Last fall, Science Today’s Barbara Tannenbaum caught up with Dave Ebert and his grad student, Paul Clerkin, as they brought deep-sea shark specimens from the Indian Ocean to their new home in the Ichthyology collection here at the Academy.

Tannebaum’s article, “Fantastic Voyage,” captured their work expanding the Academy’s collections, and Ebert, an Academy research associate and director of the Pacific Shark Research Center in Moss Landing, has been tirelessly working ever since. We caught up with him by phone this week to hear the latest.

Earlier this year, Ebert traveled to Mauritius, east of Madagascar, searching for new and unknown shark species in the Indian Ocean. Ebert also attended a workshop put on by the Food and Agriculture Organization of the United Nations, or FAO.

“We’re working on an identification catalog for sharks in that area to understand what’s being caught there,” Ebert explains.

In May, Ebert was part of a research cruise off of New Zealand, seeking more undiscovered sharks. His work was captured on film by the BBC for a segment that will air in early 2015. They hope to film him more on other expeditions in the coming year, too. “They’re doing something a little different,” Ebert says. “Kind of a day in the life of a researcher. They send us to a couple of different places to do some field surveys that will likely result in finding new or lesser known species.”

Ebert is pleased with the upcoming documentary because he’s hoping it will bring public awareness to little known shark species. “Everyone knows the white sharks and hammerheads, the charismatic species. These high profile sharks get a lot of attention and protection. But there are a lot of other species out there that for whatever reason are not known. Some of these have much higher conservation needs.”

He mentions the honeycomb cat shark (Holohalaelurus favus) off east Africa. The species was very abundant in the 1950s and 1960s, but hasn’t been seen for 40 years. “The shark didn’t even have a formal scientific name until 2006,” Ebert says. “We should know more about sharks like these and look out for them in fishery by-catch.”

When Ebert isn’t traveling, he works tirelessly on naming and describing these unknown and recently discovered shark species. The sharks he and Clerkin discovered were shipped here to the Academy for further examination. They will also find a permanent residence in our collections. “Several specimens just arrived from Taiwan and several more are due from South Africa this week,” he says.

Speaking of South Africa, Ebert will be a keynote speaker at next year’s Sharks International Conference in Durban, South Africa. The event occurs once every four years, and Ebert will be presenting on the biodiversity and conservation of sharks and rays, mostly African species.

And for true shark fans out there, Ebert is lead author on a new guidebook, Sharks of the World, due out next week.

Ebert is a busy scientist with much work ahead in discovering, describing and protecting sharks. Stay tuned for more updates on his important work.

Perhaps the most important message the Discovery Channel’s Shark Week can deliver is not how sharks may be dangerous, but how these fantastic fish are in danger.

While it’s hard to estimate the total number of sharks killed each year by humans, due to the illegal and unregulated nature of practices like shark finning, some studies put the number at around 100 million per year, says Shark Stewards’ founder David McGuire. The World Wildlife Fund reports that this number is also growing at about 5% each year.

McGuire, also an Academy research associate and a lecturer at the University of San Francisco, calls himself a “conservationist with science training” who hopes to spend the rest of his life protecting sharks.

He earned his shark chops here at the Academy, working with, and learning from, the amazing John McCosker, who has spent his life swimming with fewer and fewer sharks.

McGuire began telling his shark tales with a documentary in 2006 called “Shark Stewards of the Reef,” documenting the connection between sharks and coral reefs and highlighting the important role these top predators play in supporting the health of coral reefs.

A few years later, he was on the front lines of the shark fin ban here in California, which was successfully passed into law in 2011.

As McGuire has watched more states join the ban and other organizations get involved here in the United States, he’s moved his sights to Asia, to create more awareness about the plight of sharks worldwide. He’s working with eco-tourism and ecosystem restoration organizations, as well as focusing on educating a public that might consume sharks and shark fins without truly understanding the consequences to the health of the fish and the oceans in general.

After returning from a three-week trip to Cambodia, Malaysia, and Hong Kong, McGuire stopped by the Academy this week to give us an update on his work. “The idea is to bridge American relationships and resources to small grassroots organizations in Asia, as well as bring the message of shark conservation in a good way, not pointing fingers. We want people to have the information to make better decisions,” he explains.

Shark Stewards recently joined the Earth Island Institute in order to further its cause. McGuire is working on ads and videos providing solutions to the overhunting of sharks and recently organized two “Swim for Sharks” awareness events—3.5 mile swims here in San Francisco and also in Hong Kong, the center of the shark fin trade.

McGuire won’t stop in the fight for shark conservation. “It’s daunting,” he says of the work ahead in Asia, “but it’s also exciting.”

Follow McGuire’s work on his blog.

Image: David McGuire

Remoras could be classified as freeloaders, having evolved sucker discs on the top of their heads, which they use to attach themselves to their hosts. They hitch a ride on sharks or other large marine animals (rays, whales, turtles), even though they are fine swimmers on their own. They also eat the leftovers or possibly the feces of their host animal. Living on a large animal also protects remoras from predators.

Remoras cause no damage to their shark host, who don’t get much back from remoras, unless sharks find amusement in their oddly upside-down disc-shaped heads. Remarkably, these suckers evolved over time from the fishes’ dorsal fins.

Two recent studies, looking at a fossil remora and remora larvae, have determined how these fins develop over time into a strong sucking device.

The first study, led by Oxford University’s Matt Friedman, examined a 30 million year-old early remora fossil with a fully functioning sucker on its back.

