Download or read book Instantaneous Continental shelf Scale Sensing of Cod with Ocean Acoustic Waveguide Remote Sensing OAWRS written by Ankita Deepak Jain and published by . This book was released on 2015 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reported declines in the population of Atlantic cod have a potential to affect long-term ecological balance and the sustainability of the cod fishery along the US northeast coast. These assessments have led to severe fishing cuts over the past few years, have consequently threatened the centuries-old Atlantic cod fishery along the New England coast and put the livelihood of thousands of fishermen at risk. Amidst this fisheries crisis, calls by elected officials, environmental groups and fishing consortiums were made for an Ocean Acoustic Waveguide Remote Sensing (OAWRS) survey of the Gulf of Maine cod stock. Typically, cod stock assessments incorporate data collected from conventional acoustic and trawl line transect surveys that highly undersample the marine environment in space and time and lead to ambiguities in population estimates. The combination of conventional methods and OAWRS techniques, however, has been demonstrated to provide rapid and accurate fish stock assessments over ecosystem-scale areas for other species. In this thesis, the feasibility of accurately surveying cod stocks with OAWRS is theoretically assessed. These theoretical predictions are then experimentally verified by successfully sensing cod with OAWRS over ecosystem scales in the Nordic Seas. Following direct requests by Massachusetts state officials to determine if OAWRS could be used to detect and survey the reported waning cod populations in coastal New England waters, we obtained measurements of typical aggregation densities and occupancy depths of spawning cod in Ipswich Bay from conventional echosounder surveys conducted in Spring 2011. Cod length distributions were also measured from which we estimated the swimbladder resonance frequencies of local cod via a harmonic oscillator model that includes the effects of damping, the cod's swim bladder air volume at a given neutral buoyancy depth as well as changes to this volume for deviations from neutral buoyancy depth. The optimal frequency for OAWRS detection typically corresponds to that where the resonance peak is found. We showed that our theoretical estimates of cod swimbladder resonance matched very well with independent measurements of caged cod resonance from decades old Norwegian data. Using parabolic equation modeling of ocean waveguide propagation, the scattered level of typical spawning cod aggregations was estimated and compared with that from seafloor scattering, which is a typical limiting factor in long range active sensing. Seafloor scattering was estimated via a Rayleigh-Born approach we developed, where the magnitude squared of seafloor scattering amplitude was empirically determined from thousands of measurements made during major OAWRS experiments along the US Northeast coast. It was found that near cod swimbladder resonance (roughly 150-600 Hz), determined from the New England length and depth distribution data, OAWRS was capable of robustly detecting spawning cod aggregations from many tens of kilometers in range with high signal-to- noise ratios (SNRs) greater than 20 dB for typical spawning cod configurations in New England waters. Above the resonance frequency peak, it is possible to detect cod for typical shoaling densities because cod scattering reaches a plateau due to geometric scattering that is above the seafloor scattering trend for typical OAWRS frequencies. Well below the resonance peak, scattering from cod is expected to fall off rapidly and faster than seafloor scattering, and so provides important information about resonance behavior but can be difficult to probe given the very low frequencies involved. This theoretical feasibility study emphasized the need for a low frequency source that spans cod swimbladder resonance and helped demonstrate the potential for use of OAWRS for cod assessments over ecosystem scales. To confirm our theoretical predictions on the OAWRS detection of cod and other keystone fish species, we designed, prepared