Inland Subsistence and Seasonality in the Kodiak Archipelago, Alaska

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 360:265-283 (2008) - DOI: https://doi.org/10.3354/meps07383 Spatial and temporal variation in the diet of Steller sea lions in the Kodiak Archipelago, 1999 to 2005 Jane McKenzie*, Kate M. Wynne University of Alaska Fairbanks, School of Fisheries and Ocean Science, 118 Trident Way, Kodiak, Alaska 99615, USA *Email: janemckenzie@malpage.com ABSTRACT: Spatial and temporal variation in the diet of Steller sea lions Eumetopias jubatus was investigated using scat (fecal) samples collected from 4 regions in the Kodiak Archipelago. Over 2700 scats with identifiable prey were collected from the northern, eastern, southern and western sides of Kodiak Island from 1999 to 2005. Of 76 prey types identified using hard remains, the most important species in terms of frequency of occurrence and numerical abundance were Pacific sand lance Ammodytes hexapterus, walleye pollock Theragra chalcogramma, arrowtooth flounder Atheresthes stomias, Pacific cod Gadus macrocephalus, salmon Oncorhynchus spp., and Pacific herring Clupea pallasi. Significant differences in diet composition were found among regions, seasons, and years, suggesting that the diet of sea lions is strongly influenced by local and temporal distributions and abundances of prey. Herring dominated scat collections from the west coast and accounted for most (14 to 30%) of the differences in regional diet in spring and winter. Annual variation in diet was relatively low in winter, whereas spring and fall diets varied from year to year, with regional-specific shifts in dominant prey. Results from our study generally agree with diet studies conducted in the 1990s, but differ markedly in the relative importance of the major prey species. KEY WORDS: Eumetopias jubatus · Prey · Seasonal · Diet overlap · Forage fish · Gulf of Alaska · Theragra chalcogramma · Ammodytes hexapterus Full text in pdf format Supplementary appendix PreviousNextCite this article as: McKenzie J, Wynne KM (2008) Spatial and temporal variation in the diet of Steller sea lions in the Kodiak Archipelago, 1999 to 2005. Mar Ecol Prog Ser 360:265-283. https://doi.org/10.3354/meps07383Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 360. Online publication date: May 22, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.

Implications for measuring seasonality in the marine bivalve, Saxidomus gigantea

The Aleutian tern (Onychoprion aleuticus) is a species of high conservation concern in Alaska, USA, owing to large declines at known breeding locations since the 1960s. The small population size and ephemeral behavior of this species have limited the collection of basic biological information and hindered the identification of potential drivers of this decline. Significant unknowns include the factors, and their relative importance, influencing nest survival. To investigate these questions, we estimated daily nest survival (DNS) for 148 nests from 5 breeding colonies during 2017 to 2020 in the Kodiak Archipelago, Alaska with 105 monitored using remote cameras. We used the nest survival model in program MARK to estimate DNS rates as a function of colony location, year, within‐season time trends, vegetation cover and height, and 6 daily weather covariates. Our top model suggested that DNS rates increased with vegetation height, decreased as the season progressed, and included a significant interaction between year and colony. Average nest success (i.e., percent chance that a nest survived to hatch) over the 22‐day incubation period varied by colony but was generally very low, averaging 1.2% (95% CI = 0–11%) in 2017–2018 to 14% (95% CI = 0.1–38%) in 2019–2020 across all colonies. The importance of year in the model suggests that a large‐scale annual driver, like food availability, may have played an important role in this species' breeding success. A severe marine heatwave was present in the Gulf of Alaska during 2014–2016 and our results suggest that some effects of this anomalous event, such as reduced prey availability, lingered even after temperatures returned to normal. Additionally, the variation in DNS across colony locations indicated that local factors, such as predation pressure, may also drive significant variation in Aleutian tern productivity. These findings suggest that a combination of local factors and climate change may be important drivers of the >90% decline in Alaska's breeding population of Aleutian terns.

