Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance

American Fisheries Society Symposium 70:703 742, 2009 2009 by the American Fisheries Society Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance Fr e d J. Bu e * a n d Bo n n i e M. Bo r b a Alaska Department of Fish and Game, Division of Commercial Fisheries 1300 College Road, Fairbanks, Alaska 99701, USA Richard Cannon Office of Subsistence Management, U.S. Fish and Wildlife Service 1011 East Tudor Road, Mail Stop 121, Anchorage, Alaska 99503, USA Ch a r l e s C. Kr u e g e r Great Lakes Fishery Commission 2100 Commonwealth Boulevard, Suite 100, Ann Arbor, Michigan 48105, USA Abstract. The most abundant salmon of the Yukon River is chum salmon Oncorhynchus keta, which make annual spawning runs from the Bering Sea up the Yukon River, traversing more than 1300 river miles across Alaska into Yukon Territory in Canada. Genetically distinct summer and fall runs exist and these runs are differentiated into stocks by timing of migration and by spawning river. The fall-run stocks are harvested from mid-july through early October and most Yukon River fisheries occur on a mixture of populations or stocks. This paper provides descriptions of fall chum salmon life history, the Yukon River fishery and its management, changes in stock abundance over time, and harvest. Six fisheries occur for fall-run chum salmon: subsistence, personal use, aboriginal, domestic, sport, and commercial. Subsistence fisheries in Alaska are comparable to aboriginal fisheries in Canada, as are personal use, sport, and domestic fisheries. The fisheries use a variety of gear including gillnets and fish wheels. Jurisdictionally, management requires cooperation among state, federal, and international organizations during both the ocean and river phases of the salmon life history. The goal of management is to regulate the harvest of commercial and traditional-use fisheries to provide an adequate number of fish for spawning (escapement) to ensure the reproduction of the next generation, and to sustain Alaskan and Canadian fisheries. Subsistence and aboriginal fisheries have priority over other fisheries in allocation of harvest. Regulations are used to control how many fish are caught through restrictions on effort, fishing efficiency, and the scheduling of where, when, and how long fishery openings will be allowed. Over the period 1974 2008, the largest runs of fall chum salmon occurred in 1975, 1995, and 2005 (> 1.47 million fish) and smallest runs occurred in 1999, 2000, and 2001 < 334,000 fish). Oddyear runs tend to be larger than even-year runs. The run failures of 1998 2002 were followed by increased run numbers in 2003 2008. Primary variables that influence the total run of fall chum salmon are the spawning success of previous generations, * Corresponding author: fred.bue@alaska.gov 703

704 Bue et al. natural variability in marine and freshwater survival due to climatic and oceanographic processes, and fishery harvests in both marine and freshwater. Salmon escapement numbers typically emulated total run estimates. Every river monitored had low estimated escapements from 1998 2002. From 1974 2008, total harvest of fall chum salmon in Alaska (average 291,982 fish) exceeded Canadian harvests (average 20,314 fish) by an order of magnitude. Some lessons learned from management of this fishery are offered that may be applicable to other fisheries: stakeholder involvement is critical to effective harvest management; rapid, effective information sharing is a requirement for fast-paced, in-season decision-making; limited entry alone did not control harvest; and some things that make management difficult just cannot be changed! Introduction The Yukon River originates in British Columbia, Canada and flows over 2,300 mi to its mouth on the Bering Sea coast of western Alaska in the United States. Fewer than 130,000 people live in the drainage basin. Two urban communities, Fairbanks and Whitehorse, are located on a limited road system and account for about 80% of this population in the basin. The remainder of the population resides in over 80 small, remote villages with populations averaging 300 or fewer residents of predominately aboriginal background (Williams 1999; DCED 2002; Statistics Canada 2002). Most village residents depend to varying degrees on fish and wildlife resources for food. The most abundant salmon is chum salmon Oncorhynchus keta, which make annual spawning migrations from the Bering Sea up the Yukon River. Genetically distinct summer and fall runs exist and these runs are organized into populations (or stocks) by spawning site, typically tributary rivers within the sub-drainages (see review Utter et al. 2009, this volume). These stocks are available for harvest from June through early October, and most Yukon River fisheries harvest a mixture of populations or stocks. Three large tributaries of the Yukon River including the Koyukuk, Tanana, and Porcupine rivers all contribute immensely as chum salmon spawning areas. The fisheries in Alaska and Canada for chum salmon occur in the nearshore coastal areas around the mouths of the Yukon River, along the entire length of its main-stem, and in many tributaries. The fall-run salmon are harvested in Alaskan subsistence and personal-use fisheries in Alaska, and in Canadian aboriginal and domestic food fisheries. Commercial fisheries also exist in both countries depending on run abundance in a particular year. The fisheries use a variety of gear including gill nets and fish wheels. In addition to chum salmon, Chinook O. tshawytscha and coho O. kisutch salmon are important contributors to the Yukon River fisheries. The Yukon River drainage also supports sockeye salmon O. nerka, which are relatively rare, and pink salmon O. gorbuscha that are abundant (in millions) but undesirable in the fisheries. Therefore both species are minor components of the harvest. Other species present in the subsistence and/or sport fisheries include Arctic grayling Thymallus arcticus, Dolly Varden char Salvelinus malma, inconnu Stenodus leucichthys, northern pike Esox lucius, burbot Lota lota, several Coregonus species, and Alaska blackfish Dallia pectoralis. Large harvests occur for whitefish and sheefish species for subsistence throughout the drainage while the other species have more localized harvests. This paper provides descriptions of fall chum salmon life history, the Yukon River

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance fishery and its management, changes in stock abundance over time, and harvest. Harvest is regulated to provide escapement from the fisheries so that spawning will produce the next generation and sustain the fishery. Regulations are also used to allocate harvest among those fishing on the river and were originally based on traditional usage patterns and gear types. Life History Summer and fall runs of chum salmon are distinguished from each other by entry date to the river from the ocean, by body morphology (where fall chum salmon are typically more robust and have a higher body fat content than 705 summer chum salmon), and by spawning locations in the Yukon River drainage. Summerrun chum salmon enter the river in June and July, and spawn during July and August in the tributaries of the middle (including the Tanana River 1,000 mi from the sea) and lower Yukon River (below river mile 500) (Buklis 1981). Fall-run chum salmon enter the river in mid- July, August, and early September and spawn in spring-fed tributaries and upwelling areas of the upper Yukon River drainage from the Tanana River in Alaska upstream into Yukon Territory, Canada (Buklis and Barton 1984; Figure 1). Most fall chum salmon stocks of the Yukon River migrate unusually long distances upriver in comparison to other chum salmon stocks in North America (Salo 1991). Impor- Fi g u r e 1. Location of major fall chum salmon Oncorhynchus keta spawning areas and monitoring projects in the Yukon River drainage.

