Recently, all aspects of the food production industry, including agriculture, aquaculture and commercial fishing, have come under increased scrutiny. Various agricultural practices, such as pesticide use and irrigation techniques, have raised concerns. Some observers have suggested that aquaculture (fish and shellfish farming) may lead to increased water pollution, the spread of aquatic diseases and products high in antibiotics or other contaminants.
Commercial fishing has not been exempt from its share of the debate and here are some of the issues that have been raised.
The commercial fishing industry of California has changed greatly in the past 100 years and no more so than in the regulations governing its practices. At the beginning, all fishermen needed were vessels and a net (or trap or hook and line) and they were ready to fish in California waters. Over time, with the development of modern, more efficient fishing tools, both fishermen and fishery managers realized that some restrictions had to be placed on fisheries in order to insure their survival. Today, myriad laws govern commercial fisheries. These regulations cover who can participate in the harvest, how the resource can be captured, when and where the fishery should occur, and how many and what size the harvested species must be. California's commercial fishermen must be familiar with more than 150 pages of commercial fishing laws, in addition to those that govern any specific "limited entry" fisheries in which they fish.
Below, we present examples of fishery management techniques.
Gear restrictions and gear prohibitions are commonly placed on the use of fishing gear to decrease its efficiency in other words, to reduce its effective catch rate to conserve the resource and protect against overharvesting. One example of a gear restriction is limiting the amount or length of gillnet that can be deployed by one vessel in a specific fishery (e.g. not more than 1,000 fathoms, or 6,000 feet, of gill or trammel net may be fished in combination each day for California halibut in southern California). Minimum mesh size is another form of gear restriction mandated to select the size of fish caught, thus minimize the harvest of undersize or immature fish (e.g. minimum mesh size for halibut is 8.5" measured between knots, which selects for mature halibut measuring more than 22inches total length, the minimum size for this fish). One example of a gear prohibition: the California Fish and Game Code prohibits the capture of white seabass and barracuda with purse seine nets.
Closed seasons and closed areas are often, though not always, combined. The goal of limiting fishing periods or fishing areas is often to limit the catch or to allow mature fishes to spawn. If certain species have well-defined nursery grounds, where young fish are particularly common, closures may also be implemented to protect juveniles. In California, many species are managed via closed seasons, primarily to protect spawning individuals. For example, the harvest of spiny lobster is prohibited from mid-March through early October. The swordfish/shark driftnet fishery is closed within 25 miles of the coast from mid-December to January 31 and is closed completely from February 1 to mid-August to protect thresher shark.
In some fisheries, quotas (catch limits) may be set, either throughout the species' range, within a particular population, or even in a specific area. When the quota is met, the season closes. Fishery managers try to set quotas that allow fishermen a reasonable catch while preserving the fishery resource. Because most fish populations undergo large, natural (and often somewhat unpredictable) swings, setting a quota can be a maddening task for managers and a frustrating experience for fishermen. For instance, there have been numerous cases in salmon fisheries where managers predicted low numbers of fish for a coming year and set small quotas, only to see large numbers of fish return to their spawning grounds. In California, the Pacific herring fishery is governed by a quota, which is set annually by the Department of Fish and Game.
Trip limits, catch quotas per individual fishing trip, may also be instituted. As an example, the groundfish (rockfish, lingcod, flatfish etc.) trawl fisheries off the Pacific Northwest and California have overall poundage quotas for various species; when any one of these is filled, the fishery for that species ceases for the year. Within this fishery, vessels are only allowed to harvest a certain amount of fish per trip, and the number of trips per week or month also is regulated. The main purpose of trip limits is to extend the season over a longer portion of the year.
Minimum size limits are often established and there are several reasons for creating these restrictions. Sometimes they are instituted to ensure a reservoir of mature individuals to help stabilize or increase the resource biomass. Creating minimum size limits insures that a viable portion of the resource survives to reproduce at least once. In other instances, a species only becomes marketable when it reaches a certain size, and minimum size requirements foster a more marketable resource. There are a number of ways to prevent small individuals from being taken in a fishery. In the dive fisheries for sea urchins and abalone, fishermen can see their quarry before harvest and can measure their catch directly. Allowing escapement of undersized organisms is a common technique and this is often based on gear restrictions, most commonly by setting minimum mesh sizes for nets and mandating escape ports in traps. About 35 commercial species fished in California waters are regulated by size restrictions.
