Nature Preserve Survey Reveals Over 1,000 Species and Signs of Ocean Change > News > USC Dornsife
To create a comprehensive inventory of marine species in the Blue Cavern Point Nature Preserve on Santa Catalina Island, USC Dornsife researchers dove into kelp forests, scoured museum archives, and came face to face with face with a great white shark. [5 min read]
Blue Cavern Point, on the east end of Santa Catalina Island, about 25 miles off the coast of San Pedro, California, is a hotbed of life. In the shallow edges of the water cling starfish, sea urchins and sea cucumbers. Further out in the deeper seas, bright orange garibaldi and giant piano-sized bass s ‘settle in rolling forests of giant kelp reaching hundreds of feet from the surface of the ocean to its bottom.
The area is divided into two protected areas: offshore and onshore. The land area encompasses the first three square miles of the reserve. Its offshore zone extends about eight miles into the deeper ocean. Since 1988, the area has been fiercely protected from fishing or collecting specimens.
Foraging and pollution have pushed the F. californiansis nudibranch to the brink of extinction. (Image source: WikiCommons.)
Despite the exceptional biodiversity of this region, no one had completed a comprehensive survey of all the creatures that inhabit these waters. In 2015, David Ginsburg, a professor (teacher) of environmental studies at USC Dornsife College of Letters, Arts and Sciences, and Audrey Looby, then an undergraduate student in environmental studies, set out to change that.
Their study, “Nearshore Species Biodiversity of a Marine Protected Area Off Santa Catalina, Island, California,” an inventory of all species in this unique reserve, was published in the March 2021 edition of “Western North American Naturalist.”
They have documented over 1,000 different types of marine macroalgae, plants, invertebrates and fish. Their research also revealed that human activity and climate change appear to be altering these crystal clear waters.
Their project was first inspired by a routine environmental impact inspection of the USC Wrigley Marine Science Center on Catalina Island, where a pipe carries seawater through the lab’s aquariums and back. in nearby Big Fisherman’s Cove.
David Ginsburg has taught at USC Dornsife since 2009. (Photo: Courtesy of David Ginsburg.)
Early in the inspection process, Ginsburg quickly discovered that there was no comprehensive inventory of the marine life inhabiting the area. This posed a problem.
“Here you have this marine protected area and you’re supposed to know what’s in there, but nobody really does,” Ginsburg says. Only a scattering of research articles or incomplete catalogs gave an idea of biodiversity. His interest in undertaking a fuller investigation was piqued.
The scope of the project, however, was daunting. Cataloging each species would require both diving for specimens and diving into archives. Simply surveying the current environment would not capture the full range of what lived within the point. Some species went in and out of the creek, were seasonal, or perhaps so endangered they were rare to find these days. He should go back and find everything that had been recorded in the area.
“I’ve talked to a lot of people about it,” Ginsburg says. “My friend Gordon Hendler [curator of echinoderms] at the Los Angeles Museum of Natural History said, “You’ll never find a stopping point.” Hendler encouraged Ginsburg to pursue the project with a more realistic goal of cataloging as many as he could, given that everything would be an improvement.
Fortunately, Ginsburg wouldn’t have to go it alone. Looby received an undergraduate summer research internship at the USC Wrigley Institute for Environmental Studies, headquartered at USC Dornsife. She would spend the summer on the island and gladly agreed to participate in Ginsburg’s plans. Perhaps, between the two of them, such a complex study had a chance of succeeding.
Under the sea (and in the archives)
USC Dornsife alumnus Audrey Looby is pursuing her Ph.D. in the field of fisheries and aquatic sciences. (Photo: Courtesy of Audrey Looby.)
Looby’s enthusiasm was partly due to his new found passion for diving. She had become certified through USC’s AAUS science diving course and was eager to spend as much time in the water as possible.
Exploring life floating below the waterline was like encountering another planet, Looby says. A neon nudibranch, a mollusk so lively it could easily be mistaken for an invention of Salvador Dali, twisted along the seaweed-covered rocks. Stingrays glided through the currents.
“The first time you see them, you suddenly see the ground moving beneath you and there’s a whole fever of stingrays swimming around,” says Looby, who now has a doctorate in fisheries and aquatic science. student at the University of Florida.
Ginsburg and Looby conducted visual surveys of five intertidal reefs around the tip, meticulously identifying and recording everything from the smallest microalgae to piano-sized bass.
Some of their encounters were noteworthy. On Looby’s last dive this summer, she and her fellow divers spotted a 15ft pregnant great white shark, one of the few sightings ever recorded in the area.
The project also required less adventurous work. The duo scoured thousands of pages of documents from 1960 to the present day looking for records of specimens sighted in the area. Resources included old research papers, museum and herbarium specimen records, and citizen science records.
Through these efforts, the list of specimens sighted in the creek has grown to some 1,100 unique species, all located within the less than three square miles of the reserve.
Ginsburg and Looby’s work has also produced more disturbing findings – how human hands are changing the creek, despite efforts to protect it.
Some changes are more benign than others. Looking through the studies, they found there was no mention of seagrass, or any of the species that typically live among grasses, until the 1990s.
“The leopard sharks and rays that Catalina divers remember probably weren’t there before the dock,” says Ginsburg. “That was another part of the story that I thought was really cool. It’s not just about naming all the species; it’s also about recording really big changes in the ecosystem.
Other findings were darker. The Dali-esque nudibranch, for example, has drastically declined in numbers, likely due to pollution and collection for home aquariums. Starfish like the bat star and the spiny star, despite frequent recordings in previous surveys, were not found during their dives. Unusual sightings of subtropical species like the fine-scale triggerfish in the region indicate warming oceans.
These ecological discoveries combined with their catalog of species – the most comprehensive in history – make Ginsburg and Looby’s study an important foundation for keeping this precious region intact.