706 Bue et al. tant spawning tributaries include the Tanana, Porcupine (tributaries Sheenjek and Fishing Branch rivers), and Chandalar rivers, and the main stem of the Yukon River in Canada. A few fall chum salmon stocks occur downstream of these areas, such as in the Koyukuk River, but these stocks typically comprise less than 5% of the total run (Eggers 2001). Based on genetic data from allozymes, microsatellites, mitochondrial DNA, and amplified fragment length polymorphisms, Yukon River chum salmon populations are structured by seasonal race (summer versus fall) and by geographic region associated with tributary location in the drainage (Wilmot et al. 1994; Scribner et al. 1998; Olsen et al. 2004; Flannery et al. 2007). The level of population differentiation and geographic specificity of stocks, however, is less for chum salmon than observed for some other salmon species such as Chinook salmon (Utter et al. 2009). For management purposes, chum salmon entering the Yukon River after July 15 are considered fall chum salmon; however, late entry of summer chum salmon stocks can occur after this date and have been detected based on genetic analyses (JTC 2008). Egg incubation occurs overwinter, and fry emerge in the spring (April) and immediately migrate downstream with the recession of spring-run off to the Bering Sea. Based on tagging studies, Yukon River chum salmon feed and grow until maturity in the Gulf of Alaska and eastern Bering Sea (Myers et al. 2009, this volume). Maturity occurs after two to six years of ocean feeding (Bales 2008). Prior to river entry, maturing Yukon fall chum salmon are distributed across a broad area in the western Gulf of Alaska, along the Aleutian Islands, and eastern and western Bering Sea (Myers et al. 2009). Fall chum salmon may be caught in the False Pass salmon fishery in the Aleutians (Seeb and Crane 1999) and as bycatch in the southeastern Bering Sea walleye pollock trawl fishery (Gisclair 2009, this volume; Wilmot et al. 1998). Description of the Fisheries Prior to European contact, aboriginal populations living in the drainage developed a well-defined dependence on the abundant salmon resources. The harvest, distribution, and use of locally available, wild fish resources continue to provide essential economic, nutritional, cultural, spiritual, and social benefits to village households (Barker 1993; Berger 1985; McClellan 1987; Fienup-Riordan 1986; Wolfe and Spaeder 2009, this volume). Today, some of the fall chum salmon are frozen, dried, or smoked, and roe from females are preserved for later human consumption. However, a large percentage of salmon caught by the upper Yukon River communities are dried or frozen and fed to sled dogs (Figure 2; Andersen 1992). Six fisheries for fall chum salmon are identified by U.S and Canadian managers: subsistence, personal use, aboriginal, domestic, sport, and commercial. Subsistence fisheries in Alaska are comparable to aboriginal fisheries in Canada. Both fisheries provide for the traditional and cultural use of fishery resources. In Alaska, the subsistence fisheries are open to all state residents in areas under state management, and to qualified rural residents in areas under federal management (Buklis 2002). The Canadian aboriginal fishery is only open to First Nations people. Personal-use fisheries in Alaska and Canadian domestic food fisheries allow access to the fish for noncommercial purposes to residents in nonsubsistence areas in Alaska and to nonaboriginal residents in Canada. These fisheries provide Alaskan residents near Fairbanks and nonaboriginal Yukon Territory residents, an opportunity to efficiently harvest fish near their communities. Personal-use and domestic food fisheries are considered by management agencies as a lower priority than subsistence or aboriginal fishing in the allocation of harvest (Borba and Hamner 2001).

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance 707 Fi g u r e 2. Fall chum caught from the Yukon River fillets are cut to improve drying and and laid over poles to dry (photos by Mike Parker, ADF&G). Sport (recreational) fisheries in both Alaska and Canada harvest inconsequential numbers of fall chum salmon (Burr 2008). The sport fishery harvest of chum salmon occurs in areas accessible by roads such as the Tanana River near Fairbanks, but focuses primarily on Chinook and coho salmon (JTC 2008). Commercial fishing for fall chum salmon in the Yukon River is based on in-season assessment of run size and is managed to allow harvest for surplus fish that exceed those needed for spawning and for subsistence and aboriginal fisheries. Coho salmon are also caught in the fall season fisheries due to the overlap in run timing. In Alaska, commercial fishing may be allowed along the entire 1,200-mi length of the mainstem Yukon River and the lower 225 river mi of the Tanana River. The majority of the commercial harvest, however, occurs in the lower river downstream of the village of Russian Mission (river mile 213) where the flesh quality of the salmon is higher (Figure 1; ADF&G 1993). The fish sold are used for human consumption (fresh, frozen, smoked, and roe) and some are sold as dog food. Fish caught in the upstream districts are typically sold for roe as its ripeness is prime for the market after adult females have passed upstream of river mile 300. The Canadian commercial fishery is conducted in the main-stem of the upper Yukon River downstream of Dawson City. During recent years, the fall chum salmon commercial fishery is somewhat of a misnomer as virtually all of the catch by the license holders is used to feed their personal sled dog teams (JTC 2008). Overview Fishery Management Management of the Yukon River fall chum salmon fishery is difficult because of biological, geographical, and political complexity. Fisheries for fall chum salmon occur along the entire length of the river and harvest a mixture of stocks that enter the river over a protracted late summer and fall period. Thus, management of individual stocks or populations on the mainstem Yukon River is not possible. Because the Yukon River fisheries are largely mixed-stock fisheries, some tributary populations may not be harvested to the

708 Bue et al. levels they could sustain in relation to their abundance while others, in a particular year, may suffer overexploitation. Harvest issues exist between fishers in the lower-river versus upper-river fishers in Alaska and Canada. Fisheries that occur in the first few hundred miles of river have first access to the salmon runs before assessment of run abundance can be made. If run strength is projected to be low based on assessment in the lower river, then fisheries are restricted in-season. The effects of the regulations can be disproportionately felt by the upriver fisheries because of the sheer length of the river and the protracted time of fish entry. However, if the in-season estimate is below the actual run strength, the salmon will have already passed through the fishery and the result may be a substantial lost opportunity. Lastly, the fisheries in Alaska harvest Canada-bound chum salmon that travel over a thousand miles to their spawning grounds in Yukon Territory. The Yukon River Annex of the Pacific Salmon Treaty between the United States and Canada guides management of these trans-boundary stocks. The salmon fisheries of the Yukon River drainage are managed to achieve escapement goals in specific streams, to ensure passage of salmon from Alaska into the Canadian portion of the drainage, and when salmon abundance is projected to exceed negotiated escapement goals, to provide for consumptive uses. The details of the agreement are described in the Yukon River Salmon Agreement of 2001 (http://www.yukonriverpanel.com/library/ Other/YRS%20Agreement.pdf ). Management authority Management of salmon during their ocean phase is a complex blend of state, federal, and international authority (Gaden et al. 2009, this volume). In international waters (beyond 200 mi from Alaska s shores, governance occurs through the North Pacific Anadromous Fish Commission (NPAFC). Members of NPAFC include Canada, Japan, The Republic of Korea, Russia, and the United States. NPAFC representatives are responsible for estimating commercial salmon catch, understanding the variables affecting salmon survival, conducting salmon research (including convening scientific workshops and symposia), sharing information about each party s activities, and coordinating law enforcement. The ocean waters, from three miles to 200 mi offshore of Alaska, is referred to as the Exclusive Economic Zone (EEZ) and is managed through the North Pacific Fishery Management Council established by the Magnuson-Stevens Fishery Conservation and Management Act (USGPO 1976). The council has broad representation including the State of Alaska and is coordinated by the U.S. Federal government through the National Marine Fisheries Service. The state of Alaska has sole jurisdictional authority from the coastline out to three miles. In Alaska freshwaters, a dual management system currently exists between the state of Alaska and the U.S. federal government. The Alaska Department of Fish and Game (ADF&G) and a state regulatory Board of Fisheries (BOF), supported by fourteen local advisory committees representing the different geographic regions of the Alaskan portion of the Yukon River drainage, is the primary management authority for the Yukon River in Alaska. In 1999, the U.S. federal government assumed a management responsibility that may choose to supersede state authority for subsistence fisheries on U.S. federal public lands in Alaska, consistent with the mandates of the Alaska National Interest Lands Conservation Act of 1980, and subsequent judicial decisions (Buklis 2002). These lands comprise approximately 50% of the Yukon River drainage in Alaska. Subsistence fishery regulations in federal waters generally parallel state management and are under the purview of a regulatory Federal Subsistence Board.

