UM researchers trying to save sharks from extinction
Shark-tagging voyages help researchers
It was an awe-inspiring image. In recent weeks we’ve seen hundreds of Black Tip and Spinner sharks close to the coast on their annual spring migration north.
After seeing it, you may think our waters are teeming with sharks, but the reality is shark populations worldwide are on the path to extinction.
Dr. Neil Hammerschlag of the R.J. Dunlap Marine Conversation Program (RJD) understands many people fear sharks but says humans are not on the menu.
“If sharks were a real threat to people we could never go swimming. The fact that thousands of people, millions of people, enjoy the water recreationally each day just shows that sharks are not a real threat.”
In fact his argument is you should be afraid for them, not of them.
“They are being fished faster than they can reproduce.”
Local 10’s Christina Vazquez was invited to join Dr. Hammerschlag and his team on a research trip where the scientists catch, collect data and tag sharks. The data is shared with wildlife managers to inform conservation policy.
Also on the trip were South Broward High School Marine Magnet students. Dr. Hammerschlag explained how populations of “Great Hammerheads in our waters, in the last 20 years, have declined over 80 percent. That’s really alarming.”
He explained how shark populations worldwide are declining due to over fishing. In some cases they are what’s called “bycatch”, caught unintentionally by a fishery catching other fish.
“Most are actually caught for their fins,” explained Dr. Hammerschlag, “Shark fins are used to make Shark Fin Soup.”
Shark Fin Soup is a delicacy in many parts of Asia, a symbol of wealth according to John Oh of Malaysia. “Everyone eats Shark Fin Soup and it is almost required that you serve that at banquets. I think a lot of people are oblivious to the fact that sharks are getting close to extinction.”
Oh joined the researchers in order to put together a video for his family and friends back home. “I’m going to try to convince them to hopefully stop eating Shark Fin Soup and conserve this species.”
“As a top predator they help keep the oceans in check and in balance.” said Dr. Hammerschlag, “When you remove top predators there could be this trickle down effect that impacts other species, even cause landscape-level effects even down to the bottom of the food chain. This planet right now is losing diversity and it is important to conserve bio-diversity. The goal is sustainable fisheries.”
Researchers bait 10 drum lines and cast them into the ocean. On this trip they were just off the southern tip of Key Biscayne.
Researcher Austin Gallagher called it the search for the “urban shark”, “you can actually see Downtown Miami in the skyline. I think people have a misconception that wildlife is always in remote parts of the planet.”
They let the bait soak in the waters for about an hour.
In that time they catch their first shark. It is a Black Nose Shark. Gallagher explained how the Black Nose Shark is a common coast species small in size.
In seconds the shark is loaded onto a platform behind the research boat and that’s when the action begins. “It’s kinda like a pit crew at NASCAR,” explained Gallagher, “everybody is doing different things, some people are taking fin clips, measurements, a biopsy, it happens really quick, we'll take blood samples, we'll tag the animal, it's about five minutes and then we release the sharks.”
Helping them are students like Daniel Schultz of South Broward High School’s Marine Magnet Program, “My job was measuring. It’s much different than being in the classroom. It’s totally different when you are there and have a live animal.”
Outreach to students like Schultz is a big part of RJD’s mission, “It creates a another level of awareness,” explained Dr. Hammerschlag, “each one of those kids will tell people, who tell people and who knows what those kids will do in their life, maybe they will be in business, marketing, maybe this will create some sort of environmental ethic that they will take with them in whatever they pursue in the future.”
Each student is assigned a different task during the tagging process.
After researchers gently restrain the shark on the platform a ventilation pump is placed in the shark’s mouth. This is done for species like the Black Nose shark who need to swim to breathe. The pump allows ocean water to pass through their gills simulating swimming.
Up next, a stress test. They squirt a small amount of ocean water at the shark’s eye and observe if its “eyelid” closes. This helps them gauge if the animal is experiencing stress.
Measurements of the shark are performed as is a biopsy from the shark’s flank.
A yellow tag is placed at the base of the dorsal fin. This helps identify the shark in the event it is recaptured. They also do satellite tagging but that is often reserved for larger and more threatened sharks like the Great Hammerhead.
“Historically in order to see what sharks eat you cut them open and see what's in their stomach,” Dr. Hammerschlag told the group.
These days they can do that by taking a tiny clipping from the trailing edge of the shark’s dorsal fin, “there are no nerves in their fins so it doesn’t hurt” said Dr. Hammerschlag.
From the fin clipping they can run a chemical composition to see what the shark ate over a long period of time. They also take a blood sample from the shark which helps them identify what it ate over a short period and will let them know if the female Black Nose shark they captured is pregnant.
Finally the circle hook is removed and the shark is released back into the water.
On this shark tagging trip we would tag two black nose sharks and one feisty nurse shark. RJD averages about 300 sharks a year.
“We are collecting real data and this data is going to be published in scientific journals,” said Dr. Hammerschlag, “my hope is that wildlife managers will use the data to make informed policy decisions and effective conservation strategies.”
“Oceans are changing,” Gallagher explained, “everyday people look at the surface of the ocean and it looks the same but the honest truth is beneath the waves things are changing drastically, populations of sharks are declining rapidly, even in our waters here and so that's one of the questions we are trying to answer and one of the points we are trying to drive home. We need to be good stewards of the ocean and it starts now. This is their world, we're just visiting.”
RJD also runs an “adopt-a-shark” program. For $2,500 you buy a satellite tag and you can come on the research boat, tag and name the shark yourself and then follow him or her in real time on the internet.
To learn more about the researchers and how you can help, click here.