Restricting access to a fishery through limited entry is a relatively recent management technique. In limited-entry fisheries, either the right to fish, or the quantities of resource available to an individual fisherman, are restricted. License limitation is a common limited-entry technique. Under this program, the number of vessels allowed to participate in a fishery may be limited (e.g. salmon) or the number of fishermen may be restricted (e.g. urchin divers). In California, most commercial fisheries are regulated through the Legislature, although a few fisheries are regulated by the Fish and Game Commission. A new fisherman may enter a limited-entry fishery through a lottery (sea urchin fishery), by buying a permit (gillnet), or by buying a vessel with a permit (salmon troller).
Another limited entry method receiving attention worldwide is catch rights. The most common version is called an individual transferable quota (ITQ) or individual fisherman's quota (IFQ). Under this method, fishermen receive certificates, representing the right to catch and sell a share of the total allowable catch (TAC). The TAC for each year is set by fishery managers and may vary with fluctuations in the resource. Usually ITQ's are transferable (can be sold, bought, or leased) and they can be assigned to fishermen for a specific time period (annually, for instance) or in perpetuity. Currently ITQ's are not utilized in California fisheries, although federal resource managers are considering adopting ITQ's for specific groundfish species.
(References: Gulland and Carroz 1968, Waters 1991, Boyd and Dewees 1992)
Incidental Catch vs. Bycatch and Discards
Most fisheries catch a complex of species in a typical trip (e.g. groundfish). Fishermen targeting a single species (e.g. salmon) often catch other species incidentally (rockfish, for example). Many times this "incidental catch" is marketable and forms an important part of the fisherman's catch, providing additional revenue to offset the cost of the fishing trip. Many new and delicious seafoods have been discovered by experimental marketing of "incidental" species. For example, angel shark, popular fish and chips fare, are sometimes caught when gillnetting for California halibut. Before markets were developed, fishermen returned these fish to the sea alive as a "bycatch."
In commercial fisheries, bycatch is defined as that part of the catch that cannot be marketed. This may because these organisms are inedible, too small, currently have no market, or are illegal to possess. Bycatch may be returned to the sea alive; utilized for personal use to feed crew and family; or used as bait to catch other seafood species. Bycatch that is dead may also be returned to the ocean as a discard, where it becomes "free lunch" for opportunistic sea creatures. All fisheries have some bycatch: this varies between fisheries, and even varies within a fishery, changing with season, location and slight differences in fishing gear. Fishermen try to reduce bycatch by changing fishing locations or times, or altering their fishing practices.
Probably the best-known example of a fishery bycatch is that involving yellowfin tuna (Thunnus albacares) and various dolphin species. This bycatch occurs largely in the eastern tropical Pacific Ocean (ETP), an 8,000 square mile area roughly bounded by southern Baja California on the north, Peru on the south and out to sea several thousand miles. In these waters, adult yellowfin tunas aggregate under herds of dolphins, swimming juxtaposed in the warm tropical waters. A similar relationship between yellowfin and certain mammal species has been observed worldwide but is particularly notable in the ETP, which provides about 25 percent of the world's canned tuna supply as it is the site of the world's largest yellowfin tuna fishery Why this symbiotic relationship exists is not precisely known, although recent research suggests that the tuna follow the dolphins because the mammals are better able to find the fishes and squids that both species feed on.
In the ETP, the commercial fishery began close to shore about 1919 with pole and line vessels from California. These small boats were called bait boats because they relied on bait found near shore to attract tuna. Fishermen chummed the water, then individually poled the attracted tuna aboard with jigs attached to poles. With improvements in nets, vessels, and net retrieval technology, purse seining (encircling a fish school with a round-haul net) became a far more efficient technique for harvesting these fast-moving, schooling fish. Fishermen recognized that large yellowfin schooled with dolphins farther offshore and, because these mammals leap out of the water, that dolphins were easier to find than the tuna. The purse seine net allowed fishermen to follow the large fish further out to sea, which was impossible when the fishery relied on bait. Scientists also discovered that the dolphins associated with mature tuna stocks; thus by concentrating on dolphin-associated fish, fishermen could increase fishery production without impacting inshore stocks of juvenile tuna.
