Marine Mammal Center opens a new facility in Castroville to serve Monterey Bay animals.

The nonprofit Marine Mammal Center serves a 600-mile stretch of California coastline, with teams of volunteers responding to calls of animals in distress. Their main headquarters in Marin County is where animals stay for extended periods. But its regional hubs that serve to triage animals are an important piece of the puzzle. 

One of those regional hubs was located in Moss Landing until the end of 2024, when a lease agreement with Vistra Corp. came to an end. The Marine Mammal Center found a bigger and more permanent home in Castroville, acquiring a 4,000-square-foot building and erecting white tents (for sun protection) over concrete holding tanks outdoors where animals can be kept. 

They opened for operation about six weeks ago and have already served some 150 sea lions amid a leptospirosis outbreak. "The timing could not be better," spokesperson Giancarlo Rulli says. "There’s a real need right now."

The center celebrates with a grand opening Saturday, Aug. 23, but its first weeks in operation have been busy due to the outbreak, which usually spreads through urine. About two-thirds of rescued sea lions do not survive the bacterial infection because they arrive after it's advanced to a late stage and they are nearing kidney failure or in active kidney failure. Those that are treated early enough with antibiotics can recover, Rulli says. Others are euthanized.

Rulli adds that leptospirosis is a zoonotic disease that can spread from animal to animal and is particularly a concern in dogs; he urges dog owners to keep their animals on leash, and to get them vaccinated.  

The Marine Mammal Center uses municipal water to fill holding pens; the animals, which breathe air, can stay in freshwater for a short period before they are assessed, stabilized and then transported to the main Sausalito animal hospital if they require a longer stay. (That location injects saline into the water.) 

The new Monterey Bay Center was a project in the works for about two years, and Rulli says the organization is happy to have a larger home and a property of its own. "It gives us the opportunity to expand capacity," he says. While animals are kept outdoors, the indoor space can store veterinary equipment and other gear, as well as whale response boats for disentanglement operations. 

This regional center triages about 40 percent of the animals that the organization serves on a 600-mile stretch of coast, with most coming from Monterey and Santa Cruz counties. They are also looking for a long-term home to replace their Morro Bay location, also on a lease from Vistra which intends to expand there. 

The center will serve other mammals besides sea lions, but in its first weeks of operations, it has served exclusively sea lions during a seasonal surge. While the leptospirosis outbreak is a cause for concern—it is spiking much earlier in the season than normal—the influx of sea lions in Monterey Bay at this time of year is typical. 

On Thursday, Aug. 21, the City of Monterey announced San Carlos Beach is closed to human visitors due to an influx of sea lions on the beach. 

"This is normal," Rulli says. "In the last several years, we've seen sea lions returning to the area en masse. The Monterey Bay National Marine Sanctuary is the best marine mammal supermarket that could be offered locally."

The migratory animals, mostly adult and sub-adult males, head northward from Southern California, following their food source (fish). Once they arrive in the Monterey Bay area, they look for flat beaches to rest before their next foraging journey. 

The Marine Mammal Center celebrates its Monterey Bay facility grand opening with an open house at noon-2pm Saturday, Aug. 23. 11125 Commercial Parkway, Castroville. Free to attend. Call 415-289-7325 if you see a marine animal in distress.