Download or read book Assessing Southern Resident Killer Whale Orcinus Orca Prey Abundance written by Erin Leigh Strange and published by . This book was released on 2016 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Predator-prey dynamics and their ecological drivers have absorbed the interest of population ecologists since models were first developed describing the cyclical nature of predator-prey populations in a static framework. Empirical data has demonstrated that species life histories evolve over ecological timescales in response to changes in broad ecological processes or specific changes in population densities and/or spatial distributions. Anthropomorphic environmental impacts have influenced ecological processes on a broad scale and in many cases impacted predator-prey relationships. Southern Resident killer whale, Orcinus orca, and its preferred prey, Chinook salmon, Oncorhynchus tshawystcha, provide an opportunity to evaluate human impacts from Chinook salmon ocean harvest and hatchery production to the predator-prey dynamic between these co-evolved species. This is particularly important when considering the management of ocean fisheries and hatcheries that support those fisheries relative to the recovery of the Southern Resident killer whale population, a federally-endangered marine mammal species. The purpose of this study was to: 1) investigate the impacts of modifications in Chinook salmon ocean harvest and hatchery production inputs on their abundance as a prey species for Southern Resident killer whale; and 2) evaluate how the Southern Resident killer whale population responds to the subsequent prey availability. Time-series (1984-2011) Chinook salmon terminal run (freshwater harvest plus spawning population) and ocean fishery harvest data from British Columbia, Washington, Oregon and California, were analyzed under twelve scenarios involving different combinations of ocean fishery harvest and hatchery production. Chinook salmon terminal run results were used as input to the Southern Resident killer whale population dynamics model to evaluate the whale population response to varying levels of prey availability. Two covariates were chosen for the Chinook salmon time-series analysis: reduction in ocean fishery harvest and reduction in hatchery production. The primary response variable chosen for this analysis was Chinook salmon terminal run, although ocean fishery harvest and Chinook salmon total abundance were also evaluated. Linear regression was used to evaluate the influence that reductions in ocean harvest and hatchery production have on the relative absolute change in Chinook salmon terminal run, fishery harvest, and total abundance between the status quo and each scenario. A Mann-Whitney Test was used to determine trends between early and late periods in the Chinook salmon time-series. Results of this study indicate significant interactions between covariate and response variables, revealing that reduction in ocean fishery harvest explains the amount of Chinook salmon in the terminal run to a weak degree, while the reduction in hatchery production explains the amount of Chinook salmon in the terminal run to a moderate degree. Although percent reduction calculations showed decreasing ocean harvest as hatchery production decreased, the linear regression showed that percent reduction in hatchery production does not explain the amount of Chinook salmon ocean fishery harvest. The ocean fishery harvest reduction percentage weakly explains the Chinook salmon fishery harvest. In addition, reduction in hatchery production explains the total abundance of Chinook salmon in the ocean to a weak degree, while ocean harvest reduction explains the total abundance of Chinook salmon in the ocean to a moderate degree. Results also indicate a significant decrease in fishery impacts from an early time period (1984-1997) to a late time period (1998-2011), while no significant difference was demonstrated between the two timeframes for terminal run and total abundance. Southern Resident killer whale modeling results revealed that all of the Chinook salmon scenarios (terminal run data) resulted in a positive Southern Resident killer whale population growth response. However, statistical analysis between scenarios indicated no significant difference in the Southern Resident killer whale population growth over a 10-year projection. These results have value to fishery managers with regard to potential modifications to Chinook salmon ocean fishing harvest and hatchery production that may result in a greater prey base for the Southern resident killer whale population. Identification of the Chinook salmon populations most important as prey to Southern resident killer whale could focus natural/wild Chinook salmon population restoration and hatchery reform efforts with the target of increasing the numbers of Chinook salmon produced in those important watersheds. Chinook salmon management decisions directed at changing the focus of hatchery operations to support naturally spawning populations and improving freshwater habitats to support natural/wild spawning Chinook salmon populations may provide more prey over the long-term for Southern resident killer whale than management actions directed at further restrictions on the commercial ocean Chinook salmon fishery. However, based on prior research (Ward et al. 2013) and the results of this study, Chinook salmon management practice involving a complete closure of the ocean fishery while maintaining current levels of hatchery production may produce a higher likelihood that the Southern Resident killer whale population would reach their recovery target.

