Download or read book The Foraging Ecology of Gray Whales in Clayoquot Sound Interactions Between Predator and Prey Across a Continuum of Scales written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the ecology of an organism is fundamental for defining conservation and management priorities for wildlife and natural ecosystems. The most basic ecological framework identifies the key components of an organism's habitat, and the scale for measuring the quality of those features. How these core needs are expressed and vary in the surrounding ecosystem changes over time and space. In marine systems, the physical environment has few strict boundaries, and variations regularly occur on a scale from days to decades. The dynamic and patchy nature of marine habitat makes defining the ecological roles of an animal difficult, even where baseline data exists. In this study I analyze long term field records on the ecological interactions between foraging gray whales (Eschrichtius robustus), and their mysid prey (Family mysidae) in Clayoquot Sound, B.C. By looking at spatial and temporal shifts at both trophic levels, I measure foraging responses and requirements, and assess prey resource availability and resiliency in the marine environment at a series of scales. Appreciation for bottom-up and topdown trophic interactions provides the foundation for identifying natural variability in marine habitat, and a baseline for conservation measures that seek to use marine predators as a barometer of broader ecosystem health.
Download or read book Canadian Journal of Zoology written by and published by . This book was released on 2013-07 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gray Whales Eschrichtius Robustus and Mysids family Mysidae written by Stephanie Secord Olsen and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, I present a new approach to prey quantification in the context of the predator-prey relationship between an apex marine predator, the gray whale, (Eschrichtius robustus) and one of its primary prey, mysids (Family Mysidae) in a tertiary foraging area, in Clayoquot Sound, on the west coast of Vancouver, Island, British Columbia. With the use of a remote acoustical sounder, I first quantify mysid patches in the presence of foraging gray whales. Second, I address the biomass in those patches using a new approach to quantification. By creating an estimate of total biomass of mysids in the study area concurrently with the presence of gray whales, I demonstrate the effect that the foraging whales have on their prey. Tracking the changes of the number of whales and the number of patches, including the overall biomass of the patches provides evidence for this relationship. As the number of gray whales in the study area increases steadily from May to July, 2004, the number of mysid patches and biomass decrease during the same period. The number of foraging whales located in the study area ranged from only five in May to thirty-one on July 18th, in a region covering only 25 km of the southwest coast of Flores Island. After this period of foraging, the whales deserted the study area completely, and only one whale was seen during the month of August. The mysid population regroups slightly after the pressure of foraging whales is released, the number of patches and biomass increase a small amount, exhibiting the expected behavioral response of the prey to re-aggregate into tight swarms. The acoustic method for prey quantification is described in detail as this is a first application of this technology to the mysid-gray whale relationship. In this approach, l demonstrate that the Distorted Wave Borne Approximation model (DWBA) is useful to estimate mysid populations. This study provides a key piece in the progression of eight years of ongoing research on the foraging ecology of gray whales in Clayoquot Sound, British Columbia.
Download or read book Gray Whales Eschrichtius Robustus and Mysids family Mysidae written by Stephanie Secord Olsen and published by . This book was released on 2006 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, I present a new approach to prey quantification in the context of the predator-prey relationship between an apex marine predator, the gray whale, (Eschrichtius robustus) and one of its primary prey, mysids (Family Mysidae) in a tertiary foraging area, in Clayoquot Sound, on the west coast of Vancouver, Island, British Columbia. With the use of a remote acoustical sounder, I first quantify mysid patches in the presence of foraging gray whales. Second, I address the biomass in those patches using a new approach to quantification. By creating an estimate of total biomass of mysids in the study area concurrently with the presence of gray whales, I demonstrate the effect that the foraging whales have on their prey. Tracking the changes of the number of whales and the number of patches, including the overall biomass of the patches provides evidence for this relationship. As the number of gray whales in the study area increases steadily from May to July, 2004, the number of mysid patches and biomass decrease during the same period. The number of foraging whales located in the study area ranged from only five in May to thirty-one on July 18th, in a region covering only 25 km of the southwest coast of Flores Island. After this period of foraging, the whales deserted the study area completely, and only one whale was seen during the month of August. The mysid population regroups slightly after the pressure of foraging whales is released, the number of patches and biomass increase a small amount, exhibiting the expected behavioral response of the prey to re-aggregate into tight swarms. The acoustic method for prey quantification is described in detail as this is a first application of this technology to the mysid-gray whale relationship. In this approach, l demonstrate that the Distorted Wave Borne Approximation model (DWBA) is useful to estimate mysid populations. This study provides a key piece in the progression of eight years of ongoing research on the foraging ecology of gray whales in Clayoquot Sound, British Columbia.
