Pacific Salmon: Ecology and Management of Western Alaska’s Populations

<em>Abstract.</em>—Much is known about the importance of the physical characteristics of salmonid habitat in Alaska and the Pacific Northwest, with far less known about the food sources and trophic processes within these habitats, and the role they play in regulating salmonid productivity. Freshwater food webs supporting salmonids in Alaska rely heavily on nutrient, detritus, and prey subsidies from both marine and terrestrial ecosystems. Adult salmon provide a massive input of marine biomass to riverine ecosystems each year when they spawn, die, and decompose, and are a critical food source for young salmon in late summer and fall; riparian forests provide terrestrial invertebrates to streams, which at times comprise over half of the food ingested by stream-resident salmonids; up-slope, fishless headwater streams are a year-round source of invertebrates and detritus for fish downstream. The quantity of these food resources vary widely depending on source, season, and spatial position within a watershed. Terrestrial invertebrate inputs from riparian habitats are generally the most abundant food source in summer. Juvenile salmonids in streams consume roughly equal amounts of freshwater and terrestrially-derived invertebrates during most of the growing season, but ingest substantial amounts of marine resources (salmon eggs and decomposing salmon tissue) when these food items are present. Quantity, quality, and timing of food resources all appear to be important driving forces in aquatic food web dynamics, community nutrition, and salmonid growth and survival in riverine ecosystems.

Pacific Salmon: Ecology and Management of Western Alaska’s Populations

<em>Abstract.</em>—The Arctic-Yukon-Kuskokwim Sustainable Salmon Initiative (AYK SSI) is a research program in Alaska focused on learning from the knowledge and understanding of local indigenous fishing communities. From the mid-1990s, Alaska Natives have urged that local and traditional/indigenous knowledge be recognized as a serious body of ecological insights and stewardship traditions. This paper provides a survey of milestones in Alaska, from the early definitional debates and the rise of systematic methods for documentation, to the growing body of substantive information. The discussion on local and traditional knowledge at the AYK SSI Symposium in February 2007 provided an opportunity to assess achievements and identify obstacles. Participants underscored the continuing challenges of the diverse cultural context for joint research by biologists and local communities, directing attention to foundational questions of trust and respect. Local residents celebrated the great promise for local and traditional/indigenous knowledge to contribute to our shared scientific understanding of salmon and to promote respectful and effective systems of stewardship, but they were also acutely perceptive of the barriers to improved synthesis and mutual learning. The concluding section of this paper explores implications for the on-going research agenda of the AYK SSI, particularly the need for an on-going consultative process to insure that local communities and researchers are mutually aware of methodologies available and the substantive contributions made by local and traditional knowledge research. In this way, the on-going development of research in this area can draw more fully on the struggles and accomplishments of the preceding decade.

Pacific Salmon: Ecology and Management of Western Alaska’s Populations

<em>Abstract.</em>—The legacy of Pacific salmon <em>Oncorhynchus </em>spp. can be described as the genetic resources that are the product of past evolutionary events and which represent the future evolutionary potential of the species. A key step in conserving this legacy is identifying conservation units—major chunks of biodiversity that collectively comprise the evolutionary legacy. A variety of methods exist for defining conservation units, but all should follow a two-step process. Step One is describing the (often hierarchical) structure of biodiversity within each species—that is, the evolutionary relationships among populations and metapopulations or larger conservation units. In theory, this is an objective, data-driven exercise. Step Two involves considering questions such as, “Which level in the hierarchy is best for identifying conservation units?” and “How much biodiversity do we need to conserve?” These questions do not have a single ‘correct’ answer; instead, they must be informed by societal values. In Step Two, therefore, it is important to articulate clear program goals to provide a context for addressing these difficult questions. But defining conservation units is only part of a coherent, long-term conservation strategy; evolution is dynamic, whereas simply conserving certain fixed types promotes stasis. Therefore, equally important is the conservation of evolutionary <em>processes</em>, which are the dynamic relationships between salmon and their ecosystems that help shape their evolutionary trajectories. Evolutionary processes include patterns of connectivity, dispersal, and gene flow; sexual selection and natural selection; and interactions with physical and biological features of the habitat. Conserving evolutionary processes requires consideration of the same two steps outlined above. Reflecting on the long-term goals of the Arctic-Yukon-Kuskokwim Sustainable Salmon Initiative will help to focus efforts to identify important units for conservation and vital evolutionary processes for Alaska salmon.