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance In Alaska, subsistence fishing opportunity has priority over personal use, sport, and commercial fisheries for the consumptive uses. Management by the State of Alaska is guided by regulations adopted by the Alaska BOF. The Policy for the Management of Sustainable Salmon Fisheries (5 AAC 39.222, effective 2000, amended 2001; http://www. adfg.state.ak.us/special/susalpol.pdf) directs the ADF&G to provide the BOF with reports on the status of salmon stocks and to identify any salmon stocks that present a concern related to yield, management, or conservation during regularly scheduled BOF meetings. The Department of Fisheries and Oceans (DFO) is responsible for fishery management in the Canadian portion of the Yukon River drainage. DFO works closely with the Yukon Salmon Committee, a regulatory advisory body representing stakeholders, to develop fishery management plans (DFO 2003). Coordination of management of fall chum salmon between the U.S. and Canada is provided through an agreement appended as an annex to the Pacific Salmon Treaty. In 2001, after sixteen years of negotiation, agreement was reached on the conservation of Yukon salmon between the U.S. and Canada. This agreement revised the annex and created a bilateral Yukon River Panel, and set escapement goals and harvest sharing of the total allowable catch for Canadian-origin fall chum salmon stocks. The Panel s focus on fall chum salmon stocks is on those that spawn in the Canadian portion of the Yukon River drainage because these stocks require U.S. protection to ensure adequate numbers pass upstream across the border (border passage) for spawning and providing for fisheries in Canada. The Panel makes recommendations to management agencies in both countries. A Joint Technical Committee (JTC) composed of fishery managers and scientists from both countries advises the Panel. Stakeholder involvement 709 Stakeholders share local knowledge and recent harvest information from their local communities with Alaskan and Canadian agency biologists during weekly teleconferences (sponsored by Yukon River Drainage Fisheries Association (YRDFA)) held during the fishing season. Similarly, the agency biologists report on their fishery stock assessment data and in-season projections. This tradition of information sharing first began in 1993 and provides a real-time exchange of quantitative and qualitative information useful for assessing (in-season) the strength of the ongoing salmon run. In addition, committees of stakeholders representing the Alaska fisheries typically meet during the late fall, winter, and spring months to discuss with state and federal managers the past season, and to plan for the coming season. Fishermen s groups such as YRDFA have worked closely (by consensus) on issues brought before the regulatory body, the Alaska BOF, by working with ADF&G in developing the fall chum salmon management plans along with modifications as needed, based on changes in the fishery and the development of new tools for assessment. Over the past few years, YRDFA has also provided an international educational exchange between the fishermen of Alaska and Canada at the level of the subsistence user. Fishery management goals The primary goal of management is to regulate the harvest of commercial and traditionaluse fisheries to provide an adequate number of fish for spawning (escapement) thus ensuring the reproduction of the next generation, and to sustain Alaskan and Canadian fisheries. Management plans in Alaska and Canada comprise a suite of guidelines that help both managers and stakeholders to understand the steps necessary to meet the goals for escapement and

710 Bue et al. harvest prior to the fishing season. However, they also have the flexibility to adjust regulations in-season based on on-going assessment. Escapement and harvest objectives are established by the Alaska BOF, ADF&G, and by the Yukon River Panel within the framework of the annex to the Pacific Salmon Treaty. In Alaska, emergency order authority by the ADF&G and special actions by federal managers are used to implement time and area openings or closures and gear restrictions within very short time frames (e.g., within 24 h). Commercial fisheries in Canada are also confined to specific fishing areas where DFO announces openings and closures. Escapement goals Escapement goals specify the minimum number, or optimal range, of salmon in the run that should be allowed to spawn to ensure adequate natural reproduction required to sustain the next generation. In Alaska, the current goals are known as biological escapement goals or BEGs. ADF&G establishes BEGs based on stock recruitment relationships and manages for maximum sustained yields (MSY) (Eggers 2001). ADF&G manages the fall-season fishery as prescribed in the Yukon River Drainage Fall Chum Salmon Management Plan (5 AAC 01.249) as amended by the BOF in January 2004 (Table 1). The plan establishes a range for a drainage-wide BEG of 300,000 600,000 fall chum salmon. When the run is projected to be below 300,000 fall chum salmon, all fishing is closed. The only exception is when an individual stock may exceed its own specific escapement goal; then a subsistence fishery may be allowed. When the run size is projected to be between 300,000 and 500,000 fish, the subsistence fishery harvest is managed to achieve an escapement goal of 300,000 fish and personal-use and sport fisheries may be opened when an individual stock exceeds its escapement goal. When the projected run size is more than 600,000 chum salmon, a drainage-wide commercial fishery may be opened to harvest the surplus of above 600,000 chum salmon. As performance measures, ADF&G monitors run abundance and harvest levels in relation to the established individual tributary BEGs and the drainagewide BEG to assess whether escapement levels have been met; this includes assessment of harvest levels in the different fisheries. BEGs have been established for specific tributary systems within the upper Yukon River, including the Tanana River (61,000 136,000 spawners), Delta River (6,000 13,000 spawners), Toklat River (15,000 33,000 spawners), Chandalar River (74,000 152,000 spawners), and Sheenjek River (50,000 104,000 spawners) (Eggers 2001). Review of these BEGs is planned for 2009 in preparation for a regular cycle BOF meeting, adding seven more brood years since last evaluation and a more complete evaluation of the Kantishna/Tokat River contribution. In addition to meeting river-specific BEGs, management in Alaska (state and federal) must also consider the border passage and escapement of Canadian-origin stocks that traverse the Yukon River but are harvested in the Alaskan fishery. Under international agreement, the fall chum salmon fishery in Alaska is managed to deliver to the Canadian border a specific number of fall chum salmon to meet the spawning escapement and fishery needs of the upper river residents. Escapement goals for Canadian waters include greater than 80,000 spawners for the mainstem system, and a range of 50,000 120,000 spawners upstream from the Fishing Branch weir site in the Porcupine River (JTC 2008). The escapement goal for the Fishing Branch River has only been achieved ten times since 1974 and has been under review for the past several years. For the period 2008 2010, the JTC recommended an interim management escapement goal of 22,000 49,000 fall chum spawners and the Yukon Panel approved this recommendation (JTC 2008).

