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Warlick AJ, Johnson DS, Gelatt TS, Converse SJ. Environmental drivers of demography and potential factors limiting the recovery of an endangered marine top predator. Ecosphere 2022. [DOI: 10.1002/ecs2.4325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Amanda J. Warlick
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA
| | - Devin S. Johnson
- Pacific Islands Fisheries Science Center National Marine Fisheries Service Honolulu Hawaii USA
| | - Tom S. Gelatt
- Marine Mammal Laboratory Alaska Fisheries Science Center, National Marine Fisheries Service Seattle Washington USA
| | - Sarah J. Converse
- U.S. Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, School of Environmental and Forest Sciences & School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA
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Hastings KK, Johnson DS, Pendleton GW, Fadely BS, Gelatt TS. Investigating life-history traits of Steller sea lions with multistate hidden Markov mark-recapture models: Age at weaning and body size effects. Ecol Evol 2021; 11:714-734. [PMID: 33520160 PMCID: PMC7820167 DOI: 10.1002/ece3.6878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 09/03/2020] [Accepted: 09/10/2020] [Indexed: 11/07/2022] Open
Abstract
The duration of offspring care is critical to female fitness and population resilience by allowing flexibility in life-history strategies in a variable environment. Yet, for many mammals capable of extended periods of maternal care, estimates of the duration of offspring dependency are not available and the relative importance of flexibility of this trait on fitness and population viability has rarely been examined. We used data from 4,447 Steller sea lions Eumetopias jubatus from the Gulf of Alaska and multistate hidden Markov mark-recapture models to estimate age-specific weaning probabilities. Maternal care beyond age 1 was common: Weaning was later for animals from Southeast Alaska (SEAK) and Prince William Sound (PWS, weaning probabilities: 0.536-0.648/0.784-0.873 by age 1/2) compared with animals born to the west (0.714-0.855/0.798-0.938). SEAK/PWS animals were also smaller than those born farther west, suggesting a possible link. Females weaned slightly earlier (+0.080 at age 1 and 2) compared with males in SEAK only. Poor survival for weaned versus unweaned yearlings occurred in southern SEAK (female survival probabilities: 0.609 vs. 0.792) and the central Gulf (0.667 vs. 0.901), suggesting poor conditions for juveniles in these areas. First-year survival increased with neonatal body mass (NBM) linearly in the Gulf and nonlinearly in SEAK. The probability of weaning at age 1 increased linearly with NBM for SEAK animals only. Rookeries where juveniles weaned at earlier ages had lower adult female survival, but age at weaning was unrelated to population trends. Our results suggest the time to weaning may be optimized for different habitats based on long-term average conditions (e.g., prey dynamics), that may also shape body size, with limited short-term plasticity. An apparent trade-off of adult survival in favor of juvenile survival and large offspring size in the endangered Gulf of Alaska population requires further study.
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Affiliation(s)
- Kelly K. Hastings
- Division of Wildlife ConservationAlaska Department of Fish and GameJuneauAlaskaUSA
| | - Devin S. Johnson
- NOAA FisheriesAlaska Fisheries Science CenterSeattleWashingtonUSA
| | - Grey W. Pendleton
- Division of Wildlife ConservationAlaska Department of Fish and GameJuneauAlaskaUSA
| | - Brian S. Fadely
- NOAA FisheriesAlaska Fisheries Science CenterSeattleWashingtonUSA
| | - Thomas S. Gelatt
- NOAA FisheriesAlaska Fisheries Science CenterSeattleWashingtonUSA
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Lander ME, Fadely BS, Gelatt TS, Sterling JT, Johnson DS, Pelland NA. Mixing it up in Alaska: Habitat use of adult female Steller sea lions reveals a variety of foraging strategies. Ecosphere 2020. [DOI: 10.1002/ecs2.3021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Michelle E. Lander
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Brian S. Fadely
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Thomas S. Gelatt
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Jeremy T. Sterling
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Devin S. Johnson
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Noel A. Pelland
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
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Fritz L, Brost B, Laman E, Luxa K, Sweeney K, Thomason J, Tollit D, Walker W, Zeppelin T. A re-examination of the relationship between Steller sea lion (Eumetopias jubatus) diet and population trend using data from the Aleutian Islands. CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Prey diversity and energy density have been linked to each other and to population trends in many studies of bird and mammal diets. We re-examined these relationships in Steller sea lions (Eumetopias jubatus (Schreber, 1776)) using data collected from the Aleutian Islands, where there has been a strong longitudinal gradient in population trend. Diet diversity and energy density metrics were similar in the western Aleutians, where sea lion counts declined consistently, and in the easternmost Aleutian area, where population trends improved significantly. We compared traditional deterministic diet diversity metrics with diversity scores based on an occupancy model that accounts for differences in sample size and uncertainty in prey group detection. This analysis indicated that there was no significant change in diet diversity over the 23-year study period or any significant differences across the Aleutian Islands. These results are consistent with prey abundance data from nine groundfish bottom trawl surveys conducted over the same period. While diet studies detail what Steller sea lions eat and provide an estimate of their energy intake, they provide only limited information on the energy expended to obtain their food or the consequences of their diet and foraging ecology on individual or population fitness.