Download or read book Gray Whales Eschrichtius Robustus and Mysids family Mysidae the Predator prey Relationship and a New Approach to Prey Quantification in Clayoquot Sound British Columbia written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, I present a new approach to prey quantification in the context of the predator-prey relationship between an apex marine predator, the gray whale, (Eschrichtius robustus) and one of its primary prey, mysids (Family Mysidae) in a tertiary foraging area, in Clayoquot Sound, on the west coast of Vancouver, Island, British Columbia. With the use of a remote acoustical sounder, I first quantify mysid patches in the presence of foraging gray whales. Second, I address the biomass in those patches using a new approach to quantification. By creating an estimate of total biomass of mysids in the study area concurrently with the presence of gray whales, I demonstrate the effect that the foraging whales have on their prey. Tracking the changes of the number of whales and the number of patches, including the overall biomass of the patches provides evidence for this relationship. As the number of gray whales in the study area increases steadily from May to July, 2004, the number of mysid patches and biomass decrease during the same period. The number of foraging whales located in the study area ranged from only five in May to thirty-one on July 18th, in a region covering only 25 km of the southwest coast of Flores Island. After this period of foraging, the whales deserted the study area completely, and only one whale was seen during the month of August. The mysid population regroups slightly after the pressure of foraging whales is released, the number of patches and biomass increase a small amount, exhibiting the expected behavioral response of the prey to re-aggregate into tight swarms. The acoustic method for prey quantification is described in detail as this is a first application of this technology to the mysid-gray whale relationship. In this approach, l demonstrate that the Distorted Wave Borne Approximation model (DWBA) is useful to estimate mysid populations. This study provides a key piece in the progression of eight years of ongoing research on the foragi.
Download or read book Characterizing Site Fidelity and Habitat Use of the Eastern North Pacific Gray Whale Eschrichtius Robustus in Clayoquot Sound British Columbia written by Jacqueline Ann Clare and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A small number of eastern north Pacific gray whales (Eschrichtius robustus), known as the Pacific Coastal Feeding Group (PCFG) forage during the summer months in the coastal waters between California and Alaska. Although several studies have analyzed the population structure of the PCFG, maternal learning and predator/prey dynamics have not been studied in detail. In this study I characterize fine scale habitat use and site fidelity of eastern north Pacific gray whales in one foraging site within the PCFG's foraging range. I approach this study by examining site fidelity to Clayoquot Sound in increasing detail at different time scales. Using the variability recorded in 17 field seasons of whale census surveys (1997-2013) as a proxy for fluctuations in prey, I suggest that the combination of physical properties of the study area and the life history characteristics of the primary prey species type enable Clayoquot Sound to persist as a foraging site through time.
