Cascadia Research

Olympia, WA, United States

Cascadia Research

Olympia, WA, United States
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Ross P.S.,Canadian Department of Fisheries and Oceans | Noel M.,Canadian Department of Fisheries and Oceans | Noel M.,University of Victoria | Lambourn D.,801 Phillips Road SW | And 3 more authors.
Progress in Oceanography | Year: 2013

As high trophic level, non-migratory marine mammals, harbor seals (Phoca vitulina) inhabiting the Strait of Georgia, Juan de Fuca Strait and Puget Sound (collectively referred to as the Salish Sea) in northwestern North America provide an integrated measure of coastal food web contamination. We measured congener-specific polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), polychlorinated diphenylethers (PCDEs) and polychlorinated naphthalenes (PCNs) in blubber biopsies from free-ranging harbor seal pups inhabiting four sites in the Salish Sea in 2003. While legacy PCBs dominated the composition of these contaminants in seals at all sites (PCBs > PBDEs > PCDEs > PCNs), PBDEs were noteworthy in that they averaged as much as 59% of total PCB concentrations. We further evaluated temporal trends in seals sampled at one of these sites (Puget Sound) for PCBs and PBDEs between 1984 and 2009, and for PCDEs and PCNs between 1984 and 2003. PBDE concentrations doubled every 3.1. years between 1984 and 2003, but appeared to decline thereafter. Over the course of the 20. years between 1984 and 2003, PCB concentrations had declined by 81%, PCDEs declined by 71%, and PCNs by 98%. Overall, results suggest that regulations and source controls have noticeably reduced inputs of these contaminants to the Salish Sea, consequently reducing the associated health risks to marine wildlife. We estimate the total mass of these contaminants in the 53,000 harbor seals of the Salish Sea in 2009 to be 2.6. kg PCBs and 1.0. kg PBDEs, compared to just trace amounts of the PCDEs and PCNs. © 2013 Elsevier Ltd.

Redfern J.V.,National Oceanic and Atmospheric Administration | McKenna M.F.,West Marine | Moore T.J.,National Oceanic and Atmospheric Administration | Calambokidis J.,Cascadia Research | And 6 more authors.
Conservation Biology | Year: 2013

Marine spatial planning provides a comprehensive framework for managing multiple uses of the marine environment and has the potential to minimize environmental impacts and reduce conflicts among users. Spatially explicit assessments of the risks to key marine species from human activities are a requirement of marine spatial planning. We assessed the risk of ships striking humpback (Megaptera novaeangliae), blue (Balaenoptera musculus), and fin (Balaenoptera physalus) whales in alternative shipping routes derived from patterns of shipping traffic off Southern California (U.S.A.). Specifically, we developed whale-habitat models and assumed ship-strike risk for the alternative shipping routes was proportional to the number of whales predicted by the models to occur within each route. This definition of risk assumes all ships travel within a single route. We also calculated risk assuming ships travel via multiple routes. We estimated the potential for conflict between shipping and other uses (military training and fishing) due to overlap with the routes. We also estimated the overlap between shipping routes and protected areas. The route with the lowest risk for humpback whales had the highest risk for fin whales and vice versa. Risk to both species may be ameliorated by creating a new route south of the northern Channel Islands and spreading traffic between this new route and the existing route in the Santa Barbara Channel. Creating a longer route may reduce the overlap between shipping and other uses by concentrating shipping traffic. Blue whales are distributed more evenly across our study area than humpback and fin whales; thus, risk could not be ameliorated by concentrating shipping traffic in any of the routes we considered. Reducing ship-strike risk for blue whales may be necessary because our estimate of the potential number of strikes suggests that they are likely to exceed allowable levels of anthropogenic impacts established under U.S. laws. © 2013 Society for Conservation Biology.

Calambokidis J.,Cascadia Research | Steiger G.H.,Cascadia Research | Curtice C.,Duke University | Harrison J.,National Oceanic and Atmospheric Administration | And 4 more authors.
Aquatic Mammals | Year: 2015

In this review, we combine existing published and unpublished information along with expert judgment to identify and support the delineation of 28 Biologically Important Areas (BIAs) in U.S. waters along the West Coast for blue whales, gray whales, humpback whales, and harbor porpoises. BIAs for blue whales and humpback whales are based on high concentration areas of feeding animals observed from small boat surveys, ship surveys, and opportunistic sources. These BIAs compare favorably to broader habitat-based density models. BIAs for gray whales are based on their migratory corridor as they transit between primary feeding areas located in northern latitudes and breeding areas offMexico. Additional gray whale BIAs are defined for the primary feeding areas of a smaller resident population. Two small and resident population BIAs defined for harbor porpoises located offCalifornia encompass the populations' primary areas of use. The size of the individual BIAs ranged from approximately 171 to 138,000 km2. The BIAs for feeding blue, gray, and humpback whales represent relatively small portions of the overall West Coast area (< 5%) but encompass a large majority (77 to 89%) of the thousands of sightings documented and evaluated for each species. We also evaluate and discuss potential feeding BIAs for fin whales, but none are delineated due to limited or conflicting information. The intent of identifying BIAs is to synthesize existing biological information in a transparent format that is easily accessible to scientists, managers, policymakers, and the public for use during the planning and design phase of anthropogenic activities for which U.S. statutes require the characterization and minimization of impacts on marine mammals. To maintain their utility, West Coast region BIAs should be re-evaluated and revised, if necessary, as new information becomes available.

