In the early months of 2023, California experienced historic highs in rainfall, causing floods and mudslides, widening streams and rivers, collapsing cliffs and reshaping portions of the coastline.
With rapidly dropping atmospheric pressures increasing in severity, this extreme storm cycle, dubbed a bomb cyclone, left a wake of environmental damage in its fall out. Not exempt from the destruction was San Luis Obispo’s community of elephant seals.
With a combination of high surf from the winter’s king tides, and weeks of bombardment from the bomb cyclone, San Luis Obispo’s elephant seal population suffered a decline. Fallen cliffs, caused by heavy rainfall and high tides, rendered many of the beaches in the area regularly utilized by elephant seals for birthing and raising pups inhospitable, forcing them to relocate farther inland swimming up streams and climbing farther up coastal bluffs, or face getting washed out to sea completely.
While many of the fully grown elephant seals were able to ride out the harsh conditions in portions of the coastline less affected by the storm, the seal lion pups were especially vulnerable to these harsh weather conditions. With inadequate beaches, and ever-rising tides consuming portions of the shoreline for days at a time, some pups found little to no space to weather the harsh conditions.
The long term detrimental impact to the local population of elephant seals from the bomb cyclone remains unclear, with mortality rates even outside of massive storms commonplace in nature.
The survival rate of the first year in both male and female pups is estimated at 50% while 25% of all seals born are still alive at age four. Predators, disease, malnutrition and human interactions (boat strikes, entanglement in fishing gear and toxic contaminants) all factoring into mortality, said Kathy Curtis, President and Board Liaison for Research and Communications of Friends of the Elephant Seal Organization.
Roughly 5000 pups are born each year, according to Curtis. From mid-December to mid-January, elephant seals have their annual birthing cycle.
Though the new year’s extreme storms took a toll on the community and environment, San Luis Obispo County’s elephant seal population isn’t likely to be going anywhere anytime soon.
“There is a natural variation in pup mortality from year to year,” Curtis said. “It would seem that the ecosystem is resilient enough to accommodate those seasonal and annual differences.”