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Affiliation(s)
- L. Fritz
- NOAA Fisheries, Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - B. Brost
- NOAA Fisheries, Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - E. Laman
- NOAA Fisheries, Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - K. Luxa
- NOAA Fisheries, Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - K. Sweeney
- NOAA Fisheries, Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - J. Thomason
- NOAA Fisheries, Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - D. Tollit
- SMRU Consulting North America, 55 Water Street, Suite 604, Vancouver, BC V6V 1A1, Canada
| | - W. Walker
- NOAA Fisheries, Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - T. Zeppelin
- NOAA Fisheries, Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA
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Lefebvre KA, Quakenbush L, Frame E, Huntington KB, Sheffield G, Stimmelmayr R, Bryan A, Kendrick P, Ziel H, Goldstein T, Snyder JA, Gelatt T, Gulland F, Dickerson B, Gill V. Prevalence of algal toxins in Alaskan marine mammals foraging in a changing arctic and subarctic environment. HARMFUL ALGAE 2016; 55:13-24. [PMID: 28073526 PMCID: PMC8276754 DOI: 10.1016/j.hal.2016.01.007] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 01/14/2016] [Accepted: 01/19/2016] [Indexed: 05/10/2023]
Abstract
Current climate trends resulting in rapid declines in sea ice and increasing water temperatures are likely to expand the northern geographic range and duration of favorable conditions for harmful algal blooms (HABs), making algal toxins a growing concern in Alaskan marine food webs. Two of the most common HAB toxins along the west coast of North America are the neurotoxins domoic acid (DA) and saxitoxin (STX). Over the last 20 years, DA toxicosis has caused significant illness and mortality in marine mammals along the west coast of the USA, but has not been reported to impact marine mammals foraging in Alaskan waters. Saxitoxin, the most potent of the paralytic shellfish poisoning toxins, has been well-documented in shellfish in the Aleutians and Gulf of Alaska for decades and associated with human illnesses and deaths due to consumption of toxic clams. There is little information regarding exposure of Alaskan marine mammals. Here, the spatial patterns and prevalence of DA and STX exposure in Alaskan marine mammals are documented in order to assess health risks to northern populations including those species that are important to the nutritional, cultural, and economic well-being of Alaskan coastal communities. In this study, 905 marine mammals from 13 species were sampled including; humpback whales, bowhead whales, beluga whales, harbor porpoises, northern fur seals, Steller sea lions, harbor seals, ringed seals, bearded seals, spotted seals, ribbon seals, Pacific walruses, and northern sea otters. Domoic acid was detected in all 13 species examined and had the greatest prevalence in bowhead whales (68%) and harbor seals (67%). Saxitoxin was detected in 10 of the 13 species, with the highest prevalence in humpback whales (50%) and bowhead whales (32%). Pacific walruses contained the highest concentrations of both STX and DA, with DA concentrations similar to those detected in California sea lions exhibiting clinical signs of DA toxicosis (seizures) off the coast of Central California, USA. Forty-six individual marine mammals contained detectable concentrations of both toxins emphasizing the potential for combined exposure risks. Additionally, fetuses from a beluga whale, a harbor porpoise and a Steller sea lion contained detectable concentrations of DA documenting maternal toxin transfer in these species. These results provide evidence that HAB toxins are present throughout Alaska waters at levels high enough to be detected in marine mammals and have the potential to impact marine mammal health in the Arctic marine environment.
