The unique marine life of Catalina Island

By Barrett Burnham ‘23

22 miles off the coast of Long Beach California lies Santa Catalina island, boasting one of the most unique underwater environments in the world.

Located in the Pacific Ocean, Catalina is subject to two major ocean currents, the California Current, and the Southern California Countercurrent. The California Current brings colder water down from the northern regions of the Pacific, while the Southern California Countercurrent brings warmer water up from the southern regions.

The influence of these two currents allows for an incredible amount of biodiversity. This is because the cold and warm waters each sustain their own different ecosystems, so when they mix, the ecosystems mix as well. The Catalina Island Conservancy has identified “481 species of fish, seven species of pinnipeds (or fin-footed carnivores, such as seals), four species of sea turtles, and more than 5,000 species of invertebrates”.

This variety is what drew me to Catalina, and I have been SCUBA diving there for about 4 years. This experience has led me to be able to view and photograph many of these unique species and their habits.
Garibaldi

*Garibaldi over an algae forest - Photo by Barrett Burnham ‘23*

The state fish of California, the Garibaldi, is the most common type of fish found in Catalina. They mostly inhabit shallow rocky reefs and can be found pretty much anywhere around the island. The fish’s bright orange color and naturally curious nature lead to it being easy to spot when diving or snorkeling.

Garibaldi are solitary fish for most of their lives until they find a mate. They are very territorial, establishing territories that they defend from other Garibaldi and other fish. They will even charge inquisitive divers who get too close to their territories.

These territories are often rather small, only encompassing a small portion of a rocky reef. Garibaldi have very distinct ideas of where their territories end, and two garibaldi can be up to two feet apart without issue, as long as each is in their own territories.

California Two-Spot Octopus

The California two-spot octopus can be found in rocky reefs up to 65 feet deep, an uncommonly shallow depth for most species of octopi. The octopi can tolerate a range of temperatures from 60-80 degrees Fahrenheit, but much prefer a range from 65-72 degrees. This makes the waters off Catalina perfect for the octopus, as the converging warm water and cold water currents create this ideal temperature.

The octopus gets its name from the two blue spots that can be found on the side of the body. These spots serve as false eyes used to dissuade predators from bringing the octopi’s life to an untimely end.

The octopi are often found nestled into the cracks and crevices found in their preferred rocky reefs, but they have also been known to use debris left from human pollution as shelter as well. They do this because they are quite vulnerable to predators when out in the open sea, and the shelter of the rocks and stones provides protection.

Another way that the octopi protect themselves from predators is through their biological defense method of changing color. This is used primarily to better camouflage the octopi while they are in their dens or out in the open. This color change is made possible by leucophores, the pigment-bearing cells in an octopi’s skin that can choose a color of light to reflect, changing the octo’s color.

These octopi are also incredibly sensitive to poor water quality, especially when it is caused by pollution. This becomes problematic for them, as they inhabit coastal waters where humans often dump their waste into the ocean. Fortunately for the octopi by Catalina though, Catalina has no major sources of water pollution, making the island’s rocky reefs perfect for the octopus to inhabit.

California Spiny Lobster

Found at depths up to 100 feet underwater, the California spiny lobster is an incredibly unique species of lobster. This lobster has no claws and instead has two large antennae that protrude from its head, and is covered in tiny spines to defend itself.

Without claws, the lobster has much weaker self-defense. This results in the lobster acting much more skittish, using its tail to quickly swim away when threatened. The spines that cover its body serve as an effective deterrent to predators, especially when used in combination with its powerful tail.

Another way that the lobster protects itself is by creatively using its antenna to make up for its poor eyesight. The lobster uses its large antenna to detect nearby objects and potential threats. Additionally, the lobster can use its antenna to create an alarming grating noise that intimidates predators.

California Scorpionfish

One of the most venomous creatures in the ocean, the California Scorpionfish can be found up to 600 feet deep, often nestled in rocks and algae.

The scorpionfish is most famous for its venomous spines that it uses to defend against predators. This venom is potent enough to kill most predators, but in most cases is not enough to kill a human.

While photographing one of these venomous fish, I was most certainly worried about being stabbed by one of those spines, but luckily, there was little need to be worried. The scorpionfish does not actively desire to stab humans, and would much rather use its natural camouflage to lay in wait for a tasty-looking crustacean, squid, or octopus to obliviously swim past.

Due to this camouflage and tendency to lay low on the seabed, scorpionfish can be hazardous to people wading in the surf. Wading through the surf removes people’s ability to see the scorpionfish, and means that they may accidentally step on the fish resulting in an incredibly painful wound.

Horn Shark

Sharks often bring an image of a massive, man-eating great white swimming through the sea, looking for its next victim. However, when looking at horn sharks, this couldn’t be further from the truth.

Horn sharks are relatively small, only growing up to four feet long, and they live a very sedentary lifestyle. Oftentimes horn sharks can be found nestled in a crack or crevice, lying in wait for a small invertebrate to attack. Horn sharks are not very graceful swimmers either, often running into undersea objects when in pursuit of their prey.

Horn sharks are of no danger to humans, in fact, humans are more of a danger to horn sharks. Horn shark populations have been dwindling recently, due to overhunting. Horn sharks are often caught as bycatch by large commercial fishing boats, and are killed in the massive nets the boats use.

This unique marine environment is amazing, but it is in danger of vanishing due to climate change and overfishing. The changing climate is driving ocean temperatures up, forcing a shift in the balance of temperatures that keep the environment going. Climate change is truly the greatest threat to these wonderful species, and if not addressed soon, these species could no longer exist.