Gulf of Alaska

The decline of Steller sea lions (Eumetopias jubatus) in the Gulf of Alaska and the Aleutian Islands may be the result of them eating too much pollock (a gadid fish) instead of a more balanced and diverse diet containing fattier fishes, such as herring or sandlance. We sought to test this junk-food hypothesis by feeding six captive Steller sea lions (ages 0.9-4.5 years) only pollock or herring. All sea lions gained mass while eating herring. However, eating only pollock for short periods (11-23 d) caused the study animals to lose an average of 6.5% of their initial body mass (0.6 kg/d) over an average feeding trial of 16 d (initial mass averaged 125 kg). The animals were allowed to eat as much pollock as they wanted but did not increase their food intake to compensate for the low energy they were receiving. The sea lions showed progressive metabolic depression while losing body mass on a pollock-only diet. The loss of body mass while eating pollock was due to the lower gross energy content of pollock versus herring, the higher cost of digesting pollock, and the increased energy loss from digesting the larger quantity of fish needed to compensate for the lower energy content of pollock. Thus, our sea lions would have had to eat 35-80% more pollock than herring to maintain similar net energy intakes. Results from our captive-feeding studies are consistent with the junk-food hypothesis and have serious implications for Steller sea lions that have been eating primarily pollock in the Gulf of Alaska and the Aleutian Islands.

This paper defines the principal architectural elements present within the Pleistocene, glaciolacustrine basin-fill of the Copper River Basin in Alaska. The Copper River drains an intermontane basin via a single deeply incised trench through the Chugach Mountains to the Gulf of Alaska. This trench was blocked by ice during the last glacial cycle and a large ice-dammed lake, referred to as Lake Atna, filled much of the Copper Basin. Facies analysis within the basin floor allows a series of associations to be defined consistent with the basinward transport of sediment deposited along calving ice margins and at the basin edge. Basinward transport involves a continuum of gravity driven processes, including slumping, cohesive debris flow, hyperconcentrated/concentrated density flows, and turbidity currents. This basinward transport results in the deposition of a series of subaqueous fans, of which two main types are recognised. (1) Large, stratified, basin floor fans, which extend over at least 5 km and are exposed in the basin centre. These fans are composed of multiple lobes, incised by large mega-channels, giving fan architectures that are dominated by horizontal strata and large, cross-cutting channel-fills. Individual lobes and channel-fills consist of combinations of: diamict derived from iceberg rainout and the ice-marginal release of subglacial sediment; multiple units of fining upward gravels which grade vertically into parallel laminated and rippled fine sands and silts, deposited by a range of density flows and currents derived from the subaqueous discharge of meltwater; and rhythmites grading vertically into diamicts deposited from a range of sediment-density flows re-mobilising sediment deposited by either iceberg rainout or the ice-marginal release of sediment. (2) Small, complex, proximal fans, which extend over less than 2 km, and are exposed in the southern part of the basin. These fans are composed of coalescing and prograding lobes of diamict and gravel deposited both directly by subaqueous meltwater and from sediment-density flows. These lobes are cross-cut by a range of sand and gravel-filled troughs and channels cut by subaqueous outwash, and either overlie or are overlain by horizontal sheets of gravel and diamict deposited from a range of sediment-density flows. The fans are, therefore, characterised by a complex, and laterally variable facies, architecture. Water depth, proglacial topography, stability of meltwater portals and sediment supply may all be important in determining the type of subaqueous fan present at any one location. We suggest that the Copper River basin-fill is dominated by packages of sediment containing multiple subaqueous fans with individual fans separated by units of diamict. Each sediment package is in turn separated from the next by a palaeo-landsurface shaped by interstadial/interglacial fluvial processes and by volcanic debris flows.

