2011 Alaska Marine Science Symposium
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Alaska Marine Science Symposium website
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SFOS students win best poster awards at Alaska Marine Science Symposium (January 24, 2011 news story)
SFOS Speakers with Podcasts
Podcasts are hosted on the Alaska Marine Science Symposium website
- Arny Blanchard, Highlights from 40 years of research in Port Valdez; Listen to podcast
Investigations in Port Valdez include multidisciplinary and oceanographic assessments of the ecosystem, investigations of dominant fauna, and long-term environmental monitoring comprising 40 years of research in the fjord. The long-term database (1971 to present) allows for retrospective analysis of intertidal and subtidal data to understand sources of variability within the ecosystem. Highlights of the Port Valdez research are presented. Distributions of intertidal organisms are directly and indirectly affected by the salinity gradient and substrate characteristics and demonstrated large temporal change. Gametogenesis and shell growth of Mytilus trossulus occurs in winter when food resources are limited and limpets spawn in late fall with gametogenesis occurring in summer when food resources are higher. Within the deep basin of the fjord, distributions of sediment-dwelling macrofauna reflect recovery from the 1964 Great Alaska earthquake and a strong association with climatic variability (data from 1971-2010). Investigation of macrofauna and polycyclic aromatic hydrocarbons (PAH) at shallower sites (1989-2010) near the Valdez marine oil terminal demonstrate weak associations of PAH (derived from treated ballast-water effluent) with macrofaunal community structure. However, effects were greatest for two tube-dwelling polychaete worms (Galathowenia oculata and Melinna cristata) that responded negatively to PAH values much lower than the commonly accepted Effects Range-Low criterion. Overall, the biological data indicate an ecosystem in flux from natural variations with human stressors having minor influences. The extensive publication record for the Port Valdez ecosystem provides a basis for understanding long-term variability of benthic communities in coastal Alaska. - Melissa Deiman (student), Kelp spore susceptibility to sedimentation and light attenuation within Alaska; Listen to podcast
Canopy-forming kelps species provide structural complexity for associated communities within Alaska’s nearshore. The establishment of kelp spores plays an essential role in kelp distribution and abundance patterns. Environmental variables may control the species-specific dominance that is often observed of kelp in the field. Lab experiments were performed to determine the attachment, survival, and germination rates of the spores of two prominent Alaskan canopy-forming kelps, Nereocystis luetkeana and Eualaria fistulosa, to 1) various light levels and 2) sediment loads. Nereocystis luetkeana and E. fistulosa spores had similar attachment success (~30-60%) and germination rates (~70%) under all light levels tested. There was no significant difference between the two species; however, E. fistulosa exhibited approximately 2-3 μm longer germ tubes after 48 hours. Spore attachment for both species was significantly affected by suspended particles, settled sediment covering the substratum, and by smothering of settling sediment, decreasing by approximately 90% at the highest sediment load. These results suggest that increases in sedimentation may constrain the success of the microscopic spore stages and thus kelp abundance and distribution within Alaska’s nearshore. An understanding of the environmental variables controlling the temporal and spatial establishment of kelp forests in Alaska will help us understand how changes in these variables may affect nearshore communities. - Julie Nielsen (student), Characterizing space use of Pacific halibut during summer in Glacier Bay, Alaska using acoustic telemetry; Podcast not available
A fine-scale acoustic telemetry project on the movement of Pacific halibut was conducted in Glacier Bay, Alaska, from 1991 to 1993. Tagged halibut were located daily to weekly using vessel-based tracking during tracking periods ranging from 4-6 months each year. This work provided the first information on the scale of space use for Pacific halibut during summer, where tagged fish demonstrated both constrained and dispersive movement patterns. We will present an update on the analysis of the telemetry data that incorporates recent advances in analysis methods and information from a habitat map of the study area that was produced in 2006. By combining information on tagged halibut locations with bathymetry and habitat information, we are able to generate hypotheses about mechanisms that underlie observed patterns in space use for halibut in Glacier Bay. - Rachel Potter, Surface current measurements in the northeast Chukchi Sea using shore-based high-frequency radar; Listen to podcast