Climate change is altering the predictability of timing of resource pulses and how consumers interact with them, resulting in phenomena placed under the trophic mismatch hypothesis (TMH). This occurs when a consumer fails to overlap and capitalize on availability of a key food resource pulse. Such changes to predator-prey interactions can alter nutrient transfer, destabilize food webs, and reduce species reproduction and survival. Brown bears (Ursus arctos) on the Kodiak Archipelago, Alaska, USA, have purportedly altered their foraging toward increased use of terrestrial resources under TMH. We examined how the extent of within- and across-year overlap between abundances of Pacific salmon (Oncorhynchus spp.) and berries altered salmon assimilation by brown bears on the Kodiak Archipelago during 2015–2017. We further examined whether salmon consumption differed with brown bear sex and age. We found no decrease in salmon assimilation in response to variation in terrestrial and marine food overlap across and within years. Overall salmon assimilation was high, representing over 60% of brown bear diets in 2015 and 2017, with lower (44%) consumption of salmon in 2016 corresponding with a 28% reduction in salmon abundance. Within years, monthly salmon assimilation was lower in June when salmon began to enter the system, then increased and remained similar during July–October, despite 0–71% within month overlap in peak salmon and berry availability. Older brown bears, particularly males, consumed more salmon than did females and younger bears. While the potential ecosystem impacts of TMH may pose a lesser threat to brown bears than previously reported, possible future declines in Pacific salmon abundance due to climate change may adversely affect North American coastal brown bear populations by reducing abundance of this important food source.

Surplus production is a hallmark of Alaska's prehistoric coastal societies. Over the millennia, foragers procured greater quantities of resources with increasing efficiency, developing economies dependent upon storage and institutionalized exchange. In the central Gulf of Alaska, notable evidence of surplus production comes from the late phase of the Kachemak tradition. Since de Laguna's pioneering studies, archaeologists have noted that intensified fishing, storage, and exchange typify this tradition. However, few have investigated the roots of these behaviors. When, how, and why did foragers begin producing well beyond immediate needs? This paper explores archaeological evidence for surplus production in the Kodiak Archipelago, focusing on patterns in land use, technology, and exchange preserved in Ocean Bay II and Early Kachemak assemblages from the Chiniak Bay region. It suggests that surplus production for the purposes of seasonal food storage began in the Early Kachemak, and accelerated in the Late Kachemak as population levels climbed.

A mass die-off of Common Murres (Uria aalge) occurred from spring 2015 to spring 2016 in the northern Gulf of Alaska. Seabird die-offs have been recorded previously in the region, but this event was unique in its long duration and wide spatial extent. In response to the die-off, Kodiak National Wildlife Refuge (NWR) biologists conducted systematic beach surveys along the road system adjacent to the city of Kodiak and compiled reports from local citizens in remote locations throughout the Kodiak Archipelago to document the number of dead birds observed on beaches. Analysis of beached bird records indicated that at least 1,994 dead Common Murres were observed in the Kodiak Archipelago from 4 April 2015 to 26 April 2016. Extrapolating the density estimate, based on carcasses counted on systematic surveys on the Kodiak road system (55 murres/km, SE = 12), to all beaches in the Kodiak road system study region in the same biophysical habitat class based on Alaska ShoreZone coastal mapping, yielded an estimate of 6,305 dead Common Murres (95% CI = 3,522–9,088). In addition to Common Murres, carcasses of another 65 birds representing 15 species were found on beaches on the Kodiak road system during the die-off. The die-off event was preceded by a large-scale inshore movement by marine bird species typically seen offshore (Common Murres and shearwater species), as documented by Kodiak NWR survey data and by local observers throughout the archipelago. Survey data indicate the population estimate for Common Murres in the northeastern region of the archipelago increased from 711 in June 2012 to 31,543 in June 2015 (4,335% increase), and from 5,063 in August 2012 to 64,039 in August 2015 (1,165% increase).

Marine and estuarine habitats near urban or industrialized regions are vulnerable to contaminated runoff. Harbor seals (Phoca vitulina richardsi), which occur throughout much of the northern hemisphere, are useful mammalian biomonitors because they feed, reproduce, and rest near or on shore and are high-level trophic consumers. They have often been monitored for contaminants in Europe. To date, no studies have been reported on contaminants in harbor seals from industrialized areas of Alaska. In the vicinity of Anchorage, Alaska's largest urban and industrial city, harbor seals are sedentary and limited to coastal waters; some movements have been documents but there is no evidence of extensive migrations. Although some harbor seals in the Kodiak Archipelago move up to 100 km along the shore, strong fidelity to specific haulout sites is more common. These seals eat mainly non-migratory fishes and octopi. Harbor seal numbers have declined substantially from unknown causes in the southern part of the Kodiak Archipelago. The Alaska Department of Fish and Game (ADF G) suggested that the decline is a trend for the entire Kodiak region and other Alaskan waters. Contaminants have been suggested as a possible reason for the precipitous decline of Steller sea lions (Eumetopias jubatus) in themore » region, and were suspected in the decline of harbor seals. In this study, harbor seals were sampled from throughout the Kodiak Archipelago to determine concentrations of certain metals, metalloids, polychlorinated biphenyls (PCBs), and organochlorine pesticides, and to determine if these concentrations varied by sex or accumulated with age. All seals were collected within 75 km of Cook Inlet, an estuary next to Anchorage. The targeted elements or compounds were known to be toxic to a wide spectrum of organisms. 19 refs., 1 tab.« less

Our understanding of subduction initiation remains limited by the difficulty of making direct observations of geologically recent examples. In the geologic record, supra‐subduction zone ophiolites are often interpreted to record syn‐initiation slab rollback and upper plate extension. Unfortunately, many ophiolites are decoupled from records of subsequent arc maturation and/or lack robust geochronological constraints. In this contribution, we investigate the initiation of the Late Triassic‐Jurassic Talkeetna Arc of southern Alaska. The Talkeetna Arc is one of the world's preeminent examples of an oceanic magmatic arc, yet the timing and tectonic record of its initiation remain unconstrained. Our study integrates geologic mapping with a chemostratigraphic analysis of ∼3.5 km of pillow basalts that comprise the Lower Shuyak Formation (Kodiak Archipelago, Alaska). The Lower Shuyak Formation hosts Late Triassic calc‐alkaline plutons and is overlain by ∼2 km of volcaniclastic strata. Initial mafic volcanism was characterized by high‐Ti, E‐MORB‐like tholeiites that are enriched in high field strength elements (HFSEs) and light rare earth elements. Compositions transition up section to HFSE/LREE‐depleted island arc tholeiites that become enriched in Th. These trends are consistent with petrologic processes during subduction initiation. High‐precision U‐Pb zircon dates (CA‐ID‐TIMS) constrain initiation to ∼232 Ma or slightly earlier. Our results demonstrate that initiation of the Talkeetna Arc occurred earlier than previous estimates, slightly preceding the eruption of regionally extensive flood basalts interpreted by previous studies as plume‐related. This relationship may suggest that subduction initiation was plume‐induced, or that rifting of the upper plate was the primary driver of basaltic volcanism regionally.

The Kittlitz's Murrelet Brachyramphus brevirostris is a poorly known alcid of the Bering Sea region.It is one of the rarest breeding seabirds in the North Pacific and is listed as Critically Endangered on the IUCN Red List.It has a highly restricted breeding range, with a patchy distribution in Alaska and the Russian Far East.In this paper, we highlight its use of the Kodiak Archipelago, Alaska-an area that has received little research or monitoring attention as breeding or wintering habitat for this species.Based on observational data from the last 30+ years, we conclude that Kittlitz's Murrelets are present year round in the area and we present maps of their distribution around the archipelago.We include a description of the location and habitat characteristics of the first confirmed case of Kittlitz's Murrelet breeding on Kodiak Island and map potential nesting habitat across the archipelago.Given the conservation status and increasingly high profile of this species, we encourage increased and focused management attention on Kittlitz's Murrelets in this location.

Legal harvests of wildlife occur throughout North America, where some big game hunters preferentially target individuals with larger body parts (e.g., horn, antler, body size), a practice referred to as selective harvest. Selective harvests have the potential to influence the phenotypic and age composition of harvested animals (e.g., body size, age structure), although inference about population-level change from harvest data alone is inherently limited. Moreover, professional guides can play an important role in selective harvests by helping their clients more frequently harvest animals with larger body parts compared to hunters without guides. We used records of 6426 legally harvested brown bears (Ursus arctos) (4625 males; 1801 females) on the Kodiak Archipelago, Alaska, USA, from the 1987-2023 regulatory years to evaluate patterns consistent with two nonexclusive hypotheses regarding selective harvests. Based on the selective harvest hypothesis, we predicted that the selection of bears with larger skulls (i.e., older bears) by hunters would result in a decline in skull size and a younger age structure of harvested individuals through time. Based on the hunter origin effect hypothesis, we predicted that, because guides are generally more experienced and more familiar with hunt areas, guided hunters, on average, would harvest bears with larger skulls more often and in less time than unguided hunters. Contrary to expectations under selective harvests, we observed an increase of almost 2 years in age and 1.7 cm in skull size among harvested bears over the 37-year period. Guided hunters, on average, harvested bears with larger skulls more frequently than unguided hunters but spent more days in the field before a successful harvest, compared to unguided hunters. Our results suggest temporal and hunter-related patterns in characteristics of harvested bears and that current harvest regulations on the Kodiak Archipelago are associated with sustained availability of older, larger individuals in the harvested population.

Tree species in the northern hemisphere are currently subject to rapid anthropogenic climate change and are shifting their ranges in response. This prompts questions about the mechanisms allowing tree populations to respond quickly to selection pressures when establishing into new areas. Focusing on the northern expanding range edge of Picea sitchensis, a widespread conifer of western North America, we ask how genetic structure and diversity develop during colonization, and assess the role of demographic history in shaping the evolutionary trajectory of an establishing population. We combined 500yr of tree-ring and genotyping-by-sequencing data in 639 trees at the expansion front on the Kodiak Archipelago. We show that alleles accumulated rapidly during an increase in recruitment rate in the early 1700s. A shift from foreign to local pollen flow subsequently homogenized genetic structure at the expansion front. Taking advantage of the exceptional longevity of conifers, we highlight the major role of long-distance pollen dispersal in the rapid but incomplete recovery of genetic diversity during the initial stages of colonization. We also warn that slow initial population growth as well as long-lasting dominance of local gene flow by early founders could increase evolutionary load under a rapidly changing climate.

Habitat protection is a major component of the Exxon Valdez oil spill restoration process. The acquisition of private lands, or partial interests in private lands, is intended to promote natural recovery of spill‐injured resources and services by removing the threat of additional development impacts. The Comprehensive Habitat Protection Process is the method that was designed to achieve this objective. Over one million acres within the oil spill affected area were evaluated, scored, and ranked by a multi‐criteria evaluation process. Initially, lands were divided into large parcels encompassing entire bays and watersheds. Criteria were then used to assess the habitat and human‐use values associated with each parcel and the protection benefit that acquisition would provide for 19 injured resources and services. This process has been the basis for the acquisition of 41,549 acres of land on Afognak Island and 23,800 acres on the Kenai Peninsula and for agreements that, if consummated, will result in the acquisition of fee or lesser rights on over a half million acres of land in the Kodiak Archipelago, on the Kenai Peninsula, and in Prince William Sound. All of these lands or rights, if acquired, will be incorporated into parks or refuges or otherwise managed in a manner that will facilitate the recovery of the resources and services injured by the oil spill.

