Archive for the ‘sevengill sharks’ tag

From Tide-pooling to Shark Diving, Citizen Science with Ocean Sanctuaries

By October 5th, 2017 at 11:57 am | Comment

Tiffany Poon dives with sharks. In fact, it’s one the biggest highlights of her diving year.

“As soon as the first one appears, usually in spring, I’ll be at La Jolla Cove spending as much time as possible with them,” Poon says. “Sometimes they’re shy and keep their distance, but often they’ll come by close enough for a nice photograph, and every now and then come in close to eyeball me with my strange camera.”

Poon is a citizen scientist for Ocean Sanctuaries, a nonprofit dedicated to researching and protecting sharks and other marine species. Read the rest of this entry »

Divers Attempt to Solve Mystery of Sevengill Shark Sightings on the Pacific Coast

By July 7th, 2015 at 7:27 am | Comment

Sevengill Shark "Notorynchus cepedianus" by José María Pérez Nuñez

Sevengill Shark “Notorynchus cepedianus” by José María Pérez Nuñez CC BY-SA 2.0 via Wikimedia Commons

Diver-citizen scientists help find out why there has been a recent increase in the number of Sevengill Sharks spotted in the San Diego area

The first thing the divers noticed upon reaching the bottom was that there were absolutely no fish—anywhere. The lighting, also being strange, lent everything a deserted, eerie feel. But, says diver Mike Bear, “We continued deeper into this spooky, yellowish-green ‘ghost forest’ with its odd, dearth of fish—failing to make the obvious connection in our minds: where had they all the fish gone and why? The previous week, this same area was overflowing with life. Sometimes the fish sense something you don’t.”

Bear and diving buddy Dave Hershman had just entered the water off Point La Jolla. Swimming eastward, separated by about 12 feet of water, quite suddenly a long dark shadow materialized between them, “moving at a good clip,” says Bear. It took a couple of seconds for him to register that this was a fast-moving shark. “By the time he had pulled slightly ahead of me, I saw the characteristic long tail of the Sevengill pass before my face, and from a couple of feet recognized the species.”

What exactly is the Sevengill shark? Filmmaker, diver and founder of the Sevengill citizen science counting project Barbara Lloyd says, “Well, here’s the boring response to that question—scientifically speaking it’s officially known as the Broadnose Sevengill shark, Notorynchus cepedianus, and it’s the only existing member of the genus Notorynchus in the family Hexanchidae!

This fairly large shark grows to about 11 feet, is speckled with gray or brownish spots, and has only seven gills on each side, which distinguishes it from the Bluntnose Sixgill shark. The Sevengill lives in tropical to temperate waters excepting for the North Atlantic Ocean and Mediterranean Sea.

With this post coinciding with Discovery Channel’s Shark Week, the more important question might be—have there been any attacks, since such a large predator inhabits these shallow near-shore waters? “Only three suspected attacks have been documented in the last fifty years,” says Lloyd, “with the most recent being in New Zealand in 2009.” They do get aggressive when feeding, mating, are provoked, and interestingly enough in aquariums. “Prior to that the Shark Attack File shows that there have only been five since the 17th Century.”

Lloyd and Bear began the Sevengill Shark ID Project in 2010, after hearing numerous reports of local divers encountering them, reports that had not previously surfaced. “I had been diving regularly in the San Diego area since 2000, averaging about 100 dives per year,” says Bear, “mainly in the area of La Jolla Shores, La Jolla Cove, Wreck Alley and Point Loma, as well as being actively involved in the San Diego diving community. I do not recall hearing any diver reports of encounters with Sevengill sharks much before 2007—and then suddenly we began hearing the first reports from local divers,” he notes.

The project website began as a simple spreadsheet which allowed local divers to log their encounters without photos. From there it developed into the site you see today, which uses photographs and a pattern recognition algorithm to ID individual sharks. The motivation was to answer the scientific question: why was there an apparent increase in encounters between divers and this species from 2007 onward?