Hourly surface currents were measured from the shore of Barrow and Wainwright, Alaska, from mid-September through mid-November 2009 and from mid-July through freeze-up 2010, using High-Frequency Radar. Data collected has six kilometer spatial resolution, extends up to 200 km offshore, and is representative of the top two meters of the water column. Preliminary results have yielded numerous circulation features, including an intermittent, a strong coastal current approximately 30 km in width with speeds in excess of 50 cm/s. Frequent mesoscale eddy variability was observed on time scales of less than a day. Eddies were commonly located near the head of Barrow Canyon and southeast of Hanna Shoal and were approximately 30 – 40 km in diameter. Average currents for the 2009 fall deployment period were generally westward at 6.1 cm/s, under mean winds from the northeast at 5.9 m/s; however, south of 71.25 N there was more variability in the mean current direction and magnitude. Principal axes of variance are alongshore within the coastal current and oriented east/west farther offshore. Variance nearshore is a factor of five greater than the offshore variance. The cross-shore correlation length scale of the alongshore velocity is ~40 km, consistent with the width of the coastal current. A third field site was installed in Point Lay, Alaska, in mid-September 2010, in order to extend coverage to the south, and all three systems will again be operational beginning in July 2011. Current maps may be viewed in real-time at www.chukchicurrents.com. - Peter Winsor, AUV glider missions in the Northeast Chukchi Sea; Listen to podcast
Here we report on Autonomous Underwater Vehicle (AUV) missions in the Chukchi Sea during summer 2010. Hydrographic data was collected using two Webb Slocum gliders deployed from the 32’ vessel Tukpuk operating off Wainwright. Gliders are low-power high-endurance AUVs propelled by small buoyancy changes, making the AUV slightly more (less) buoyant than ambient water, generating forward motion by gliding on wings attached to the body towards the surface (bottom). The gliders performed two month-long missions from mid-July to mid- August and mid-September to mid-October collecting data continuously at 1 Hz. A total of 70 days of AUV missions resulted in over >800 km of track length covered, collecting >3500 vertical profiles of pressure, temperature and conductivity (salinity) along with estimated depth-average currents. The month-long missions represent the first successful long-term AUV missions in this area. The detailed data from the gliders gives a unique view of the Chukchi Sea, with <150 m horizontal resolution and sub-meter vertical resolution. We were able steer the gliders from offshore of Wainwright to both the Burger and Klondike hydrocarbon lease patches while operating under the HF Radar surface data mask, providing a detailed 3D spatial and temporal view of the ocean. We present preliminary high-resolution cross-sections, time-average properties and oceanic response to frequent storms. The glider surveys show that using AUVs can be a cost effective ways to observe remote areas and generate uniquely high-resolution data; both gliders will be deployed again in 2011. Lastly, we present some novel ways to use gliders in the Arctic for biochemical and marine mammal studies. - Bodil Bluhm, Arctic Ocean Diversity (ArcOD) Synthesis: How many species are there?; Listen to podcast
One of ArcOD’s mission as part of the Census of Marine Life was to complete the first pan-Arctic inventory of biodiversity in the Arctic’s three major realms: sea ice, water column and seafloor – from the shallow shelves to the deep basins. The current inventory, based on compilation of historic and recent data and on new field collections, demonstrates highest diversity in the smallest size classes with: 4500 OTUs (operational taxonomic units) of archaea (estimate), 45,000 OTUs of bacteria (estimate), close to 2000 single-celled eukaryote phytoplankton species, >1000 single-celled eukaryote ice-associated species, ~60 ice-associated metazoans, 350 zooplankton species (with nearly half of them occurring only in deep water), nealy 200 macrophytic algae, close to 3000 benthic shelf macro- and megafaunal species, more than 1000 benthic deep-sea species (including meiofauna), 240 fish species, at least 64 breeding seabird species, and 16 marine mammal species. More