Resource Competition Space Use And Forage Ecology Of Sea Otters Enhydra Lutris In Southern Southeast Alaska

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Resource Competition Space Use And Forage Ecology Of Sea Otters Enhydra Lutris In Southern Southeast Alaska

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Author : Zachary N. Hoyt
language : en
Publisher:
Release Date : 2015

Resource Competition Space Use And Forage Ecology Of Sea Otters Enhydra Lutris In Southern Southeast Alaska written by Zachary N. Hoyt and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Sea otter categories.

The growing sea otter population in southern Southeast Alaska is impacting commercial shellfish, through foraging and expanding in range and abundance except where hunted for subsistence. Sea otters and their prey have coexisted in the North Pacific Ocean for approximately 750,000 years, but due to exploitation of sea otters from the 1770s until 1911, the species became extinct over much of its range, including southern Southeast Alaska. Subsequently, invertebrate species flourished and were commercially targeted in the late 1900s. Sea otters were relocated (n = 106) to southern Southeast Alaska in 1968. In this dissertation, I evaluated this marine mammal-fisheries conflict through multiple approaches. In Chapter 1, I analyzed geoduck clam and red sea urchin abundance surveys (1994-2012) and catch and effort data from commercial Dungeness crab fisheries (1969-2010) to identify interactions between sea otters and commercial shellfish. In Chapter 2, I collected geo-locations from 30 instrumented sea otters (2011-2014) to identify space use and range expansion. In Chapter 3, I collected sea otter abundance and distribution data from fixed wing aircraft (2010-2014) and observational forage data from sea otters (2010-2013) to determine contemporary population growth and consumption of commercially important shellfish by sea otters. The sea otter population in southern Southeast Alaska has grown from 106 to an estimated 13,139 individuals between 1968 and 2011 with an annual growth rate of 12% and expansion of its range by 117 km2 y-1. Results from a before-after, control-impact analysis indicate that sea otters are rapidly impacting red sea urchin and significantly reducing geoduck clam densities. Further, breakpoints predicted from regression models of Dungeness crab catch are correlated with known sea otter colonization timing. Forty-six percent of the population level diet of sea otters represented commercially important prey. Sea otters targeted commercially important species, specifically red sea urchins and Dungeness crab, when first colonizing an area, after which the diet of sea otters became more diverse as colonization durations increased. Using habitat models based on a bivariate normal probability distribution function, environmental covariates and subsistence hunting pressure on sea otters, I determined that sea otter range expansion was limited by subsistence hunting. Further, female and non-territorial males segregated based on habitat and likely prey preferences. I conclude that sea otter populations will likely continue to grow, and that current shellfisheries cannot coexist with sea otters under existing management. Further, conservation and management of sea otter populations, whether to increase the distribution through translocation efforts or reduce the distribution to avoid human conflicts, could benefit from insights gained from spatially explicit modeling at the landscape level.

Ethology And Behavioral Ecology Of Sea Otters And Polar Bears

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Author : Randall W. Davis
language : en
Publisher: Springer Nature
Release Date : 2021-07-03

Ethology And Behavioral Ecology Of Sea Otters And Polar Bears written by Randall W. Davis and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-07-03 with Science categories.

Sea otters and polar bears are carnivorous marine mammals that still resemble their terrestrial ancestors. Compared with Cetacea (whales and dolphins), Sirenia (dugongs and manatees), and Pinnipedia (seals, sea lions, and walrus), they are less adapted for an aquatic life and the most recently evolved among marine mammals. Sea otters are amphibious but seldom come ashore, and polar bears primarily occur on sea ice or along the shore. When at sea, both species spend most of their time swimming at the surface or making short, shallow dives when foraging or pursuing prey. Indeed, polar bears rarely pursue seals in water. Nevertheless, polar bears are powerful swimmers and will stalk seals from the water. As with many other large carnivores, they are solitary hunters. Although sea otters are gregarious and form aggregations at sea called rafts, they are primarily asocial. Except during mating, the principal interaction among sea otters occurs between a female and offspring during the six-month dependency period. In large carnivores (e.g., wolves and lions) that feed on ungulates, sociality and cooperation are favored because of the need to capture large prey and defend carcasses. Polar bears, which are the largest terrestrial carnivore, are solitary hunters of seals and are neither gregarious nor social. Males and females briefly associate during courtship and mating. During this time, males aggressively compete for females. At other times, males generally avoid each other except for aggregations of males that form while summering on land, and females with cubs avoid males, which are known for infanticide. As with sea otters, the interaction of polar bears outside of mating occurs between a female and her offspring during the 2-3 year dependency period. This interaction is critically important when altricial cubs are born in the winter den. This book provides new insight into the ethology and behavioral ecology of sea otters and polar bears. Each chapter reviews the discoveries of previous studies and integrates recent research using new techniques and technology. The authors also address historic and current anthropogenic challenges for their survival as climate change alters entire marine ecosystems.