Download or read book Approaches to Understanding the Cumulative Effects of Stressors on Marine Mammals written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2017-05-04 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine mammals face a large array of stressors, including loss of habitat, chemical and noise pollution, and bycatch in fishing, which alone kills hundreds of thousands of marine mammals per year globally. To discern the factors contributing to population trends, scientists must consider the full complement of threats faced by marine mammals. Once populations or ecosystems are found to be at risk of adverse impacts, it is critical to decide which combination of stressors to reduce to bring the population or ecosystem into a more favorable state. Assessing all stressors facing a marine mammal population also provides the environmental context for evaluating whether an additional activity could threaten it. Approaches to Understanding the Cumulative Effects of Stressors on Marine Mammals builds upon previous reports to assess current methodologies used for evaluating cumulative effects and identify new approaches that could improve these assessments. This review focuses on ways to quantify exposure-related changes in the behavior, health, or body condition of individual marine mammals and makes recommendations for future research initiatives.

Download or read book Marine Mammal Populations and Ocean Noise written by National Research Council and published by National Academies Press. This book was released on 2005-01-24 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Attention has been drawn to the subject of how ocean noise affects marine mammals by a series of marine mammal strandings, lawsuits, and legislative hearings, and most recently, the report from the U.S. Commission on Ocean Policy. One way to assess the impact of ocean noise is to consider whether it causes changes in animal behavior that are "biologically significant," that is, those that affect an animal's ability to grow, survive, and reproduce. This report offers a conceptual model designed to clarify which marine mammal behaviors are biologically significant for conservation purposes. The report is intended to help scientists and policymakers interpret provisions of the federal Marine Mammal Protection Act.

Download or read book Primates and Cetaceans written by Juichi Yamagiwa and published by Springer Science & Business Media. This book was released on 2013-11-20 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, the editors present a view of the socioecology of primates and cetaceans in a comparative perspective to elucidate the social evolution of highly intellectual mammals in terrestrial and aquatic environments. Despite obvious differences in morphology and eco-physiology, there are many cases of comparable, sometimes strikingly similar patterns of sociobehavioral complexity. A number of long-term field studies have accumulated a substantial amount of data on the life history of various taxa, foraging ecology, social and sexual relationships, demography, and various patterns of behavior: from dynamic fission–fusion to long-term stable societies; from male-bonded to bisexually bonded to matrilineal groups. Primatologists and cetologists have come together to provide four evolutionary themes: (1) social complexity and behavioral plasticity, (2) life history strategies and social evolution, (3) the interface between behavior, demography, and conservation, and (4) selected topics in comparative behavior. These comparisons of taxa that are evolutionarily distant but live in comparable complex sociocognitive environments boost our appreciation of their sophisticated mammalian societies and can advance our understanding of the ecological factors that have shaped their social evolution. This knowledge also facilitates a better understanding of the day-to-day challenges these animals face in the human-dominated world and may improve the capacity and effectiveness of our conservation efforts.

