Brad Erisman tallies fish while diving in the San Diego-La Jolla Ecological Reserve.
Photo by: Courtesy
Survey compared local environment with two other reserves
The San Diego-La Jolla Ecological Reserve is doing its job.
That's what Phil Hastings, professor of marine biology and curator of marine vertebrates at UCSD's Scripps Institution of Oceanography found in a four-year survey funded by California Sea Grant.
He compared the reserve with two other marine environments: nearby "Boomers" beach south of the reserve and a control site off Palos Verdes in Los Angeles.
"The project," he said, "was an attempt to establish a baseline on the fish community structure in the reserve. We wanted to get a picture of the overall fish community."
The primary method of analysis was simple - counting. Hastings utilized a technique called "belt transects," where divers swim along an unmarked line and count all of the fishes that they see. Matthew Craig and Brad Erisman, both recent recipients of doctorate degrees in marine biology from UCSD, donned the scuba gear.
The pair visited each site six times a year, where they swam transects - all 50 meters long - at depths of 3, 6, 9 and 12 meters.
Each pass took about five minutes and was repeated three times at each depth.
Similar sitings The number of species at each site was very similar, with 52 at the La Jolla reserve and 50 at each of the others. They found the two most common species, the blacksmith (Chromis punctipinnis) and senorita (Oxyjulis californica), the same at all three locations.
But the numbers of individual fishes is what stood out; more than 52,000 were spotted at the reserve, compared to roughly 41,000 at Boomers and just over 16,000 at Palos Verdes.
Hastings summed up his conclusions from the data: "The reserve area - the La Jolla area - has a pretty healthy, diverse fish community."
No baseline available He noted that analysis of the reserve's effectiveness is somewhat limited, as no information exists regarding the state of the area before the impact of humans, or even before the creation of the reserve in 1971. However, he confirmed that the fish population is stronger than at Palos Verdes, which offers a similar habitat but is heavily fished.
"Reserves actually have a significant impact on improving diversity and abundance of fishes," he said.
Hastings advocated the addition of marine reserves and stressed the importance of the La Jolla reserve as an educational tool.
"A lot of reserves," said Hastings, "are way offshore. It is really critical to keep this reserve and perhaps expand it because it's so visible."
The La Jolla reserve's reach could be expanded within the next few years. The Marine Life Protection Act (MPLA), passed in 1999, has spawned an initiative to examine and revamp California's system of marine protected areas (MPAs). The South Coast region, which extends from Point Conception in Santa Barbara to the Mexican border, is currently under review, and the La Jolla reserve is one of the areas that scientists have recommended expanding.
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