A central issue in archaeology is the study of technological change, and yet we have relatively little theory to explain the origin of technological novelty. Most models assume that inventions are generated as needed to solve adaptive problems. Alternatively, some view innovation as a creative and random process capable only of generating variation on which selection operates. This article considers the role of risk sensitivity in the production of technological invention. It is argued that evolutionary ecological models of risk and opportunity cost establish expectations for the contexts in which individuals are likely to stick to conservative technologies and when they are likely to be inventive. Archaeological evaluation of the risk-sensitivity theory of technological change requires attention to components of technological systems and their associated mechanical, operational, and strategic costs. The framework is examined with a case study of technological change from the prehistory of the Kodiak Archipelago in the Gulf of Alaska.

In the modern ocean, oxygen minimum zones (OMZs) are potential traces of a primitive ocean in which Archean bacteria lived and reduced chemical anomalies occurred. But OMZs are also keys to understanding the present unbalanced nitrogen cycle and the oceans' role on atmospheric greenhouse control. OMZs are the main areas of nitrogen loss (as N 2 , N 2 O) to the atmosphere through denitrification and anammox, and could even indirectly mitigate the oceanic biological sequestration of CO 2 . It was recently hypothesized that OMZs are going to spread in the coming decades as a consequence of global climate change. Despite an important OMZ role for the origin of marine life and for the biogeochemical cycles of carbon and nitrogen, there are some key questions on the structure of OMZs at a global scale. There is no agreement concerning the threshold in oxygen that defines an OMZ, and the extent of an OMZ is often evaluated by denitrification criteria which, at the same time, are O 2 -dependent.

In spite of more than a half-century of exploration, no de"nitive evidence has yet come to light for human occupation in eastern Beringia preceding 12,000 yr BP. The oldest dates * between 11,500 and 12,000 yr BP * are from sites in interior and northern Alaska. Archaeological sites dating to this time period, such as the Broken Mammoth site in the central Tanana River Valley, have yielded evidence of pioneer colonization by groups with relatively little knowledge of lithic resources. Three possibly older cave sites * Blue"sh Caves, Lime Hills Caves, and Trail Creek Caves * have stratigraphic and taphonomic problems that are not easily resolved. No sites in the glaciated coastal zone of southern Alaska are Pleistocene in date, and numerous objections can be raised to the viability of the coastal migration hypothesis, particularly in the western Gulf of Alaska region. For northern and interior Alaska, the earliest colonization appears to have been a`push}pulla phenomenon, linked to the dissolution of the Bering Land Bridge through a combination of rising sea levels and ameliorating climate. The climate of the`Birch-Poplara rise in the terminal Pleistocene may have forced the extinction of obligate grazers such as mammoth and horse, but it seems to have favored other taxa such as bison and elk, at least until 9000 yr BP. Faunal data from the Broken Mammoth site in the central Tanana valley, with good organic preservation, demonstrate the utilization of a wide diversity of taxa, including small game, waterfowl, and "sh. Faunal and sedimentological data give slight support to a Younger Dryas reversal, but this was dwarfed by the mid-Holocene period of dry, windy conditions during which interior Alaska may have been largely abandoned.

As part of the international MENU collaboration, we compared and contrasted ecosystem responses to climate-forced oceanographic variability across several high latitude regions of the North Pacific (Eastern Bering Sea (EBS) and Gulf of Alaska (GOA)) and North Atlantic Oceans (Gulf of Maine/Georges Bank (GOM/ GB) and the Norwegian/Barents Seas (NOR/BAR)). Differences in the nitrate content of deep source waters and incoming solar radiation largely explain differences in average primary productivity among these ecosystems. We compared trends in productivity and abundance at various trophic levels and their relationships with sea-surface temperature. Annual net primary production generally increases with annual mean sea-surface temperature between systems and within the EBS, BAR, and GOM/GB. Zooplankton biomass appears to be controlled by both top-down (predation by fish) and bottom-up forcing (advection, SST) in the BAR and NOR regions. In contrast, zooplankton in the GOM/GB region showed no evidence of top-down forcing but appeared to control production of major fish populations through bottom-up processes that are independent of temperature variability. Recruitment of several fish stocks is significantly and positively correlated with temperature in the EBS and BAR, but cod and pollock recruitment in the EBS has been negatively correlated with temperature since the 1977 shift to generally warmer conditions. In each of the ecosystems, fish species showed a general poleward movement in response to warming. In addition, the distribution of groundfish in the EBS has shown a more complex, non-linear response to warming resulting from internal community dynamics. Responses to recent warming differ across systems and appear to be more direct and more pronounced in the higher latitude systems where food webs and trophic interactions are simpler and where both zooplankton and fish species are often limited by cold temperatures.