than 70 undescribed species were discovered during field expeditions. For the invertebrates, species inventories appear to be relatively complete for zooplankton, but not for benthos. Within the metazoan fauna, crustaceans dominate species richness in all three realms while diatoms dominate ice algal and phytoplankton richness. There appears to be no zoogeographical barrier between the Eurasian and Amerasian basins in all three realms. Distinct zooplankton communities exist for different depth zones with high within-depth similarity. For benthic communities, regional differences appear to be larger on the shelves than in the deep sea. A mid-depth (500- 2000 m) peak in species richness was found for zooplankton, but not for benthic taxa. Recent changes in diversity include range extensions, changed ratios of warm-water to cold-water species, species replacements, and changes in species densities: most are probably related to climate change. - Brenda Norcross, 50 years of demersal fishes in the Chukchi Sea; Listen to podcast
Assessment of demersal fish in the northeast Chukchi Sea is important because of the potential for changes to the ecosystem with changing climate and anthropogenic use of the region, e.g., oil and gas exploration, fisheries, and vessel use of the area. From 1959 through 2009, data were available from 19 cruises in the Chukchi Sea. Fourteen cruises occurred only in the northeast area with the most recent collections focusing on oil and gas lease sale areas. The remaining five were in the southeast Chukchi Sea and three of these also sampled in Russian waters. All collections occurred in the ice-free months of July-October. More than 80 taxa of fishes in 17 families were captured. Because 11 different types of demersal trawls were used, catch-per-unit-effort could not be standardized across cruises; thus analysis was of fish presence/absence. To analyze fish assemblages and examine community structure, we used hierarchical clustering analyses that grouped stations according to species composition. Fishes tended to cluster by time and location of sample collection, resulting in variations in characteristics of fish assemblages over time. The composition of fish assemblages in the Chukchi Sea was often dominated by the same, dominant species. Over the historic collection period, >90% of the fish collected was composed of 9 species in three families: Cottidae – Artediellus scaber, Gymnocanthus tricuspis, Myoxocephalus scorpius; Gadidae – Boreogadus saida, Eleginus gracilis; Pleuronectidae – Hippoglossoides robustus, Limanda aspera, Pleuronectes quadrituberculatus. The dominant species differed among collections with place and time. It is unlikely that location per se affected fish assemblages, but rather that the physical parameters associated with those locations were the driving factors. Temperature, salinity, and sediments explained demersal fish assemblages in the Chukchi Sea; these factors are likely to be affected by climate change. Therefore, we speculate that changes in distribution of individual fish species, as might be expected with influences of climate change, could restructure the species composition and spatial extent of fish assemblages. - Sara Carroll (student), What's in the mix: Treatment of ice seal prey sources within stable isotope mixing models; Listen to podcast
Incorporation of stable isotopes in Bayesian mixing models estimate and attribute proportions of dietary items to a consumer. Stable isotope analysis is a robust technique often used to evaluate carbon and nitrogen sources within the diet of an organism. Mixing models can be employed to infer the importance of particular prey species within ecosystems and estimate temporal trends responding to external variables. Changing sea ice conditions and potentially associated changes in available prey to Arctic pinnipeds make these models invaluable tools. However, variability of lipid content within tissues introduces confounding factors when assessing foraging dynamics of predators. Compared to protein-rich tissues, lipids are depleted in carbon-13 thus analysis of nonlipid- extracted prey tissues may lead to a distortion of carbon signatures relative to assimilated food. Our results demonstrated that using non-lipid-extracted prey samples in mixing models mischaracterized pelagic foraging ringed seals, Pusa hispida, as benthic foragers. Though we also lipid extracted the predator tissues, there was no significant difference in δ13C. Lipid-extracted prey sources in mixing models accurately portrayed ringed seals as pelagic and bearded seals as benthic feeders. Examination of seal tissues documented inter-annual differences in the proportions of prey items. Ringed seal diet consisted of higher proportion of pelagic fishes in 2003 relative to 2009 diets that had more crustaceans or similar low trophic level species. In 2003 and 2009, bearded seals (Erignathus barbatus) fed on a higher proportion of benthic species compared to 2007 and 2008. Isotopic mixing models are powerful tools in marine ecosystem studies, though care should be taken with sample treatment as lipid-removal is essential in preventing misinterpretations of diets. - Seth Danielson, The BEST years from a mooring array's perspective; Listen to podcast