Dr. John Hyde a marine biologist with the National Oceanic and Atmospheric Administration in San Diego wonders if the answer to that question might just be that it is a combination of more Sevengill sharks congregating in the area, and more divers in the water. “Overall we don’t have a good sense for changes in abundance of Sevengill sharks, but it is likely that they are increasing in number since the 1994 moratorium on nearshore (within three miles) gillnet fisheries in California.” The nearshore gillnet fishery had a significant effect on abundance of many fish species, especially sharks and rays, both as direct mortalities and indirectly by removal of prey items. Hyde adds, “This coupled with increasing numbers of recreational divers, cheaper and better underwater camera systems, and increased awareness of these sharks through social media has led to better documentation of their presence.” Though sevengills are fairly common these days, especially in bay and nearshore regions, there is still a lot of research to be done.

“We want to know why sevengills have been attracted to the La Jolla area over the past five years,” says Bear. “Is it the ocean conditions, changing water temperature, has the location just developed into the ideal nursery or pupping ground, or is it particularly mating-related? There may be an increase in prey, or it could be a combination of a number of these?”

The project has amassed a sizable database of still photographs and video, but they are still in the early stages of data collection and evaluation, and have not published any results yet. Barbara Lloyd has had some success using the pattern recognition algorithm to identify individual sharks.

For all, the most sublime Shark Week sensation would also be the most benign—to be able to dive with these magnificent predators, to be in their presence as they glide majestically by.

Are you a diver who lives in the San Diego area? Help the Sevengill Shark ID project answer their questions! Visit the project page on SciStarter to sign up and learn how to enter your sightings according to the specified protocols.


It’s Shark Week! And that means we’re lining up shark themed citizen science projects that you can participate in. Sign up for our newsletter to know which projects are being featured and watch this space for more blog posts!

How Are Cows and Purses Related to Sharks?

By August 17th, 2014 at 10:49 am | Comment

Look back at two shark citizen science projects featured on the SciStarter blog.

Want to learn about and protect sharks? We’ve got you covered!

 

Broadnose sevengill shark (Notorynchus cepedianus) in False Bay

Broadnose sevengill shark (Notorynchus cepedianus) in False Bay

Sharks often get a bad rap; they’re featured in the media as dangerous killers that prey upon helpless human beings and animals.  Although shark attacks occur, they are rare; and attempts to decrease the shark population to prevent attacks leads the ocean ecosystem down a dangerous path, because sharks are important members of the aquatic food chain.  Through education, observation in their natural habitat, and participation in citizen science projects dedicated to sharks, we can learn about and protect these misunderstood animals.  In that light, we featured two shark citizen science projects last year that deserve another read.

For some strange reason, some ocean animals have bovine names.  For example, there are sea cows (or manatees).  But did you know there are a family of sharks known as cow sharks?  The sevengill shark is one example of a cow shark, and Dr. Ashley Rose Kelly wrote about the Sevengill Shark Tracking Project, which was developed to monitor the rise of these particular cow sharks near San Diego.  You can find her blog post here.

In the aquatic world, a mermaid’s purse is not a fancy accessory; rather, it’s an egg case, or a case that surrounds the fertilized eggs of sharks and other fish.  Dr. Melinda T. Hough featured Shark Trust, a project that identifies and catalogs mermaid’s purses with the intention of protecting marine nurseries.  Read about the project here.

Image: Derekkeats, Wikimedia Commons.


About the Authors:

Dr. Ashley Rose Kelly is Assistant Professor of Communication,Networks, and Innovation at Purdue University. Kelly’s work is in the areas of science studies and science communication. You can find Ashley on Twitter as @ashleyrkelly

Dr. Melinda T. Hough is a freelance science advocate and communicator dedicated to sharing the inspiring stories of life science and helping the general public explore their world. She holds a PhD from the University of Edinburgh for research into how antibiotics kill bacteria, was a policy fellow at the National Academy of Sciences, and is a published photographer. Naturally curious, it is hard to tear Melinda away from science. Not content to stay in one place for very long, she might be found exploring, often behind the lens of her Nikon D80, plotting her next epic adventure, or training for the next half marathon.