Energy budget models for five marine ecosystems were compared to identify differences and similarities in trophic and community structure. We examined the Gulf of Maine and Georges Bank in the northwest Atlantic Ocean, the combined Norwegian/Barents Seas in the northeast Atlantic Ocean, and the eastern Bering Sea and the Gulf of Alaska in the northeast Pacific Ocean. Comparable energy budgets were constructed for each ecosystem by aggregating information for similar species groups into consistent functional groups. Several ecosystem indices (e.g., functional group production, consumption and biomass ratios, cumulative biomass, food web macrodescriptors, and network metrics) were compared for each ecosystem. The comparative approach clearly identified data gaps for each ecosystem, an important outcome of this work. Commonalities across the ecosystems included overall high primary production and energy flow at low trophic levels, high production and consumption by carnivorous zooplankton, and similar proportions of apex predator to lower trophic level biomass. Major differences included distinct biomass ratios of pelagic to demersal fish, ranging from highest in the combined Norwegian/Barents ecosystem to lowest in the Alaskan systems, and notable differences in primary production per unit area, highest in the Alaskan and Georges Bank/Gulf of Maine ecosystems, and lowest in the Norwegian ecosystems. While comparing a disparate group of organisms across a wide range of marine ecosystems is challenging, this work demonstrates that standardized metrics both elucidate properties common to marine ecosystems and identify key distinctions useful for fisheries management.

Populations of Steller sea lions, northern fur seals, and northern sea otters declined substantially during recent decades in the Bering Sea and Aleutian Islands region, yet the population status of harbor seals has not been assessed adequately. We determined that counts obtained during skiff-based surveys conducted in [1977][1978][1979][1980][1981][1982] represent the earliest estimate of harbor seal abundance throughout the Aleutian Islands. By comparing counts from 106 islands surveyed in 1977-1982 (8,601 seals) with counts from the same islands during a 1999 aerial survey (2,859 seals), we observed a 67% decline over the ∼20-yr period. Regionally, the largest decline of 86% was in the western Aleutians (n = 7 islands), followed by 66% in the central Aleutians (n = 64 islands), and 45% in the eastern Aleutians (n = 35 islands). Harbor seal counts decreased at the majority of islands in each region, the number of islands with >100 seals decreased ∼70%, and the number of islands with no seals counted increased ∼80%, indicating that harbor seal abundance throughout the Aleutian Islands was substantially lower in the late 1990s than in the 1970s and 1980s.

Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976--77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid-trophic levels. The east--west asymmetry of the oceanic response to climate forcing after 1976-- 77 is consistent with both the temporal aspect (populations decreased after the late 1970s) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad-scale climate variations appear to b...

Plankton populations in Prince William Sound, Alaska, exhibited pronounced seasonal, annual and longer-period variability in composition and standing stock in response to physically influenced differences in nutrient availability, and possibly currents that modify local biomass by exchanges with water from the bordering Gulf of Alaska. During springs in which early, strong physical stratification developed, intense, short-lived phytoplankton blooms occurred. These blooms had relatively short residence times in the water column. In contrast, during springs in which slower, weaker stratification developed, phytoplankton blooms were prolonged and took longer to peak. These slower blooms prolonged the period of phytoplankton production, prolonged interaction with the springtime grazing community and led to the incorporation of more organic matter into pelagic food webs. A coupled biological-physical simulation of plankton production was used to examine the implications of seasonally varying air and mixed-layer temperatures, surface winds and incident light on the timing, duration, annual production and standing stock of plankton. Our modelling results reproduced the observed characteristics of the springtime production cycle, and the magnitude of zooplankton stocks for the period 1992–97 but not for 1981–91. These results suggest that for most of the 1990s, bottom-up influences on nutrient supplies controlled levels of primary consumers, whereas for the 11 years before that, other unknown factors dominated this process. We present the results of a comprehensive, multiyear study of relationships between plankton and physical limitations, and a retrospective analysis of earlier conditions to explore the possible causes for these differences.