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance Ta b l e 1. Yukon River drainage fall chum salmon O. keta management plan. Subsistence fishing is managed to achieve a minimum drainage-wide escapement goal of 300,000 salmon. When projected run size is above 600,000 salmon drainage-wide, commercial fisheries may be opened and the harvestable surplus of above 600,000 fish is distributed by district or sub-district in proportion to the guideline harvest levels (5ACC 05.362 (f) and (g) and 5ACC 05.365). 711 Run size range Recommended management actions Targeted estimates escapements (numbers of (numbers fish) of fish) Commercial Personal Use Sport Subsistence <300,000 Closure Closure Closure Closure a 300,001 Closure Closure a Closure a Possible 300,000 to to 500,000 Restrictions a 600,000 500,001 Closure Normal Retention Normal to 600,000 Closure schedule allowed Schedule >600,000 Commercial Normal Retention Normal fishing schedule allowed Schedule considered a Less restrictive regulations may be allowed in areas where in-season project data suggest escapements will be achieved. Information for decision-making Escapement goals are the foundation for management because they help ensure the long-term conservation of salmon stocks, and thus have a logical priority to be met before harvest objectives are considered. Herein lays the greatest challenge to management! Reliable information on the actual run size in a particular year is not known until the majority of returning fish have entered the river, traversed often more than 1,000 mi of river, and arrived on their spawning grounds. However, the fishery begins in mid-july when the first fall chum salmon enter the river and extends until river freeze-up in late September or October. Fall chum salmon do not enter the river in a bell shaped curve; building and then satiating, they surge in pulses with large orders of magnitude differences over two or three days time and spread throughout the season, making the estimation of total run size a formidable challenge. By the time the run size is known with confidence, the fishery is over in much of the drainage. Thus, management decisions are implemented without having this critical piece of information for comparison to the escapement goals. Every year a variety of assessment studies are conducted in the open-water period to provide information to help the ongoing prediction of the abundance of the salmon run and to determine whether adequate escapement of spawning-condition adults occurred within specific drainages. In-season predictions of run size are made at least weekly and usually more frequently. Management agencies, aboriginal organizations, and other nongovern-

712 Bue et al. mental organizations in Alaska and Canada cooperatively conduct projects throughout the drainage (Figure 1). The first projection of run size is made preseason, based on brood year returns and maturity schedules. The next projection is made after the cessation of the summer chum salmon run based on its relationship with the fall chum salmon run size. After which, during the early portion of the fall chum salmon season, assessment information comes from gillnetting indices and hydro-acoustic estimation near the mouth of the river, combined with fishing reports from down-river villages communicated through the weekly teleconferences. In August, reports from mid-river villages and other assessment projects are added to the in-season accumulation of data that is used to make predictions of the run-size. Fishing periods are adjusted frequently through emergency orders in Alaska as predictions of the run size change over the course of the season. A regulatory management plan adopted by the Alaska BOF provides direction for how managers, during the fishing season, could determine where fishing can occur, the amount of fishing time allowed, and how many fish can be harvested. Key to this entire process is the effective communication of information to the fishery participants. Information is routinely compiled daily and shared among stakeholders and managers via weekly teleconferences, by fax and e-mail during the fishing season, and during postseason meetings in the fall and preseason fisheries planning meetings in late winter and spring. Some of the types of projects that provide information for management decision-making are described below. Escapement and Run Assessment Projects. Hydro-acoustic estimates are used to index fall chum salmon runs migrating up the main-stem Yukon River near Pilot Station about 123 mi upstream from the mouth of the river. These sonar passage estimates provide the most complete assessment of the size of the fall chum salmon run moving into the middle and upper portions of the drainage. Daily estimates of fish passage are provided to fishery managers who use these data to evaluate in-season run strength for the Yukon River (Pfisterer 2002). Test fisheries are conducted to provide data on catch rate, species composition, run timing, age-sex-length composition, and relative abundance of fall chum salmon stocks. The ADF&G conducts test fishing with gillnets in the lower Yukon River about 25 river mis upstream from the ocean (Bales 2008). The Mountain Village Tribal Council also operates a drift gillnet test fishery near Mountain Village (river mile 87) in association with the hydro-acoustic estimation project conducted by the ADF&G near Pilot Station (river mile 123). Assessment of fall chum salmon abundance occurs in upriver areas as the fish move into spawning tributaries in Alaska and Canada. Historically, aerial surveys were flown to monitor spawning escapements in major index systems throughout the Yukon River drainage. In the Alaskan portion of the drainage, the longest escapement monitoring data set compiled is for the Sheenjek River and includes data from aerial surveys (Barton 1984) and since 1980, hydro-acoustic estimates (e.g., Barton 2000; Dunbar 2008). Similar estimates of fall chum salmon are provided for the Chandalar River (Daum and Osborne 1998; Melegari 2008). With the advent of new technologies and methods of assessment, more precise estimates of abundance have been achieved therefore a shift away from aerial surveys has occurred. The ADF&G and the U.S. Fish and Wildlife Service have conducted annual markrecapture projects in the middle portions of the Yukon River drainage. The ADF&G has conducted annual mark-recapture studies in the Tanana River from 1995 2007, upstream of the Kantishna River at river mile 793 and from 1999 2007 on the Kantishna River (Cleary and Hamazaki 2008).

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance In the Canadian portion of the drainage, DFO has annually estimated the abundance of fall chum salmon crossing the U.S./Canada border of the Yukon River since 1980 (excluding 1981 and 1984) using mark-recapture estimation (Milligan et al. 1984; JTC 2008). The objectives of this program are to provide in-season estimates of the border passage of fall chum salmon, and to provide postseason estimates of the total spawning escapements, harvest rates, migration rates, and run timing. This project is currently transitioning over to hydroacoustic estimates since 2006. The sonar project is a collaborative effort between ADF&G and DFO located on the main-stem of the upper Yukon River near Eagle, Alaska, just downstream from the U.S.-Canadian border (Dunbar and Crane 2007) (Figure 1) and provides estimates of fall chum salmon passage. The latter project assists in evaluating whether the main-stem escapement goal of 80,000 fall chum salmon will be provided for in the Canadian portion of the drainage (Carroll et al. 2007). The ADF&G conducts weekly spawning ground foot surveys of the major fall chum spawning area in the Delta River of the upper Tanana River, allowing estimates of total spawning abundance to be made annually (JTC 2008). Biologists make visual counts of spawning fish and carcasses on stream walks typically conducted during the peak spawning time. Intensive ground surveys have also been made of the major spawning area in the upper Toklat River at river mile 838 (Barton 1997). In addition, DFO has operated a weir since 1972 and cooperatively with the Vuntut Gwitchin Government since 1991 in the Fishing Branch River to count fall chum salmon escapement to this Porcupine River tributary (JTC 2008). 713 harvest fish tickets. A similar process is administered by DFO for Canadian commercial harvests. Reliable estimates of commercial harvest are generally available to managers soon after a fishing period has ended. Post season harvests are reported at various fisheries meetings such as the JTC (JTC 2008), as well as summarized in annual season summary documents and annual management reports. Other types of harvest information are available and are often used while reviewing the outcome of the previous season and planning for the next. Personal-use in Alaska and domestic food fisheries in Canada require reporting of harvest. However, in most areas of the Yukon River drainage no regulatory requirement exists for reporting subsistence harvests. To estimate the subsistence salmon harvest from the majority of the villages, the ADF&G uses a voluntary postseason survey program. Survey data are collected via postseason interviews and follow-up telephone or postal surveys (Busher et al. 2007). In other portions of the Yukon area near the road system, households are required to obtain an annual household subsistence permit prior to fishing. In these areas, harvest is documented on the permit and returned to the ADF&G at the end of the fishing season. In Canada, the Umbrella Final Agreement committed the federal government and First Nations to conduct annual studies to estimate the total catch in the aboriginal fishery in areas where the levels of need have not been determined. This estimation project, called The Yukon River Drainage Basin Harvest Study, has been conducted annually since 1996 (DFO 2003). Actions used to control harvest Harvest Projects. Commercial harvest reporting regulations in Alaska require fishery participants and processors to record the number and species of all salmon sold on Regulations are used to control how many, when, and where fish are caught within the Yukon River drainage for each type of fishery. This type of management is accom-