Activity Budget Field Metabolic Rate And Foraging Ecology Of Female Sea Otters Enhydra Lutris Kenyoni With Dependent Pups In Alaska

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Author : Ryan Christopher Wolt
language : en
Publisher:
Release Date : 2015

Activity Budget Field Metabolic Rate And Foraging Ecology Of Female Sea Otters Enhydra Lutris Kenyoni With Dependent Pups In Alaska written by Ryan Christopher Wolt and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.

Sea otter (Enhydra lutris kenyoni) foraging behavior and prey preference (2001-2004) and the behavior and activity budgets of females with dependent pups (2005-2010) were studied during the summer (June-August) in Simpson Bay, Prince William Sound, Alaska. Unlike most previous studies of sea otters which were conducted in coastal areas with a rocky benthos and kelp canopy, the benthic habitat in this study was primarily soft sediment (mud or mixed mud and gravel) with no canopy-forming kelps. Foraging behavior and prey preference. A total of 1,816 foraging dives from 211 bouts were recorded. 87% of foraging dives were successful, and 44% of the prey was identified: 75% clams, 9% Pacific blue mussels, 6% crabs, 2% scallops and a variety of other invertebrates. Significantly more prey items/area were brought up from mixed mud/gravel than mud (p-value

Foraging Ecology And Population Dynamics Of Northern Sea Otters Enhydra Lutris Kenyoni In Washington State

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Author : Jessica Rhian Hale
language : en
Publisher:
Release Date : 2022

Foraging Ecology And Population Dynamics Of Northern Sea Otters Enhydra Lutris Kenyoni In Washington State written by Jessica Rhian Hale and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with categories.

Many marine mammal populations are currently recovering from population depletion after overharvest. As marine mammals are often important predators in shaping marine ecosystems, there is a need to understand the impacts of recovering populations on other species and the marine ecosystem as a whole. The depletion and subsequent recovery of these species presents biologists with natural experiments to study their ecology, including drivers of their population dynamics and the function of the species in the ecosystem. This dissertation focuses on the recovery of a translocated population of sea otters (Enhydra lutris kenyoni) in Washington State. The presence or absence of sea otters, a keystone species, can dramatically influence marine community structure. The overall aim of this dissertation was to utilize the natural experiment of sea otter translocation to Washington State to understand drivers of sea otter population dynamics as well as the ecological role that sea otters play in Washington State. In Chapter 2, my coauthors and I found that the sea otter population in Washington has grown from an estimated 21 adult sea otters in 1977 to 2,336 adult sea otters in 2019, and the population is predicted to continue to grow and expand primarily to the south of the current range over the next 25 years. We also estimated that Washington State can support twice as many sea otters than previously estimated (equilibrium abundance of 6,080 vs. 2,734 sea otters), and that estimates of mean equilibrium density in currently occupied areas had the largest impact on predictions of population growth and range expansion. In Chapter 3, we quantified how sea otter population status (i.e., sea otter cumulative density) and habitat type (i.e., sea otter foraging in open water, kelp canopy, emergent rock, or intertidal) influence sea otter diet, and found that habitat was 1.77 times more important than sea otter population status in determining sea otter diet composition. We also found that sea otter long-term average rate of energy intake and diet diversity were negatively and positively correlated with sea otter cumulative density, respectively. In Chapter 4, we demonstrated the ecological role of sea otters in the nearshore marine ecosystem in Washington as a keystone species. We found that temporal transitions in the amount of kelp canopy were related to the duration of sea otter occupation, and that this relationship was more complex than a simple linear function. We also found that sea urchins were present at higher densities at sites more recently occupied by sea otters compared to long-occupied sites. In Chapter 5, we demonstrated the impact of sea otters as a recovering predator on the Pacific razor clam (Siliqua patula). We found that the magnitude of sea otter predation effects varied over time and space, with sea otter-caused razor clam mortality surpassing natural mortality in 2018 at Kalaloch Beach, occupied by sea otters since 2005. We also found that sea otters selectively consume the larger “recruit” size razor clams, the size that is also targeted in the recreational fishery, despite the smaller pre-recruit size clams being more abundant. Collectively, these results provide a deeper understanding of sea otter recolonization in Washington State as well as the ecological consequences of this recolonization.

