Spatial and Temporal Distribution, Haulout Use and Movement Patterns of Steller Sea Lions (eumetopias Jubatus) in Northern California PDF Download

Author: Allison R. Fuller
Publisher:
ISBN:
Category : Steller's sea lion
Languages : en
Pages : 148

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Author: Claudio Campagna
Publisher: Springer Nature
ISBN: 3030591840
Category : Nature
Languages : en
Pages : 667

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This book is focused on the marine mammalian groups the Otariidae and the Odobenidae, otherwise known as fur seals, sea lions and the walrus. In 30 chapters, more than 60 authors from 30 institutions and 13 nationalities, discuss a broad suite of topics from maternal care and mating behavior, through play, cognition and personality, to adaptation to life in the Anthropocene. The authors explore the behaviors that have allowed these semi-aquatic mammals to thrive in the marine realm. Many populations have recovered following historical decimation, with interesting evolutionary consequences which are explored. Detailed, selected, individual species descriptions are also provided, showcasing the behavioral diversity of this engaging, adaptive and highly successful group of marine mammals.

Author: Jonathan Scordino
Publisher:
ISBN:
Category : Marine mammal populations
Languages : en
Pages : 186

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Book Description
The Steller Sea Lion Research Initiative was passed in 2001 to provide funding to help scientists determine causes and solutions for the population crash of Steller sea lions (Eumetopias jubatus). In response to need to understand population dynamics of Steller sea lions, NOAA Fisheries has spearheaded a large-scale, range-wide research program. The study involved capturing and hot-iron branding sea lions at rookeries from northern California around the Pacific Rim to Russia to provide individually recognizable animals for studies of behavior and vital rates. I report the results of monitoring pups branded and tagged at Rogue Reef, Oregon and St. George Reef, California to determine movement patterns and the affects of branding on apparent survival of Steller sea lion pups immediately after branding. Counts of Steller sea lion adult female, adult male, juveniles, and pups were collected at haulouts and rookeries of Oregon and northern California from 2002 through 2005. Movement patterns of Steller sea lions were inferred from count data. Adult males were seasonal inhabitants of Oregon and California during the breeding season from May through September before dispersing to northern feeding grounds. Females, juveniles, and pups were dispersed throughout haulouts in Oregon and northern California during all seasons but have seasonally high concentrations at Sea Lion Caves, Oregon in the winter and at the breeding rookeries during the summer breeding season. The high wintertime abundance of females and pups at Sea Lion Caves suggests that it should be considered as critical habitat for Steller sea lions of the eastern stock. Resights of marked sea lions collected between northern California and Alaska between 2001 and 2005 were analyzed to determine juvenile and pup dispersal patterns. Most pups stay close to their natal rookery, although 9 - 22% of individuals each year were observed to disperse further than 500 km. As 1-year olds, the mean maximum dispersal range expanded, which may have been a sign of weaning. Sexually dimorphic patterns in sea lion movements were apparent at 3 years of age as males were observed to disperse farther north than females. The percentage of females observed at their natal rookery increased each year to a maximum of 87% as 4-year-olds. This suggested that sexual maturity occurs at, or close to, 4 years of age for females. Branding provided a useful tool for analyzing movements of Steller sea lions, yet it may have impacts on survival of individuals. Concerns raised by NOAA Fisheries over branding impacts on pup survival were addressed with a study at Rogue Reef in 2005. One-hundred-and-sixty pups captured on 18 July, 2005 were randomly assigned to a treatment of flipper tag only (unbranded pups) or flipper tag and hot-iron branding (branded pups). Aside from the treatment of branding, all pups were handled and treated identically. Over the 73-day course of this study, I found lower apparent survival for branded pups than unbranded pups, with a final apparent survivorships of 0.23 (95% CI 0.01? 0.48) for branded pups and 0.46 (95% CI 0.15? 0.77) for unbranded pups. Apparent survivorship includes both mortality and emigration, so differences may be due to differences in emigration rates of the two groups, mortality rates, or both. The scope of inference for this study is only to Rogue Reef in 2005. However, it should provide a good model for future brand evaluation studies at other rookeries and for other pinniped species. Branding is currently the best and only available tool for long-term studies of survival, reproduction rates, and age at sexual maturity which are all critical for demographic models. Nonetheless, researchers should assess the impacts of branding at each rookery, and will need to consider whether knowledge from branding Steller sea lions is worth the potential reduction in pup survival or change in pup emigration behavior observed in this study.

Author: Michael A. Bigg
Publisher: Fisheries and Oceans, Scientific Information and Publications Branch
ISBN:
Category : California sea lion
Languages : en
Pages : 32

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Book Description
Aerial censuses were undertaken for Steller sea lions (Eumetopias jubatus) and California sea lions (Zalophus californianus) during 1971-84, and a review was made of published and unpublished data on numbers seen and numbers killed since 1913. These data were used to describe the location of haulout sites, season of occupation at haulout sites, regional movement patterns, and trends in numbers seen for each species during this century.

Author: Randall W. Davis
Publisher: Springer Nature
ISBN: 331998280X
Category : Science
Languages : en
Pages : 302

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Book Description
This comprehensive book provides new insights into the morphological, metabolic, thermoregulatory, locomotory, diving, sensory, feeding, and sleep adaptations of Cetacea (whales and dolphins), Pinnipedia (seals, sea lions and walrus), Sirenia (manatees and dugongs) and sea otters for an aquatic life. Each chapter reviews the discoveries from previous studies and integrates recent research using new techniques and technology. Readers will gain an understanding of the remarkable adaptations that enable marine mammals to spend all or most of their lives at sea, often while hunting prey at depth.

