Gillnets

Generally speaking, gillnets are mesh panels of varying dimension deployed to catch fish. (The word gillnet actually is a misnomer: most fish are caught around their midsection, not by their gills.) Used by fishermen since prehistoric times, the "gillnet" has become a catch-all word describing a multitude of nets -- set, drift, nearshore, offshore, and high-seas. Each type of net is constructed differently and fished differently, targeting different species in different areas. Importantly, in different areas, each net has different effects.

Research has shown gillnets to be among the most size-selective of fishing gears: By regulating mesh size, resource managers can control the size of fish caught. Undersized, juvenile fish pass through the webbing, allowing them to reach maturity before entering the fishery. Gillnets are economically efficient, enabling fishermen to provide a consistent supply of top-quality fish at reasonable cost.

Set Gillnets

Fishermen use set gillnets primarily to catch California halibut, certain shark species, white seabass, barracuda, white croaker, flying fish, and rockfish. Mesh sizes, seasons, and other restrictions vary by species and area.

Set gillnets are anchored to the bottom of the ocean and typically retrieved 24 hours or less after the set. Fish are usually alive when retrieved and are of top-quality when delivered to market.

Halibut: minimum mesh size is 8 1/2" measured diagonally between knots. Available yearlong, halibut landings peak in spring and summer. Virtually all California halibut are caught in water less than 180 feet (30 fathoms) deep. In normal cycles, approximately 75 percent of the state's halibut catch is landed in southern California. Until inshore gillnets were prohibited by the end of 1993, up to 80 percent of the catch was provided by gillnet.

White seabass: minimum mesh size is 6". Season runs June 16 - March 15. Fishermen usually deploy nets near the ocean surface in springtime to catch seabass. In late summer and fall, fish go to the bottom and fishermen set their nets on the bottom. Fishermen also use drift nets submerged under the surface to target white seabass.

Rockfish: Mesh size is 4 1/8" - 5" Nets are set in deep water, sometimes 600 feet deep or deeper, to catch rockfish. Studies indicate that there is virtually no accidental taking of marine mammals in rockfish nets.

White croaker, bonito, flying fish: Mesh size is 2 3/4" - 3".

Drift Gillnets

Attached to the stern of the fishing boat, drift gillnets are usually deployed at night to drift below the ocean surface. These nets are retrieved at dawn.

Drift gillnet fisheries include:

White seabass: minimum mesh size 6". Fishermen drift for white seabass in springtime.

Barracuda: mesh size 3-3 1/2".

With super-wide mesh size of 18-22", California's limited-entry shark drift net fishery operates seasonally, August 15 - December 15. Broad areas of southern California are closed to drift nets during summer to provide an exclusive zone for swordfish harpoon fishermen. Fishermen have cooperated with the Legislature to enact additional seasonal closures to protect marine mammals and conserve the thresher shark resource.

California's swordfish drift net fishery * is among the most valuable fisheries in the Golden State. From 1981 to 1991, California swordfish landings averaged 2.76 million pounds per year, valued at approximately $40 million wholesale. Fishermen deploy super-wide mesh nets no more than one mile in length for both swordfish and thresher shark. These nets are completely different from large-scale, small-mesh foreign high seas drift nets, which may be up to 15 - 20 miles long and fish at the surface, where most interactions with non-target marine life occurs.

California's drift net swordfish and shark fisheries are the most strictly managed net fisheries in the world, with numerous seasonal and area closures implemented to provide exclusive areas for other fisheries and to conserve marine resources. The swordfish fishery is open May 1 - August 14 outside 75 miles of the mainland coast. From August 15 - December 15, both swordfish and shark fisheries are open with sub-area closures and restrictions. The drift net fisheries are closed within 25 miles of the mainland December 15 - January 31 to protect gray whales.

Gillnet Interactions

During the years 1980-1987, the California Legislature enacted 17 bills regulating the use of gillnets in California. Ten bills implemented gillnet closures in nearshore waters from Point Reyes to Point Sal in central California to protect marine mammals and seabirds. Gillnet fishermen cooperated with the Department of Fish and Game to close sensitive areas.

Despite biological studies indicating that marine mammal populations were healthy and expanding in the presence of gillnet fisheries, in 1990 voters passed a controversial ballot initiative, Proposition 132, also called the Marine Resources Protection Act of 1990, which prohibited the use of gillnets within three miles of the mainland coast in southern California and within one mile of the Channel Islands beginning January 1, 1994. In southern California, coastal gillnets interacted primarily with California sea lions and harbor seals.

California gillnet fisheries classified as Category 1 under the Marine Mammal Protection Act's Interim Exemption program for fisheries ("frequent" unintentional taking of marine mammals) have carried observers since 1990. Fishermen continually seek ways to reduce interactions with marine mammals.

As one example, swordfish fishermen helped to fund a study testing the effectiveness of accoustic "pingers" on drift nets to alert whales and dolphins to the net's presence. The experiment was so successful that the National Marine Fisheries Service mandated pingers on California-Oregon shark and swordfish driftnets, effective in the fall of 1996. Observer data indicates that by using accoustic pingers on their nets, fishermen are reducing the rate of cetacean entanglement to near zero.

* For more information on California's swordfish fishery, refer to Fish Facts - Swordfish