When you picture a sea turtle you probably think of endless tropical blue water, colorful corals and a perfectly brown-green watercolor turtle shell coasting along the reef. Perhaps you think of the tiny, minutes hatched baby sea turtles making a break for their big blue home on the beaches of Caribbean countries… Regardless of whatever picturesque ‘Blue Planet’ turtle scene pops into your mind, it probably isn’t one off Southern California, or Catalina to be specific. Although we may not imagine sea turtles to be majestically roving the SoCal oceans, they are indeed here! What?! YES! I know… it’s awesome. Out here on Catalina we are seeing them more and more, almost as if they have made a home and are here to stay! We love seeing these turtles, especially on snorkels with kids so we all can enjoy their incredibly chill demeanor, but what has brought them to Catalina and why are they sticking around?!
The Green Turtle, Chelonia mydas, is typically found in tropical to subtropical waters. It is common for some turtles to wander up the coast in warm summer months and retreat south once the water temperature starts to drop. The one exception is a resident green turtle population in the South San Diego Bay. In this area the water is warmed by thermal output from the Duke Energy power plant which then keeps the turtles year round in the warmer water. This warm water outflow provides a great habitat for eel-grass and other marine plants to flourish, giving the turtles a constant meal. Because of these specific circumstances it isn’t unlikely to see turtles cruising the South San Diego Bay all year, then why we are starting to see them year round north of San Diego? What could that mean?!
Here at CIMI we are able to find green turtles all year round. This means that, just like us, some of these turtles must have deemed residency on the island, even during the cool winter months. There is a resident sea turtle in Cherry Cove, as well as Guano Rock and a few that seem to wander in between Torqua and Toyon Bay. Our waters seem to be providing a suitable home for these adorable turtles, even though it is a bit out of their normal range. Perhaps these turtles have adapted to withstand colder water for a few months or maybe our waters aren’t dipping to such frigid temperatures. Whatever the reason may be, it appears our turtles are here to stay so keep an eye out on your next snorkel for one! This isn’t the first time we’ve seen warm water species breaching their ranges moving up the coast of California.
Between 2014 and 2016 California experienced an extended marine heatwave. Typically winds blow from the north down the coast, keeping the entire west coast cool along with southern currents that push warm water toward Mexico. During this event, these winds were weakened and surface currents reversed, pushing warm water north causing southern species to be brought in those currents. This marine heatwave of warm water is often referred to as “the blob”. The Blob caused sea surface temperatures to peak 7 degrees above normal temperatures resulting in many ecological implications.
During this lengthy heatwave, the Blob pushed many warm water species from Baja up to northern California. A total of 67 non-native species were recorded out of their range and 37 of those had never been recorded that far north before!! Species like bottlenose dolphins, spiny lobsters, several types of sea slugs, pelagic red crabs (tuna crabs), comb jellies, and pink striped barnacles had all been pushed up the coast in the Blob all the way to Bodega Bay (north of San Francisco). See if you recognize any animals from the collage below of a few species that were found in chilly NorCal waters!
Dramatic weather events like The Blob make us consider the future of our coasts. Will these species continue to move north as sea surface temperatures rise? If that is the case then we may start seeing many more resident sea turtles around Catalina. Warmer ocean temperatures can cause ecological shifts in habitats, food chains and abundances of animals. We will be keeping our eyes peeled during any future heatwave events, potentially even more severe, for any foreign friends, especially more turtles!!!
Written By: Erin Moran