and conducted a major oceanographic experiment in the Nordic Seas in the Arctic in the winter (February-March) of 2014 using three major research vessels, the US RV Knorr, the Norwegian RV Johan Hjort and the Norwegian FV Artus. The Nordic Seas 2014 experiment was conducted in difficult gale and hurricane force weather conditions along most of Norway's western and northern coast. MIT's OAWRS Source, obtained through a NSF-Sloan MRI grant, spanned the 800-1600 Hz range, and the receiver was ONR's Five Octave Receiver Array (FORA). Unlike the declining trend of cod population in New England waters, cod population in the Nordic Seas has been thriving for many years and is currently at its healthiest recorded state. The experiment period was chosen such that it coincided with the peak spawning period of cod along the coastal Lofoten region in Norway where they congregate in high densities, as well as other keystone species that migrate from the ice-edge to spawn in some of the world's largest mass migrations. In planning, we determined likely spawning grounds for cod, and other keystone species such as capelin, herring, and haddock using historic survey data collected along the Norwegian coast. With our calibrated model of fish swimbladder resonance and historic length distribution data from Norway, swimbladder resonance frequencies and target strengths of these fish species were estimated. We also determined optimal OAWRS ship tracks for remote detection of these species above seafloor scattering using waveguide propagation modeling. While the OAWRS frequencies were greater than those expected for cod swimbladder resonance, cod shoals over ten kilometers in length were robustly detected and successfully imaged from tens of kilometer ranges during the experiment. This produced the first instantaneous images of a vast cod shoal. It also confirmed our predictions that OAWRS can be used to remotely sense and survey cod populations. Our theoretical predictions suggest that the use of lower OAWRS frequencies near cod swimbladder resonance would lead to greater dynamic range in population density estimates. The Nordic Seas experiment provided the first look revealing the entire horizontal morphology of vast cod, capelin, haddock and Norwegian herring shoals. This was done with instantaneous OAWRS imaging. The presence of multiple shoaling fish species during the Nordic Seas experiment provided us with a unique opportunity to study general shoaling behavior across species over ecosystem scales with OAWRS. For example, many pelagic and demersal fish species are known to undergo distant migrations for feeding, spawning and overwintering year after year. This suggests that migrating populations have an ability to efficiently sense their environment. By combining OAWRS estimates of fish scattering strength and population density obtained from simultaneous depth echo-sounding along line transects, areal population densities over entire shoals were determined. This enabled estimation of total shoal population, shoal aspect ratio, and shoal migration speed via cross correlation of population density over time. It was shown that across several species, as shoal population increased (tens of thousands to hundreds of millions of individuals), shoal aspect ratio also increased (roughly from one to ten). Single-celled organisms with higher aspect ratios have been shown to more efficiently and accurately detect chemical gradients at microscopic scales. The high-aspect ratio or elongated morphology of a large migrating fish shoal is consistent with the entire shoal serving the function of a biological antenna for efficient spatial and temporal sensing of mesoscale processes in the environment. We also studied the evolution of air resonance power efficiency in the violin and its ancestors. We collected historical data, including samples from roughly 500 classical Cremonese violins from the renowned workshops of Amati, Stradivari and Guarneri, to establish historic time series of key design traits. We determined the primary physical mechanisms governing radiated air resonance power in the violin and its ancestors and used this knowledge to explain the evolutionary trends we discovered.