714 Bue et al. plished primarily through restrictions on effort, fishing efficiency, and the scheduling of where, when, and how long commercial fishery openings will be allowed. Subsistence fisheries in Alaska and the Aboriginal fishery in Canada are managed less intensively than the commercial fisheries. Subsistence fisheries can be restricted or closed to ensure escapement and when the conservation of salmon stocks is at stake. Limited entry. Fishing effort is controlled by limiting the number of participants in the Alaskan and Canadian commercial fisheries. In Alaska, an open entry commercial fishery existed until the mid-1970s. Anyone could participate in the fishery and consequently effort levels grew. In 1976, effort was capped at approximately 700 commercial gillnet fishing permits that were issued in the lower three fishing districts (Figure 3). Additionally, about 70 gillnet and 160 fish wheel permits were issued in the upper river fishing districts. Permits are considered property, and can be purchased or sold. In the 1980s and early 1990s, about 550 of the lower river permit holders and less than 80 of the upper river permit holders generally participated in the fall fishery. In 2008, of a total of 428 commercial permit holders, 251 permits (57%) were issued for the District 1 in the lowest portion of the river (Table 2; Figure 3). In Canada, the fishery is limited to 21 licensed commercial fishers with an additional eight licenses guaranteed to, and distributed at the discretion of First Nations. In the Canadian portion of the drainage, commercial fisheries in the main-stem are restricted to portions below Dawson City at river mile 1,319 (DFO 2003). During 2007, 17 of the 21 eligible commercial fishing licenses were issued (JTC 2008). Management of the aboriginal fishery is implemented through the issuance of communal fishing licenses to First Nations to conduct fisheries within the traditional territories of First Nations. Currently, a total of twelve communal licenses are issued annually to First Nations within the Yukon Fi g u r e 3. State of Alaska s Yukon River fisheries management areas.

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance 715 Ta b l e 2. Number of Alaska commercial salmon fishing permit holders who made at least one delivery by district, Yukon River, 1971-2008. Since 1984, the subtotal for the Lower Yukon Area was the unique number of permits fished. Consequently, the Districts 1, 2, and 3 totals may add up to be greater than the Lower Yukon Area subtotal. Before 1984, the Districts 1, 2, and 3 totals are summed and the resulting subtotals may reflect that some permit holders operated in more than one district during the year. The sum of Districts 4, 5, and 6 averages may not equal Upper Yukon Area district subtotal due to rounding error. Fall Chum and Coho Salmon Season Permits Lower Yukon Area Upper Yukon Area Yukon Area Year District 1 District 2 District 3 Subtotal District 4 District 5 District 6 Subtotal Total 1971 352 - - 352 - - - - 352 1972 353 75 3 431 - - - - 431 1973 445 183 0 628 - - - - 628 1974 322 121 6 449 17 23 22 62 511 1975 428 185 12 625 44 33 33 110 735 1976 422 194 28 644 18 36 44 98 742 1977 337 172 37 546 28 34 32 94 640 1978 429 204 28 661 24 43 30 97 758 1979 458 220 32 710 31 44 37 112 822 1980 395 232 23 650 33 43 26 102 752 1981 462 240 21 723 30 50 30 110 833 1982 445 218 15 678 15 24 25 64 742 1983 312 224 18 554 13 29 23 65 619 1984 327 216 12 536 18 39 26 83 619 1985 345 222 13 559 22 39 25 86 645 1986 282 231 14 510 1 21 16 38 548 1987 0 0 0 0 0 0 0 0 0

716 Bue et al. Ta b l e 2. Continued. Fall Chum and Coho Salmon Season Permits Lower Yukon Area Upper Yukon Area Yukon Area Year District 1 District 2 District 3 Subtotal District 4 District 5 District 6 Subtotal Total 1987 0 0 0 0 0 0 0 0 0 1988 328 233 13 563 20 20 32 72 635 1989 332 229 22 550 20 24 28 72 622 1990 301 227 19 529 11 11 27 49 578 1991 319 238 19 540 8 21 25 54 594 1992 0 0 0 0 0 0 22 22 22 1993 0 0 0 0 0 0 0 0 0 1994 0 0 0 0 0 1 11 12 12 1995 189 172 0 361 4 12 20 36 397 1996 158 109 0 263 1 17 17 35 298 1997 176 130 0 304 3 8 0 11 315 1998 0 0 0 0 0 0 0 0 0 1999 146 110 0 254 4 0 0 4 258 2000 0 0 0 0 0 0 0 0 0 2001 0 0 0 0 0 0 0 0 0 2002 0 0 0 0 0 0 0 0 0 2003 75 0 0 75 2 0 5 7 82 2004 26 0 0 26 0 0 6 6 32 2005 177 0 0 177 0 0 7 7 184

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance 717 Ta b l e 2. Continued. Fall Chum and Coho Salmon Season Permits Lower Yukon Area Upper Yukon Area Yukon Area Year District 1 District 2 District 3 Subtotal District 4 District 5 District 6 Subtotal Total 2005 177 0 0 177 0 0 7 7 184 2006 219 71 0 286 0 4 11 15 301 2007 181 122 0 300 0 2 8 10 310 2008 251 177 0 428 0 3 8 11 439 Average 1971-2007 236 127 9 364 11 17 17 45 406 1998-2007 82 30 0 112 1 1 4 5 117 2003-2007 136 39 0 173 0 1 7 9 182

718 Bue et al. and Porcupine river systems. Eight domestic fishery licenses are available on the Canadian portion of the Yukon River. Gear restrictions. In Alaska, restrictions have been placed on the length and depth of gillnets used in the commercial fishery to limit fishing efficiency. For example, commercial fishers in the lower river districts are restricted to using set gillnets that do not exceed 900 ft in length and drift gillnets not longer than 300 ft. Gillnets with a six-inch or smaller stretch mesh used for chum salmon cannot be more than 50 meshes deep. These gillnet regulations vary somewhat from district to district (5ACC 05.331). Commercial fishing gear was established based on traditional uses such that, fish wheels were most common in up river areas where logs are abundant for construction, drift gillnets were more prominent in the lower river areas, and set gillnets were used in both areas, and these became established as allowable commercial gear types. Subsistence and personal-use fishers can use gillnets, beach seines, angling, and fish wheels but restrictions exist on the length, operation, and number of gillnets fished. For example, a set gillnet cannot exceed 900 ft in length and only one type of gear can be used at the same time. In the Canadian fishery, fishing gear is restricted with each commercial license and is limited to the use of no more than 294 ft of gillnet gear or the operation of no more than three fish wheels (Figure 4). Quotas. Allowable quotas for the commercial fisheries vary with predictions of run size (Table 1). The commercial guideline harvest range for fall chum salmon in Alaskan commercial fisheries is from 72,750 320,500 fish, provided that the escapement goal will be met (5 AAC 05.365). This guideline harvest range is further allocated among geographic districts in the Yukon River drainage. Proportional allocations by district were established Fi g u r e 4. Fish wheels are a type of gear used to catch fall chum salmon in subsistence and commercial fisheries, and are also used by biologists in mark and recapture studies. (Photo by Stan Zurray).

