Farnsworth Offshore

Farnsworth Offshore SMCA covers Farnsworth Bank, the offshore dive site that defines the back side of Catalina. The bank sits about a mile and a half off Ben Weston Point, rising from a sand floor more than 250 feet down to a series of pinnacles whose tops peak about 50 feet below the surface. It is a seamount, the top of an underwater mountain, and one of roughly 63 along the California coast. The water around it is much deeper than the bank itself, which is what makes the structure dive-able.

The pinnacles are not narrow spires. They are steep rocky hills with flat plateaus at the top, and there are enough of them clustered together that the gaps between form a network of ravines. The ravine walls carry the largest known colony of California purple hydrocoral on the West Coast. The hydrocoral is rare, found in concentration only at a handful of California seamounts including San Clemente Island, Tanner-Cortes Bank, and Cordell Bank, and the Farnsworth Bank colony is the densest of them.

The vertical pinnacles and the deep ravines between them are canyon structure, the sharp depth change that defines that biome. The bank also sits in deep open water about a mile and a half off the back-side coast, with the tidal currents and migratory species that come with that position, which is what makes it a pelagic biome as well.

Access is boat-only. Most charters originate at San Pedro or Long Beach, because the back-side run from Avalon is longer than the mainland crossing. Within Farnsworth Offshore SMCA, take is restricted to spearfishing of white seabass and pelagic finfish, plus hook-and-line take of pelagic finfish. The boundary should be verified with a chartplotter, because the adjacent Farnsworth Onshore SMCA at Ben Weston Point operates under different rules.