The purse seine net was introduced in 1957, but the technology had a drawback: unfortunately, when the dolphin-tuna aggregations were enclosed, some of the mammals became trapped in the nets and died. Fishermen, who relied on dolphins to locate fish, realized that these dolphin mortalities were unacceptable (both for humanitarian and ecological reasons) and began experimenting with ways to reduce the problem.
Two of the major advances in reducing dolphin mortality were developed by tuna fishermen. The first was a procedure created in 1957 by Anton Misetich, called the "backdown." In this procedure, the top of the deployed purse seine is intentionally pulled underwater, allowing dolphins to swim over the top of the net and escape. The second advance was the placement in the nets of "Medina panels," developed by Harold Medina. Constructed of fine mesh webbing, Medina panels sewn into the upper part of the purse seine net protected dolphins from becoming tangled.
Over the years, teams of fishermen and scientists have further developed techniques to minimize dolphin mortality in the tuna fishery. Backdowns, Medina panels, advanced skipper training and numerous other techniques springing from research and workshops have been adopted as regulations in the Marine Mammal Protection Act, which was first passed by Congress in 1972 and has since governed U.S. tuna fleet operations in the ETP. (The international tuna fleet fishing in the ETP is supervised by the Inter-American Tropical Tuna Commission, a scientific group which has been very successful at introducing U.S. techniques to foreign fishermen.) These measures have dramatically reduced dolphin mortality in the ETP. For many years, the U.S. tuna fleet has achieved a notable dolphin safety record: more than 99 percent of dolphins encircled are released alive.
In 1990 U.S. canners adopted a "dolphin-safe" policy, refusing to buy tuna caught in association with dolphins. In 1992 Congress also passed the Dolphin Protection Consumer Information Act; canneries may now label their tuna "dolphin safe" if it is not caught by driftnets on the high seas or by encirclement of dolphins in the ETP. However, an extensive study on dolphins and the tuna industry sponsored by the National Research Council concluded: "the committee was unable to identify any currently available alternative to setting nets on dolphins that is as efficient as dolphin seining for catching large yellowfin tuna"
Indeed, some environmentalists and researchers, in addition to fishermen, have begun questioning the wisdom of the current "dolphin-safe" policy. This policy prohibits a catch from being labeled dolphin safe if only one dolphin is encircled, even if it is released unharmed. The prohibition on setting on dolphin has forced fishermen to shift to setting on tuna aggregated under logs or other floating objects. "Log fishing" has produced a 30 percent bycatch rate of juvenile tuna, other fish, and even marine turtles. Scientists estimate that if the entire fleet in the ETP were to fish this way, yellowfin production would be reduced by 30 to 60 percent. Most likely there would be an equally significant impact on bycatch species. Many observers now believe that the most balanced approach is to permit setting on mature tuna associated with dolphin, but to require the use of the best technology and training available, thus minimizing dolphin mortality. Fishermen have suggested that "dolphin safe" be redefined to mean any catch where 100 percent of the involved marine mammals are released unharmed.
(References: Pleschner 1990; Edwards 1992; National Research Council 1992; Kronman 1992; Freeman 1993)
There is a tremendous amount of confusion and misunderstanding concerning gillnets. These are nylon or monofilament nets of many different dimensions and characteristics, which are hung much like a curtain. Gillnets may either drift in the water column, usually attached to the boat, or they may be set, anchored on the ocean bottom. Fish in the area swim into the nets and are caught, usually around their midsection (the term "gillnet" is actually a misnomer). The advantage of gillnets is that they can be regulated to control the size of fish caught, thus targeting mature fish. In fact, gillnets are among the most size-selective of fishing gears. Moreover, they catch fish consistently, even when the fish aren't hungry. In hook-and-line fishing, the fish must be lured into biting a hook, and oftentimes for reasons of their own, the fish don't bite. Used properly, gillnets are a relatively inexpensive and efficient way to provide a consistent seafood supply yearlong. In California waters, there are as many as nine different gillnet fisheries, each of which targets a specific species complex. Eight of these fisheries operate near shore and the ninth, the swordfish/shark driftnet fishery, ranges up to 200 miles or more out to sea.
Many of the problems associated with gillnets are linked to observations and reports of excessive bycatch and unregulated fishing by foreign high-seas driftnet fleets. In contrast, California's gillnet fisheries are among the most strictly regulated fisheries in the world.