Rae Moore is the Managing Editor of the SciStarter and PLOS blogs. She studied Bioinorganic Chemistry as a graduate student at McGill University, and is currently the Undergraduate Chemistry Lab Coordinator at Harvard University.

Celebrate Shark Week with Some Citizen Science

By August 16th, 2012 at 5:45 pm | Comment

You might not realize it, but it’s always out there. Planning. Growing. Waiting for the perfect time to strike. You never quite know when it will happen. Maybe July. Maybe August. But you know it’s coming, and you can’t escape it. In an awesome display of speed and power, it bursts from an otherwise calm summer sea and takes over. Terrifying though it is, you just can’t look away.

I’m talking, of course, about the Discovery Channel’s Shark Week, the seven-day marathon of programming celebrating the world’s most feared—and revered—predator. Now, in the midst of it’s 25th year of sidelining would-be beach-goers, Shark Week enjoys ratings (drawing in 3.3 million viewers in its first hour in 2011) previously reserved for major television events and pop culture phenomena like the Super Bowl or American Idol.


Scientists, meanwhile, are hard at work studying these creatures, and they need your help! I know you’re thinking, and don’t worry.
We saw Jaws too. But did you know that several of the over 400 species of sharks, including the iconic Great White, are endangered or vulnerable due to commercial fishing and shark finning?

Courtesy of ECOCEAN.

Courtesy of ECOCEAN.

Here’s a few citizen science projects from around the world enlisting the help of divers, fishermen and boaters to contribute data for scientific study or conservation purposes. Happy Shark Week!

Shark Trust

Shark Trust invites everyone, especially recreational divers, to report their shark sightings and send in photos for inclusion in their global database used by scientists and conservationists to track and manage sustainable shark populations around the world. Shark Trust ensures the security of its data and safeguards local populations by listing only the region of the sighting, never the exact location, lest it be misused by hunters or fishermen.

Sevengill Shark Sightings

According to Michael Bear of California Diver Magazine, divers in the waters off San Diego suddenly began reporting sevengill sightings in 2009. “So little is known about them and their [migration] habits,” said Bear, “[so I wanted to find out why] they began appearing and congregating in a specific spot.” Through his partnership with the Shark Observation Network, the Sevengill Shark Sightings data will contribute to a global database available to researchers and the general public. Bear also founded Citizen Scientists of the Ocean on Facebook, whose relatively modest (but active) membership includes “Her Deepness,” oceanographer and explorer Dr. Sylvia Earle. Like it!

New England Basking Shark Project

Photo by Matt Dube. Courtesy of Carol Carson.

Photo by Matt Dube. Courtesy of Carol Carson.

Spot a fin and email it in! The Basking Shark Project from the New England Coastal Wildlife Alliance invites fisherman, whale watchers, and boaters to report their sightings of the basking shark, one of the world’s largest fish at 39 feet long, second in size to only the whale shark. Their triangular dorsal fin often breaches the surface when they feed—a chilling image from an all-but-harmless beast. They’re filter feeders! Your data will help scientists better understand their local population size and distribution patterns.

ECOCEAN’s Whale Shark Photo-Identification Project

If you’re lucky enough to spot or swim alongside one of these rare, majestic (and endangered) creatures, snap a photo and send it to ECOCEAN’s Whale Shark Photo-identification Library. Using the same algorithm that NASA astronomers use to analyze star patterns and thus compare photos of the night sky to guide telescopes, scientists can identify and track individual whale sharks by the unique spot patterns on their backs. According to Wired, the approach is not limited to whale sharks, having been adapted for tracking polar bears by their whisker patterns and humpback whales by the shape of their fins, and could revolutionize wildlife tagging and tracking as we know it.
Why Sharks Matter

If you find yourself in Charleston, SC, you can help David Shiffman from Southern Fried Science and the South Carolina Department of Natural Resources capture, tag, and release their resident shark species. At least you’ll be on a boat. Anyone can volunteer, but beware of seasickness!