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Introduction:
On October 15, 2007, the 8th grade from Phoenix Country Day School went
on a trip to Catalina Island. We traveled to the scenic island to investigate
the ocean and the creatures that lie within it. Our group included Kelsey,
Danielle, and Aida. On our visit to the island we learned about the landscape,
the animals that live there, the fish, and other environmental issues.
We thought that this experience to Catalina would help give us a better
understanding of our question.
Research: Our research question was, “What are some of the marine animals that are most commonly seen near Catalina Island?” We studied three animals in particular: the harbor seal, the short-beaked common dolphin, and the sea otter. We chose these animals because these are well-known marine mammals and we predicted that we would be able to see them at Catalina Island.
The short-beaked common dolphin’s scientific name is delphinus delphis.
Male dolphins can be up to 8 feet 10 inches long, while the females can
be up to 8 feet 6 inches. All have a v-shaped dark saddle on their backs
and a downward-facing point on their side directly below the dorsal fin.
Short-beaked common dolphins have a light gray or yellowish patch on their
sides, in front of the dorsal fin. Their sides are light grey and they
have a caudal peduncile. They also possess a tall, dark dorsal fin, often
with gray or whitish areas in the center. Short-beaked
common dolphins live in the waters of the Atlantic and Pacific Ocean,
in the tropical and temperate waters. They often travel in fairly large
groups of about 30 dolphins or less, and are very active at the surface.
Their gestation lasts up 11 months and their calving interval is at least
2 years. Small schools of fish, and squid are their main prey. Some other
types of fish that they eat are anchovies, lanternfish, hake, and deep
sea smelt.
The harbor seal was another animal that we chose to study. It lives in
the coastal areas of the North Pacific and the North Atlantic. They are
medium sized pinnipeds with short, spindle-shaped bodies. The females
can grow up to 5 feet 7 inches, weigh up to 290 pounds, and live up to
25 years. The male harbor seal can grow up to 6 feet 3 inches, weigh 370
pounds, and live up to 35 years. Harbor seals are either tan to a silver
color with dark spots or dark with light rings. They live in cobble and
sandy beaches, tidal flats, sand bars, and rocky reefs. There are five
subspecies distinguished by their location. The seals’ diet consists
of demersal fish, pelagic schooling fish, octopus, and squid.
The last animal we studied is the sea otter. Sea otters are members of the weasel family. Their diet consists of snails and shellfish, and they can dive distances greater than 400 feet. They can also stay under water for up to four minutes. Sea otters spend most of their life in water. They have a short, broad head, their body is completely covered in fur, and their tails are shaped like oars. When eating, the seat otter floats and swims on their back, often at the surface of the water. They are found in coastal North Pacific and the Southern Bering Sea. Sea otters are float alone or in small groups consisting of a dozen or more. An adult male weighs up to 99 pounds, and a male’s average life span is 15 years. A female sea otter weighs up to 73 pounds, with a longer life span of 20 years.
During our visit to Catalina Island, we collected data from our kayak
and on our snorkel trips. The depth of the water at Catalina Island by
Indian Rock was almost 38 feet. The ocean at the time of our data collection
was very clear; therefore, we could see all the way to the bottom of the
ocean floor. The temperature was 64 degrees Fahrenheit. We gathered this
information near Indian Rock.
Conclusion:
Unfortunately, we did not see any of the marine animals that we were researching while snorkeling. We believe that we didn’t see any harbor seals because all the harbor seals that were sighted near Catalina Island were seen in May, so therefore October was not the best time to see the seals. When we started the project, we thought that sea otters would be one of the marine mammals that would be sighted off Catalina Island. Sea otters like to be in shallow waters, up to 55 meters, and in dense kelp forests, both requirements that were met at the site that we were kayaking at. After our trip to Catalina Island, we further researched the sea otters only to find out that there have never been any sightings of them near Catalina Island. Most of the sea otters sighted off the California coast were outside of Santa Barbara. We didn’t see any dolphins because they are found farther off the coast than we were because they are found in deeper water than the water that we were snorkeling in.
The trip to Catalina helped us to learn more about our animals. Although
we didn’t see any of them, the trip helped us to understand why
we wouldn’t see them, therefore we developed a better understanding
of their normal environment. When we didn’t see any dolphins, our
first thought was, “Why?” When we got back from our trip,
we went straight to My World to learn more about where the dolphins had
been sighted. We noticed that there was what looked like a big hole near
Catalina where there weren’t any dolphins. We put a bathymetry layer
on our map, which showed the depth of the water. We then took out the
shallowest water, and observed that there were almost no dolphins in the
shallowest water.
If we had the opportunity to do future work, we would like to go to the optimum place near Catalina Island and at the optimum time so we could sight the harbor seals and short-beaked common dolphins and learn more about their behavior and environment. We would go near Santa Barbara to sight some sea otters, and learn about them as well.
Works Cited:
Folkens, Pieter, Randall Reeves, Brent Stewart, Phillip Clapham, and James Powell. Guide to Marine Mammals. New York: A Chanticleer Press Edition, 2002.
Tim Hauf. Channel Islands National Park. Hong Kong: Tim Hauf Photography,
1996.
Michelle Bailey. California Marine Life. Hong Kong: Roberts Rinehart Publishers,
1998.
Trevor Day. Exploring the Ocean. New York City: Oxford University Press,
Inc, 2003.