The gillnet controversy began several years ago when foreign high-seas drift gillnet fleets from Japan, Taiwan, and Korea escalated operations in the North and South Pacific, fishing for squid and albacore tuna. These fleets deployed small-mesh nets up to 15-20 miles in length, typically set right at the ocean surface, and incurred a large bycatch of seabirds, marine mammals and turtles, as well as salmon returning to spawn in the Pacific Northwest and Alaska. Large-scale driftnetting in international waters has since been prohibited by the United Nations.
Driftnetting off California is a very different endeavor from foreign high-seas practices; it has developed in ways to minimize bycatch. For example, swordfish/shark driftnets are hung suspended so the top of the net is 12 to 60 feet below the ocean surface, depending on water temperature. Most interactions with marine mammals and birds occur at the surface. Similarly, to protect migrating gray whales, California fishermen lobbied successfully for a law prohibiting the use of swordfish/shark driftnets within 25miles of the coast during the whales' peak migration period. (Bottom-set gillnets deployed near shore are prohibited within one mile of headlands during this time, and the nets must be constructed with breakaway panels.) To minimize the bycatch of smaller fish and blue sharks (a species largely unmarketed), fishermen increased the mesh size of swordfish/shark drift nets to 22inches nearly as wide as an open car window.
The California Department of Fish and Game (DFG) closely regulates all of California's gillnet fisheries. Besides the driftnet fishery for shark and swordfish, there are seasonal driftnet fisheries for white seabass, yellowtail and barracuda, and set-net fisheries for rockfish, white seabass, white croaker, flying fish, and an inshore complex that includes California halibut, angel shark, and several other shark species. A six-year study by the DFG on California's gillnet fisheries documented that 83 percent of the catch in the inshore set net fishery was either marketed or released alive. Many inshore gillnetters utilize their entire catch, reserving their unmarketable species for crab bait, which otherwise costs $.15 per pound or more. (Crab fishermen typically use 10 pounds of bait per trap per week, and many fishermen deploy 100 to 200 traps.)
Regarding marine mammals in gillnets, some marine mammals and seabirds do get caught in California's gillnet fisheries, despite precautions. Commercial fishermen make concerted efforts to avoid marine mammals whenever possible, but the mammals have learned to fish the nets (and hooks), and sometimes get caught in the process.
Over the years, gillnet fishermen have cooperated with DFG and the Legislature to implement closures and gear restrictions (such as breakaway panels, for instance) to protect sensitive areas and creatures. Nearshore closures on the central coast and in the San Francisco area to protect sea otters, harbor porpoise and seabirds resulted in the elimination of the halibut fishery in those areas. Coastal gillnets in southern California have virtually no interactions with otters, harbor porpoise or seabirds. Of the eight types of nets utilized near shore, only one, used in the halibut fishery, has had periodic interactions with marine mammals, primarily California sea lions and harbor seals.
In 1990, California voters passed Proposition 132, which phased out all coastal gillnets in state waters of southern California (within three miles of the mainland and one mile of offshore islands) by 1994. This action curtailed local supplies of several popular fish, including California halibut and white seabass.
In addition to DFG regulations, the federal National Marine Fisheries Service (NMFS) has placed observers on California's inshore halibut set net fishery and the offshore swordfish/shark driftnet fishery to monitor the interactions with marine mammals and other marine life, and has required all other fishermen to report any mammals killed accidentally in the course of fishing. (Federal laws exact a $10,000 fine per incident for deliberate harassment or killing of a marine mammal.) The effectiveness of these laws, among other measures, can be seen in the fact that many marine mammal populations in California are approaching or have exceeded historic population levels in the presence of gillnets. This is especially true for gray whales, elephant seals, California sea lions, and harbor seals. Harbor porpoise and sea otter populations also are healthy and increasing. According to marine mammal scientists, there is no evidence that the relatively small number of marine mammals taken in California's gillnet fisheries is having a detrimental effect on their populations.
(References: Pleschner 1990, 1991; Vojkovich et al. 1990; Hanan et al. 1992; Jameson 1993)
Ghost nets usually refer to gillnets which have been lost and, in theory, keep fishing. Netting may be lost due to extreme sea conditions. However, these are expensive pieces of equipment (gillnets cost several thousand dollars apiece) and fishermen take pains to ensure that their equipment does not get lost. More to the point, there is no scientific evidence that ghost nets continue fishing.