Author: Norma A. Vazquez
Publisher:
ISBN:
Category : Spatial behavior in animals
Languages : en
Pages : 77

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Book Description
The first objective of this study was to quantify the intensity of space use of 70 juvenile (12-26 months old) Steller sea lions (SSLs) from the western Distinct Population Segment (DPS) in the Kenai Fjord(KF)/Prince William Sound (PWS) region of Alaska as derived from externally attached ARGOS satellite transmitter tags. A Bayesian state-space model (SSM) approach was used to process and interpolate the ARGOS-based locations. The resulting tracks were then used to quantify the spatio-temporal distribution of SSLs by way of a gridded utilization distribution (UD) in the study area. Each of six combined two-month UDs had an average of 24 ± 4.16 animals (range: 20-30) contributing around 5,090 ±1,879 filtered locations (range: 2,757-7,593). Results of the bimonthly UDs show juvenile SSL remained within the KF/PWS study region during the tracking period, with the exception of one individual, TJ16 (male), who crossed the 144° W Meridian separating the western and eastern DPS. Furthermore, results revealed that juveniles exhibit different spatial distributions depending on the time of year. They remain confined to a relatively smaller area (6,500-12,075 km2) in the 100% UD months of March through August compared to a larger area of 11,300-22,575 km2 in the 100% UD months September through February. In general, in winter (November-April) 90% of observations fell within 30km of the nearest haul-out, whereas in summer (May-October) 90% fell within 20km. A multifactor analysis of covariance (MANCOVA) revealed a significantly higher percent time spent at sea from November through April than May through October (n=63; age as covariate F1=3.796, p=0.056; season as factor F1=13.147, p=0.001). Thus, while age contributed to the observed variance, the main effect was clearly by season. The second objective of this study was to characterize the density effects of predator-prey interactions based on the spatial distribution of actual juvenile Steller sea lion predation events in relation to their utilization distribution. Fifteen predation events were detected from archival Life History Transmitter (LHX) tags implanted into a subset of n=36 of the 70 juvenile SSLs. A Bayesian SSM approach was used to process and interpolate the ARGOS locations received post-mortem from LHX tags. The processed tracks were then used to extrapolate the most likely locations of predation events. All 15 predation events occurred in the western DPS from 2008 through 2013. We expected predation events to occur uniformly in all areas for non-specialized predators, and more often in areas of high utilization such as near rookeries and haul-outs for predators that are specialized on SSLs and focus hunting efforts on high use areas. Results suggest the opposite, with four of the 15 predation events occurred in the 91-100% UD, or areas of the lowest relative frequency distribution of animal locations, 3 events occurred in the 81-90% UD, and only 1 event in the 21-30% UD corresponding to an area of higher relative frequency distribution of animal locations. Seven of the 15 predation events occurred outside the UD range, and therefore in areas likely of the lowest relative frequency distribution of animal locations. The winter predation rate was twice that of summer, with 10 predation events during the winter periods (November-April), and 5 events during the summer periods (May-October). Six predation events occurred in January-February. One predation event occurred in March-April, 2 events in May-June, 1 event in July-August, 2 events in September-October, and 3 events in November-December. A Rayleigh test for circular distribution showed a significant difference from uniformity with a mean ordinal date of January 6th (for n=7 animals ≤ 22 months of age), p=0.016). Studying predation in the marine environment comes with many challenges due to limitations in locating and tracking highly mobile marine predators over a long period of time and over a wide geographic range. Previous Steller sea lion studies looking at predation have inherent biases due to only sampling during the summer months and only near rookeries and haul-outs. Our study shows that we can detect predation all year round, including winter, and far away from rookeries and haul-outs. Since juvenile survival is low, and thus poses a significant risk for population-level survival, increased knowledge of the specifics of juvenile SSL space utilization patterns is of vital importance to assessing the importance of predation risk as one of the main drivers of their survivability. This is the first study to relate actual predation events to the intensity of space use of juvenile SSLs in a declining population in the KF/PWS region of Alaska.

Author:
Publisher:
ISBN:
Category : Rare mammals
Languages : en
Pages : 108

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Author: Nathan James Soboleff
Publisher:
ISBN:
Category : Steller's sea lion
Languages : en
Pages : 248

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"Are spatial and temporal patterns of Steller sea lion declines consistent with development of certain state-managed commercial fisheries and vessel activity? This question motivated our analysis of data from the National Marine Fisheries Service count database and the Alaska Department of Fish and Game's (ADF & G) Fish Ticket database on state managed commercial fisheries from 1976 to 2002. Rookery groupings for Steller sea lions were formed based on spatial patterns of covariation of similar population declines. Using query reports from ADF & G, commercial fisheries statistical areas were selected within 50-nm radii of rookery groupings and analyzed for potential fisheries interactions. Negative correlations between state-managed fisheries for groundfish and salmon fisheries were found but few were statistically significant. Low statistical power constrained some of these tests. Many state-managed fisheries for shellfish (shrimp, king, and Tanner crab) were positively correlated with Steller sea lion declines, but again few were statistically significant. Rather than suggesting that somehow sea lions benefit from these fisheries, positive correlations are more likely to be indicative of covariation of sea lions and fisheries with common environmental factors. Field research into groundfish and salmon fisheries interactions, perhaps coupled with experimental management, is necessary to confirm causes of Steller sea lion declines"--Leaf iii.

Author: Dana J. Seagars
Publisher:
ISBN:
Category : California sea lion
Languages : en
Pages : 72

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Author: John L. Sease
Publisher:
ISBN:
Category : Mammal populations
Languages : en
Pages : 130

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