On a clear summer’s day, you’re likely to find Andy Nosal in or near the warm waters of La Jolla Shores, a pristine beach located in San Diego. However, unlike fellow beachgoers, Nosal is there to conduct research on leopard sharks, a harmless species of shark that congregates at the Shores every summer when the calm, crystal clear water reaches temperatures upwards of 80 degrees.
Nosal, a marine biologist and alumnus from Scripps Institution of Oceanography at UC San Diego, is now serving as the DeLaCour Postdoctoral Fellow in Ecology & Conservation at Birch Aquarium at Scripps.
As a postdoctoral researcher, Nosal is continuing his groundbreaking research on shark behavior and ecology. Earlier this month, he published a new study in the journal PLoS One that examines how leopard sharks navigate by using their sense of smell. (Photo gallery here.) After tracking leopard sharks from La Jolla to Catalina Island, Nosal wanted to better understand how this nearshore species was able to navigate the deep blue sea of the San Pedro Channel, a vast space with no obvious visual cues. He hypothesized that the sharks’ keen sense of smell must play a role in their navigation.
To test this theory, Nosal captured leopard sharks from La Jolla and transported them 10 miles offshore (with depths exceeding 500 meters), where he dropped them off and tracked them to see how they made their way back to the coast. Some of the sharks had small pieces of petroleum jelly-soaked cotton balls inserted in their nostrils. The results of this experiment showed that sharks swimming under “normal” circumstances swam straight back to shore, while the sharks with plugged noses took a longer, windier path.
“We think that smell is part of what they’re using to find their way back to shore,” said Nosal. “They almost certainly have other senses that they’re using—such as geomagnetic cues like birds use, but it does seem that smell is part of the solution of finding their way in the open ocean.”
In recent months, the charismatic early-career scientist has been honing his science communication skills. In 2015, Nosal was one of five winners of iBiology’s Young Scientist Series (YSS) Competition. YSS is a new video series featuring accomplished PhD students and postdocs presenting their research. Nosal’s scientific merit, communication skills, and passion for science communication, education, and outreach made him stand out from the large, international pool of individuals who applied for this award.
“There’s a real need for scientists to communicate complex findings to others who are not experts in their field,” said Nosal. “I really enjoy giving talks and I think I’m a good communicator, so I thought that this competition was the perfect way to test that and try to really hone those skills. I was really excited when I found out that I won.”
Along with the other YSS winners, Nosal attended a science communication workshop at the prestigious Alan Alda Center for Communicating Science at Stony Brook University, where he learned effective communication techniques through improvisational exercises, group breakout sessions, and individual coaching.
“I was really impressed by the Alan Alda Center. There are very few places like that and I think we should have more of them,” said Nosal, noting that he hopes to incorporate similar workshops into his own classes in the future.
At the close of the workshop, each winner utilized his or her newly sharpened communications skills in a final video presentation, recorded at Stony Brook in a green screen studio. Nosal’s presentation, titled “Not Just on Vacation: Why Leopard Sharks Hang Out in La Jolla,” emphasizes the importance of protecting this species.
Nosal credits Scripps Oceanography and Birch Aquarium for opening his eyes to the importance of science communication. As a PhD student, he took a class offered through Birch Aquarium called “Communicating Ocean Science to Informal Audiences,” or COSIA. This course was Nosal’s first exposure to formal science communication training, and raised some important questions about how to engage and entertain audiences, such as visitors at the aquarium or at a museum.
“I learned a lot from the COSIA class, and I think a lot of what I learned there can be applied to a formal classroom setting as well,” said Nosal. “The more opportunities we have for students to hone their communication skills, the better.”
Growing up in New Jersey, Nosal spent many summers near the beach, but he didn’t become interested in pursuing marine biology until years later, when he spent a semester abroad at the University of Queensland in Australia. There, he learned how to scuba dive and conducted field work along the Great Barrier Reef, where he first saw sharks in the wild and became hooked.
After obtaining his BS in biology from the University of Virginia, Nosal pursued a PhD in marine biology from Scripps Oceanography, where he graduated in 2013. While a Scripps student, he discovered that nobody knew exactly why leopard sharks congregated in La Jolla every summer, so he decided to uncover this mystery as part of his dissertation.
He discovered that nearly all of the leopard sharks in the area are mature, pregnant females. Using acoustic transmitters, Nosal tracked the sharks’ movement patterns and found that during the day, they stayed close to shore, swimming in the warm shallow water. At night, they moved a bit further out into a nearby marine canyon where they foraged for squid.
Leopard sharks are ectothermic, meaning their body temperature is the same as the surrounding water, therefore, Nosal concluded that pregnant females are likely attracted to La Jolla because it’s the perfect place to incubate their embryos and speed up gestation, “like a lizard basking in the sun or a mother bird sitting on eggs to keep them warm and maintain that optimal temperature for development,” he explained.
As part of his postdoctoral fellowship, Nosal is building upon his previous research and studying aspects of leopard sharks’ social behavior, specifically if and how much social attraction contributes to their aggregation or schooling behavior.
Recently, Nosal collected aerial video footage of the La Jolla leopard sharks by using a helium balloon and a GoPro. He and researchers at Princeton University and Harvey Mudd College are now digitally tracking and analyzing the sharks’ behavior.
Nosal is also currently studying how public perception of sharks affects people’s willingness to conserve them. After noticing that shark documentaries often use ominous, dark background music—as compared to the triumphant, peppy music commonly found in dolphin documentaries—Nosal began wondering if music can affect somebody’s emotions and perception of what they’re seeing. He teamed up with researchers at the Rady School of Management at UC San Diego to conduct a marketing psychology experiment using shark videos paired with different types of music and word associations. Though more testing is needed, preliminary studies showed that scary music does indeed affect the way people perceive sharks.
Nosal hopes that his research can help illuminate the need for shark conservation and dispel common shark myths. As an expert in the field, he is often asked what people can do to protect themselves from sharks, and to this he has a simple reply.
“What I want people to remember is that the ocean is wilderness. There’s no such thing as shark-infested waters—that’s where the sharks live. If anything, the ocean is infested with humans,” said Nosal. “We need to share that space and respect that this is their home, and it’s a wild place.”
– Brittany Hook