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance by the Alaska BOF based on historic harvest records compiled during the development of the fishery. Canadian fishery managers regulate the harvest of fall chum salmon in the main-stem of the Yukon River within a range established by the Yukon River Salmon Agreement. Total allowable catch (TAC) for the Canadian stocks is between zero and 120,000 fall chum salmon; the agreement specifies a Canadian guideline harvest range between 29% and 35% of the TAC. When the TAC is above 120,000 fish, the harvest range in Canada is increased by 50% of the portion of the TAC above 120,000 fish (JTC 2008). Seasons (fishing periods). Managers rely on setting the time and area of fishery openings as the primary means to control harvest. Although the number of participants and the types of gear used are controlled, fishing power or capability can still far exceed than that required to catch an allowable harvest. During the 1980s, fishing power further increased because of larger, faster fishing skiffs, increased processing capability, and the use of electronic fish finders. A preseason harvest plan is developed collaboratively with stakeholders by the ADF&G and for the Canadian fisheries, by DFO, using a forecast of the return expected in the coming season based on the past parent-year escapements, and the run abundance and age composition of the previous year. A subsistence harvest schedule in Alaska specifies the date and hours in which subsistence fishing can occur. During the fall season when the forecast is adequate, the lower river districts are open to subsistence fishing seven days a week. Once commercial fishing begins in lower river districts, subsistence closures are typically scheduled 12 h before, during, and after commercial periods. These measures are taken in attempts to keep subsistencecaught fish from being sold commercially. Subsistence fishing in the upper river district in Alaska is on a weekly fishing schedule with 719 period length varying between areas based on the efficiency of harvest in those areas and with the intent to spread harvest. Subsistence and commercial fishing in the upper river districts occur concurrently because subsistence dominates the harvest. Adjustments to the subsistence fishing schedule are made in-season to provide more fishing time when subsistence needs are not being met, or to reduce the subsistence harvest to increase spawning escapement when the drainage-wide, run-size estimate is below 300,000 fish. Similarly, DFO fishery managers assess the timing and abundance of fall chum salmon passing the border and announce fishing periods for Canadian fisheries. The difficulty for fall chum salmon management is that the majority of the commercial harvest is taken in the lower Yukon Area while the majority of the subsistence harvest is taken in the upper Yukon Area. Because subsistence harvest has priority over commercial use, commercial fisheries must be managed conservatively to ensure subsistence harvests are met. Allocation Priorities. In Alaska, given the biological escapement goals can be met, the subsistence fishery then has the highest priority for harvest allocation. This aspect of management has become exceedingly complex as fish pass through the patchwork of lands managed by state and federal authorities (Buklis 2002). The subsistence fishery could be closed on state lands but open on federal lands; however, state and federal managers try to develop common regulations. Subsistence-use requirements are determined in Alaska when customary and traditional uses occur in a region. Customary and traditional use, in general, means the noncommercial, long-term and consistent taking of, use of, and reliance upon fish in a specific area, and that the patterns of fish use have been established over a reasonable period of time, taking into consideration the availability of the

720 Bue et al. species. Once the customary and traditional use is determined by the state, then the subsistence harvest requirements are determined. In 1993, the Alaska BOF made a finding for customary and traditional use for all salmon in the Yukon River drainage. This finding was amended in 2001 to include specific amounts reasonably necessary for subsistence (5ACC 01.236) by salmon species. The amount of fall chum salmon considered necessary for subsistence harvests is from 89,500 167,900 fish. In Canada, the aboriginal fishery that provides food for social and ceremonial purposes is constitutionally protected and given priority in management. Only conservation concerns for a stock may supersede this priority. DFO sets a harvest target for the First Nations fishery and offers suggestions for restricting harvest but allows First Nations to determine their own specific measures to control harvest. Options can include scheduling openings and closures, reducing days of fishing for each fish camp, reducing the number of fish camps, establishing family quotas, or allowing only elders or specific families to fish (DFO 2003). Role of communication The regular sharing of information is critical for effective in-season harvest management of Yukon River fall chum salmon and must take place among the biologists and managers representing many federal, state, and territorial agencies, and with stakeholder groups. The weekly teleconferences held during the fishing season to discuss the latest information about the ongoing salmon run are critical to this process. Stakeholders communicate important information that helps shape in-season decisions that are culturally compatible and guide the overwinter planning for the next fishing season. In Alaska, several stakeholder groups are organized to provide input to state and federal fishery managers. For example, the Yukon River Drainage Fisheries Association (YRDFA) was formed in 1989 and has a membership of over 200 Yukon River fishers and organizations. Other organizations representing fishery interests, in addition to YRDFA, include the Association of Village Council Presidents, Council of Athabascan Tribal Governments, Tanana Chiefs Conference, and the Bering Sea Fishermen s Association. Many of the members of these groups are also members of federal subsistence regional advisory committees, which provide recommendations to federal managers in Alaska (Buklis 2002) and members of state advisory committees. In Canada, the main instrument for stakeholder consultation and involvement is the Yukon Salmon Committee, which was established pursuant to the Canadian Yukon Indian Land Claims, Umbrella Final Agreement. The committee develops recommendations for legislation, research, policies, programs, and management plans for Yukon River salmon. The members of the committee come from all parts of the Yukon Territory and represent both First Nations and nonfirst Nations populations to ensure diversity and balance (DFO 2003). Total Return, Escapement, and Harvest Total return and basin-wide escapement Annual variation. Total run size of fall chum salmon, based on data from escapement projects and harvest estimates, has varied from the low runs of 333,941 fish in 1998, 239,299 fish in 2000, and 382,741 fish in 2001 to high runs of 1,938,275 fish in 1975, 1,470,302 fish in 1995, and a record of 2,286,883 fish in 2005 (Figure 5; Appendix Table 1). The run failures of 1997 2002 were followed by a strong improvement in run sizes between 2003 and 2008. Interestingly, the substantial run and escapement that occurred

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance 721 Fi g u r e 5. Estimated escapement and estimated total return of Yukon River fall chum salmon, with basin-wide escapement goals, 1974 2008. from 1994 1997 produced of the lowest returns (1998 2002) estimated over the period 1974 2008. The phenomenal return of 2005 was from the reproduction of the lowest escapements of the 2000 and 2001 runs (Figure 5). Two distinct periods of variation occurred within this time series. The first period from 1974 1991 showed comparatively low variation from year-to-year and ranged from 553,347 (1982) to 1,938,275 (1975) salmon (Figure 5). The second period from 1992 to 2008 showed much greater variation than the first period including both the highest run estimated of 2,286,883 salmon (2005) and the lowest run estimated of 239,299 salmon (2000). Consecutive low runs were experienced over the five-year period from 1998 2002. Basin-wide escapement of salmon to the spawning grounds generally followed the same variation as total return (Figure 5). Basin-wide escapement goals varied somewhat since their initial establishment in 1993; but, were not met in 1993 and 1998 2001. Escapement was greater than 350,000 fish every year from 2002 2008, exceeding the current minimum goal of 300,000 fish. The large run and subsequent escapement of 2005 was three times the drainage-wide escapement goal. Primary variables that influence the total run of fall chum salmon are the spawning success of previous generations, natural variability in marine and freshwater survival due to climatic and oceanographic processes, and ocean fishery harvests. The poor returns and escapement of 1992 1993 can be attributed to poor recruitment from spawning during 1988 and 1989. Extremely cold winter temperatures accompanied by a lack of snow cover may have contributed to poor overwinter survival of eggs and fry. In contrast, the cause of the poor returns and es-