Energetic pressure fluctuations at periods longer than 30 s are a ubiquitous feature of pressure spectra from instruments sited on the deep seafloor in both the Atlantic and the Pacific oceans. We show these pressure fluctuations are caused by freely propagating ocean surface waves. The waves are generated in the near shore region along the entire coastline of an ocean basin through nonlinear transfer of energy from short-period waves. This view contrasts with some earlier work, which described these long-period pressure fluctuations as trapped waves tied to groups of short waves. We have constructed a model based on the average energy in the short (wind driven and swell) wave band along the North Atlantic coast to predict the energy in the long wave band at a site in the Atlantic. Maximum likelihood wave number-frequency spectra calculated on data from an 11 element array in the North Pacific confirm that the long wave energy is confined to wave numbers corresponding to the surface gravity wave dispersion relation. We have used the wave number spectra to isolate particular regions of the Pacific Ocean which are sources of long wave energy. Energetic short-period waves are incident on the coastline in these regions. Long waves are detected at the army which originate in the Gulf of Alaska, the northwestern Pacific, and at the southern tip of South America.

Large whales were extensively hunted in coastal waters off Alaska, but current distribution, population sizes and trends are poorly known. Line transect surveys were conducted in coastal waters of the Aleutian Islands and the Alaska Peninsula in the summer of 2001-2003. Abundances of three species were estimated by conventional and multiple covariate distance sampling (MCDS) methods. Time series of abundance estimates were used to derive rates of increase for fin whales (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae). Fin whales occurred primarily from the Kenai Peninsula to the Shumagin Islands, but were abundant only near the Semidi Islands and Kodiak. Humpback whales were found from the Kenai Peninsula to Umnak Island and were more abundant near Kodiak, the Shumagin Islands and north of Unimak Pass. Minke whales (B. acutorostrata) occurred primarily in the Aleutian Islands, with a few sightings south of the Alaska Peninsula and near Kodiak Island. Humpback whales were observed in large numbers in their former whaling grounds. In contrast, high densities of fin whales were not observed around the eastern Aleutian Islands, where whaling occurred. Average abundance estimates (95% CI) for fin, humpback and minke whales were 1652 (1142-2389), 2644 (1899-3680), and 1233 (656-2315), respectively. Annual rates of increase were estimated at 4.8% (95% CI ¼ 4.1-5.4%) for fin and 6.6% (5.2-8.6%) for humpback whales. This study provides the first estimate of the rate of increase of fin whales in the North Pacific Ocean. The estimated trends are consistent with those of other recovering baleen whales. There were no sightings of blue or North Pacific right whales, indicating the continued depleted status of these species. r

The abundance and availability of food are critical determininants of reproductive success and population dynamics of marine top predators. However, recent work has indicated that the quality of the food may also be critically important for some marine predators. The 'junkfood hypothesis' was originally suggested as a potential explanation for a dramatic population decline of Stellers sea lions Eumetopias jubatus in the Gulf of Alaska. According to the hypothesis, a dietary switch to prey of low energy content led to detrimental effects on the population of sea lions. A number of observations indicate that the hypothesis is relevant for several population parameters. Recent work on piscivorous seabirds has provided substantial evidence indicating the relevance of this hypothesis in food webs in e.g. the North Pacific, the North Sea and the Baltic Sea. The emergence of 'junk-food' in these systems may be coupled to large scale changes in climatological and oceanographic forcing, although predation, fishing and competition provide additional plausible hypotheses. It may be possible to predict which kinds of animals will be particularly sensitive to food quality; these seem to be species with limited ability to carry food loads, with energetically-expensive foraging behaviour, and with digestive anatomy evolved to minimize mass at the cost of digestive efficiency. This review suggests that the junk-food hypothesis is a highly relevant factor in relation to sustaining ecosystem resilience, and is an important consideration in ecosystem management. Sustaining healthy populations of marine top-predators requires an understanding of the role of food quality, in addition to food abundance and availability.