Pacific Salmon: Ecology and Management of Western Alaska’s Populations

<em>Abstract.</em>—This paper provides an overview of Arctic-Yukon-Kuskokwim (AYK) commercial salmon fisheries, reviews economicvariables affecting the fisheries, and discusses the challenge of increasing the economic benefits from these fisheries. During the years 2004–2006, AYK fisheries accounted for about 1% of total Alaska harvest volume and 2% of total Alaska harvest value. AYK fisheries accounted for 18% of total Alaska permit holdings and 14% of permits fished, but only 1.6% of total earnings. AYK commercial salmon fisheries have faced significant challenges over the past two decades. Harvest volumes fell sharply from the late 1980s to 2002. By 2007, total harvest volume in five of the six AYK fisheries had recovered somewhat from the low levels of the early 2000s, but remained well below the levels of the late 1980s. Prices fell during the 1990s, most importantly because of the growth of salmon farming, which dramatically increased world salmon supply and reduced the market share of Alaska wild salmon. Currently, prices for AYK coho <em>Onchorhynchus kisutch </em>and chum salmon <em>O. keta </em>remain far below levels of the 1980s, while prices for the Chinook salmon <em>O. tshawyscha </em>fisheries are comparable to levels of the late 1980s. Other challenges have included a steep decline in the number of buyers, and a dramatic increase in fuel prices in the late 2000s. AYK wild salmon producers also face new opportunities in world markets to market wild salmon not as a commodity but as a specialty product. Some AYK salmon runs, such as Yukon River Chinook and chum salmon, have unusually high oil content, which have given them reputations as among the best-tasting salmon in the world. To reduce costs and increase value for AYK salmon fisheries, a need exists for (a) implementing improvements in the quality and consistency of salmon products by improvements in how fish are handled at every stage of harvesting, processing, and transportation; (b) sustained investments in marketing; and (c) investments in infrastructure, ranging from ice machines to airport runways, to reduce costs and improve quality.

Pacific Salmon: Ecology and Management of Western Alaska’s Populations

<em>Abstract.</em>—In the late 1990s and early 2000s, large declines in numbers of chum salmon <em>Oncorhynchus keta </em>and Chinook salmon <em>O. tshawytscha </em>returning to the Arctic-Yukon-Kuskokwim (AYK) region (Alaska, USA) illuminated the need for an improved understanding of the variables controlling salmon abundance at all life stages. In addressing questions about salmon abundance, large gaps in our knowledge of basic salmon life history and the critical early marine life stage were revealed. In this paper, results from studies conducted on the estuarine ecology of juvenile salmon in western Alaska are summarized and compared, emphasizing timing and distribution during outmigration, environmental conditions, age and growth, feeding, and energy content of salmon smolts. In western Alaska, water temperature dramatically changes with season, ranging from 0°C after ice melt in late spring/early summer to 19°C in July. Juvenile salmon were found in AYK estuaries from early May until August or September, but to date no information is available on their residence duration or survival probability. Chum salmon were the most abundant juvenile salmon reported, ranging in percent catch from <0.1% to 4.7% and most research effort has focused on this species. Abundances of Chinook salmon, sockeye salmon <em>O. nerka</em>, and pink salmon <em>O. gorbuscha </em>varied among estuaries, while coho salmon <em>O. kisutch </em>juveniles were consistently rare, never amounting to more than 0.8% of the catch. Dietary composition of juvenile salmon was highly variable and a shift was commonly reported from epibenthic and neustonic prey in lower salinity water to pelagic prey in higher salinity water. Gaps in the knowledge of AYK salmon estuarine ecology are still evident. For example, data on outmigration patterns and residence timing and duration, rearing conditions and their effect on diet, growth, and survival are often completely lacking or available only for few selected years and sites. Filling gaps in knowledge concerning salmon use and survival in estuarine and near-shore habitats within the AYK region will aid in assessing the relative roles of all habitats (freshwater to marine) in controlling salmon abundance.