722 Bue et al. 2500 Number of Salmon (thousands) 2000 1500 1000 Odd year returns Odd year Mean 500 Even year returns Even year Mean 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 Fi g u r e 6. Estimated Yukon River fall chum salmon run size for odd years (solid line; circles) versus even years (dashed line; squares), 1974 2008 Year capement 1998 2002 were not due to poor escapement in earlier years and inadequate egg deposition, as the runs and escapement from 1994 1997 were at, or above average. Returns to individual tributaries were poor throughout the drainage 1998 2002 (see below), and was therefore not due to the collapse of one particularly important contributing stock. The number of returning salmon per spawner by brood year was much less than one and averaged 0.49 from 1994 1997 (range 0.34 0.75) (Appendix Table 2). Salmon returns across the region were also generally poor these same years in Norton Sound drainages (Menard et al. 2009, this volume) and in the Kuskokwim River drainage (Linderman and Bergstrom 2009, this volume) suggesting instead that a common variable among stocks across geographically dispersed drainages caused the poor returns rather than weak or low escapement. Poor returns of fall chum salmon to the Yukon River can be more likely attributed to poor ocean environments (e.g., Kruse 1998; Scheuerell and Williams 2005; Farley et al. 2009, this volume; Mantua 2009, this volume; Myers et al. 2009). Competition with Asian-origin hatchery chum salmon may have also contributed to the poor returns these years (Myers et al. 2009). Unlike many salmon fisheries throughout the Pacific Northwest in the U.S. (NRC 1996), habitat loss for salmon has been minimal in the Yukon River drainage. Mining has degraded some stream habitats; however, most historical mining activity occurred on localized, discrete, headwater streams using manual labor, which helped to minimize impacts on salmon spawning habitat (Higgs 1995). Odd versus Even-Year Run Strength. Regular cycles in Yukon River fall chum salmon were evident in the estimated total returns of fall chum salmon from 1974 2008 (Figures 5 and 6). Generally, smaller run sizes occurred during even-numbered years than in odd-numbered years; the regularity of this difference was particularly evident over the

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance 723 1.00 0.90 0.80 Age 4 0.70 Proportion 0.60 0.50 0.40 0.30 Age 5 0.20 0.10 Age 3 Age 6 0.00 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 Year Fi g u r e 7. Age composition data of returning salmon by brood year (year class) for Yukon River fall chum salmon, 1974 2002. period from 1974 1991. From 1974 through 2007, estimated total run size in odd-numbered years averaged 1,000,000 fall chum salmon, ranging from approximately 382,000 fish (2001 lowest odd-numbered year run on record) to 2,286,000 fish in 2005. Run size in even-numbered years averages 682,000 fall chum salmon and ranges from approximately 239,000 fish (2000 lowest run on record) to 1,144,000 fish in 2006. The years 1996 and 2006 were the only even-numbered years that total fall chum salmon run size exceeded the average run size for odd-numbered years. The regularly observed low abundance on even-numbered years in fall chum salmon corresponds with the typically abundant pink salmon runs on even-numbered years in the region (e.g., Menard et al. 2009), and possibly the pattern of reduced abundance of evennumbered year fall chum salmon has been caused by the competition with pink salmon (Ruggerone and Nielsen 2009, this volume). Variation in Age-Class Contribution. From 1974 to 2003, fall chum salmon runs have been dominated by returning age-4 and age-5 fish with much smaller contributions from age-3 and age-6 fish (Figure 7; Appendix Table 2; age data from several sources e.g., Menard 1996; Bales 2008). In all years, except 1989, age-4 fish contributed more than age-5 salmon. Estimated annual age composition from 1977 through 2007 has averaged approximately 4% for age-3, 69% for age-4, 27% for age-5, and less than 1% for age-6 fish. From 1974 1990, age of maturity for Yukon River fall chum salmon increased with declining proportions of age-4 salmon and increasing proportions of age-5 salmon (Figure 7). Since 1990, this trend seems to have reversed showing increased variation over the earlier period. In-season estimates of age prior to 1981 were based on fish sampled at Emmonak from 6-in stretch mesh commercial gillnet catches. Estimates of age from 1981 2000 were based on 6-in set gillnet test fish catches at Big Eddy and Middle Mouth sites. In 2001, fishing gear was changed to 6-in drift gillnets. All test

724 Bue et al. 450 400 Tanana River BEG Range: 61,000 to 136,000 salmon Number of Salmon (thousands) 350 300 250 200 150 100 50 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 Number of Salmon (thousands) 450 400 350 300 250 200 150 100 50 ~501,000 ~496,000 Chandalar River BEG Range: 74,000 to 152,000 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 Number of Salmon (thousands) 450 400 350 300 250 200 150 100 50 Sheenjek River BEG Range: 50,000 to 104,000 ~600,000 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 Fi g u r e 8. Fall chum salmon escapement estimates for Tanana, Chandalar, and Sheenjek rivers located in Alaska, 1974 2008. fishery age-composition data were weighted by daily CPUE from 1981 through 2007. Estimates for 1994 and 2000 were obtained by apportioning daily CPUE among ages, fitting age specific run timing curves to each age, and extending the curves to the end of the season because the projects were terminated early due to the poor runs. Tributary escapement Escapement Variation. Annual variation in escapement of fall chum salmon to spawning tributaries of the Yukon River has been similar among rivers and followed the variation in estimated total run sizes to the Yukon River (Figures 5 and 8 9). For example, every river

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance 725 Number of Salmon (thousands) 450 400 350 300 250 200 150 100 50 Fishing Branch River Negotiated Goal: 50,000 to 120,000 Interim Goals: 2003 >15,000; 2004 >13,000; 2005 >24,000; 2006 >28,000; 2007 >33,667; 2008 >22,000 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 Number of Salmon (thousands) 450 400 350 300 250 200 150 100 50 Mainstem Yukon River Minimum Escapement Goal: 1998-2001, 2006-2008: >80,000; 2002: >60,000; 2003-2005: >65,000 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 Fi g u r e 9. Fall chum salmon escapement estimates for Fishing Branch River and main-stem Yukon River located in Canada, 1974 2008. monitored had low estimated escapements from 1998 2002. Similarly, every river system had large escapements in 2005. Deviation from this consistent pattern, however, has occurred. For example, poor to average escapement occurred within most tributary systems in 1991; hovever, escapement in the Tanana River was well above average this year (Figures 8-9; Appendix Table 3). Differences in escapement among spawning streams could be due to stock-specific differences in returns and harvest. As another example, in recent years, escapement goals have been met every year from 2003 2008 in the Tanana River, Chandalar River, and the Canadian portion of the main-stem of the Yukon River, the three largest components of the run. However, recovery from the low runs of 1998 2002 was less dramatic in the Porcupine River system than elsewhere (Figure 1). Over the period 1998 2008, the escapement goals have only been met in the Fishing Branch River in 2005 over the period 1997 2008 and in the Sheenjek River only in 2001 and 2005 2007 (Figures 8 9). In terms of border passage as negotiated via the Yukon Salmon Agreement, goals have been met every year from 2002 2008 for mainstem of the Yukon River but only in 2005 for the Fishing Branch River over the same period (Figure 9). Stock Contributions to Total Return. Escapement estimates to tributaries can be used to approximate the representation of stocks in the total run because the majority of

