Download or read book Predictive Modeling of Cetacean Densities in the California Current Ecosystem Based on Summer fall Ship Surveys in 1991 208 written by Elizabeth Ann Becker and published by . This book was released on 2012 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: "We use data from six ship-based cetacean and ecosystem assessment surveys in the California Current Ecosystem (CCE) to update habitat-based density models for 11 species and one small-beaked-whale guild. We previously had modeled cetacean density as a function of oceanic variables for the same 12 species/guild using data collected during four line-transect ship surveys conducted in the CCE in summer and fall of 1991, 1993, 1996, and 2001. An independent set of survey data collected in the summer and fall of 2005 was used to validate the models. These estimates were incorporated into a web-based system that allows users to estimate cetacean density within any user-defined region within the CCE study area. In this study, data from an additional line-transect survey conducted in 2008 were pooled with the 1991-2005 data and used to re-build the habitat-based density models. We also refit the 1991-2008 data to the previous 'best' models to compare model performance. The additional year of data provided increased sample sizes and a greater range of oceanic conditions for robust model development. Predicted densities for each year were smoothed and then averaged to produce a composite grid that represents our best estimate of CCE cetacean density over the past 20 years. The final model predictions were used to update the web-based system and also provided to the U.S. Navy to help assess potential impacts from their at-sea training and testing activities"--Abstract.
Download or read book Predicting Seasonal Patterns of California Cetacean Density Based on Remotely Sensed Environmental Data written by Elizabeth Ann Becker and published by . This book was released on 2007 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Changes in Cetacean Abundance in California Coastal Waters written by Jay Barlow and published by . This book was released on 1993 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Potential Overlap Between Cetaceans and Commercial Groundfish Fleets that Operate in the California Current Large Marine Ecosystem written by Blake Edward Feist and published by . This book was released on 2015 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cetacean populations are confronted by many anthropogenic threats, including commercial whaling, noise, vessel collisions, gear entanglement, exploitative competition, habitat disturbance, and global climate change. Evidence indicates that commercial fishing activities can have both direct (e.g., gear entanglement and bycatch) and indirect (e.g., prey reduction and noise) effects on cetaceans. However, few studies have addressed the potential vulnerability of a given cetacean species to an entire fishing fleet that operates over a large marine ecosystem. In this study, we overlaid spatially explicit multiyear predicted mean densities of 11 cetacean species and 1 species guild within the California Current Large Marine Ecosystem with data for commercial fishing effort of the fixed-gear, at-sea hake mid-water trawl, and bottom trawl fleets of the west coast groundfish fishery. We quantified the exposure of each species to each fleet type by multiplying the predicted mean cetacean density by the measured fishing fleet effort. We found large interspecific and interfleet variability in the overlap between cetaceans and fishing fleets. Although many of the species had relatively low overlap rates, others had substantial exposure to some of the fishing fleets, particularly those species with more nearshore distributions. Direct mortality from these fleets has been documented to be low, but our results indicate that there is opportunity for fisheries interactions with some cetacean species, particularly in the fixed-gear fleet. Our analyses make up an important first step in generating formal risk assessments for quantification of the impacts of various fishing fleets on populations of cetacean species that occur in the California Current.
Download or read book The Abundance of Cetaceans in California Waters Estimated from Ship Surveys in Summer fall 1991 written by Jay Barlow and published by . This book was released on 1993 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cetacean Population Density in the Eastern Pacific Ocean written by Megan Caton Ferguson and published by . This book was released on 2005 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cetaceans of Central and Northern California 1980 1983 written by Thomas P. Dohl and published by . This book was released on 1983 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Patterns of Variability and Environmental Models of Relative Abundance for California Cetaceans written by Karin A. Forney and published by . This book was released on 1997 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predictive Modeling of Cetacean Densities in the Eastern Pacific Ocean written by Jay Barlow and published by . This book was released on 2009 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cetacean Distributions Relative to Ocean Processes in the Northern California Current System written by and published by . This book was released on 2004 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Associations between cetacean distributions, oceanographic features, and bioacoustic backscatter were examined during two process cruises in the northern California Current System (CCS) during late spring and summer 2000. Line-transect surveys of cetaceans were conducted across the shelf and slope, out to 180 km offshore from Newport, Oregon (44.6 degrees N) to Crescent City, California (41.9 degrees N), in conjunction with multidisciplinary mesoscale and fine-scale surveys of ocean and ecosystem structure. Occurrence patterns (presence/absence) of cetaceans were compared with hydrographic and ecological variables (e.g., sea surface salinity, sea surface temperature, thermocline depth, halocline depth, chlorophyll maximum, distance to the center of the equatorward jet, distance to the shoreward edge of the upwelling front, and acoustic backscatter at 38, 120, 200 and 420 kHz) derived from a towed, undulating array and a bioacoustic system. Using a multiple logistic regression model, 60.2% and 94.4% of the variation in occurrence patterns of humpback whales Megaptera novaeangllae during late spring and summer, respectively, were explained. Sea surface temperature, depth, and distance to the alongshore upwelling front were the most important environmental variables during June, when humpbacks occurred over the slope (200-2000 m). During August, when humpbacks concentrated over a submarine bank (Heceta Bank) and off Cape Blanco, sea surface salinity was the most important variable, followed by latitude and depth. Humpbacks did not occur in the lowest salinity water of the Columbia River plume. For harbor porpoise Phocoena phocoena, the model explained 79.2% and 70.1% of the variation in their occurrence patterns during June and August, respectively.