We describe initial results from a temperature, salinity and current meter-mooring array deployed on the eastern Bering Sea shelf from July 2008 to July 2010. The circulation resultant from individual storm events varies across the array as do water column shears. Band-pass filtering highlights the ocean’s response within different frequency intervals. In the mid-frequency portion of the spectrum (1.5-14 days), the velocity variance increases in the fall to spring time period relative to the summer months. In the low frequency portion of the spectrum (14 days and longer), extended periods of enhanced advection (5-10 cm/s for 2-8 weeks) are observed at many of the mooring locations, during which times the average velocity shear can exceed 5 cm/s between the 5 m and 30 m depth levels. The observations suggest that interaction of the non-uniform and temporally variable wind field with the ocean’s natural response leads to appreciable net cross-isobath transport. Although both winters resulted in extensive sea ice cover, the wind forcing was considerably different. The inter-annual differences in wind mixing resulted in varying evolutions of the water column stratification. In October 2008, strong winds in one major storm event resulted in significant water column overturn whereas the breakdown of stratification in fall of 2009 resulted in a more gradual erosion of the pycnocline. Likewise, stronger winds in the spring of 2009 accompanied a delayed onset of re-stratification while weaker winds in the spring of 2010 accompanied an earlier re-stratification. - Jared Weems (student), Isotopic assimilation in the bivalve Nuculana radiata: possible trophic consequences in changing Bering Sea ice-benthic coupling; Listen to podcast
The close coupling of sea ice-benthic trophic processes are a general characteristic of Arctic systems, including the Bering Sea shelf. The predicted climate-induced reduction in sea ice presence could lead to large ecosystemwide impacts on trophic level interactions; however, species-specific consumer dependence on ice-algal production needs to be assessed. Our objectives were to utilize stable carbon and nitrogen isotope ratios as naturally occurring food source markers to track feeding in the benthic bivalve, Nuculana radiata. Using isotopically enriched (δ13C and δ15N) ice-algal food, we determined the isotopic assimilation in lipid-extracted muscle, isolated lipid extracts, and mass-balanced whole clams in two experiments. Isolated N. radiata jar experiments over 42 days revealed an assimilation rate in muscle tissue no greater than 0.010% day-1 for δ13C and δ15N, with nearly three times higher rates in lipid extracts for both C and N. Mass-balanced whole clam enrichment was 0.017% for δ13C day-1 and 0.020% for δ15N day-1. In contrast, N. radiata incubated in sediment cores over 18 days had lower isotopic assimilation rates than those in the sediment free jars. This suggests that clams in the cores may be using food sources available within the sediments in addition to the experimentally added ice algal food. Overall, assimilation in N. radiata was very slow and complete isotopic turnover in both experiments would likely be on the order of several months. - Franz Mueter, Effects of temperature and density on spatial dynamics and interactions among Bering Sea groundfishes; Listen to podcast
One of the most direct effects of climate variability on fish and shellfish populations is a spatial shift in distribution in response to temperature changes. Northward shifts during warm years have been documented for many regions, including the eastern Bering Sea. Similarly, temperature-related changes have been observed in the depth distribution of fish and invertebrates. However, these shifts do not represent simple linear responses to temperature, as evident in non-linear changes over time that are unrelated to temperature. Changes in distribution are not spatially uniform and may be affected by the abundance of the species and by the abundance and distribution of its competitors and predators. Trawl survey data from the eastern Bering Sea for 1982-2010 were used to examine major