Gillnets must be anchored at both ends to stay open and effectively catch fish. This is why set nets are deployed with heavy anchors at each end. Driftnets are deployed with a buoy at one end and the other end is usually attached to the vessel (or to another buoy). This tension holds the net open. When gillnets are no longer held in place by anchors or vessels, they tend to deform quickly, balling up into heaps of webbing. Few fish can be trapped by these masses of material.
Marine mammal interactions with fisheries
Marine mammal populations in California are healthy and expanding in part as a result of protection from hunting and the cooperation of fishermen in developing low-impact fishing techniques. However, increasing populations of marine mammals, specifically California sea lions, harbor seals, and increasingly, sea otters, have created many problems for fishermen.
At heart, commercial fishermen, recreational fishermen, and marine mammals are competitors for many of the same resources. But whereas fishermen are regulated, marine mammals are not in fact, they are fully protected under the MMPA. Federal law does not allow management by resource managers who are mandated to conserve a balance of resources. Accidental entrapment is only one of the interactions that occurs between marine mammals and fishermen. Seals and sea lions are intelligent animals that quickly learn to associate fishing vessels with "free lunch." Sea lions have been documented following a fishing boat for hours, waiting for the fisherman to pull his catch. Gillnetters often retrieve their gear to find only fish heads. This problem is particularly acute in southern California, where marine mammal rookeries and haul-outs now extend throughout all the northern Channel Islands and increasingly along the mainland coast. Rookeries and haul-outs also are expanding at Año Nuevo and the Farallon Islands, in northern California. Gillnet and hook-and-line fishermen report that their only relief from seal and sea lion predation is in early springtime, during breeding season.
A classic example of the resource conflict between marine mammals and man involves the sea otter, Enhydra lutris. Hunted to near extinction during the 1800's, small remnant populations survived in Alaska and along the central California coast. Protection from hunting under international treaty, state law, and finally the federal Endangered Species Act, where California sea otters were listed as "threatened" in 1977, allowed this species to grow and, in Alaska, to reoccupy much of its historic range. Today there are more than 150,000 sea otters in Alaska and the Aleutians, growing colonies in British Columbia and Washington State, and more than 2,000 off the central California coast extending from Pt. Año Nuevo in the north beyond Pismo Beach in the south.
Sea otters are extremely efficient predators, feeding primarily on large shellfishes such as sea urchins, abalones, crabs, and clams. Lacking a fatty layer of blubber, otters rely on dense fur and a high metabolism to stay warm. California sea otters spend most of their time in the chill Pacific Ocean, rarely coming ashore, and they consume 25 percent or more of their body weight daily: a typical adult male consumes more than two tons of shellfish per year (this is muscle material, not counting shell weight).
Among few tool-using animals, sea otters are quite flexible in their feeding behavior, capable of smashing abalone open with a rock or digging three feet down in the mud to capture clams. Otters are able to forage in waters from the intertidal zone down to depths of 300 feet. Numerous studies have documented the impact of sea otters on shellfish resources: otters quickly reduce exposed shellfish numbers to very low levels. In Alaska, overpopulation of sea otters at Amchitka Island in the 1960's resulted in starvation and a die-off, prompting biologists to "translocate" animals to other areas with abundant shellfish reserves.
In California, the near absence of sea otters in the early 1900's enabled shellfish resources to rebound. California sea otters were "officially" rediscovered in Monterey in 1938, coinciding with the decline of Monterey's abalone fishery. By the 1960's sea otters had expanded into rich abalone beds north of Morro Bay: Morro Bay's abalone fishery collapsed in the early 1970's. As the sea otter population has grown, subdominant and juvenile male otters, pushed to the edges of their established range, form"migrant fronts" and colonize new areas where food is abundant. In this wave like fashion California sea otters have increased their range.
Sea otters have been documented as a primary cause for the collapse of several fisheries, including a Dungeness crab fishery in Prince William Sound, Alaska; the red abalone fishery off central California; and the recreational Pismo clam fishery at Pismo Beach. In the Pismo Beach area alone, sea otters were estimated to eat 80 clams per otter per day, consuming an estimated 700,000 clams in one year. Sea urchins also are one of the otter's preferred foods, and continued sea otter expansion jeopardizes the future of a major sea urchin fishery both north and south of the current sea otter range. In fact, sea urchins are now California's top valued fishery.
