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What lies beneath the surface of Morro Bay’s harbor? We took a dive to find out

Morro Bay is known for its dramatic sights, sea otters and surfing, but there’s a hidden world under the water’s surface that is more difficult for people to explore.

So, the Tribune’s summer science fellow and marine scientist Joana Tavares and intern reporter Mariana Duran took a plunge in the bay’s cold waters to document some of the wildlife that lives under the shadow of Morro Rock.

Guided by local ocean enthusiast and expert diver Caroline Skae, the reporters swam through kelp and rocks and took a look at some of the colorful species that live in the area.

Swimming through kelp in Morro Bay “is just like being in a wonderland,” Skae told the reporters before the dive. “It just looks so unreal. ... Even if you don’t see any wildlife, just watching the way the water is here and the colors and the seaweed is really beautiful.”

The group went free diving near Target Rock, a dive site with abundant marine life because of an artificial reef created by boulders placed at the entrance of Morro Bay’s harbor.

Diving in this area can sometimes be dangerous due to the strong currents and potential kelp entanglements, so it’s important to go accompanied by someone familiar with Morro Bay, such as Skae.

Fish swim through the giant kelp that creates a refuge for the many sea otters that rest near the shore of Morro Bay.
Fish swim through the giant kelp that creates a refuge for the many sea otters that rest near the shore of Morro Bay.

With cold water and murky visibility, diving in Morro Bay is not always easy, but in good conditions, such as the ones The Tribune had during its swim, divers can find a colorful world full of marine wildlife and vegetation.

Target Rock has some bright green eelgrass and lots of kelp, both of which provide protection for many marine species. Some of these creatures grow on the kelp leaves, like the crust bryozoan, or even use the kelp as a food source, which is what bright purple sea urchins do.

A purple sea urchin clings to a rock in Morro Bay.
A purple sea urchin clings to a rock in Morro Bay.

Sea otters and sea stars like eating these urchins in turn, but with both of their populations decreasing, sea urchins have begun to proliferate, reducing the amount of kelp in the area in recent years.

Other invertebrates found among the rocks included bright red sea stars, mussels, hermit crabs, barnacles and an orange sea cucumber that shapeshifted when it began to eat plankton using its extended tentacles.

Orange sea cucumbers hide between the algae of Target Rock in the Morro Bay harbor.
Orange sea cucumbers hide between the algae of Target Rock in the Morro Bay harbor.

Several fish were also seen swimming along the reef, including a long and eel-like monkeyface prickleback frowning from its hideout in a small crevice.

The colorful wildlife isn’t all that Morro Bay’s underwater offers, though. The area is a marine estuary, a place where saltwater and freshwater meet.

Many of the kelp leaves in the Morro Bay harbor have white patches, which are actually animals called crust bryozoans.
Many of the kelp leaves in the Morro Bay harbor have white patches, which are actually animals called crust bryozoans.

According to Morro Bay National Estuary Program’s executive director Melodie Grubbs, Morro Bay is “one of the smallest” National Estuary programs but it’s also “one of the most healthy and thriving estuaries, at least in California.”

Like other estuaries, Morro Bay is a transitory ecosystem that creates a safe habitat for migratory species, such as fish or invertebrates that are reproducing and hungry sea birds, Grubbs said.

An orange sea star rests on the floor of the Morro Bay harbor. Sea stars are predators that eat invertebrates such as purple sea urchins.
An orange sea star rests on the floor of the Morro Bay harbor. Sea stars are predators that eat invertebrates such as purple sea urchins.

Estuaries can protect people too. Their vegetation and muddy soil have the ability to “sequester huge amounts of carbon out of the air,” Grubbs said.

By sequestering carbon, the estuaries can help mitigate climate change, as they are able to reduce the amount of CO2 in the atmosphere. So by protecting areas like Morro Bay, people can help the planet cool off.

A pink sea star clings to a rock in the Morro Bay harbor. Sea stars are predators that eat invertebrates such as purple sea urchins.
A pink sea star clings to a rock in the Morro Bay harbor. Sea stars are predators that eat invertebrates such as purple sea urchins.