This review summarizes forefield and lacustrine records of glacier fluctuations in Alaska during the Holocene. Following retreat from latest Pleistocene advances, valley glaciers with land-based termini were in retracted positions during the early to middle Holocene. Neoglaciation began in some areas by 4.0 ka and major advances were underway by 3.0 ka, with perhaps two distinct early Neoglacial expansions centered respectively on 3.3-2.9 and 2.2-2.0 ka. Tree-ring cross-dates of glacially killed trees at two termini in southern Alaska show a major advance in the AD 550s-720s. The subsequent Little Ice Age (LIA) expansion was underway in the AD 1180s-1320s and culminated with two advance phases respectively in the 1540s-1710s and in the 1810s-1880s. The LIA advance was the largest Holocene expansion in southern Alaska, although older late Holocene moraines are preserved on many forefields in northern and interior Alaska. Tidewater glaciers around the rim of the Gulf of Alaska have made major advances throughout the Holocene. Expansions were often asynchronous with neighboring termini and spanned both warm and cool intervals, suggesting that non-climatic factors were important in forcing these advances. However, climatic warming appears to have initiated most rapid iceberg-calving retreats. Large glaciers terminating on the forelands around the Gulf of Alaska may have had tidewater termini early in the Holocene, but have progressively become isolated from the adjacent ocean by the accumulation and subaerial exposure of their own sediments.

In recent years, large anticyclonic eddies have been observed quasi-annually in the region seaward of Kodiak Island, Alaska. In situ sampling in 3 of these eddies was undertaken in 2002, 2003, and 2004. Satellite altimetry data showed that these 3 eddies had 3 different formation regions but their translation pathways were similar near Kodiak Island. Eddies in this region can persist for several years, moving southwestward along the Alaskan Peninsula to the Aleutian Archipelago. Water properties in the cores of the 2003 and 2004 eddies were significantly different from each other, probably because the 2003 eddy formed on the shelf near Yakutat while the 2004 eddy formed farther out in the basin in the northern Gulf of Alaska. Calculation of heat, salinity, and nutrient anomalies associated with the eddies showed that, in their subsurface core waters, the eddies carry excess heat, salt, nitrate and silicic acid seaward from the eddy formation regions. r

The abundance and availability of food are critical determininants of reproductive success and population dynamics of marine top predators. However, recent work has indicated that the quality of the food may also be critically important for some marine predators. The 'junkfood hypothesis' was originally suggested as a potential explanation for a dramatic population decline of Stellers sea lions Eumetopias jubatus in the Gulf of Alaska. According to the hypothesis, a dietary switch to prey of low energy content led to detrimental effects on the population of sea lions. A number of observations indicate that the hypothesis is relevant for several population parameters. Recent work on piscivorous seabirds has provided substantial evidence indicating the relevance of this hypothesis in food webs in e.g. the North Pacific, the North Sea and the Baltic Sea. The emergence of 'junk-food' in these systems may be coupled to large scale changes in climatological and oceanographic forcing, although predation, fishing and competition provide additional plausible hypotheses. It may be possible to predict which kinds of animals will be particularly sensitive to food quality; these seem to be species with limited ability to carry food loads, with energetically-expensive foraging behaviour, and with digestive anatomy evolved to minimize mass at the cost of digestive efficiency. This review suggests that the junk-food hypothesis is a highly relevant factor in relation to sustaining ecosystem resilience, and is an important consideration in ecosystem management. Sustaining healthy populations of marine top-predators requires an understanding of the role of food quality, in addition to food abundance and availability.