The controversy over sea otters and shellfisheries has continued since the early 1950's. In 1986, in an effort to achieve a balance between sea otter protection and important shellfisheries, Congress passed an amendment to the Endangered Species Act, enacted as Public Law 99-625, that authorized a "zonal management" system in southern California as part of a translocation of otters to San Nicolas Island, the outermost island in the Channel Island chain. Sea otters were protected at the island and in their central coast range, and a management zone was established throughout the rest of southern California south of Point Conception. PL 99-625 mandated that any otters found in the management zone were to be relocated by federal and state biologists, employing all feasible nonlethal means. The continuation of PL 99-625 now is uncertain, as federal biologists seek to abandon the management zone (state biologists disagree). Biologists and others now acknowledge that continued sea otter expansion into northern and southern California will eliminate fisheries for abalones, sea urchins and clams, and will adversely affect, if not eliminate, fisheries for crab and spiny lobster.
(References: Miller 1974; Calkins 1978; Pleschner 1984; Wendell et al. 1986; Booth 1988)
Americans are increasingly asking questions about the safety of our food, and the rising popularity of "organically" grown produce attests to this growing awareness. Concerns have also risen regarding seafood. In particular, consumers want to be assured that the seafood they eat is wholesome, of good quality, and does not contain hazardous levels of chemical contaminants.
Chemical contaminants may be of two types, natural and man-made. The major natural toxins (biotoxins) are produced by microscopic marine algae, which may be assimilated by filter-feeding bivalve shellfish (oysters, clams and mussels). Concentrated levels of these biotoxins do not harm the shellfish but in humans they can cause paralytic shellfish poisoning (PSP) or amnesiac shellfish poisoning (ASP). PSP in humans is uncommon in California waters and there is no record of any person contracting ASP in this state. The California Department of Health Services tests all of California's shellfish growing areas every week for marine biotoxins, and all harvesters and growers must obtain a certificate from the CDHS prior to harvest.
Pollutants such as various pesticides (e.g.. DDT), industrial chemicals (e.g. PCBs) and such heavy metals as mercury also have caused concerns. These contaminants may enter fishes and shellfishes in several ways. Small amounts are absorbed by these organisms directly from the water through their gills and other tissues. However, most of the pollutants found in aquatic organisms arrive there through the food chain. First, these materials are absorbed by phytoplankton, bacteria, fungi and other small organisms. In turn, these are eaten by larger animals, eventually ending up in the organisms we eat.
California has a wide range of agencies that monitor the marine environment, both the water and the organisms. At the state and federal level, the agencies responsible for this oversight include the California Department of Health Services, Department of Fish and Game, California Environmental Protection Agency, Water Quality Control Board and the National Marine Fisheries Service. At the local level, some sanitation districts also monitor fishes.
How serious a problem is pollutant contamination in California marine seafood? In general, pollution is not considered a significant problem in California's commercially-harvested seafood. One exception came to light in a major study of fishes from southern California (Office of Environmental Health Hazard Assessments, 1991). This research showed that, of important commercial fishes, white croakers from a limited area off southern California (around Santa Monica Bay) should not be consumed. Commercial fishing in Santa Monica Bay is now prohibited. The fishing industry works closely with health agencies to safeguard the ocean and California's seafood supply.
One of the most difficult problems a commercial fisherman faces is the loss of marine resources due to environmental degradation. Water pollution (from pesticides, oil spills, heavy metals, etc.) and the outright destruction of habitat have had a profound effect on the animal life in our ocean. Often this effect is subtle. Rarely, for instance, are there massive kills of fishes or shellfishes off California. More often, environmental alteration acts to reduce the number of larval or juvenile organisms that survive to adulthood. A good example is the California halibut (Paralichthys californicus). After hatching from eggs, larval halibut spend about one month drifting in the nearshore surface waters along our coast. When they are ready to settle out and take up a bottom-dwelling existence, these little fish search for quiet, calm back bays and estuaries, where they live for one or more years. Very few young halibut live on the open coast. Unfortunately, over the last 100 years, most of these coastal embayments have been destroyed, either filled in for housing and businesses or dredged for marinas. Undoubtedly this has decreased the number of California halibut which survive to become adults.
