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Catalina Island Leadership Program

Phoenix Country Day School

Kelp Forest Information Links

Channel Islands National Marine Sanctuaries

Introduction: The ocean is full of life and unknown mysteries. Recently, we experienced the mystery of the underwater world first hand. Before we traveled to Catalina’s kelp forest, we proposed an interesting theory that the density of kelp affects fish of different colors that live there, choosing four fish to study in their relationship with the kelp. The four fish we selected because of their color diversity were: garibaldi, senorita, kelp/calico bass, and sardines. Garibaldi are orange, senoritas are yellow-topped, white-bellied, sardines are silver, and kelp/calico bass are mottled gray-green. Our hypothesis was that fish would be more likely to be found near a habitat that would camouflage them. For example, we theorized that a darker, greener fish such as a kelp/calico bass would make its home in the kelp, which would disguise it from predators. We also thought that a brightly colored fish, such as the garibaldi, would stay away from a habitat that would cause it to stand out. However, we learned slightly otherwise.
Most of the fish that we selected were found in and around Emerald Bay, Indian Rock, and Howland’s Landing off the north shore of Santa Catalina Island. Our first data-collecting snorkel took place on October 17th. This snorkel took place mid-morning, and was in the waters around our campsite at Howland’s Landing. Our second data-collecting snorkel was the next day, in the afternoon. This snorkel took place in Emerald Bay, around Indian Rock. The Emerald Bay area had a drastically different atmosphere compared to Howland’s Landing. Rather than rocky bottomed, it was comparatively sandy and smooth. Howland’s Landing also had slightly less kelp. While snorkeling, we were interested to see the different colored fish.

Research: At Catalina, we began collecting the basic data for our project. Necessary data sets included generalized kelp density and a count of garibaldi, senoritas, sardines, and kelp bass in selected areas. To acquire our fish counts, we swam or kayaked to a specific point and then snorkeled around, counting the fish. The fish numbers were recorded as single, few (2-10), many (11-100), or abundant (over 100). Once every member in the group had surfaced, the numbers were pooled onto one recoding sheet, and the point was marked on a GPS. This process is called a Roving Diver Fish Count, simply because we are roving around and counting fish. Through the use of a Roving Diver Fish Count, we were able to collect all of our data.
Our initial project revolved around kelp density and how it affected different colored fish. The fish included in our study were, garibaldi, senoritas, sardines, and kelp/calico bass as we mentioned before. We discovered that, in general, there were more fish near Indian Rock, where the water was shallower and the kelp was denser. Though Howland’s Landing had many fish, their numbers were less in comparison to those of Emerald Bay/Indian Rock. Our thought was that fish would prefer to live where they blend in: Kelp/calico bass in the kelp forest, senoritas and sardines over sandy bottoms, and garibaldi over rocky bottoms. As it turns out, the fish didn’t exactly live up to our expectations.
Around Indian Rock (-118.5254°E, 33.468°N), we recorded many garibaldi and kelp bass, few senoritas, and an abundance of sardines. In the waters around Howland’s Landing (-118.5226ºE, 33.463º N) we recorded few garibaldi and kelp/calico bass, a single senorita, and an abundance of sardines. Indian Rock is known for its amazing snorkeling, so it didn’t surprise us much that there were more fish there than at Howland’s. What surprised us was in what habitat in which we found those fish. The last place we had expected to see a bright-orange garibaldi was darting in and out of the dark kelp fronds, but that is the only place that we saw them. The same was true for the gray-green kelp bass, which we never saw in its ideal kelp forest habitat, but rather above sandy bottoms, where its dark patterns stood out against the white sand. In contrast, we found a small school of senoritas right where we had expected to: swimming lazily above a sandy bottom. Senoritas blend in perfectly with their surroundings; looking down, the light sand disguises their yellow backs, and looking up, their white bellies are undetectable against the surface. This tells us that senoritas probably feel more of a need to camouflage themselves from predators than the larger, more aggressive calico bass and garibaldi. These three fish display the extremes of the spectrum; they either blend in perfectly, or stand out radically. The sardine is an example of a happy medium, swimming in large schools over any and every terrain. For sardines, it’s safety in numbers, so the need to camouflage themselves is nonexistent.
True or false: Kelp levels affect the populations of different colored fish who live there. Before traveling to Catalina, we believed that the above statement was true. However, after five days of first-hand research, we learned otherwise. Though it is true that where there was more kelp (Indian Rock/Emerald Bay) there were more fish, but it was where we found specific species of fish that our results began to veer from our expectations. As shown by our data sets, many fish do not use kelp as a habitat simply for protection. In fact, some fish, such as the garibaldi and kelp bass, live in habitats that they do not blend in with. Upon coming to this realization, we began thinking that our original thoughts might be flawed. Why would a fish live where it would be exceedingly easy to spot? The only reasonable explanation we could come up with was that fish relied more on the kelp for food than for protection, meaning that their priority was eating, not playing defensive against predators. However, not all fish came with unexpected results. Senoritas, a slightly more vulnerable fish, used their color to the advantage that we had been looking for. Blending in perfectly with their sandy-bottomed home, senoritas exhibited all the self-preservation traits we had been expecting. Finally, there were sardines, which used their fellow sardines for protection rather than their habitat, swimming wherever they pleased. For the silvery sardine, life is good when you keep to the school, wherever that school may be.

Conclusion: It seems that with fish, vulnerability is a discerning factor in choosing a home. A small fish that doesn’t swim in large schools would want to live where it can hide from predators. A large fish, such as a kelp bass, that can handle itself and its predators has no need to hide, and can swim in whichever habitat suits their other needs. Schooling fish can truly swim wherever they please, because their safety is found in their numbers. Whether it is instinct or reasoning, the fish of Catalina choose their habitat wisely.