Download or read book Preliminary Estimates of Cetacean Abundance Off California Oregon and Washington Based on a 1996 Ship Survey and Comparisons of Passing and Closing Modes written by Jay Barlow and published by . This book was released on 1997 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Visual sighting surveys on two ships in summer/fall 1996 were used to estimate the abundance of most cetaceans found within 555 km (300 nmi) of the coasts of California, Oregon, and Washington. Surveys systematically covered 14,400 km of pre-determined transect lines within this study area... The 1996 survey was conducted using two National Oceanographic and Atmospheric Administration (NOAA) research vessels... Teams of three observers searched from the flying bridge deck of both vessels using line-transect methods... Two observers searched through 25x pedestal-mounted binoculars while the third observer searched with unaided eyes and a 7x hand-held binocular..."--p.1-2.
Download or read book Potential Overlap Between Cetaceans and Commercial Groundfish Fleets that Operate in the California Current Large Marine Ecosystem written by Blake Edward Feist and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cetacean populations are confronted by many anthropogenic threats, including commercial whaling, noise, vessel collisions, gear entanglement, exploitative competition, habitat disturbance, and global climate change. Evidence indicates that commercial fishing activities can have both direct (e.g., gear entanglement and bycatch) and indirect (e.g., prey reduction and noise) effects on cetaceans. However, few studies have addressed the potential vulnerability of a given cetacean species to an entire fishing fleet that operates over a large marine ecosystem. In this study, we overlaid spatially explicit multiyear predicted mean densities of 11 cetacean species and 1 species guild within the California Current Large Marine Ecosystem with data for commercial fishing effort of the fixed-gear, at-sea hake mid-water trawl, and bottom trawl fleets of the west coast groundfish fishery. We quantified the exposure of each species to each fleet type by multiplying the predicted mean cetacean density by the measured fishing fleet effort. We found large interspecific and interfleet variability in the overlap between cetaceans and fishing fleets. Although many of the species had relatively low overlap rates, others had substantial exposure to some of the fishing fleets, particularly those species with more nearshore distributions. Direct mortality from these fleets has been documented to be low, but our results indicate that there is opportunity for fisheries interactions with some cetacean species, particularly in the fixed-gear fleet. Our analyses make up an important first step in generating formal risk assessments for quantification of the impacts of various fishing fleets on populations of cetacean species that occur in the California Current.
Download or read book Spatial Distribution and Density of Cetaceans in the Eastern Tropical Pacific Ocean Based on Summer fall Research Vessel Surveys in 1986 96 written by Megan Caton Ferguson and published by . This book was released on 2001 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spatial Distribution and Density of Cetaceans in the Eastern Tropical Pacific Ocean Based on Summer fall Research Vessel Surveys in 1986 96 written by Megan Caton Ferguson and published by . This book was released on 2003 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book GLOBEC Northeast Pacific Analyses Linkages Between Cetaceans and Oceanographic Features written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Associations between cetacean distributions, oceanographic features and bioacoustic backscatter were examined during two process cmises in the northern California Current System (CCS) during late spring and summer 2000. Line-transect surveys of cetaceans were conducted across the shelf and slope, from Newport, Oregon to Crescent City, California, in conjunction with surveys of ocean and ecosystem structure. Occurrence patterns (presencelabsence) of 4 cetacean species were compared with hydrographic and ecological variables (e.g., sea surface salinity, SST, thermocline depth, halocline depth, chlorophyll maximum, distance to the center of the equatorward jet, distance to the upwelling front, and acoustic backscatter at 38, 120, 200 and 420 kHz). Using a multiple logistic regression model, 60.2% and 94.4% of the variation in occurrence pallems of humpback whales during spring and summer, respectively, were explained. For harbor porpoise, the model explained 79.2% and 70.1% of the variation in their occurrence pattems during June and Auqust, respectively. The responses of cetaceans to upwellinq processes were seasonally and spatially specific.
Download or read book California s Living Marine Resources written by William S. Leet and published by University Of California, Division of Agriculture and Natural Resources; Califorinia Sea Grant. This book was released on 2001 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 592-page spiral-bound reference provides a baseline of information for all those involved with managing living marine resources in California and chronicles changes that have occurred in many of the state’s fisheries. Organized by marine ecosystems: bays and estuaries, nearshore and offshore. Includes illustrated species descriptions with details of biological knowledge, fishery history, landings data, population status and references. Also includes sections on marine birds and mammals and appendices containing management considerations (by species), a glossary of technical terms and acronyms and fishing gear illustrations. Jointly produced by the California Sea Grant Extension Program and the California Department of Fish and Game following the passage of the Marine Life Protection Act in January 1999.
Download or read book Hearing by Whales and Dolphins written by Whitlow W.L. Au and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 499 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, experts in different areas of the field provide an overview of the bioacoustics of whales and dolphins as well as a thorough introduction to the subject for investigators of hearing in other animals. Topics covered include the structure and function of cetacean auditory systems, the unique sound production system of odontocetes, acoustic communication, psychoacoustics, echolocation and models of sound propagation.