Dawson tephra, recently recognized in the Klondike area of Yukon Territory, records one of the largest Quaternary volcanic eruptions in Beringia. Its composition is similar to that of Old Crow tephra, indicating a source in the Aleutian arc-Alaska Peninsula region of southwestern Alaska. Its primary thickness in central Yukon is nearly twice that of Old Crow tephra, which has an estimated eruption volume of >50 km 3 . The distribution of Dawson tephra is still poorly known, but based on its source area and occurrence in central Yukon, it should be widespread across southern Alaska, Yukon and the Gulf of Alaska. New radiocarbon ages indicate the eruption occurred at about 24,000 14 C yr BP (ca 27,000 cal yr BP). The Dawson tephra is a valuable marker bed for correlating late Pleistocene records across large areas of eastern Beringia and adjacent marine records. r

Walleye pollock, Theragra chalcogramma, are one of the dominant fishes in the Gulf of Alaska (GOA) ecosystem, yet relatively little information is available on the diet and prey selectivity of pollock in the northern GOA. Stomachs of midwater trawled adult pollock were collected in April, August and November 2003 in the northern GOA. Euphausiids were the dominant prey in April, averaging 59% by number and 70% by weight. Euphausiids persisted as the dominant prey in August, averaging 84% by number and 95% by weight. Decapods were the dominant prey item in November. This was primarily due to the shrimp Pandalus borealis, which averaged 68% by number and 53% by weight. Stomach contents were also compared with available prey fields using chi-square-based resource selection statistics. This analysis revealed significant differences between the environmental and dietary distributions of prey types. Additional analysis found significant selection for euphausiids over all other categories of available zooplankton in both spring and summer. Amongst euphausiids, there was significant selection for Thysanoessa inermis in spring and T. spinifera in summer.

Climate change impacts in large marine ecosystems (LMEs) are driven by global climate variability, often communicated over large distances by atmospheric teleconnections, and modified by the dominant local and regional ocean processes. The focus of this paper is to summarize the key processes and features that characterize the major coastal LMEs of the Pacific, as part of a greater effort to understand the role of past and future global climate change in driving (possibly synchronous) fluctuations in marine populations. The physical setting of five LMEsthe Humboldt Current System (HCS), California Current System (CCS), Gulf of Alaska (GOA), Kuroshio Current System (KCS), and Oyashio Current System (OCS)and the mechanisms and impacts of climate variability on these systems are described. Because of their pivotal role in linking and perhaps synchronizing climate variability in disparate LMEs, we also review teleconnections and analyze past global atmospheric teleconnections and regional ocean response patterns. The major Pacific eastern boundary current systems, the CCS and HCS, feature similar dominant processes (e.g., coastal upwelling), and share atmospheric forcing from common teleconnection patterns that vary together. Sea level pressure variations forcing the KCS and OCS systems on climate scales, however, are not strongly teleconnected to the CCS and HCS. A common factor analysis of sea surface temperature (SST) within these ecosystems provides an example of how LMEs have responded to past climate variability. All LMEs display a persistent warming tendency since 1900, with multi-decadal fluctuations superimposed. However, SST fluctuations in the western Pacific lag those in the east by about a decade. Global synchrony in climate forcing is modulated by distinct processes within each LME, which reduce the correlation between long-term fluctuations.

The Black-legged Kittiwake Rissa tridactyla is the most abundant gull species in the world, but some populations have declined in recent years, apparently due to food shortage. Kittiwakes are surface feeders and thus can compensate for low food availability only by increasing their foraging range and/or devoting more time to foraging. The species is widely studied in many respects, but long-distance foraging and the limitations of conventional radio telemetry have kept its foraging behavior largely out of view. The development of Global Positioning System (GPS) loggers is advancing rapidly. With devices as small as 8 g now available, it is possible to use this technology for tracking relatively small species of oceanic birds like kittiwakes. Here we present the first results of GPS telemetry applied to Black-legged Kittiwakes in 2007 in the North Pacific. All but one individual foraged in the neritic zone north of the island. Three birds performed foraging trips only close to the colony (within 13 km), while six birds had foraging ranges averaging about 40 km. The maximum foraging range was 59 km, and the maximum distance traveled was 165 km. Maximum trip duration was 17 h (mean 8 h). An apparently bimodal distribution of foraging ranges affords new insight on the variable foraging behaviour of Black-legged Kittiwakes. Our successful deployment of GPS loggers on kittiwakes holds much promise for telemetry studies on many other bird species of similar size and provides an incentive for applying this new approach in future studies.

Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of Conceptual Model of the Prince William Sound Ecosystem natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems.

The eastern North Pacific population of right whales (Eubalaena japonica) is among the most endangered whale populations, with an estimated size of only 10s of individuals. The effectiveness of measures (e.g., protected areas, abundance surveys) intended to promote recovery of this population will be enhanced by understanding its distribution, habitat use, and habitat characteristics. In order to facilitate such understanding, we summarized relevant right whale biology, reviewed the life history of their zooplankton prey species, and related North Pacific oceanography to the production, distribution, and concentration of these prey at three scales of variability. We discuss how ocean processes may drive zooplankton distribution and concentration, and present hypotheses about how prey patches suitable for right whale foraging might be formed. Such hypotheses, combined with available distributional data and descriptions of the ocean environment, would be suitable for predicting potential right whale foraging habitat.

Polycyclic aromatic hydrocarbons (PAH) are sensitive recorders of past human activities in Prince William Sound, Alaska. In the nearshore subtidal sediments of bays, the ®ngerprints of the pyrogenic (combustion-derived) PAH record numerous sites of both present and historical human activities including active settlements, ®sh hatcheries, ®sh camps and recreational campsites, in addition to abandoned settlements, canneries, sawmills, and mining camps. In instances, there are high levels of PAH attributable to past human activities even though there is little remaining visual evidence of these activities on the shorelines. Forest ®res are also an important source of pyrogenic PAH in subtidal sediments at certain time periods and locations and pyrogenic PAH from atmospheric fallout forms part of the regional PAH background. These pyrogenic PAH ®ngerprints are superimposed on a regional background of natural petroleum hydrocarbons derived from seeps in the eastern Gulf of Alaska. In isolated locations, weathered traces of the Exxon Valdez oil spill were detected as a minor part of the total PAH present from all sources. Ó

Cyclogenesis is known to take place frequently near the principal mountain complexes of the earth. However, a coherent and comprehensive theory of orographic cyclogenesis has never been offered in the fiterature. We propose here a unified theory of cyclogenesis in the presence of orography of various configurations, based on the generalization of a theoretical model concerning the interaction of baroclinic waves with local orography. This model has recently proved to be successful in accounting for some basic properties of Alpinecyclogenesis . We consider, in particular, cyclogenesis in proximity of the Rocky Mountains (both to the west of the ridge, in the Gulf of Alaska, and to the east of it, over North America) and in proximity of the Himalaya-Tibetan Plateau.

Relationships of diversity, distribution and abundance of benthic decapods in intertidal and shallow subtidal waters to 10 m depth are explored based on data obtained using a standardized protocol of globally-distributed samples. Results indicate that decapod species richness overall is low within the nearshore, typically ranging from one to six taxa per site (mean = 4.5). Regionally the Gulf of Alaska decapod crustacean community structure was distinguishable by depth, multivariate analysis indicating increasing change with depth, where assemblages of the high and mid tide, low tide and 1 m, and 5 and 10 m strata formed three distinct groups. Univariate analysis showed species richness increasing from the high intertidal zone to 1 m subtidally, with distinct depth preferences among the 23 species. A similar depth trend but with peak richness at 5 m was observed when all global data were combined. Analysis of latitudinal trends, confined by data limitations, was equivocal on a global scale. While significant latitudinal differences existed in community structure among ecoregions, a semi-linear trend in changing community structure from the Arctic to lower latitudes did not hold when including tropical results. Among boreal regions the Canadian Atlantic was relatively species poor compared to the Gulf of Alaska, whereas the Caribbean and Sea of Japan appeared to be species hot spots. While species poor, samples from the Canadian Atlantic were the most diverse at the higher infraordinal level. Linking 11 environmental variables available for all sites to the best fit family-based biotic pattern showed a significant relationship, with the single best explanatory variable being the level of organic pollution and the best combination overall being organic pollution and primary productivity. While data limitations restrict conclusions in a global context, results are seen as a first-cut contribution useful in generating discussion and more in-depth work in the still poorly understood field of biodiversity distribution.