Download or read book Southern Resident Killer Whales Orcinus Orca written by Deborah A. Giles and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation concerns the southern resident killer whales (Orcinus orca), a genetically isolated population of fish-eating killer whales that frequent the international waters of the Salish Sea between the United States and Canada in the eastern Pacific Ocean. Research was conducted from June 1 to October 31, 2007 and from June 7 to October 31, 2008, between geographic coordinates: 48°12' to 49° N latitude by 122°43' to 123°50° W longitude. The southern resident killer whale population has experienced multiple fluctuations since population surveys were initiated by the Center for Whale Research (CWR) in the mid 1970's. In November 2005, the U.S. National Oceanic and Atmospheric Administration's National Marine Fisheries Service (NMFS), Northwest Regional Office listed the southern resident killer whales as an endangered distinct population segment of the species Orcinus orca under the United States Endangered Species Act (ESA). Several risk factors including reductions in the quantity and quality of prey (salmon), exposure to persistent toxins, and disturbance from vessel presence and associated noise were identified as contributing to the decline of this already small population. With the listing under the ESA, critical habitat was designated in the inland waters around the U.S. San Juan Islands, Washington State and the Canadian Gulf Islands, British Columbia, Canada. Chapter one, Managing Vessel-based Killer Whale Watching: A Critical Assessment of the Evolution from Voluntary Guidelines to Regulations in the Salish Sea, provides background on the southern resident killer whales and the robust international whale watching industry in the region. This chapter also provides a detailed history of local, state, federal and international vessel laws and guidelines for watching whales in the Salish Sea. Chapter two, Non-invasive methods to study southern resident killer whales and vessel compliance with regulations, describes a novel equipment package, consisting of a differential GPS integrated with a digital compass and laser rangefinder that allowed me to collect accurate geo-referenced locations and behavioral data on whales and vessels throughout the whale's critical habitat. To improve both the spatial and temporal data on whale-vessel interactions, the information collected with this equipment was used to assess vessel compliance with local, state and federal laws and the regionally accepted best-practices Be Whale Wise Guidelines. Chapter three, The effects of vessels on group cohesion and behavior of southern resident killer whales (Orcinus orca), discusses research investigating changes in killer whale group cohesion in response to vessel density, distance and mode of operation. Future cetacean studies would benefit from using the equipment and methods presented here, especially in areas that are not conducive to land-based theodolite collected data.

Download or read book Space Use Patterns and Population Trends of Southern Resident Killer Whales Orcinus Orca in Relation to Distribution and Abundance of Pacific Salmon Oncorhynchus Spp in the Inland Marine Waters of Washington State and British Columbia written by Shannon Marie McCluskey and published by . This book was released on 2006 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Swimming with Orca written by Ingrid Visser and published by Penguin Global. This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Meet the woman whose life revolves around orca, or killer whales. This book tells the fascinating story of Dr Ingrid Visser, a marine scientist who has spent the past ten years studying these creatures. During this time she has got to know many New Zealand orca intimately; she calls them her friends and can identify some by sight. Ingrid has a hands-on approach to her study - getting into the water with them, watching them hunt and interacting in any way she can. Ingrid is the only person to work with orca in the South Pacific and has discovered many differences between their behaviour here and in the northern hemisphere. The book is packed with interesting facts about orca in New Zealand and also tells Ingrid's own personal story and the inspiring encounters she has had with these intriguing animals.

Download or read book Population Viability Analysis for the Southern Resident Population of the Killer Whale Orcinus Orca written by Martin Taylor (Ph. D.) and published by . This book was released on 2000 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: The killer whale, once abundant in the Pacific Northwest waters, has been declining in population since 1996. This is attributed to the lack of preferred foods, pollution, and disturbance from whale watching boats.

Download or read book Determinants of Group Splitting written by Eva Helene Stredulinsky and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Group living is a social strategy adopted by many species, where individuals can exhibit long-term social affiliation with others, strengthened through cooperative behaviour and often kinship. For highly social mammals, changes in group membership may have significant consequences for the long-term viability and functioning of a population. Detecting significant social events is essential for monitoring the social dynamics of such populations and is crucial to determining the factors underlying these events. Detecting when changes in social organization occur, especially with incomplete data, poses significant analytical challenges. To resolve this issue, I developed and assessed a straightforward, multi-stage and generalizable method with broad utility for ecologists interested in detecting and subsequently investigating causes of changes in social organization. My approach illustrates the frequency and ecological relevance of group fission and fusion events in a population of fish-eating 'Resident' killer whales (Orcinus orca). Group fission is a process commonly found in social mammals, yet is poorly described in many taxa, and has never been formally described in killer whales. To address this gap, I provided the first description of matrilineal fission in killer whales, from a threatened but growing Northern Resident killer whale population in which matrilineal fission has been observed for the past three decades. I also undertook the first comprehensive assessment of how killer whale intragroup cohesion is influenced by group structure, demography and resource abundance. Fission in Northern Resident killer whales occurred both along and across maternal lines, where animals dispersed in parallel with their closest maternal kin. I show that fission in this population is driven primarily by population growth and the demographic conditions of groups, particularly those dictating the nutritional requirements of the group. I posit that intragroup food competition is the most likely explanation for group fission in this population, where prey abundance also has ancillary effects. As group fission can have a direct impact on the fitness of group members and the long-term viability of a population, my findings underscore the importance of incorporating studies of sociality into the management of threatened populations of social mammals.

