Sources of Variation in the Foraging Behavior and Demography of the Sea Otter, Enhydra Lutris PDF Download
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Author: Martin Tim Tinker
Publisher: Ann Arbor, Mich. : University Microfilms International
ISBN:
Category : Sea otter
Languages : en
Pages : 398
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Book Description
Author: Martin Tim Tinker
Publisher: Ann Arbor, Mich. : University Microfilms International
ISBN:
Category : Sea otter
Languages : en
Pages : 398
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Book Description
Author: Kathy J. Lyons
Publisher:
ISBN:
Category : Sea otter
Languages : en
Pages : 390
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Book Description
Author: Gena Beth Bentall
Publisher:
ISBN:
Category :
Languages : en
Pages : 190
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Book Description
Author: Randall W. Davis
Publisher: Springer Nature
ISBN: 3030667960
Category : Science
Languages : en
Pages : 366
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Book Description
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.
Author: Kathy J. Lyons
Publisher:
ISBN:
Category : Sea otter
Languages : en
Pages : 100
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Book Description
Author: Leah Darshan Honka
Publisher:
ISBN:
Category :
Languages : en
Pages : 44
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Book Description
As preferred prey become scarce, theory suggests that predator per-capita consumption rates decline and predator diets diversify. As a keystone predator, sea otters (Enhydra lutris) are known to have remarkable impacts on their macroinvertebrate prey, however, variation in the magnitude of these effects through time remain less well known. Using a space-for-time substitution, we quantified sea otter foraging behaviour at 5 rocky reef sites that fell along a gradient in otter occupation time (0.1-33 years) on British Columbia, Canada's central coast. As site occupation time increased, sea otters targeted increasingly smaller, more diverse macroinvertebrate prey suggesting the serial depletion of preferred to less valuable prey. We found strong evidence that urchin density and occupation time were important drivers of sea otter per-capita consumption rates on urchins, strongly interacting rocky reef herbivores, well known to drive the distribution and abundance of kelps. In addition, there was greater strength of evidence for prey-dependent over predator-dependent functional response models of sea otter consumption of urchins. These results have implications for nearshore productivity, commercial and subsistence shellfish fisheries and balancing the trade-offs inherent to ecosystem-based management.
Author: Glenn R. VanBlaricom
Publisher: Springer Science & Business Media
ISBN: 3642728456
Category : Science
Languages : en
Pages : 261
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Book Description
The impetus for this volume comes from two sources. The first is scientific: by virtue of a preference for certain large benthic invertebrates as food, sea otters have interesting and significant effects on the structure and dynamics of nearshore communities in the North Pacific. The second is political: be cause of the precarious status of the sea otter population in coastal California, the U.S. Fish and Wildlife Service (USFWS) announced, in June 1984, a proposal to establish a new population of sea otters at San Nicolas Island, off southern California. The proposal is based on the premise that risks of catastrophic losses of sea otters, due to large oil spills, are greatly reduced by distributing the population among two geographically separate locations. The federal laws of the U.S. require that USFWS publish an Environmental Impact Statement (ElS) regarding the proposed translocation of sea otters to San Nicolas Island. The EIS is intended to be an assessment of likely bio logical, social, and economic effects of the proposal. In final form, the EIS has an important role in the decision of federal management authority (in this case, the Secretary of the Interior of the U.S.) to accept or reject the proposal.
Author: Shawn Larson
Publisher: Academic Press
ISBN: 0128016876
Category : Nature
Languages : en
Pages : 468
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Book Description
Sea otters are good indicators of ocean health. In addition, they are a keystone species, offering a stabilizing effect on ecosystem, controlling sea urchin populations that would otherwise inflict damage to kelp forest ecosystems. The kelp forest ecosystem is crucial for marine organisms and contains coastal erosion. With the concerns about the imperiled status of sea otter populations in California, Aleutian Archipelago and coastal areas of Russia and Japan, the last several years have shown growth of interest culturally and politically in the status and preservation of sea otter populations. Sea Otter Conservation brings together the vast knowledge of well-respected leaders in the field, offering insight into the more than 100 years of conservation and research that have resulted in recovery from near extinction. This publication assesses the issues influencing prospects for continued conservation and recovery of the sea otter populations and provides insight into how to handle future global changes. Covers scientific, cultural, economic and political components of sea otter conservation Provides guidance on how to manage threats to the sea otter populations in the face of future global changes Highlights the effects that interactions of coastal animals have with the marine ecosystem
Author: Nicole Marie Thometz
Publisher:
ISBN: 9781321088618
Category :
Languages : en
Pages : 147
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Book Description
The integration of physiological and behavioral studies can yield valuable information important to the conservation and management of imperiled species. In the following chapters, I examine a suite of physiological characteristics and behavioral attributes of southern sea otters (Enhydra lutris nereis) across a variety of life stages and discuss resulting population level consequences in this threatened species. In my first data chapter (Chapter 2), I use open-flow respirometry to determine age- and activity- specific metabolic rates of immature southern sea otters throughout ontogeny. These data are then combined with activity budgets of wild sea otters to determine the energetic cost of pup rearing for adult females. In Chapter 3, I determine age-specific oxygen storage capacity and diving abilities of sea otters from birth through adulthood. Finally, in Chapter 4, I examine the foraging behavior of sea otters off the coast of central California. I found that sea otter pups have elevated mass-specific metabolic rates in comparison to adult conspecifics, which are highest for molting pups and begin to approach adult levels around the average age of weaning (6 mo.). In addition, immature sea otters have limited blood and muscle oxygen stores throughout dependency, which result in a limited capacity for diving and high dependence on adult females throughout lactation. The high energetic demands of pups result in elevated field metabolic rates (FMR) for lactating females. Female FMR is increased 17% by three weeks postpartum and continues to increase throughout lactation. By the average age of weaning female FMR is increased 96% above pre-pregnancy levels. These heightened energetic demands are reflected in the foraging behavior of wild sea otters. Adult females appear behaviorally constrained by dependent young during an already energetically costly life stage. Both physiological and behavioral data suggest that it takes sea otters approximately two years to develop comparable diving abilities to adults; however, individuals at this stage are likely inefficient foragers when compared to adults. Together these data indicate that late-lactation and the first years post-weaning are the most physiologically challenging life stages for sea otters and that these groups are likely the most sensitive to disturbance and resource limitation. The high energetic demands of dependent pups influence body condition, parental provisioning strategies, and life history decisions in adult females. In addition, high energy demands, physiological limitations, and behavioral naivete make maintaining positive energy balance difficult for juvenile and sub-adult sea otters. Ultimately, these chapters provide novel information regarding age-specific energy demands, physiological abilities, and foraging behavior of southern sea otters across a variety of life stages, and elucidate mechanisms underlying current population level trends.
Author: Jessica Rhian Hale
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
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.