Download or read book The Importance of the Mid trophic Layers in Ecosystem Structure Process and Function written by Rianna Elizabeth Burnham and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While the impact of top-down and bottom-up drivers of ecosystem functions has been given considerable argument, here the mid-trophic level is given focus. In marine systems the influence of mid-trophic level species operates in a 'wasp-waisted' structure, where they exert regulatory control by acting as a valve to energy flow between large seasonal pulses of primary production and upper level species. In this study I examine the impact of foraging eastern Pacific gray whales (Eschrichtius robustus) on mysid species at the 'wasp-waist' (Order Mysidacea), and vice versa, at feeding sites in Clayoquot Sound off the west coast of Vancouver Island. I appraise previously unknown aspects of the?prey-scape', and further explore life-history traits that allow prey populations to persist in a given species array. The set of problems that I examine are all based on the whales' top-down forcing in a localized area, and the prey response. I use several scales of observation as dictated by the nature of each question. I examine top down forcing and subsequent prey switching over a 25-year period, the variation in foraging intensity over a 15 year period, the differential prey species' response to persistent predatory pulses that creates dominance and diversity among the mysid species flock, and whales' within-season response to possible satiation. Each of these studies is linked by the common goal of illuminating the intimate relationship between predator and prey. Gray whale foraging has decimated amphipod prey resources in the study area past the point of recovery over the last 25 years, and the prey resource is no longer a viable energy source. This has led to the abandonment of benthic-feeding by gray whales in the area, and a switch to mysids as a primary prey source. It is in investigating these mysid species' ability to rebound following severe foraging pressure that I uncovered two principal life history strategies, one held by the single dominant mysid species, and another used by 9 or 10 others consistently sampled. The capacity for renewal of mysid swarms is imperative if Clayoquot Sound is to persist as a productive foraging area for gray whales. The pattern of this relationship that I present, based on a 15 year span, was previously unknown. Intense foraging of mysids by gray whales during a summer affects the reserves for the following season, leading to a biennial fluctuation in the number of whales the area can sustain, although some of the heaviest foraging seasons require several years to show mysid recovery. I state 9 or 10 other species, as through the intense examination of mysids here, there may be a new species designated. The data gathered by myself and colleagues over the past 25 years that whales have been studied in Clayoquot Sound, clearly shows that predation by baleen whales can affect the future quality of their foraging areas, as well as influencing the population, life-stage and diversity of prey species. My work furthers knowledge in life history characteristics of the mysid species present in the study area, particularly growth and reproduction, and ability to capitalize on a release of predation pressure over winter to recover. That, in turn creates a series of following questions about how different life history strategies make use of a variety of possible energy pathways to stabilize ecosystems at least at discrete spatial scales.
Download or read book The Dynamic Relationship Between Foraging Gray Whales Eschrichtius Robustus and Their Mysid Prey Mysidae Along the Southwest Coast of Vancouver Island British Columbia written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gray whales (Eschrichtius robustus Lilljeborg) forage predominantly on hyper-benthic mysids (Mysidae) along the southwest coast of Vancouver Island, British Columbia. The role of mysids in the abundance and distribution of foraging gray whales prompted interest in this study. I relate the inter- and intra-annual foraging behaviour of gray whales to the number of mysid patches and biomass through boat based surveys of foraging whales, and the application of acoustic techniques for estimating mysid prey. I examine the spatial pattern of foraging gray whales and the 10 m isobath. The abundance and distribution of mysid patches are more common at a water depth of 10 m, and the likely mechanism driving the spatial pattern between foraging gray whales and the 10 m isobath. I examine whale abundance and distribution patterns during three consecutive foraging seasons. More whales forage in years when mysid prey are more abundant, and mysid patches are of larger size and higher in biomass. Whales have a considerable top-down effect on mysid populations. Years of heavy whale predation depletes mysid stocks. Mysid populations tend to increase in years of low whale activity. I examine whale abundance and distribution patterns of habitat use during a foraging season along the southwest coast of Flores Island and Nootka Sound. The abundance of mysid patches and biomass in Nootka Sound does not influence the whales' use of Flores Island; rather the whales exploited both areas concurrently. This study expands the understanding of gray whale habitat use along the southwest coast of Vancouver Island, British Columbia.