We review age-specific growth, recruitment, and population diversity of herring (Clupea pallasi) in the North Pacific. Eastern Pacific herring are smaller, grow slower, and reach a lower asymptotic weight (W 1) than western Pacific herring. In the eastern Pacific, there are latitudinal differences in size but this variation is slight compared to east-west differences. The east-west growth differences match geographic patterns of genetic variation between eastern and western Pacific herring described in earlier reports. Both the genetic studies and the growth variation show that virtually all western Pacific herring populations, including those in the Bering Sea, cluster in one group, and all eastern Pacific herring, from the Gulf of Alaska to California, cluster in a second group. Population diversity, estimated as the number of separate populations per degree of latitude, is highest in the mid-ranges (latitudes) of herring distribution but the available supporting data are limited. Recruitment variation, examined by comparing the coefficient of recruitment variation for nine eastern Pacific herring populations, was highest in the Gulf of Alaska and lowest in southern populations. We suggest that the broad geographic differences in herring populations are adaptive, evolving in response to local prey resources, competitive and climate regimes. If so, examination of these differences can provide insight about potential effects of future climate change.

The coastal region affected by the Exxon Valdez oil spill, although a beautiful and sensitive maritime wilderness with bountiful fish and wildlife, was not a pristine environment in 1989. Prior to the spill, Prince William Sound and the northern Gulf of Alaska region had experienced extensive human impacts from the commercial fur trade, commercial sea-mammal hunting, commercial fishing, logging, mining and introduced exotic species including foxes, Sitka black-tailed deer and hatchery-reared pink salmon. The spill occurred in a scenic area that was (and is) paradoxically both the source of subsistence food for local residents and the scene of extensive natural resource exploitation. Contrary to media sound bites and news headlines, the Exxon Valdez oil spill did not destroy a pristine wilderness. The Russian and American fur traders, commercial whalers and commercial fishermen, miners, loggers, fox farmers and military construction crews had transformed the region long before March 24, 1989. The Exxon Valdez spill was an important chapter in the history of human impacts to the areaÕs maritime ecosystem, but it was not, as many continue to claim, the mother of all environmental impacts in the region.

Temporal and spatial patterns of recruitment (R) and spawning stock biomass (S) variability were compared among functionally analogous species and similar feeding guilds from six marine ecosystems. Data were aggregated into four regions including the Gulf of Maine/Georges Bank, the Norwegian/Barents Seas, the eastern Bering Sea, and the Gulf of Alaska. Variability was characterized by calculating coefficients of variation and anomalies for three response variables: ln(R), ln(R/S), and stock-recruit model residuals. Patterns of synchrony and asynchrony in the response variables were examined among and between ecosystems, between-and within-ocean basins and among functionally analogous species groups using pairwise correlation analysis corrected for within-time series autocorrelation, multivariate cross-correlation analyses and regime shift detectors. Time series trends in response variables showed consistent within basin similarities and consistent and coherent differences between the Atlantic and Pacific basin ecosystems. Regime shift detection algorithms identified two broad-scale regime shift time periods for the pelagic feeding guild (1972-1976 and 1999-2002) and possibly one for the benthic feeding guild (1999)(2000)(2001)(2002). No spatial patterns in response variable coefficients of variation were observed. Results from multivariate cross-correlation analysis showed similar trends. The data suggest common external factors act in synchrony on stocks within ocean basins but temporal stock patterns, often of the same species or functional group, between basins change in opposition to each other. Basin-scale results (similar within but different between) suggest that the two geographically broad areas are connected by unknown mechanisms that, depending on the year, may influence the two basins in opposite ways. This work demonstrates that commonalities and synchronies in recruitment fluctuations can be found across geographically distant ecosystems but biophysical causes of the fluctuations remain difficult to identify.