Download or read book Investigating Group Behavioral Quantization of Oceanic Fish with Continental shelf Scale Ocean acoustic Sensing written by Dong Hoon Yu and published by . This book was released on 2018 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent fish population decline due to increased human presence has led to calls for predictive methods to help reverse or stabilize the situation. It has been difficult, however, to establish such methods primarily due to the technical obstacles in observing fish populations in natural habitats. Here we use acoustics to observe the ocean environment and study fish behavior during the critical spawning period over continental-shelf scales. Fish are known to be one of the main sources of strong natural returns in the continental-shelf environment, and so identified as a major source of clutter for wide-area undersea surveillance. The first continental-shelf scale acoustic measurements of Atlantic cod over thousands of square kilometers using towed source and receiver arrays were made by an international, multi-disciplinary team led by MIT researchers including myself in the historic Lofoten cod spawning ground in Norway during the peak spawning period in Winter 2014, where extensive but spatially discrete groups of spawning cod were successfully imaged. These initial instantaneous wide-area observations of cod aggregations suggest that these observed spawning groups have quantifiable properties that are linked to essential collective behavioral functions. We find that the mean group population per annual spawning season of Northeast Arctic cod over the entire spawning ground in Lofoten Norway is remarkably invariant across the available 30 years of line-transect survey data. The marked stability of the annual mean spawning group size in contrast to the large variations in total spawning population across years supports the interpretation of the expected spawning group size over the 30-year data set as the group behavioral quantum empirically expected for reliable spawning. Time series of the total Atlantic cod spawning population for major spawning regions across the North Atlantic show that once the total spawning population declined below a quantum, recovery to preindustrial levels did not occur in that region even after decades, which is an apparent consequence of large difference between the pre-industrial level and one quantum level. Quantized group behavior during spawning is also investigated for the Atlantic herring species. We find that the daily herring spawning group population is stable over the peak annual spawning period from wide-area acoustic measurements of spawning herring in the Gulf of Maine in Fall 2006. This supports the quantum concept that the mean spawning group population has evolved to a stable optimal size to fulfill the essential behavioral function of reliable spawning for Atlantic herring. As with cod, time series of the Atlantic herring spawning population for major spawning grounds across the North Atlantic show that when total spawning population declined below the empirically determined quantum level, return to pre-industrial levels required decades. Our findings show that to be sustained at pre-industrial levels the total spawning population must greatly exceed the mean spawning group size found at pre-industrial levels for any oceanic fish population we investigated, and likely many others. The migration of extensive social groups towards specific spawning grounds in vast and diverse ocean environments is an integral part of the regular spawning process of many oceanic fish species. Oceanic fish in such migrations typically seek locations with environmental parameters that maximize the probability of successful spawning and egg/larval survival. The 3D spatio-temporal dynamics of these behavioral processes are largely unknown due to technical difficulties in sensing the ocean environment over wide areas. Here we use ocean acoustic waveguide remote sensing (OAWRS) to instantaneously image immense herring groups over continental-shelf-scale areas at the Georges Bank spawning ground. Via multi-spectral OAWRS measurements, we capture a shift in swimbladder resonance peak correlated with the herring groups' up-slope spawning migration, enabling 3D spatial behavioral dynamics to be instantaneously inferred over thousands of square kilometers. We show that herring groups maintain near-bottom vertical distributions with negative buoyancy throughout the migration. We find a spatial correlation greater than 0.9 between the average herring group depth and corresponding seafloor depth for migratory paths along the bathymetric gradient. This is consistent with herring groups maintaining near-seafloor paths to both search for optimal spawning conditions and reduce the risk of predator attacks during the migration to shallower waters where near-surface predators are more dangerous. This analysis shows that multi-spectral resonance sensing with OAWRS can be used as an effective tool to instantaneously image and continuously monitor the behavioral dynamics of swimbladder-bearing fish group behavior in 3 spatial dimensions over continental-shelf scales. Recent research has found a high spatial and temporal correlation between certain baleen whale vocalizations and peak annual spawning processes of Atlantic herring in the Gulf of Maine. These vocalizations are apparently related to feeding activities of baleen whales with suggested functions that include communication, prey manipulation, and echolocation. Here the feasibility of the echolocation function is investigated. Physical limitations on the ability to detect large herring shoals and the seafloor by acoustic remote sensing are determined with ocean acoustic propagation, scattering, and statistical theories given baleen whale auditory parameters. Detection is found to be highly dependent on ambient noise conditions, herring shoal distributions, baleen whale time-frequency vocalization spectra, and geophysical parameters of the ocean waveguide. Detections of large herring shoals are found to be physically feasible in common Gulf of Maine herring spawning scenarios at up to 10 ± 6 km in range for humpback parameters and 1 ± 1 km for minke parameters but not for blue and fin parameters even at zero horizontal range. Detections of the seafloor are found to be feasible up to 2 ± 1 km for blue and humpback parameters and roughly 1 km for fin and minke parameters, suggesting that the whales share a common acoustic sensation of rudimentary features of the geophysical environment. No effect of anthropogenic sound on marine mammal vocalization behavior was found during our measurements. Some published statistical tests assessing the impact of anthropogenic sound on marine mammal behavior were found to have 98-100% false positive biases with no true positive confirmation, and so lack statistical significance.