Download or read book The Dynamic Relationship Between Foraging Gray Whales Eschrichtius Robustus and Their Mysid Prey Mysidae Along the Southwest Coast of Vancouver Island British Columbia written by Christopher J. Pasztor and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecological Interrelationships Between Summer Resident Gray Whales Eschrichtius Robustus and Their Prey Mysid Shrimp Holmesimysis Sculpta and Neomysis Rayi Along the Central Oregon Coast written by Carrie Newell and published by . This book was released on 2010 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ecological interaction between the largest coastal predator, the gray whale (Eschrichtius robustus) and the most abundant shallow water marcrozooplanktonic prey, mysids, were examined in a poorly-understood predator-prey relationship along the central Oregon coast. From 2002-2008, 83 seasonal gray whales were identified. These whales returned each year around Memorial Day and stayed until mid October preying on mysid swarms as determined from fecal material and feeding behaviors. The two mysid species preyed upon were Holmesimysis sculpta and Neomysis rayi. This resea rch provided information on the spatial/temporal pattern of mysid distribution, patch composition, density and reproductive dynamics of the mysids and how they affect gray whale distribution, abundance, residency and body condition. A determination was also made how climate affected predator-prey interactions during a warm water climate regime in 2005. In 2005, gray whales spent little time in foraging and fewer days in residence than in other years and many were in poor body condition. Mysid swarms were also sparse until August and a large percentage of females had empty brood pouches.
Download or read book Variations in Gray Whale Feeding Behavior in the Presence of Whale watching Vessels in Clayoquot Sound 1993 1995 written by Joanna Bass and published by . This book was released on 2000 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Co location of Blue Whales and Their Euphausiid Prey Across Multiple Spatial Scales written by Catherine Frances Nickels and published by . This book was released on 2017 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Blue whales (Balaenoptera musculus Linnaeus) eat almost exclusively euphausiids and must find dense aggregations above the local mean to satisfy their energetic needs. The paradox implied by the predator-prey relationship between these large baleen whales and euphausiids is how the whales can acquire sufficient food from such small, patchily distributed prey. This problem can be conceptualized as interactions on multiple spatial scales. Through analysis of the euphausiid mandible remains in whale fecal samples, I determined that the prey of blue whales from the northeast Pacific population is consistently and overwhelmingly dominated by Thysanoessa spinifera Holmes, a large neritic euphausiid. Based on the blue whales' extremely limited diet, I hypothesized that blue whales and T. spinifera would be consistently co-located across a range of spatial scales. I investigated the spatial relationship between the predator and prey at multiple spatial scales: the North Pacific Ocean, the California Current System, a regional scale where there is long-term sampling by the CalCOFI program, and a local scale near blue whale aggregation centers. The distributions of blue whales and T. spinifera were only related at the two largest scales investigated. An apparent northward blue whale range expansion beginning around 1997 did not appear to be related to reductions in T. spinifera prey in more southern waters. As sampled, the regional and local scales did not capture the scale of interaction between these predators and prey, suggesting that a smaller scale of sampling was necessary closer to the ambit of a foraging whale. Focusing on a single bathymetric feature (Nine Mile Bank near San Diego, California) I tested the hypothesis that both prey euphausiids and baleen whales aggregate at such abrupt changes in topography. Instead of serving as a point of increased relative abundance, the bank actually represented an offshore limit for blue, fin, and humpback whales feeding on T. spinifera. T. spinifera adults were found deeper in the water than less energetically valuable smaller individuals. The results of this dissertation suggest that blue whales are highly selective predators that can locate and feed on vertical aggregations of T. spinifera located near steep topography.
Download or read book Gray Whale Prey and Whale Distributions in Clayoquot Sound British Columbia Canada 1996 1997 written by J. S. Dunham 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 An Exploratory Investigation of Gray Whale Eschrichtius Robustus Spatial Foraging Strategy and the Effect of Vessel Traffic written by Steven Garner and published by . This book was released on 1994 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Micro scale Spatial Behavior of a Foraging Grey Whale Eschrichtius Robustus in Clayoquot Sound British Columbia Canada written by Christopher Duncan Malcolm and published by . This book was released on 1997 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Small scale Distributions and Dynamics of the Mysid Prey of Gray Whales Eschrictius Robustus in Clayoquot Sound British Columbia Canada written by Heather Michelle Patterson and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Feeding Behavior of Gray Whales in Relation to Patch Dynamics of Their Benthic Prey written by Jo A. Guerrero and published by . This book was released on 1989 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