However, in at least one case, commercial fishermen are taking the lead in reversing decades of environmental abuse. California's salmon populations have declined drastically and this has occurred from a variety of causes. Among the leading abuses are poor logging practices which cause erosion and burying salmon spawning grounds, gravel mining which removes spawning gravel beds, and water diversion which lowers water levels and raises water temperatures. Beginning in 1978, commercial salmon fishermen began to tax themselves, creating the Salmon Stamp Program. All of this money, now totaling millions of dollars, goes to restoring salmon populations.
Some of the money has gone into capturing salmon that have entered the once-productive San Joaquin River. This was once a major salmon river, but dams, water diversion and other environmental alterations have created a system with almost no spawning habitat. Salmon which do enter this system usually die without reproducing. Eggs and sperm from these fish are removed, the eggs hatched and the larvae raised in hatcheries. To improve survival rates, the young salmon are often trucked downstream. Research has shown that an estimated 500,000 additional salmon have been added to the fishery through these efforts, and some 250,000 have returned to spawn either at hatcheries or into several Central Valley streams.
But salmon fishermen do more than just donate money towards salmon enhancement; they also donate their time. A good example is the Eel River Salmon Restoration Project, formed by salmon trollers in 1983. This volunteer group focused on improving the habitat of a number of salmon streams in northern California by repairing years of damage done to them. Erosion caused by logging and other activities, is a major problem because it promotes sediment runoff that covers the gravel in which salmon spawn. Trollers planted trees on stream-side hills and removed piles of dirt and tree debris left in abandoned logging areas. Metal culverts, used as bridges in some streams, are also a problem because they impede fish movement. Fishermen removed those that were not needed and, in one case, even built a new bridge to replace a pipe that was still necessary. Many streams have few pools for fish to rest in, and fishermen spent considerable time narrowing stretches of streams, which increased water flow and scoured out new pools. In some cases, fishermen even put new gravel into old spawning areas which had lost this material.
(References: Hashagen 1987, Pleschner 1990b)
Booth, W. 1988. Reintroducing a political animal. Science 241:154-158.
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Edwards, E. F. 1992. Energetics of associated tunas and dolphins in the eastern tropical Pacific Ocean: a basis for the bond. Fish. Bull. US 90:678-690.
Freeman, K. 1993. Dolphin deaths drop even further. Nat. Fish. West Coast Focus, Sept., p. 1-4.
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Hanan, D., L. Jones and M. Beeson. 1992. Harbor seal, Phoca vitulina richardsi, census in California, May-June, 1991. NMFS SWFC Admin. Rpt. LJ-92-03.
Jameson, R. 1993. Results of spring 1993 survey of the mainland California sea otter population. US Fish Wildl. Serv., National Ecology Research Center, Piedra Blancas Research Station.
Kronman, M. 1992. Life in the dolphin safe era. Nat. Fisherman. May, 1992.
Miller, D. J. 1974. The sea otter Enhydra lutris. Its life history, taxonomic status, and some ecological relationships. Calif. Fish. Game, Mar. Res. Leaflet. 7.
National Research Council. 1992. Dolphins and the tuna industry. National Academy Press.
Office of Environmental Health Hazard Assessments. 1991. A study of chemical contaminants of marine fish from southern California. Vol. 2. Comprehensive Study.
Pleschner, D. B. 1984. Sea otters. Pac. Fish., July, p. 39-47.
Pleschner, D. B. 1990. California swordfish gillnetters. Pac. Fish. May, p. 44-51.
Pleschner, D. B. 1990. King of the River. Pac. Fish. June, p. 40-49.
Pleschner, D. B. 1991. Gillnet wars. Pac. Fish. January, p 53-59.
Vojkovich, M., K. Miller and D. Aseltine. 1990. A summary of 1983-1989 southern California gill net observation data with an overview on the effects of gill nets on recreational catches. Calif. Dept. Fish Game.
Waters, J.R. 1991. Restricted access vs. open access methods of management: Toward more effective regulation of fishing effort. Mar. Fish. Rev. 53:1-10.
Wendell, F.E., R. A. Hardy, J.A. Ames and R. T. Burge. 1986. Temporal and spatial patterns in sea otter, Enhydra lutris, range expansion and in the loss of Pismo clam fisheries. Calif. Fish and Game 72:197-212.