Concerns about Harlequin Duck (Histrionicus histrionicus) population recov- ery following the Exxon Valdez oil spill led biologists to ask whether birds located in different molting and wintering areas belong to genetically distinct and, thus, demographically in- dependent populations. Owing to the lack of direct observations of movements among ma- rine areas, three classes of genetic markers that differed in mode of inheritance were used to evaluate the degree of genetic differentiation among wintering areas within Prince Wil- liam Sound (PWS) and the Alaska Peninsula and Kodiak Archipelago (APKA). We could not reject the null hypothesis that the wintering aggregations within each region are composed of a single genetically panmictic population. Differences in genotype frequencies among wintering locations within PWS and APKA were low and nonsignificant for all three classes of markers. Furthermore, we saw no evidence for deviations in Hardy-Weinberg equilibrium or gametic disequilibrium between loci within a winter collection site as would be expected if these locales were composed of individuals from reproductively isolated (and genetically distinct) breeding locales. Finally, no evidence for significant structuring was noted between PWS and APKA. Lack of spatial genetic structuring could be due to the cumulative effects of low levels of gene flow over long time periods, low levels of gene flow by immature birds moving between marine habitats, or to episodic dispersal caused by habitat alteration (e.g.

Paralytic shellfish poisoning (PSP) is a pervasive human health concern associated with subsistence, recreationally and commercially harvested Alaskan shellfish. PSP is caused by saxitoxins (STX), a family of structurally similar neurotoxins produced by the marine microalgae Alexandrium catenella (formerly A. fundyense). These toxins accumulate in filter-feeding shellfish such as clams, mussels and oysters. While PSP is commonly associated with consuming bivalves, toxic STX levels can also be found in crab viscera (crab butter). The first cases of PSP from consuming Dungeness crab viscera (Metacarcinus magister) were reported in 1992. Although this incident and others did not involve commercially harvested crab, they did impact management of the Dungeness crab fishery in Alaska. Current regulations in southeast Alaska permit the sale of whole Dungeness crab, whereas those in the Kodiak Archipelago must have their viscera removed post-harvest to prevent PSP. This study examines the impacts of STXs and current regulations on the Alaskan crab fishery, with a focus on Dungeness crab. Data on commercial landings and the value of harvested Dungeness crab and processed products showed that regulations to protect human health, combined with market forces over the past 30 years, have shifted the fishery's focus toward Dungeness crab products without viscera. The study also presents time series data on STX concentrations in Dungeness crab from 1992 to 2023, along with maps indicating collection locations and their associated toxicity levels. The same data for King crab (Paralithodes or Lithodes spp.) and Tanner (Snow) crab (Chionoecetes spp.) are included to assess the prevalence of STX in these commercially harvested species. Further, a preliminary analysis suggests regional variations in the toxicity of A. catenella strains could affect regional shellfish toxicity.

Conditions in Alaska, USA, pose a challenge for monitoring populations of Brachyramphus murrelets using standard survey methods, because of strong winds, 2 sympatric species, short nights, and variable nesting habitat. We tested 3 methods for monitoring Brachyramphus murrelets breeding in the Kodiak Archipelago, Alaska, in 2010–2012. In addition to standard audio‐visual and radar methods, we tested—for the first time with murrelets in Alaska—the application of autonomous acoustic recorders for monitoring vocal activity. We completed 74 radar, 124 audio‐visual, and 134 autonomous acoustic surveys, focused on presunrise activity peaks; this yielded 26,375 murrelet detections. Marbled ( B. marmoratus ) and Kittlitz's murrelets ( B. brevirostris ) could not be distinguished using combinations of radar and acoustic recordings; therefore, at‐sea surveys will be required to determine localized species proportions. Of the 3 methods, radar sampled the largest area and detected silently flying murrelets, providing the most reliable data on local populations; however, radar identification of murrelets was unreliable in winds exceeding 18 km/hr. Audio‐visual surveys were useful for species identification and to document behaviors associated with local nesting, whereas autonomous acoustic recorders allowed season‐long monitoring of murrelet vocal activity. Within potential forest‐nesting habitat of marbled murrelets, all 3 methods gave similar measures of presunrise murrelet activity, but only radar reliably sampled murrelets commuting between nest and ocean. Because of their low cost and flexible programming, automated sound recorders offer an affordable way to sample vocal activity prior to more intensive or expensive radar and audio‐visual surveys. We recommend that population monitoring and habitat studies of Brachyramphus murrelets in Alaska include combinations of all 3 methods. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.