modes of spatial variability in the abundance of 46 groundfish taxa, their associated time trends, and the relative importance of temperature and total abundance (density) in explaining the observed trends. Results suggest that changes in abundance are strongly associated with changes in the spatial distribution of most species, while changes in temperature are of secondary importance or are not significant. Together, these two factors account for most of the variability in the major mode of spatial variability for 39 of 45 species examined. In addition, significant residual trends over time were evident in most taxa even after accounting for the effects of temperature and density, suggesting long-term directional shifts in the spatial distribution of many species. Results highlight the importance of spatial dynamics in structuring trophic interactions among species. - Russ Andrews, Luncheon Presentation: Steller's curse: The unfortunate fate of Alaska's first naturalist and the marine mammals that bear his name; Listen to podcast
- Greg Albrecht (student), Genetic population structure of snow crab (Chinoecetes opilio); Listen to podcast
The snow crab (Chionoecetes opilio) is a cold water crab distributed throughout the high latitude waters of the Pacific, Atlantic and Arctic Oceans. It has been recently observed that a northward range shift may be occurring due to a number of factors, including environmental, ecological and anthropogenic forces. In the Bering Sea, snow crab are an economically valuable species comprising one of the largest crab fisheries in the world. Currently, there is little known about the genetic population structure within their Pacific/Arctic range and the Eastern Bering Sea stock is managed as a single panmictic population. The goal of our research is to better define population structure by using microsatellite analysis techniques. Genetic analysis of approximately 600 specimens from numerous locations throughout their range was conducted and results are currently being combined with ecological knowledge of the stock to identify whether or not distinct population subunits occur. Snow crab have a long larval dispersal phase lasting from approximately 2-4 months, which would support the hypothesis of a large degree of genetic mixing; however, areas of potential larval retention have recently been hypothesized which may support population divergence. Deciphering population structure throughout the highly exploited Bering Sea populations is not only important for proper management of the current fishery, but for areas of the arctic which are "downstream" and may see fishing pressures in the future. - James Strong (student), Institutional structure and profit maximization in the eastern Bering Sea fishery for Alaska pollock; Listen to podcast
Walleye pollock (Theragra chalcogramma) is the largest whitefish fishery in the world and largest in U.S. by volume. The Alaska fishery has gross exvessel revenues of $300 million and a first wholesale value of over $1 billion. The market for U.S. pollock products has evolved significantly since the early 1990s, when U.S. pollock processors focused mainly on selling surimi and roe to Japan. The formation of harvesting cooperatives, resulting from the passage of the American Fisheries Act, has resulted in a complex suite of alternatives that includes increasing global markets and a diverse mix of product forms. Understanding how benefits of the fishery are distributed requires an understanding of international trade in pollock products. This paper reports on the development of an international market model for pollock products for 2000-2008, with a particular emphasis on surimi, fillets, and roe and their primary markets in the United States, Europe, and Japan. The simultaneousequation equilibrium model included nine structural equations, with four allocation equations and five inverse demand equations. The model was fitted using a full information maximum likelihood systems estimator. Results conformed with theoretically anticipated relationships with respect to price, income, and substitution effects. Initial simulations indicate that that the first wholesale pollock revenues over fillets, surimi, and roe products are maximized at levels above the 2000- 2008 mean harvest level but below the maximum harvest of over 1.5 million mt in 2006. The model and its results will assist fishery managers in determining optimum yield for the fishery.
Student Winners
• Mandy Keogh, winner, best student poster (Ph.D. category)
Poster title: Body condition and endocrine profiles of Steller sea lion (Eumetopias jubatus) pups during the early postnatal period
Mandy Keogh's winning poster. Click to enlarge.