“The remora sucker is a truly amazing anatomical specialization but, strange as it may seem, it evolved from a spiny fin,” Friedman says. “In this fossil the fin is clearly modified as a disc but is found on the back of the fish. It enables us to say that first fin spines on the back broadened to form wide segments of a suction disc. After the disc evolved, it migrated to the skull, and it was there that individual segments became divided in two, the number of segments increased, and a row of spines were developed on the back of individual segments.”

The second study looked at the development of remora from the earliest larval stages and compared it to the larval development of white perch, fish that have typical dorsal fins.

The research team found that up to a certain stage in the fish’s development, the dorsal fin develops in the same way and looks very similar in both fishes. Then, through a series of small changes, the remora’s dorsal fin begins to expand and shift toward the head. By the time the remora has reached about 30 millimeters (1.18 inches) in length, the dorsal fin has become a fully-formed two-millimeter sucking disc. It still has the components found in the dorsal fin—the tiny fin spines, spine bases and supporting bones—but the spine bases have greatly expanded.

The study confirms that the specialized sucking disc is formed by a massive expansion of the dorsal fin through small changes while the fish is developing. This completely new structure is homologous to other fish with dorsal fins and is not an evolutionary offshoot.

Fins turning into suckers? It sounds like a super-power! Well done, remoras.

Image: Dave Johnson, Smithsonian Institution

Studies of bears and sea lions have enabled us to understand how these mammals reserve energy in the form of fat and blubber, sustaining them through winter or allowing them to travel great distances. And they aren’t alone in facing such physical challenges. Great white sharks also need a way to store energy during their long migrations, but until recently, their specific mechanism was unknown. (Maybe no one wanted to get too close to them…)

Great white sharks migrate between foraging and reproductive areas, traveling over 2,500 miles annually. While they are not known to be picky eaters, there is little food available far out in the Pacific Ocean.

Researchers at Stanford University and the Monterey Bay Aquarium studied how great whites could accomplish such a journey while fasting. But again, because great whites are, shall we say, just a wee bit dangerous, scientists needed to find ways to study the sharks’ lives without risking their own.

“The most difficult thing about this research was finding a way to bring all of the different sources of data together into a coherent and robust story,” said Gen Del Raye, a Stanford undergraduate who initiated the project. He knew that if they succeeded, they might shed light on storage strategies for other ocean mammals.

First the team studied a (well-fed) great white shark living at the Monterey Bay Aquarium. Over time the shark gained mass (but still maintained its flattering, streamline figure) and simultaneously increased in buoyancy.

Next the researchers pulled data from shark archival tags. Shark location information is time-stamped, enabling researchers to focus on one specific behavior, “drift-diving.” Huge marine animals sometimes act like hang gliders—they relax their fins while currents and momentum carry them forward. Drift-diving data provided the final clue to the research team: they established that migrating sharks lost buoyancy over time.

By measuring the rate at which sharks sink during drift dives, the researchers were able to estimate the amount of oil in the animals’ livers, which accounts for up to a quarter of their body weight. Sharks store oil before migration (making them float) then gradually use that energy throughout their journey (making them sink).

“Sharks face an interesting dilemma,” said Sal Jorgensen, a research scientist at the Monterey Bay Aquarium. “They carry a huge store of energy in the form of oil in their massive livers, but they also depend on that volume of oil for buoyancy. So, if they draw on those reserves, they become heavier and heavier.”

The new research paper might not only be used to help solve mysteries about other marine animals, but can also be used to assist conservation efforts around coastal feeding grounds.

“We have a glimpse now of how white sharks come in from nutrient-poor areas offshore, feed where elephant seal populations are expanding—much like going to an Outback Steakhouse—and store the energy in their livers so they can move offshore again,” said researcher Barbara Block, a professor of marine sciences and a senior fellow at the Stanford Woods Institute for the Environment. “It helps us understand how important their near-shore habitats are as fueling stations for their entire life history.”

Alyssa Keimach is an astronomy and astrophysics student at the University of Michigan and interns for the Morrison Planetarium.

Image: Pterantula (Terry Goss)/Wikipedia

Is it just Shark Week, or did thresher sharks get smarter?

Divers off the coast of Cebu, an island in the Philippines, called Simon Oliver when they noticed sharks exhibiting some strange behavior.

Oliver, an expert on these sharks since he began studying them in 2005, dropped everything to see what all the fuss was about. Apparently they were using their tails to hunt—strange behavior because it was thought that only smart mammals like dolphins and whales practiced tactical use of the tail fin.

Equipped with underwater camera equipment, the Thresher Shark Research and Conservation Project set out to film the new shark activity. They captured footage of 25 hunting events, then went back to the lab to analyze the videos.

The researchers found that the sharks hunt schooling sardines using a four-step procedure. This way, instead of collecting just one fish in their mouth per hunting event, they first stun the fish to eat an average of 3.5 sardines.

Thresher sharks’ tails comprise about 50% of their total length, which is particularly impressive for the 20-foot, 1,000-pound individuals. A sardine lucky enough to survive its initial fear would witness an incredible “tail-slap,” only to die or become stunned shortly after.

First the shark prepares. This preparatory lunge lasts longer than the other three phases, allowing the shark to perform some advanced physics calculations in order to determine tail velocity needed based on mass… Just kidding, they aren’t that smart! The shark then strikes, recovers briefly, and collects its prey.

“This extraordinary story highlights the diversity of shark hunting strategies in an ocean where top predators are forced to adapt to the complex evasion behaviors of their ever declining prey,” said Oliver.

These sharks had been studied previously, but Oliver thinks that lack of food has caused the sharks to hunt near the surface, finally giving humans a glimpse of their unique hunting techniques.

The footage is pretty incredible, and you can check it out here!

Alyssa Keimach is an astronomy and astrophysics student at the University of Michigan and interns for the Morrison Planetarium.