Berman-Kowalewski M.,Santa Barbara Museum of Natural History | Gulland F.M.D.,The Marine Mammal Center | Wilkin S.,National Oceanic and Atmospheric Administration | Calambokidis J.,Cascadia Research | And 7 more authors.
Aquatic Mammals | Year: 2010

Blue whales (Balaenoptera musculus) are distributed worldwide, and although severely depleted by commercial whaling, their abundance off the California coast now appears to be increasing. Little is known about natural causes of mortality of blue whales, but human-related mortality continues despite legal protection. Ship strikes are a significant mortality factor for other species of baleen whale, and changes in shipping traffic have been advocated to minimize further deaths. Between 1988 and 2007, 21 blue whale deaths were reported along the California coast, typically one or two cases annually. Three pulses in strandings were observed, with three carcasses observed in fall 1988, three in 2002, and four in fall 2007. Two of the four animals in 2007 were first observed dead in the Santa Barbara Channel and had wounds typical of a ship strike. Blue whale strandings were spatially associated with locations of shipping lanes, especially those associated with the Ports of Los Angeles and Long Beach, and were most common in the fall months.

Levy R.,Harvey Mudd College | Uminsky D.,University of California at Los Angeles | Park A.,Harvey Mudd College | Calambokidis J.,Cascadia Research
International Journal of Non-Linear Mechanics | Year: 2011

Whale flukeprints are an often observed, but poorly understood, phenomenon. Used by whale researchers to locate whales, flukeprints refer to a strikingly smooth oval-shaped water patch which forms behind a swimming or diving whale on the surface of the ocean and persists up to several minutes. In this paper we provide a description of hydrodynamic theory and related experiments explaining the creation and evolution of these "whale footprints." The theory explains that the motion of the fluke provides a mechanism for shedding of vortex rings which subsequently creates a breakwater that damps the short wavelength capillary waves. The theory also suggests that the role of natural surfactants are of secondary importance in the early formation of these prints. © 2011 Elsevier Ltd. All rights reserved.

Relationships between apex predators and mesopredators have been poorly documented in predatory birds. Prediction from intraguild predation (IGP) theory suggests that following the recovery of Peregrine Falcon (Falco peregrinus) populations, the potential for Merlins (F. columbarius) to experience mesopredator suppression should increase where these species share habitat and prey resources. In Washington, both falcons prey on Dunlins (Calidris alpina) in estuarine ecosystems during the nonbreeding season. To investigate whether mesopredator suppression may have occurred, I compared aspects of the hunting behavior of Merlins at an estuary in western Washington between 1999 and 2009, when Peregrine Falcons were regularly present, with hunting behavior in the 1980s, when Peregrine Falcons did not occur at the site. Merlin hunting behavior changed substantially between the two periods. Following Peregrine Falcon recovery, Merlins hunted less frequently, used hunting flights of shorter duration and that involved fewer capture attempts per successful flight, and captured prey closer to the cover of vegetation, results that are consistent with IGP theory. Prior to Peregrine Falcon recovery, Merlins appear to have assumed the role of apex falcon predator at the site; Merlins currently coexist with Peregrine Falcons, and have altered their hunting behavior which may reduce their risk of IGP. © 2012 The Raptor Research Foundation, Inc.

Gendron D.,National Polytechnic Institute of Mexico | Serrano I.M.,University of Veracruz | de la Cruz A.U.,National Polytechnic Institute of Mexico | Calambokidis J.,Cascadia Research | Mate B.,Oregon State University
Endangered Species Research | Year: 2015

During the last 3 decades, tagging technology has been used to study different aspects of cetacean ecology. Tags implanted in animal's blubber, muscle and surrounding tissue have produced successful results, providing information on long-term movements. However, apart from the reports of 'divots' (depressions) and swelling at the tag sites in re-sighted large whales, little has been published about the long-term effects of tagging. Based on sighting history databases of photo-identified blue whales, we monitored the wound site of a satellite tag on an adult female blue whale over a period of 16 yr (1995 to 2011). This report describes the swelling reaction to a broken subdermal attachment from a tag designed early in the evolution of large whale tagging. The tag attachment remained embedded for a decade (much longer than expected), and may have affected the female's reproductive success during this period. The whale's calving history showed a total of 3 calves; 2 were prior to, and one ocurred after, the swelling period (1999 to 2007). We demonstrate the value of long-term monitoring programs in evaluating tag impacts, especially on endangered species. © The authors 2015.