Download poster as PDF (906KB)
Advisor: Shannon Atkinson
Abstract:
Steller sea lions (Eumetopias jubatus) (SSL) are the largest otariids, with the western distinct population segment currently listed as endangered under the Endangered Species Act. The aim of the present study was to quantify circulating levels of cortisol, aldosterone, total and free thyroxine, total triiodothyronine, and leptin in 61 wild pups ranging in age from 5 to 38 days old. Given that postnatal development is a period of high-energy demand and that SSL pups have a fast growth rate for an otariid, we expect body condition to be an important factor in the health of individual pups. However, no relationship between body condition index (BCI) and circulating concentration of hormones quantified in the present study was detected. The SSL pups sampled in the present study appeared to uniformly be in good body condition, which likely explains why circulating hormone concentrations assessed were not associated with the BCI. Male pups were larger than female pups in body mass, standard length and axillary girth while only cortisol and aldosterone concentrations showed differences between male and female pups with females having higher cortisol and lower aldosterone concentrations. Circulating concentrations of cortisol, total and free thyroxine, and total triiodothyronine were affected by the capture and handling inherently required in sampling wild pinnipeds. However, the overall variation attributed to the rookery disturbance was low (r2<0.293). These findings are relevant for comparative endocrinology and offers baseline concentrations of several hormones for free ranging SSL pups from an apparently healthy population.
• Shiway Wang, winner, best student poster (Ph.D. category)
Title: Compound-specific stable isotope anlayses of fatty acids in primary production from the Bering Sea: A foundation for food web biomarker studies
Contact Shiway for a PDF of this poster.
Advisor: Matthew Wooller
Abstract:
The Bering Sea experiences the largest seasonal sea ice advances and retreats of any region in the Arctic and sub-Arctic. Climate-related changes in seasonal sea-ice cover will impact primary production patterns in the Arctic and likely be propagated through the marine food web. In particular, significant changes in the nutritional quality of fatty acids (FAs) derived from primary production in sea ice will likely impact upper trophic levels that are dependent on these resources. FAs have been used to study marine food web dynamics but more specific markers, such as compound-specific isotope analysis (CSIA) of FAs, originating from different sources of primary production are necessary to trace the relative importance of these sources to upper trophic levels. The goal of this study was to characterize the FA profiles and their compound-specific isotope ratios of arctic marine primary production in the Bering Sea. Sea ice algae and water-column particulate organic matter (POM) samples were collected in the Bering Sea between 14 April and 2 May 2009 and analyzed using CSIA. Results from the CSIA of FAs showed the ?13C of 14:0, 16:4n-1, 20:5n-3, and 22:6n-3 in ice algae to be isotopically enriched (~4‰) relative to those in POM, while 18:0 was depleted in ice algae (~2‰) relative to POM. These preliminary findings indicate that CSIA analysis will allow us to track the proportional contributions of sea ice algae and POM fatty acids into higher trophic levels (i.e., zooplankton, ice seals) in the Bering Sea. Comparing
•Wesley Strasburger, winner, best student poster (M.S. category)
Title: A comparison of feeding patterns between larval and juvenile walleye pollock and Pacific cod in the eastern Bering Sea
Download poster as a PDF (300KB)
Wesley Strasburger's winning poster. Click to enlarge.
Advisor: Nicola Hillgruber
Abstract:
The goal of this study is to examine and compare feeding patterns of pelagic larval and juvenile walleye pollock (Theragra chalcogramma) and Pacific cod (Gadus macrocephalus), collected in spring, early summer, and fall of 2008, an exceptionally cold year, on a large scale station grid covering the eastern Bering Sea from Unimak Pass to the vicinity of St. Lawrence Island. Previous studies have found that growth, and thus feeding success during the first summer are important conditions for overwinter survival and, subsequently, recruitment success of marine fishes. This study will benefit greatly from available data on zooplankton abundance, composition, and biomass which were collected as part of the Bering Sea Fisheries Oceanography Cooperative Investigations (Bering Sea FOCI) in spring, the Bering Ecosystem Studies (BEST) and the Bering Sea Integrated Research Project (BSIERP) in early summer and the Bering Aleutian Salmon International Survey (BASIS) cruises in the fall, respectively. As part of this study, we will quantify feeding success, prey selection, and potential dietary overlap. Results from this study will provide first insight into resource allocation and the potential for dietary overlap and may allow the assessment of the probability of food competition between early pelagic life stages of walleye pollock and Pacific cod prior to their first winter during an exceptionally cold year in the eastern Bering Sea.