726 Bue et al. fall chum salmon spawning areas were monitored and the harvests were relatively small. In numerical terms from 1974 2008, the stocks providing the smallest contributions (~32% of the total run) have been those using the Toklat/Kantishna (8%), Sheenjek (16%), and Fishing Branch (8%) rivers whereas the largest stocks (~77% of the total run) use the Chandalar River (26%), upper Tanana River (24%), and the Canadian main-stem of the Yukon River (17%) (Figures 8 9; Appendix Table 3; JTC 2008). These proportions have remained fairly constant over time. In recent years (2004 2008), the average contributions when compared to the long-term averages declined in the Fishing Branch (from 8 to 4%) and Sheenjek (from 16 to 13%) rivers and increased in the main-stem of the Yukon River (from 17 to 25%). Stock designation by the State of Alaska. Concerns over the conservation of fall chum salmon stocks first arose because below average spawning escapements occurred during the 1980s and early 1990s. Unfortunately, these problems arose again in the late 1990s and early 2000s. In 1999, fall chum salmon runs were particularly low in the Toklat, Sheenjek, and Fishing Branch rivers (Figures 8 9; Appendix Table 3). In response to the guidelines established in the Policy for the Management of Sustainable Salmon Fisheries (5 AAC 39.222), the BOF, in September 2000, classified the Yukon River fall chum salmon stock as a yield concern and classified the fall chum salmon stocks of the Toklat and Fishing Branch rivers as a management concern. A stock of yield concern is defined as, a concern arising from a chronic inability, despite use of specific management measures, to maintain expected yields, or harvestable surpluses, above a stock s escapement needs. A stock of management concern is defined as a concern arising from a chronic inability, despite use of specific management measures, to maintain escapements for a salmon stock within the bounds of the Sustainable Escapement Goal (SEG), Biological Escapement Goal (BEG), Optimum Escapement Goal (OEG), or other specified management objectives for the fishery (5 AAC 39.222(f)(21)). The policy further goes on to define chronic inability as the continuing or anticipated inability to meet escapement goals (management concern) or average surplus yield (yield concern), over a four to five year period based on a salmon life cycle. The BOF determination for the entire Yukon River fall chum salmon stock as a yield concern was based on the substantial decrease in yields and harvestable surpluses during the period 1998 2000. The determinations for stocks of the Toklat and Fishing Branch rivers as management concerns were based on escapements not meeting the escapement goals of 33,000 fish for the Toklat River from 1996 2000 and not meeting the escapement goal of 50,000 120,000 salmon for the Fishing Branch River from 1997 2000. The ADF&G reassessed the salmon stocks during the 2003 2004 regulatory cycle and presented recommendations to the BOF (Bue et al. 2004). Based on these recommendations and supporting materials, the BOF continued the classification of the Yukon River fall chum salmon as a yield concern because the combined commercial and subsistence harvests showed a substantial decrease in fall chum salmon yield over the 10-year period of 1989 1998 to the more recent 5-year (1999 2003) average. The Toklat River stock was removed as a management concern as a result of the BEG review presented at that BOF meeting (ADF&G 2004). The Fishing Branch River stock was also removed as a management concern because management of that portion of the drainage was covered by the Yukon River Salmon Agreement. In 2007, the BOF removed the yield concern status of the Yukon River fall chum salmon stock. Run strength, though poor from

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance 1998 through 2002, showed steady improvement since 2003. The 2005 run was the largest in 30 years and the 2006 run was above average for an even-numbered year run. The drainage-wide escapement goal of 300,000 fall chum salmon was consistently exceeded. The recent 5-year-average (2002 2006) total reconstructed run of approximately 950,000 fish was greater than the 1989 1998 10-year average of approximately 818,000 fish, indicating a return to historical run levels. Harvest Subsistence and commercial fisheries Alaska. Subsistence harvest (including the personal use fishery) averaged 125,000 fish (range 19,307 233,347 fish) over the period 1979 2008, excluding 1987 (Figure 10; Appendix Table 1). Restrictions on subsistence fishing occurred in 1993, 1998, 2000, and 2001 in efforts to reduce harvest to meet escapement goals. Over the 20-year period from 1974 1993 (excluding 1987), the subsistence fishery averaged 171,000 fish (range 76,925 233,347 fish) and showed less variation and a higher average than over the 15- year period from 1994 2008 (average 82,374 fish; range 19,307 163,693 fish). In 2001, the BOF established for the Alaskan portion of the Yukon River drainage, the amount necessary for subsistence (ANS) as 89,500 167,900 fall chum salmon. From 2004 2008, the lower limit of the ANS harvest level was only met in 2005 (91,597 fish) and 2007 (98,886 fish). The low subsistence harvest during these recent years was primarily due to the preceding poor years when fishermen reduced the size of dog teams for lack of adequate feed (Wolfe and Spaeder 2009) and the shutting down of commercial markets, which led to a loss in available gear for subsistence fishing. Over the same period during the first twenty years, the subsistence 727 harvests ranged from 76,925 233,347 fish (Figure 10). It is possible that the amounts necessary for subsistence harvest have declined in the Yukon River drainage. The subsistence harvest and effort in recent years have been influenced by many variables besides fishing regulations and total run size. For example, gasoline prices, elders unable to fish, water and debris levels in the rivers, and forest fires have affected fishing effort and thus harvest (Busher et al. 2007; JTC 2008). Fishers in many communities avoided repetitive travel to fish camps because of high fuel costs. In many cases, they fished near their home or waited until the peak of the run occurred in their area before fishing. In 2004 and 2005, severe fire conditions occurred in interior Alaska. Smoke conditions limited river travel to traditional fishing areas (Busher et al. 2007). Also, some residents took advantage of work opportunities on fire crews for much of the summer and did not fish (JTC 2006). Commercial harvest of fall chum salmon averaged 152,104 fish (range 0 472,603 fish) over the period 1974 2008 (Figure 10; Appendix Table 1). The commercial fishery was closed during 1987, 1993, 1998, and 2000 2002. From 1974 1983, the commercial fishery typically caught much more than the long-term average of 150,000 fish (average 286,851 fish, range 156,390 472,603 fish; Figure 10). In contrast, the commercial fishery only averaged 6,508 fish during 1999 2003 (range 0 21,542 fish) and averaged 113,793 fish (range 4,110 180,249 fish) during 2004 2008. Year-to-year variation in harvest followed the variation observed in total run with an early period of comparative stability (1974 1991) followed by a period of wide variation (1992 2008) (Figures 5 and 10). Given the improved total return in recent years, greater commercial harvest of salmon might have been expected. The decline of salmon stocks from 1998 through

728 Bue et al. Fi g u r e 10. Estimated commercial and subsistence harvest of Yukon River fall chum salmon for Alaska and Canada, and total harvest by Alaska and Canada with drainage-wide total return estimate, 1974 2008.

Yukon River Fall Chum Salmon Fisheries: Management, Harvest, and Stock Abundance 2002 changed the character of the fisheries. Many fishers moved away from using long established fish camps, fishing gear fell into disrepair or was replaced with other types, prices for salmon fell, and market interest shifted to other available fisheries outside the region. With the return of the salmon, fishers and markets are slowly returning and may improve in the future (Figure 11). To encourage market improvement, fishery managers have worked closely with commercial fish buyers to maximize processing capacity and available transportation opportunities (JTC 2008). Frequent short open fishing periods were provided recently and were based on anticipated daily market capacity. Buyers and fishers also worked together to improve the quality of their harvest by more careful fish handling, improved icing techniques, and quicker deliveries. 729 Canada. Estimated subsistence harvest (aboriginal, and domestic fisheries harvest combined) averaged 6,443 fish (range 2,068 18,100 fish) over the period 1974 2008 (Figure 10; Appendix Table 1; JTC 2008). Over the time period 1974 2008, the top three harvest years occurred in 1975 (18,100 fish), 1979 (13,000 fish), and 1980 (13,218 fish). The high harvest levels from 1974 2003 (average 8,762 fish; range 3,500 18,100) contrast to the lower levels of the past five years when an average of 5,056 salmon were caught (range 2,068 7,700 fish) (Figure 10). The preliminary harvest in 2007 was 6,721 salmon and was above the five-year average. Participants in the 2007 fall chum salmon fishery described fishing as excellent (JTC 2008). Similar to Alaskan subsistence harvest levels in recent years, the recent low harvests were surprising because the passage of salm- Fi g u r e 11. Chum salmon caught by fish wheel on the main-stem of the Yukon River near Rampart, Alaska (Photo by Stan Zuray).