This is an oldie but goodie for the Lost and Found archives. In a letter dated February 2nd, 1915 to the California Department of Fish and Game, lighthouse keeper John W. Astrom reported on a small southern sea otter (Enhydra lutris nereis) population of the coast of Big Sur. Little did Mr. Astrom know that his observations would help launch one of the greatest and most iconic conservation success stories in history. A few decades later, in the June 1938 issue of LIFE magazine, a story on this recovery marked the public’s rediscovery of the southern sea otter, a species that was widely believed to be extinct since the early 1900s (exact date unknown). Although biologists at the California Department of Fish and Game knew as early as 1915 that a few had survived, unbeknownst to the public, and that their numbers appeared to be increasing since receiving total protection under state law in 1913. The “herd” of sea otters described in the LIFE 1938 article showed the world that about 50 individuals remained and was a remnant colony of a species that was overhunted due to their highly coveted pelts. Fast forward to 2017, and the number of sea otters in California now exceeds 3000, but there is still a long way to go for this population, as they are still listed as threatened according to the United States Endangered Species Act and the International Union for Conservation of Nature’s Red List of Threatened Species .
For me, as a biologist who studies sea otters from time to time, the rediscovery of sea otters opens up lots of questions. However, one question in particular has been shaping my own research and is advancing the conservation of our fuzzy little friends. That question is: “Why was the last remnant colony of southern sea otters discovered on a remote stretch of Big Sur?”
To get at that question, we must first consider the local geology of Big Sur. If you have never been to the Big Sur coast, let’s just say it lives up to its name. It has big mountains, big rocks, and big kelp forests (Figure 1), with the latter being a key habitat for sea otters. The coastline is dramatic, with granite cliffs shooting up from the sea. It is also fully exposed to the Pacific Ocean, and because of its westward-facing orientation, massive waves can form, sometimes up to 10 meters in height.
The combination of these land and sea features makes for a treacherous passage through Big Sur by boat, car, bike, or foot, and thus makes for an ideal hiding spot for animals being overhunted by humans. Even 90 years after the rediscovery of sea otters, humans are still battling Mother Nature to keep passage through Big Sur open. In the past year we have witnessed heavy rains in California that have caused massive landslides in Big Sur, leading to the collapse of sections of the Pacific Coast Highway (PCH) making it extremely challenging, if not impossible, to reach certain parts of the Big Sur coast.
The raft of sea otters, discovered by lighthouse keeper John Astrom in 1915, was likely and unintentionally there because of the jagged Big Sur coast, which served as a refuge from human hunters. By the time they were rediscovered laws had been enacted to protect those animals from further hunting, namely the Fur Seal Treaty of 1911 and state protections in 1913. Later the congress of the United States would pass further legislation protecting sea otters and other vulnerable animals through the Marine Mammal Protection Act of 1972 and the Endangered Species Act of 1973. These pieces of legislation have been the catalyst for sea otter recovery.
Sea otters once ranged across most of the coast of the Pacific Rim in the northern hemisphere, from Japan to Russia to Alaska and down the west coast of North America to Baja California, Mexico. Along the coast of California it is generally thought that sea otters are primarily kelp forest animals, like the group that was rediscovered in Big Sur. However, starting in the 1980s southern sea otters were observed using California estuaries (calm, shallow embayments where the land meets the sea). Within their current range in California there are two estuaries in particular inhabited by sea otters: Morro Bay and Elkhorn Slough. At first, many thought that sea otters using estuaries was just a weird coincidence or temporary phenomenon. However, after several decades of research, we are finding that estuaries can provide plenty of food (crabs and clams) and habitat (seagrass beds and salt marshes), and that the sea otter in turn can also help protect estuaries by removing overabundant crabs that can cause all sorts of nasty effects (Figure 2). Since human predators have been removed from the equation in California (it’s illegal to hunt or harass a sea otter), and since estuaries are devoid of sea otter predators (great white sharks and killer whales), the sea otter is left with a happy home to feed, rest, and raise pups.
So I finish this post with a question for you: “If you were a sea otter, where would you want to raise your kids?”
Acknowledgement: I thank Lilian Carswell from the U.S. Fish and Wildlife Service for providing useful comments for this blog post. Photos courtesy of Brent Hughes, Caltrans and KCBX, and Ron Eby
Author: Brent Hughes
I am a marine conservation biologist and ecologist who focuses on conservation issues facing coastal ecosystems. My research has spanned many different ecosystems, from kelp forests to the rocky intertidal to estuaries. Much of this research involves careful collaborations with other scientists, government organizations, non-profits, and the general public to address threats to our oceans. My biggest thrill is to get outside and observe nature in all types of setting and to explore new places. In my spare time I enjoy the company of family and friends, and can often be spotted around biking and hitting the beach with my wife and two kids in my hometown of Santa Cruz, California. Currently I am a David H. Smith Conservation Research Fellow at Duke University and the University of California Santa Cruz. Find out more about my research here
- Elkhorn Slough Sea Otter Cam, where you can observe sea otters in their marshy habitat in realtime:
- Hughes et al. 2013 Proceedings of the National Academy of Sciences USA, paper on sea otter impacts to imperiled seagrass
- Sea Otter Heroes, by Patricia Newman, children’s book (Ages 8-14) on the sea otter’s life in estuaries and beyond
- Al Jazeera Earthrise documentary on sea otters in Elkhorn Slough