This summer, our community has been faced with a direct impact of human activity on local marine mammals. Recent harmful algal blooms have stranded thousands of pinnipeds, such as seals and sea lions, and dolphins along California’s beaches. During these blooms, shellfish and smaller fish that consume the algae also ingest domoic acid–a neurotoxin found in the algae. As marine mammals feed on these species, they end up consuming large quantities of domoic acid. The result is domoic acid toxicosis which leads to brain damage, behavior changes, seizures, and heart failure. Algal blooms are often caused by nutrient-rich agricultural runoff, but climate change is exacerbating the blooms and increasing the frequency with which they occur. Rising ocean temperatures prevent the mixing of water from different layers of the ocean, allowing algae to collect and thrive. According to 2019 data analysis from NOAA, since 2013, the combination of a decrease in prey species and an increase in toxic algae blooms has led to several consecutive years in which the California sea lion experienced heightened levels of mortality, particularly in the first year of life. With climate change worsening and fish stocks continuing to decline, this trend can be expected to continue.
A local rehabilitation facility working to protect California’s pinnipeds is the Marine Mammal Care Center (MMCC) in San Pedro. They are one of many aiding in the rescue and rehabilitation of sea lions, harbor seals, elephant seals, and more. In addition to providing medical care, MMCC conducts research to track population trends and evolve marine mammal treatment for facilities across the country. With the recent spike in domoic acid cases, the center has been flooded with sick animals–sometimes over 120 at a time. Rehabilitation at institutions like San Pedro’s MMCC and the aquariums’ Sea Otter Surrogacy Program offer suffering mammals the greatest chance of survival–playing a crucial role in ongoing efforts to prevent population decline.
Over the past twenty years, Monterey Bay Aquarium’s Sea Otter Surrogacy Program has successfully rescued and released over 60 pups. There are hopes to expand on this success through the partnership with the Aquarium of the Pacific. As they prepare their facility, Aquarium of the Pacific staff have trained with members of the Monterey Bay Aquarium for the 24-hour care of young pups. Specific procedures are to be followed from the moment the pup is rescued to the moment they are returned to permit their re-release. Husbandry staff are not the only ones preparing. The Aquarium’s resident otters, priorly deemed unviable for re-release, have the chance to act as surrogate mothers–teaching rehabilitating pups foraging, self-care, and social skills as they pass through the program.
In addition to giving pups and their populations a second chance at survival, institutions like the Marine Mammal Care Center, Aquarium of the Pacific, and Monterey Bay Aquarium bring the public together to learn about the important role these species play and garner support for their conservation. In turn, humans will work to rebalance ocean ecosystems and the role they play in every economic, social, and cultural aspect of our lives.