Download or read book Resource Competition Space Use and Forage Ecology of Sea Otters Enhydra Lutris in Southern Southeast Alaska written by Zachary N. Hoyt and published by . This book was released on 2015 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Ethology and Behavioral Ecology of Sea Otters and Polar Bears written by Randall W. Davis and published by Springer Nature. This book was released on 2021-07-03 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book The Community Ecology of Sea Otters written by Glenn R. VanBlaricom and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 261 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book The Sea Otter Enhydra Lutris written by Marianne Riedman and published by . This book was released on 1991 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sea Otters in Southeast Alaska written by Wendel W. Raymond and published by . This book was released on 2020 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Foraging Ecology and Population Dynamics of Northern Sea Otters Enhydra Lutris Kenyoni in Washington State written by Jessica Rhian Hale and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Sea Otter Conservation written by Shawn Larson and published by Academic Press. This book was released on 2014-12-23 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Addressing a Complex Resource Conflict written by Sonia Natalie Ibarra and published by . This book was released on 2021 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Sea Otter Diet Composition with Respect to Recolonization Life History and Season in Southern Southeast Alaska written by Nicole L. LaRoche and published by . This book was released on 2020 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Until translocation efforts in the 1960s, sea otters (Enhydra lutris) were absent from Southeast Alaska due to extirpation by the fur trade in the 18th and 19th centuries. About 400 sea otters were reintroduced to six Southeast Alaska locations, including two sites near Prince of Wales Island in southern Southeast Alaska. The most recent US Fish and Wildlife Service population count, completed in 2012, estimated that about 25,000 sea otters inhabited Southeast Alaska. Sea otters will reduce invertebrate prey biomass when recolonizing an area. By quantifying sea otter diets and caloric intake according to recolonization patterns, we can better understand the ecosystem impacts of sea otter population increase and range expansion. The goal of this study was to quantify changes in seasonal diet composition and assess the energetic quality of sea otter prey in southern Southeast Alaska. I made visual foraging observations of 3,385 sea otter dives around Prince of Wales Island (POW) to determine diet composition during the spring and summer months. I then collected vibrissae from 45 sea otters obtained from subsistence hunters to assess year-round sea otter diets using stable isotopes. I collected sea otter prey items throughout POW in three seasons (May 2018, August 2018, and February 2019) to measure energy, lipid and protein content, and delta13C (carbon) and delta15N (nitrogen) values. Sea otter diets mainly consisted of clams, as quantified both from visual observations and stable isotope analysis. However, there was more variation in the diet estimates from stable isotope analysis. Stable isotope analysis revealed variation among individual diets of sea otters and individuality in diet within the POW region of sea otters. Sea otters seasonally increased consumption of some prey when the prey was highest in lipid and overall caloric content. Sea otters switched prey types when the prey was more energetically valuable. The results of this study will aid in future management of shellfisheries, subsistence hunting, and implementing co-management of a protected species by providing quantitative diet composition data for stakeholders. This work is a part of a large-scale project examining how the recovery of sea otters structures nearshore marine ecosystems, provides ecosystem services, and affects community sustainability.

Download or read book The Sea Otter Enhydra Lutris written by Marianne Riedman and published by . This book was released on 1990 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: A current review of the biology, ecology, and behavior of the sea otter (Enhydra lutris). Emphasis is placed on the populations and habitat in central California but results of studies in Alaska, Canada, and the Soviet Union are also covered. Management and conservation problems such as conflicts with shellfisheries and concerns about oil pollution are also touched on.

Download or read book A Summary of Knowledge of the Sea Otter Enhydra Lutris L in California and an Appraisal of the Completeness of Biological Understanding of the Species written by Charles D. Woodhouse and published by . This book was released on 1977 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Final Environmental Impact Statement for Translocation of Southern Sea Otters Technical support documents written by and published by . This book was released on 1987 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 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 published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Sources of Variation in the Foraging Behavior and Demography of the Sea Otter Enhydra Lutris written by Martin Tim Tinker and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 2004 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research Program on the Sea Otter Enhydra Lutris and Its Environment written by and published by . This book was released on 1980 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Draft Revised Recovery Plan for the Southern Sea Otter Enhydra Lutris Nereis written by and published by . This book was released on 2000 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Southern Sea Otter Recovery Plan written by and published by . This book was released on 1982 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: