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Catalina Island Leadership Program

Phoenix Country Day School

Kelp Forest Information Links

Channel Islands National Marine Sanctuaries

Introduction:
This field project was conducted by Kate and Leah during an expedition to the California coast and the Channel Islands. In order to do our research we traveled to Catalina Island from October 15 to October 19, 2007. Our area of interest was the California Sea Lions, also known as the Zalophus Californianus. The California Sea Lion interested us both because we have had experience with the California Sea lion before. For several years, we have been attending a summer camp, where part of our time was committed to the discoveries and particulars of the sea lions. Photos, snorkel trips, and kayak adventures have all been dedicated to enjoying the California Sea Lions. Having visited Catalina before, and in seeing the California Sea Lions once again, our interest for the sea lions grew and the topic for this project was initiated.

Research:
How does the diet of sea lions effect where they live? Why do they prefer one bay over another? After both of us had chosen our question we decided to begin researching background information on sea lions. Some key information that we discovered is that sea lions can be found from Baja California all the way up to Alaska. They prefer to live on rocky, sandy beaches of the coastal islands and the coast of the mainland. They can live on land for a long period of time if the weather is warm. While they are resting or sleeping they like to lie on a rock facing the sun.
Their prey is located in all different types of habitats. Sea lions primarily eat squid, octopus, northern anchovy, hake, opaleye, and herring. Squid is found in cold water. The octopus lives in dens or caves of rocky areas. The northern anchovy is found in bays and estuaries. Hake lives on muddy and sandy bottoms. Opaleye is located near rocky, sandy beaches, close to shore. Lastly, herring is found in inshore waters of the pacific.
It is not difficult for the sea lions to locate their food because they have sensitive whiskers, which are called vibrissae, which help locate their food. They also have flippers which enable them to walk on land. All of their prey lives in water, unlike the California Sea Lions which spends time both on land and in the water.
While at Catalina we had a chance to do many activities that were beneficial to our projects. On day four, while our group was snorkeling at Emerald Bay we had a chance to conduct a roving diver fish count. This fish count helped us realize where the sea lion’s prey was in relation to the actual sea lion. On day five, during the kayak we noted where we saw the sea lions, getting a better understanding of their habitat. Even though we did not see many sea lions on the trip, we were still able to have a better understanding of the animal. We snorkeled through the kelp and kayaked around the rocky, sandy beaches seeing their habitat.
Over the course of five days, we were limited to the two sea lions we were able to observe both on day five. When we spotted the California sea lions, one was sleeping on a rocky beach, while the other was swimming rapidly through a dense kelp forest which was populated with many fish. The lack of California Sea lion population that we saw was compensated by exploring the fish that the sea lions eat. Unable to actually see the squid or octopus, our background research came in handy, and we were able to explore the other fish’s habitat while we were snorkeling.
The limitation of only two sea lion’s led to not enough data making us not being able to fully answer our question. We were able to answer our question superficially from our background research. The California Sea Lion’s prey inhabits a variety of locations. The California Sea Lion feeds in cool upwelling seamounts and occasionally on the sea bottom. They prefer to live on rocky and sandy beaches of coastal islands and the mainland coast. The California Sea Lion lives in cooler waters, and so does their prey. On our map we located where they live and were they feed. Where they live is different from where they feed. Where they prey live can affect where they live. The California Sea Lion’s source of diet is located abundantly from Baja California to Alaska. This is why the sea lion’s live there; they will not live far from their food source.
In order to answer our sub-question, why they prefer one bay over another, we investigated the seafloor and sea scenery. We noticed that the sea habitat type could change dramatically within a few feet. A Zalophus Californianus prefers one bay over the next because it meets all their living requirements. It could have a rocky and sandy beach, while another bay could have deep waters. This however, does not mean that the California Sea Lions don’t interact with the other bays. One bay is where they live, while others are ideal locations to catch a prey.

Conclusion:

While we are thrilled with all of the new information that we learned about sea lions, we would like to return and do a few steps differently. First, we would try to see more sea lions by taking more trips to deserted rocky, sandy beaches. Second, we would increase our observation time giving us more time to research the animals. Additionally, we would return all four seasons to compare the number of sea lions in each season. We would also explore the island to see if those factors such as temperature, wind, the sun, and rain effect the number of sea lions in different locations.
Although we were not able to answer our question fully, we did find other key information. We found out that the sea lion’s do not live where they feed. We also found out that they live from Baja California to Alaska because that is where their source of food lives. We also found out the reason they prefer one bay over another which is because one bay may have all of their living requirements, while another does not.
The time spent on Catalina was very interesting and enjoyable. The sightings of the Zalophus Californianus’s prey made up for the lack of California Sea lion. Proving our research answers right, the times that we saw the California Sea Lion we saw them at where they are supposed to be located according to our research.