Just when you think you’ve seen all the charismatic animals in the Monterey Bay Aquarium’s Kelp Forest exhibit, a lumbering giant catches your eye. It’s the giant sea bass (Stereolepis gigas), a fish that can reach 500 pounds but is so gentle it likes to have its chin scratched by divers.
The Aquarium has four of these enigmatic and threatened fish in different exhibits. The largest—five feet and 177 pounds—is in the Monterey Bay Habitats exhibit. (Update: 188 pounds as of January, 2011.) While smaller fish dash about with bravado, the exhibit’s largest inhabitant lingers in the shadows near the wharf pilings. Despite the fish’s imposing size, visitors can miss it if they don’t look carefully. “I’m not sure why he hangs out in the corner,” says Senior Aquarist Kevin Lewand, who has cared for the all the Aquarium’s giant sea bass since 2004. “He seems to like being next to something.”
This particular fish also qualifies as one of the Aquarium’s elder statesmen, having been here since 1994. Another giant sea bass, acquired in 2003, now weighs over 100 pounds.
“I feel really good about these fish,” says Kevin. “They all started in the Splash Zone Kelp Gallery at about 10 pounds, and you can see how long it takes for them to get this big. They’re a success story for us.”
Hand-feeding a Giant
Kevin really “immerses” himself in his work. Twice each week, he puts on his diving gear and gets in the water to hand-feed the giant sea bass. This helps ensure that they get the right amount of food and are not “out-competed” by faster fish. Kevin has come to enjoy the weekly ritual. “They’re actually bright,” he says of the big bass. “They know who you are and come right over.”
Feeding time is fun to watch. Kevin reaches into his container and waves the food in front of the fish, trying to simulate live mackerel. (The giant sea bass eat prawns, squid, and occasionally salmon on exhibit.) It all goes quickly down the hatch. “The biggest one takes everything,” he says. “He’d take my hand if he could!”
Feeding by hand has another benefit, too. “I know they’re getting a balanced diet,” he says. “If you’re not careful, fish can get pretty fat.”
The Aquarium’s Bass Get a Bath
The Aquarium’s husbandry staff has learned a lot over the years about how to keep giant sea bass healthy. Besides hand feeding, they also give the bass freshwater baths every few months. This helps keep them free of “flukes”—small animals that adhere to the fish like ticks on a dog. The occasional baths also provide an opportunity to measure and weigh the fish, and assess their overall health.
A Better Future for Bass
The fish’s range extends from Humboldt Bay in northern California to Mexico. Once the target of a thriving fishery, the species experienced a precipitous decline starting in the 1960s. In 1981 a law was passed that prevented taking sea bass for any purpose, though small incidental catches were still allowed. Nonetheless, the population continued to decline. The law was amended in 1988, restricting incidental catches even further.
Despite these steps, the giant sea bass is on the “Red List” of the International Union for Conservation of Nature (IUCN), meaning that it’s “critically endangered.”
Merely bringing a giant sea bass to the surface causes its swim bladder to inflate. Thus, for a well-meaning fisherman who catches a bass accidentally and intends to release it, it may already be too late. The now-buoyant fish has difficulty diving, and may fall prey to seabirds and other predators as it bobs on the surface of the water.
Marine Protected Areas—the so-called “Yosemites of the Sea” where human activities are restricted—may give a critical boost to the species in California, providing a place where giant sea bass can safely gather and spawn.
“It’s an iconic fish,” says Kevin. “When the fishery closed in 1981, it was really bad. It’s well regulated now, and we’re hoping they’re staging a comeback.”