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Affiliation(s)
- Kathi A Lefebvre
- Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA, USA.
| | - Lori Quakenbush
- Alaska Department of Fish and Game, Arctic Marine Mammal Program, 1300 College Road, Fairbanks, AK, USA
| | - Elizabeth Frame
- Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA, USA
| | - Kathy Burek Huntington
- Alaska Veterinary Pathology Services (AVPS), 23834 The Clearing Drive, Eagle River, AK, USA
| | - Gay Sheffield
- University of Alaska Fairbanks, Alaska Sea Grant, Marine Advisory Program, PO Box 400, Nome, AK, USA
| | - Raphaela Stimmelmayr
- North Slope Borough Department of Wildlife Management, PO Box 69, Barrow, AK, USA
| | - Anna Bryan
- Alaska Department of Fish and Game, Arctic Marine Mammal Program, 1300 College Road, Fairbanks, AK, USA
| | - Preston Kendrick
- Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA, USA
| | - Heather Ziel
- Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA, Seattle, WA, USA
| | - Tracey Goldstein
- One Health Institute, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Jonathan A Snyder
- U.S. Fish and Wildlife Service, Marine Mammals Management, 1011 East Tudor Rd., Anchorage, AK, USA
| | - Tom Gelatt
- Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA, Seattle, WA, USA
| | - Frances Gulland
- The Marine Mammal Center, 2000 Bunker Road, Fort Cronkhite, Sausalito, CA, USA
| | - Bobette Dickerson
- Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA, Seattle, WA, USA
| | - Verena Gill
- U.S. Fish and Wildlife Service, Marine Mammals Management, 1011 East Tudor Rd., Anchorage, AK, USA
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Etheredge CR, Wiggers SE, Souther OE, Lagman LL, Yarrow G, Dozier J. Local-Scale Difference of Coyote Food Habits on Two South Carolina Islands. SOUTHEAST NAT 2015. [DOI: 10.1656/058.014.0209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Hui TCY, Gryba R, Gregr EJ, Trites AW. Assessment of Competition between Fisheries and Steller Sea Lions in Alaska Based on Estimated Prey Biomass, Fisheries Removals and Predator Foraging Behaviour. PLoS One 2015; 10:e0123786. [PMID: 25950178 PMCID: PMC4424003 DOI: 10.1371/journal.pone.0123786] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 03/08/2015] [Indexed: 11/18/2022] Open
Abstract
A leading hypothesis to explain the dramatic decline of Steller sea lions (Eumetopias jubatus) in western Alaska during the latter part of the 20th century is a change in prey availability due to commercial fisheries. We tested this hypothesis by exploring the relationships between sea lion population trends, fishery catches, and the prey biomass accessible to sea lions around 33 rookeries between 2000 and 2008. We focused on three commercially important species that have dominated the sea lion diet during the population decline: walleye pollock, Pacific cod and Atka mackerel. We estimated available prey biomass by removing fishery catches from predicted prey biomass distributions in the Aleutian Islands, Bering Sea and Gulf of Alaska; and modelled the likelihood of sea lions foraging at different distances from rookeries (accessibility) using satellite telemetry locations of tracked animals. We combined this accessibility model with the prey distributions to estimate the prey biomass accessible to sea lions by rookery. For each rookery, we compared sea lion population change to accessible prey biomass. Of 304 comparisons, we found 3 statistically significant relationships, all suggesting that sea lion populations increased with increasing prey accessibility. Given that the majority of comparisons showed no significant effect, it seems unlikely that the availability of pollock, cod or Atka mackerel was limiting sea lion populations in the 2000s.
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Affiliation(s)
- Tabitha C. Y. Hui
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, Vancouver, B.C., Canada
- * E-mail:
| | - Rowenna Gryba
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, Vancouver, B.C., Canada
| | - Edward J. Gregr
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, Vancouver, B.C., Canada
| | - Andrew W. Trites
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, Vancouver, B.C., Canada
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Hoskins AJ, Costa DP, Arnould JPY. Utilisation of intensive foraging zones by female Australian fur seals. PLoS One 2015; 10:e0117997. [PMID: 25692978 PMCID: PMC4333298 DOI: 10.1371/journal.pone.0117997] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 01/03/2015] [Indexed: 11/19/2022] Open
Abstract
Within a heterogeneous environment, animals must efficiently locate and utilise foraging patches. One way animals can achieve this is by increasing residency times in areas where foraging success is highest (area-restricted search). For air-breathing diving predators, increased patch residency times can be achieved by altering both surface movements and diving patterns. The current study aimed to spatially identify the areas where female Australian fur seals allocated the most foraging effort, while simultaneously determining the behavioural changes that occur when they increase their foraging intensity. To achieve this, foraging behaviour was successfully recorded with a FastLoc GPS logger and dive behaviour recorder from 29 individual females provisioning pups. Females travelled an average of 118 ± 50 km from their colony during foraging trips that lasted 7.3 ± 3.4 days. Comparison of two methods for calculating foraging intensity (first-passage time and first-passage time modified to include diving behaviour) determined that, due to extended surface intervals where individuals did not travel, inclusion of diving behaviour into foraging analyses was important for this species. Foraging intensity 'hot spots' were found to exist in a mosaic of patches within the Bass Basin, primarily to the south-west of the colony. However, the composition of benthic habitat being targeted remains unclear. When increasing their foraging intensity, individuals tended to perform dives around 148 s or greater, with descent/ascent rates of approximately 1.9 m•s-1 or greater and reduced postdive durations. This suggests individuals were maximising their time within the benthic foraging zone. Furthermore, individuals increased tortuosity and decreased travel speeds while at the surface to maximise their time within a foraging location. These results suggest Australian fur seals will modify both surface movements and diving behaviour to maximise their time within a foraging patch.
