Every year from June to December, hundreds to thousands of leopard sharks (Triakis semifasciata) congregate in this one particular spot along the southern California shoreline. Why are they here? Andrew Nosal answers this question and articulates why we should care. He carefully studied these sharks and their behavior over the course of several years. He discovered that most of the sharks are mature pregnant females. During the day, these pregnant females spend most of their time swimming in the warm, calm waters that are unique to the La Jolla area. At night, they forage for squid in a nearby marine canyon. Because sharks lack the ability to regulate their internal temperature (i.e., they are ectothermic), Nosal concludes the pregnant sharks are attracted to La Jolla’s warm waters to support the developing fetuses – much like hens sitting on eggs. He emphasizes the importance of protecting the leopard sharks, especially considering how they carry the next generation of sharks and could easily be wiped out by careless human activity.
This talk is part of the Young Scientist Seminars, a video series produced that features young scientists giving talks about their research and discoveries.
Andrew P. Nosal is currently a postdoctoral researcher at Scripps Institution of Oceanography, where he conducts research on the behavior, ecology, and conservation of sharks and rays. Nosal is most interested in the causes and consequences of movement phenomena like aggregation (grouping) behavior, sexual segregation (spatial separation of males and females), and seasonal migration. He… Continue Reading