul Ensor

Scientists conducting deep-sea research in the Galapagos have described a new species of catshark, Bythaelurus giddingsi, in the March 5 issue of the journal Zootaxa. The new shark is approximately a foot long and has a chocolate-brown coloration with pale, irregularly distributed spots on its body. The spotted patterns appear to be unique to each individual. John McCosker of the California Academy of Sciences collected the first specimens of this new catshark while diving to depths of 1,400 -- 1,900 feet aboard the Johnson Sea-Link submersible.

"The discovery of a new shark species is always interesting, particularly at this time when sharks are facing such incredible human pressure," said McCosker, Chair of Aquatic Biology at the Academy and lead author on the paper. "Many species have become locally rare and others verge on extinction due to their capture for shark-fin soup. The damage to food webs is dramatic, since sharks provide valuable ecological services as top-level predators -- when they disappear, their niche is often filled by other species that further imbalance ecosystems. Most deepwater shark species are not very susceptible to overfishing; however, since this catshark's range is restricted to the Galapagos, its population is likely limited in size, making it more susceptible than more widely distributed species."

The California Academy of Sciences sent its first scientific expedition to the Galapagos Islands in 1905 and has since organized dozens of return trips. As a result, the Academy is now home to the world's most comprehensive collection of scientific specimens from these famous islands. Most Academy field work in the Galapagos today focuses on the marine environment, where dozens of new species have been discovered in recent decades. In the 1990s, McCosker made a series of dives inside the submersible Johnson Sea-Link to explore the marine life on the islands' steep volcanic slopes and sandy bottoms. Submersibles allow scientists to explore a vast part of the Galapagos that was not accessible to Charles Darwin or earlier Academy scientists. It was during two such dives in 1995 and 1998 that McCosker collected the seven specimens used to describe B. giddingsi. Using research collections at the Academy and elsewhere as a basis for comparison, Academy Research Associate Douglas Long and Smithsonian Institution scientist Carole Baldwin worked with McCosker to confirm that the specimens did indeed represent a new species.

Text and Photo by California Academy of Sciences