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Affiliation(s)
- Andrew J. Hoskins
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria, 3125, Australia
| | - Daniel P. Costa
- Center for Ocean Health, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, California, 95060, United States of America
| | - John P. Y. Arnould
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria, 3125, Australia
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Fras M, Gosak M. Spatiotemporal patterns provoked by environmental variability in a predator-prey model. Biosystems 2013; 114:172-7. [PMID: 24055250 DOI: 10.1016/j.biosystems.2013.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 04/26/2013] [Accepted: 09/10/2013] [Indexed: 10/26/2022]
Abstract
The emergence of spatiotemporal patterns in the distribution of species is one of the most striking phenomena in ecology and nonlinear science. Since it is known that spatial inhomogeneities can significantly affect the dynamics of ecological populations, in the present paper we investigate the impact of environmental variability on the formation of patterns in a spatially extended predator-prey model. In particular, we utilize a predator-prey system with a Holling III functional response and introduce random spatial variations of the kinetic parameter signifying the intrinsic growth rate of the prey, reflecting the impact of a heterogeneous environment. Our results reveal that in the proximity of the Hopf bifurcation environmental variability is able to provoke pattern formation, whereby the coherence of the patterns exhibits a resonance-like dependence on the variability strength. Furthermore, we show that the phenomenon can only be observed if the spatial heterogeneities exhibit large enough regions with high growth rates of the prey. Our findings thus indicate that variability could be an essential pattern formation mechanism of the populations.
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Affiliation(s)
- Maja Fras
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, SI-2000 Maribor, Slovenia
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Plagányi EE, Butterworth DS. The Scotia Sea krill fishery and its possible impacts on dependent predators: modeling localized depletion of prey. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2012; 22:748-61. [PMID: 22645808 DOI: 10.1890/11-0441.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The nature and impact of fishing on predators that share a fished resource is an important consideration in ecosystem-based fisheries management. Krill (Euphausia superba) is a keystone species in the Antarctic, serving as a fundamental forage source for predators and simultaneously being subject to fishing. We developed a spatial multispecies operating model (SMOM) of krill-predator fishery dynamics to help advise on allocation of the total krill catch among 15 small-scale management units (SSMUs) in the Scotia Sea, with a goal to reduce the potential impact of fishing on krill predators. The operating model describes the underlying population dynamics and is used in simulations to compare different management options for adjusting fishing activities (e.g., a different spatial distribution of catches). The numerous uncertainties regarding the choice of parameter values pose a major impediment to constructing reliable ecosystem models. The pragmatic solution proposed here involves the use of operating models that are composed of alternative combinations of parameters that essentially try to bound the uncertainty in, for example, the choice of survival rate estimates as well as the functional relationships between predators and prey. Despite the large uncertainties, it is possible to discriminate the ecosystem impacts of different spatial fishing allocations. The spatial structure of the model is fundamental to addressing concerns of localized depletion of prey in the vicinity of land-based predator breeding colonies. Results of the model have been considered in recent management deliberations for spatial allocations of krill catches in the Scotia Sea and their associated impacts on dependent predator species.
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Affiliation(s)
- Eva E Plagányi
- Marine Resource Assessment and Management, Department of Mathematics and Applied Mathematics, University of Cape Town, Private Bag, Rondebosch 7701, South Africa.
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Hastings KK, Jemison LA, Gelatt TS, Laake JL, Pendleton GW, King JC, Trites AW, Pitcher KW. Cohort effects and spatial variation in age-specific survival of Steller sea lions from southeastern Alaska. Ecosphere 2011. [DOI: 10.1890/es11-00215.1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Lander ME, Logsdon ML, Loughlin TR, Van Blaricom GR. Spatial patterns and scaling behaviors of Steller sea lion (Eumetopias jubatus) distributions and their environment. J Theor Biol 2011; 274:74-83. [DOI: 10.1016/j.jtbi.2011.01.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 01/05/2011] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
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