Pacific Salmon: Ecology and Management of Western Alaska’s Populations

<em>Abstract.</em>—The Arctic-Yukon-Kuskokwim (AYK) Salmon Research and Restoration Program explicitly recognizes the integration of human dimensions with salmon ecosystems. This paper addresses the collaborative management approach to integration by summarizing how collaborative processes work and how they influence management performance. Collaborative fishery management includes stakeholders in a number of management functions such as data collection, research, planning, design, decision-making, monitoring, evaluation, and enforcement. This approach is included in the general category of “co-management,” which refers to the sharing of authority and responsibility among government and stakeholders. Co-management is a process, rather than a tool, of management. The direct involvement of stakeholders in the planning and control of their fisheries offers the potential of improving the performance of fishery management in promoting sustainability. Realizing the potential depends on the extent to which key co-management principles are addressed. These principles relate to three management components: background conditions in the fishery, management structure, and management operations. Background conditions that affect the performance of co-management include uncertainty, history, and context. Elements of fishery structure relating to co-management performance include boundaries, scale, representation, and participation. Fishery management operations influence co-management performance through stability and flexibility, cost effectiveness, and equity. The principles underlie co-management performance through the effect they have on transaction costs and incentives. Columbia River salmon recovery provides a good example of the influence of transaction costs and uncertainty on collaborative management and resource recovery. The complexity of Columbia River Basin co-management includes scale, fragmentation, scientific uncertainty, and legacy. These variables lead to co-management research suggestions for the AYK Salmon Research and Restoration Program.

Pacific Salmon: Ecology and Management of Western Alaska’s Populations

<em>Abstract.</em>—Data were collected in Norton Sound from 2002 through 2006 to support the development of habitat-based models of coho salmon smolt production and adult escapements. Length of stream rearing habitat available to juvenile coho salmon in the summer was estimated at 83 km on the Nome River and 277 km on the North River, using a combination of <em>a priori </em>predictions of fish distribution and subsequent field sampling. The likely range of smolts produced by this habitat was modeled using three different relationships of habitat quantity and smolt production developed elsewhere. The estimated escapement of adult salmon needed to produce this range of smolts resulted in counts from 2,632 to 3,649 fish in the Nome River and from 8,766 to 10,481 fish in the North River, using various literature values of production, survival, and fecundity. A field study conducted in the next two years to estimate actual smolt abundance in the Nome River yielded estimates of 92,820 (95% CI = 84,615 – 101,026) in 2005 and 122,079 (95% CI = 112,612 – 131,546) coho salmon in 2006; these smolt abundances were within the range estimated by the <em>a priori </em>models. Through 2007, average adult coho salmon escapement to both rivers had also been within the 95% confidence interval predicted from two of the three smolt models, within 2% and 18% of the point estimate of one model, and within 27% and 32% of the second. Overall, models based on production estimates and life history variables developed outside of the region were relatively accurate for predicting coho salmon rearing distributions, smolt production per km of total rearing habitat, and adult spawner abundance. Based on this, habitat-based models used to help develop escapement goals in other regions may be similarly useful in the Norton Sound region.

Pacific Salmon: Ecology and Management of Western Alaska’s Populations

<em>Abstract.</em>—Limits to the capacity of the North Pacific Ocean to support salmon are suggested based on widespread observations of decreasing size and increasing age of salmon at maturation during time periods where the abundance of salmon has increased throughout the North Pacific rim. The increase in abundance of salmon is partially due to successful establishment of large-scale hatchery runs of chum salmon <em>Oncorhynchus keta </em>and pink salmon <em>O. gorbuscha</em>. The largest hatchery runs are chum salmon, and because of their long life span relative to the more abundant pink salmon, the increase in hatchery terminal run biomass under-represents the actual increase in salmon biomass. To put the increase in hatchery runs in perspective, the historical (since 1925) terminal runs and biomass of hatchery and wild pink, chum, and sockeye salmon <em>O. nerka </em>in the North Pacific Ocean were reconstructed. Various data sets of smolt releases from hatcheries, wild salmon estimates of smolt out-migrants, and subsequent adult returns by age and size were assembled. Age-structured models were fit to these data sets to estimate brood-year specific rates of natural mortality, growth, and maturation. The rates were then used to reconstruct total biomass of the “smolt data” stocks. The estimated ratio of terminal runs to total biomass estimated for the “smolt data” stocks were used to expand the historical time series of terminal run biomass on a species and area basis. The present total biomass (~4 million mt) of sockeye, chum, and pink salmon in the North Pacific Ocean is at historically high levels and is ~3.4 times the low levels observed in the early1970s. At least 38% of the recent ten-year average North Pacific salmon biomass is attributed to hatchery stocks of chum and pink salmon. Recent year terminal run biomass has been greater than the peak levels observed during the mid 1930s.