Download or read book A Historical Ecology of Salish Sea Resident Killer Whales Orcinus Orca with Implications for Management written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cumulative Effects Assessment for Northern and Southern Resident Killer Whale Orcinus Orca Populations in the Northeast Pacific written by Cathryn Clarke Murray and published by . This book was released on 2019 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ethology and Behavioral Ecology of Odontocetes written by Bernd Würsig and published by Springer. This book was released on 2019-08-02 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book concentrates on the marine mammalian group of Odontocetes, the toothed whales, dolphins, and porpoises. In 23 chapters, a total of 40 authors describe general patterns of ethological concepts of odontocetes in their natural environments, with a strong bent towards behavioral ecology. Examples are given of particularly well-studied species and species groups for which enough data exist, especially from the past 15 years. The aim is to give a modern flavor of present knowledge of ethology and behavior of generally large-brained behaviorally flexible mammals that have evolved quite separately from social mammals on land. As well, the plight of populations and species due to humans is described in multiple chapters, with the goal that an understanding of behavior can help to solve or alleviate at least some human-made problems.

Download or read book Circulation in the Strait of Juan de Fuca written by James Holbrook 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 Species in the Spotlight written by and published by . This book was released on 2016 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Southern Resident killer whale DPS was listed as endangered under the Endangered Species Act (ESA) in 2005 following an almost 20% decline in the population. The Southern Residents were chosen as one of the eight most at-risk species because the population has relatively high mortality and low reproduction and they are currently well below the population growth goals identified in the Recovery Plan (NMFS 2008). Unlike other North Pacific killer whale populations, which have generally been increasing since federal protection was initiated in the 1970's, the Southern Resident population remains small and vulnerable and has not had a net increase in abundance since the mid-1980s. The comprehensive recovery program requires engagement from vital partners and long-term support over a large range from California to Alaska"--page 2, paragraph 1.

Download or read book The Power of Prey written by Stefanie Ann Hawks-Johnson and published by . This book was released on 2003 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Little Less Arctic written by Steven H. Ferguson and published by Springer Science & Business Media. This book was released on 2010-05-30 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Arctic Canada, Hudson Bay is a site of great exploration history, aboriginal culture, and a vast marine wilderness supporting large populations of marine mammals and birds. These include some of the most iconic Arctic animals like beluga, narwhal, bowhead whales, and polar bears. Due to the challenges of conducting field research in this region, some of the mysteries of where these animals move, and how they are able to survive in such seemingly inhospitable, ice-choked habitats are just now being unlocked. For example, are polar bears being replaced by killer whales? This new information could not be more salient, as the Hudson Bay Region is undergoing rapid environmental change due to global warming, as well as increased pressures from industrial development interests. A Little Less Arctic brings together some of the world’s leading Arctic scientists to present the current state of knowledge on the physical and biological characteristics of Hudson Bay.

Download or read book The Dusky Dolphin written by Bernd Würsig and published by Academic Press. This book was released on 2009-07-17 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Dusky Dolphin: Master Acrobat Off Different Shores covers various topics about the dusky dolphin, including its taxonomy, history and demography, ecology, and behavior. After introducing the dusky dolphin as a member of the genus Lagenorhynchus under the family Delphinidae, the book continues by describing its life history, its demographic patterns, and its role in the food web considering predation, parasitism, and competition. The book also includes chapters that discuss the interaction of the dusky dolphin with its habitats, such as the dusky dolphin's sound production, its foraging at night and in daylight, its survival strategies in response to predator threats, the mating habits of New Zealand duskies, calf rearing, sexual segregation, and genetic relationships. Other chapters address the interaction of dusky dolphins with humans. This book offers information about dusky dolphins off Southern Africa and discussions about the patterns of sympatry in Lagenorhynchus and Cephalorhynchus. Finally, comparisons between dusky dolphins and great apes as large-brained mammals are also reviewed in this book. - Only book fully devoted to the southern hemisphere "dusky" dolphin - Heavily illustrated with charts, figures, tables, and all color photos - Written by a cadre of experts intimately familiar with dolphin field work - Written in an accurate yet accessible style for the scientist and natural historian alike