The Community Ecology Of Sea Otters

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Author : Glenn R. VanBlaricom
language : en
Publisher: Springer
Release Date : 1988

The Community Ecology Of Sea Otters written by Glenn R. VanBlaricom and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 1988 with Nature categories.

Sea otter foraging habits and effects on prey populations and communities in soft bottom environments; effects of foraging by sea otters on mussel dominated intertidal communities; kelp communities and sea otters; effects of sea otter foraging on subtidal reef communities off central California; fish populations in kelp forests without sea otters, effects of severe damage and destructive sea urchin grazing; effects of kelp forests on nearshore environments, biomass, detritus, and altered flow; sea otters and nearshore benthic communities.

Sources Of Variation In The Foraging Behavior And Demography Of The Sea Otter Enhydra Lutris

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Author : Martin Tim Tinker
language : en
Publisher: Ann Arbor, Mich. : University Microfilms International
Release Date : 2004

Sources Of Variation In The Foraging Behavior And Demography Of The Sea Otter Enhydra Lutris written by Martin Tim Tinker and has been published by Ann Arbor, Mich. : University Microfilms International this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with Sea otter categories.

Research Program On The Sea Otter Enhydra Lutris And Its Environment

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Author :
language : en
Publisher:
Release Date : 1980

Research Program On The Sea Otter Enhydra Lutris And Its Environment written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1980 with Sea otter categories.

Sea Otters In Southeast Alaska

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Author : Wendel W. Raymond
language : en
Publisher:
Release Date : 2020

Sea Otters In Southeast Alaska written by Wendel W. Raymond and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Food chains (Ecology) categories.

The recovery of sea otters (Enhydra lutris) to Southeast Alaska is a conservation success story, but their increasing population raises questions about sea otter population dynamics and the ecological role of this top-level predator. In Chapter 1, we addressed these questions by investigating patterns and population effects of subsistence sea otter harvest. Subsistence harvest reduced populations at a small scale, with potential to slow or stop population growth, but across Southeast Alaska the population continues to grow, even with an average 3% subsistence harvest rate. In Chapters 2 and 3 we investigated the ecological role of sea otters in seagrass (Zostera marina) communities. When we tested for generality in a sea otter - seagrass trophic cascade across a large spatial scale in Southeast Alaska, we found a positive relationship between sea otters and seagrass. However, we found no evidence of a relationship between crabs and epifauna, suggesting that the ecological mechanisms in Southeast Alaska may differ from other regions. Our comparison of carbon and nitrogen stable isotopes (SI) to assess the role of sea otters on trophic structure and energetic pathways of seagrass beds found little effect of sea otters in overall community trophic niche space, suggesting similar carbon sources and food chain length in seagrass meadows regardless of sea otters. Conversely, the FA profiles of diverse consumer suggest variation in dietary sources with and without sea otters. This result suggests that the trophic cascade may not be the only or primary energetic pathway in Southeast Alaska seagrass communities. In all, our studies have revealed that sea otters in Southeast Alaska are linked to both people and a common Southeast Alaska nearshore habitat, seagrass. These results describe the varied interactions of a recovering top predator and highlight a need to consider these diverse interactions in resource management, conservation, and ecological research.

Addressing A Complex Resource Conflict

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Author : Sonia Natalie Ibarra
language : en
Publisher:
Release Date : 2021

Addressing A Complex Resource Conflict written by Sonia Natalie Ibarra and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with Alaska Natives categories.

Complex resource conflicts may benefit from the inclusion of social-ecological systems approaches that recognize the complex linkages between humans and their environment. Competition for shared shellfish resources by sea otters and humans in Southeast Alaska has caused food security concerns, cultural and economic losses, and uncertainty about the future of various fisheries, including rural subsistence-based fisheries. In rural Alaska Native communities, access to subsistence resources are critical to maintaining a way of life, with deeply rooted knowledge systems that are tied to the land, water, and natural resources. This dissertation documents Indigenous and local knowledge of Alaska Native customary and traditional food experts, sea otter hunters, and elders (hereafter harvest experts) to understand empirical observation and interpretations of restoring balance with sea otters. This work took place within the traditional territories of the Tlingit and Haida people of Southeast Alaska in four rural communities, Kake, Klawock, Craig, and Hydaburg. With Tribal leaders and harvest experts, my collaborators and I used a participatory framework that became a formal partnership to co-develop study goals, objectives, and methodology. Through a multiple evidence-based approach, I co-conducted semidirected and site visit interviews, structured questionnaires, mapping exercises, and participant observation in all four communities, and intertidal bivalve (shellfish) surveys in Hydaburg and Kake. Qualitative and quantitative approaches revealed local and Indigenous knowledge about sea otters caused changes to subsistence shellfish resources and harvesting patterns that included declines in availability and spatial extent of shellfish harvests, and shifts in shellfish harvest hotspots. Community adaptive strategies to observed shellfish declines include shifting harvest locations away from sea otter presence. Community management recommendations about restoring balance with sea otters include increasing sea otter hunting locally using spatially explicit techniques. Financial subsidies for sea otter hunters, creating local tanneries, legal changes to the Marine Mammal Protection Act, and market creation and development for sea otter handicrafts were noted as solutions to barriers of local implementation to management recommendations. Commercial and charter fisheries are other factors that have contributed to shellfish declines. Butter clam (Saxidomus gigantea) size and density declined with increased distance to community and increased sea otter activity near Hydaburg, demonstrating the influence of sea otters and human harvests on bivalve population dynamics. Application of these results about Indigenous knowledge, management, and governance systems to sea otter management in Alaska could create a more inclusive, equitable and community-driven management approach.

Photo Identification Summer Activity Pattern Estimated Field Metabolic Rate And Territory Quality Of Adult Male Sea Otters Enhydra Lutris In Simpson Bay Prince William Sound Alaska

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Author : Shannon Elizabeth Finerty
language : en
Publisher:
Release Date : 2010

Photo Identification Summer Activity Pattern Estimated Field Metabolic Rate And Territory Quality Of Adult Male Sea Otters Enhydra Lutris In Simpson Bay Prince William Sound Alaska written by Shannon Elizabeth Finerty and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Sea otter categories.

This project describes a portion of a long-term study of the behavioral ecology of sea otters. Sub-studies of this project include the development of an individual recognition program for sea otters, the construction of male sea otter activity and energy budgets, and the assessment of male sea otter territory quality. The Sea Otter Nose Matching Program, or "SONMaP", was developed to identify individual sea otters in Simpson Bay, Prince William Sound, Alaska, using a blotch-pattern recognition algorithm based on the shape and location of nose scars. The performance of the SONMaP program was tested using images of otters collected during the 2002-03 field seasons, and previously matched by visually comparing every image in a catalog of 1,638 animals. In 48.9% of the visually matched images, the program accurately selected the correct image in the first 10% of the catalog. Individual follows and instantaneous sampling were used during the summers of 2004-06, to observe male sea otter behavior. Six behaviors (foraging, grooming, interacting with other otters, patrolling, resting, and surface swimming) were observed during four time periods (dawn, day, dusk, night) to create 24-hr activity budgets. Male sea otters spent 27% of their time resting, 26% swimming, 19% grooming, 14% foraging, 9% patrolling and 5% interacting with other otters. Field Metabolic Rate (FMR) was estimated by combining the energetic costs for foraging, grooming, resting, and swimming behaviors of captive otters from Yeates et al. (2007) with these activity budgets. "Swimming" accounted for the greatest percentage (43%) of energy expended each day followed by grooming (23%), resting (15%), feeding (13%) and other (5%). With a peak summer sea otter density of 5.6 otters km-2, the low percentage of time spent foraging indicates that Simpson Bay is below equilibrium density. Territory quality was assessed for male sea otters using four attributes: territory size, shoreline enclosure, accessibility, and number of females observed feeding in each territory. Each attribute was coded with a score of 0-2, and total quality scores ranged from 0.14-1.96 (0.9 + 0.61 SD). High quality territories had large areas, moderate shoreline enclosure, high accessibility, and many foraging females