Yack T.M.,Southwest Fisheries Science Center | Yack T.M.,Bio Waves Inc. | Barlow J.,Southwest Fisheries Science Center | Calambokidis J.,Cascadia Research | And 3 more authors.
Journal of the Acoustical Society of America | Year: 2013

Beaked whales are diverse and species rich taxa. They spend the vast majority of their time submerged, regularly diving to depths of hundreds to thousands of meters, typically occur in small groups, and behave inconspicuously at the surface. These factors make them extremely difficult to detect using standard visual survey methods. However, recent advancements in acoustic detection capabilities have made passive acoustic monitoring (PAM) a viable alternative. Beaked whales can be discriminated from other odontocetes by the unique characteristics of their echolocation clicks. In 2009 and 2010, PAM methods using towed hydrophone arrays were tested. These methods proved highly effective for real-time detection of beaked whales in the Southern California Bight (SCB) and were subsequently implemented in 2011 to successfully detect and track beaked whales during the ongoing Southern California Behavioral Response Study. The three year field effort has resulted in (1) the successful classification and tracking of Cuvier's (Ziphius cavirostris), Baird's (Berardius bairdii), and unidentified Mesoplodon beaked whale species and (2) the identification of areas of previously unknown beaked whale habitat use. Identification of habitat use areas will contribute to a better understanding of the complex relationship between beaked whale distribution, occurrence, and preferred habitat characteristics on a relatively small spatial scale. These findings will also provide information that can be used to promote more effective management and conservation of beaked whales in the SCB, a heavily used Naval operation and training region. © 2013 Acoustical Society of America.

Thompson S.A.,Farallon Institute for Advanced Ecosystem Research | Sydeman W.J.,Farallon Institute for Advanced Ecosystem Research | Santora J.A.,Farallon Institute for Advanced Ecosystem Research | Black B.A.,Oregon State University | And 4 more authors.
Progress in Oceanography | Year: 2012

Upwelling in eastern boundary current systems is a primary driver of ecosystem productivity. Typically, peak upwelling occurs during spring and summer, but winter upwelling may also be important to ecosystem functions. In this study, we investigated the hypothesis that winter and spring/summer upwelling, operating through indirect trophic interactions, are important to a suite of top predators in the California Current. To test this hypothesis, we collated information on upwelling, chlorophyll-a concentrations, zooplankton and forage fish, and related these to predator responses including rockfish growth, salmon abundance, seabird productivity and phenology (timing of egg-laying), and whale abundance. Seabird diets served in part as food web indicators. We modeled pathways of response using path analysis and tested for significance of the dominant paths with multiple regression. We found support for the hypothesis that relationships between upwelling and top predator variables were mediated primarily by intermediate trophic levels. Both winter and summer upwelling were important in path models, as were intermediate lower and mid trophic level functional groups represented by chlorophyll-a, zooplankton, and forage fish. Significant pathways of response explained from 50% to 80% of the variation of seabird (Cassin's auklet (Ptychoramphus aleuticus) and common murre (Uria aalge)), humpback whale (Megaptera novaeangliae) and Chinook salmon (Oncorhynchus tshawytscha) dependent variables, whereas splitnose rockfish (Sebastes diploproa) showed no significant response pathways. Upwelling and trophic responses for salmon were established for both the year of ocean entry and the year of return, with zooplankton important in the year of ocean entry and forage fish important in the year of return. This study provides one of the first comparative investigations between upwelling and predators, from fish to marine mammals and birds within a geographically restricted area, demonstrates often difficult to establish "bottom-up" trophic interactions, and establishes the importance of seasonality of upwelling to various trophic connections and predator demographic traits. Understanding change in the seasonality of upwelling is therefore required to assess dynamics of commercially and recreationally important upper trophic level species in eastern boundary current ecosystems. © 2012 Elsevier Ltd.

PubMed | Copenhagen University, Baylor College of Medicine, Cascadia Research, National Oceanic and Atmospheric Administration and 5 more.
Type: | Journal: Nature communications | Year: 2016

Analysing population genomic data from killer whale ecotypes, which we estimate have globally radiated within less than 250,000 years, we show that genetic structuring including the segregation of potentially functional alleles is associated with socially inherited ecological niche. Reconstruction of ancestral demographic history revealed bottlenecks during founder events, likely promoting ecological divergence and genetic drift resulting in a wide range of genome-wide differentiation between pairs of allopatric and sympatric ecotypes. Functional enrichment analyses provided evidence for regional genomic divergence associated with habitat, dietary preferences and post-zygotic reproductive isolation. Our findings are consistent with expansion of small founder groups into novel niches by an initial plastic behavioural response, perpetuated by social learning imposing an altered natural selection regime. The study constitutes an important step towards an understanding of the complex interaction between demographic history, culture, ecological adaptation and evolution at the genomic level.

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