Studying Elephant Seals of the Central California Coast

Scientists at Vandenberg Space Force Base in Central California first observed newborn elephant seal pups on a small, remote beach on the base in 2017. The seals have returned every year since, claiming the area as a rookery, or breeding site. 

Led by Cal Poly Associate Professor Dr. Heather Liwanag as the principal investigator and funded by Vandenberg Space Force Base (U.S. Army Corps of Engineers, Department of Defense), our collaborative study compares the movements and behaviors of pups born at this new rookery on Vandenberg Space Force Base to pups born at a longstanding rookery at Naval Base Ventura County on San Nicolas Island. Researchers monitor the elephant seal colonies at each site to better understand the population counts and dynamics, as well as study and track 10 weaned pups (five pups per rookery) each year throughout their first migration. 

The research team travels by plane to study the elephant seals on San Nicolas Island, the farthest from shore of California’s Channel Islands. And the trek to the seals at Vandenberg Space Force Base is certainly an adventure as well—in fact, the remote beach is only accessible to researchers by rope, rappelling with the help of experienced climbers. Holding steady to the ropes with their heavy gear secured, our veterinary experts climb down the rocky cliffs alongside partners at Cal Poly and Vandenberg Space Force Base. 

The Center’s veterinarian Dr. Heather Harris and registered veterinary technicians Lauren Campbell and Liz Eby provide their animal care skills and knowledge to make this research possible, including sedating and monitoring the tagged elephant seals.  

Sedating the elephant seals is crucial to conducting the research safely, as it allows the animals to be calm enough to not endanger themselves or the scientists during hands-on conservation work like attaching and removing satellite tags.  

The amount of sedative varies from animal to animal, as it is based on their weight, age and body condition. In order to determine weight, the research team carefully lifts the animals up with a specially designed canvas weigh bag and a tripod with a hanging scale. 

Then using a syringe, sometimes on an extended pole, the Center’s veterinary team safely administers the precise amount of sedative. During the entire time the pups are sedated, our experts closely monitor their vital signs like heartbeat and breathing rates.  

In addition to working with our partners at Cal Poly to understand weaned pups’ movements and behaviors, Dr. Harris expanded the study to include the pups’ clinical health as part of the Center’s ongoing disease investigation research. 

As the world’s largest marine mammal hospital, the Center gathers an extraordinary amount of information from our sick and injured patients, and we have created a robust collection of data and health samples in our clinical laboratory. Our researchers process and analyze thousands of samples collected from rescued marine mammals such as blood, tissue, blubber and fur.  

In order to identify a stranded animal’s ailments and continue developing innovative medical techniques, it’s critical to first understand what a healthy animal is supposed to look like. So, while the weaned pups at San Nicolas Island and Vandenberg Space Force Base are already sedated for satellite tag recovery, our veterinary experts have the unique scientific opportunity to collect samples from these healthy wild elephant seals. 

Blood, fur and other samples collected from the healthy seals in the wild are analyzed and used as study comparisons to sick patients rehabilitating at our hospital. Common diseases we are studying that we see in our elephant seal patients include lymphoma, herpesvirus, skin diseases and parasites like lungworm.  

Results from clinical health samples support our experts in identifying diseases and pathogens in our patients, investigating the reasons why marine mammals strand and determining how these factors are connected to ecosystem and human health.