Download or read book Continuous Monitoring of Fish Population and Behavior by Instantaneous Continental Shelf Scale Imaging with Ocean Waveguide Acoustics written by and published by . This book was released on 2007 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long-term goals of this program are to (1) instantaneously detect, image and spatially chart fish populations over continental-shelf scales, and (2) continuously monitor the areal densities and behavior of these fish populations over time using a novel audible frequency acoustic system (300- 5000Hz) referred to as Ocean Acoustic Waveguide Remote Sensing (OAWRS). This new method is being applied to explore the abundance, temporal and spatial distributions and behavior of fish populations in the Gulf of Maine on and near Georges Bank, a marine ecosystem being studied in the Census of Marine Life program. OAWRS is a valuable conservation tool for rapid imaging and enumeration of large scale fish populations over thousands of square kilometers to effectively monitor and manage the national fish stock.

Download or read book Automatic Detection and Tracking of Fish Shoals Over Large Areas Using Ocean Acoustic Waveguide Remote Sensing OAWRS written by Felix Piavsky and published by . This book was released on 2021 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurately tracking multiple fish shoals can help understand fish migration patterns, better estimate fish populations, and lead to better decisions regarding fishery routines and preservation of the related marine ecosystems. Previously, fish shoals and their characteristics were identified manually for each shoal. Here we present techniques to automatically detect, track, and predict small fish shoal characteristics using Ocean Acoustic Waveguide Remote Sensing (OAWRS) over large areas and extended time periods. OAWRS system allows us to instantaneously map, image, and monitor fish populations over continental shelf-scale areas of thousands of square kilometers. Conventional fishery sonars operate at much higher frequencies and so have detection ranges limited the immediate vicinity of research vessels. The methods presented here can provide near real-time analysis during experiments or later analysis. In this work, we continuously tracked the migration of multiple fish schools during the 2014 Norwegian Sea experiment and 2003 Atlantic US coast experiment. Each shoal goes through image processing, tracking, feature extraction, and track management analysis. We take into account special cases such as splitting or merging of shoals. The results of this work can provide reliable tracking of small fish shoals, marine mammals, and underwater vehicles.

Download or read book Acoustic Clutter and Ocean Acoustic Waveguide Remote Sensing OAWRS in Continental Shelf Environments written by and published by . This book was released on 2009 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic clutter is the primary problem encountered by active sonar systems operating in Continental Shelf environments. Clutter is defined as any return from the environment that stands prominently above the diffuse and temporally decaying reverberation background and so can be confused with or camouflage returns from an intended target such as an underwater vehicle. Many environmental factors may contribute to acoustic clutter and adversely affect the performance of tactical Navy sonar by introducing false alarms in the system. In order to develop adaptive algorithms or technology to mitigate acoustic clutter, it is critical to identify, understand, and be able to accurately model the leading order physical mechanisms which cause clutter in existing sonar systems. The long-term goal of this program is to determine and understand the physical mechanisms that cause acoustic clutter in continental shelf environments and to use this knowledge to develop predictive tools to enhance the detection, localization and classification of underwater targets.

Download or read book Remote Sensing of Submerged Objects and Geomorphology in Continental Shelf Waters with Acoustic Waveguide Scattering written by Purnima Ratilal and published by . This book was released on 2002 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) A generalized extinction theorem for object scattering in a stratified medium is derived that can be applied to detect and classify objects from the total field in the forward scatter direction in a waveguide. Analytic expressions are derived for the attenuation and dispersion in the forward propagated field due to scattering from random surface and volume inhomogeneities in a waveguide. The unified model is applied to show that the active sonar equation is not in general valid for scattering in a waveguide. It is shown that the sonar equation may be made approximately valid in a waveguide by lowering the active frequency of operation sufficiently for the given measurement scenario to simplify analysis for target classification and localization.

Download or read book Oceanic Internal Waves from Ship Aircraft and Spacecraft written by Atlantic Oceanographic and Meteorological Laboratory. Ocean Remote Sensing Laboratory and published by . This book was released on 1978 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceanic Internal Waves from Ship Aircraft and Spacecraft written by Atlantic Oceanographic and Meteorological Laboratories. Ocean Remote Sensing Laboratory and published by . This book was released on 1978 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Ocean Remote Sensing Laboratory (ORSL) has been studying internal waves using remote sensing techniques employing three different types of observational platforms: ships, aircraft, and spacecraft. Internal waves and their manifestations have been observed using the following techniques: Satellite multispectral scanning imagers (principally in the visible and near-infrared); Radar--both coherent imaging radar and standard meteorological radar (all from aircraft); Hand-held visible photography (from spacecraft, aircraft, and ship; Ship-towed thermistors; and STD and XBT casts.

Download or read book Remote Sensing of Shelf Sea Hydrodynamics written by J.C.J. Nihoul and published by Elsevier. This book was released on 2000-04-01 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: Remote Sensing of Shelf Sea Hydrodynamics

Download or read book Tracking and Speed Evaluation of Cod Schools in the 2014 Nordic Seas Experiments written by Mordechai Ben Mordechai (S.M.) and published by . This book was released on 2018 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Observing and tracking fish shoals over long periods enables us to understand and establish the behavior processes of fish shoals in their ecosystem and different phases of migration, spawning and feeding. In the past, researchers have observed fish shoals for days and even weeks for that purpose. However, previous studies were limited by conventional methods such as echosounders and acoustic tagging of fish, which are only able to track one or a few schools at a time with low spatial sampling. In 2014, the Ocean Acoustic Waveguide Remote Sensing system (OAWRS) was employed in the Nordic Seas for the study of fish shoal behavior in that region. The OAWRS system enables the study of multiple shoals simultaneously over long periods. The experiment took place in three main spawning areas on the shores of Norway, and lasted from Feb 18 to Mar 8 for the study of three commercially important species: cod, herring, and capelin. In this paper, we use the data gathered by the OAWRS system in the Nordic Seas experiment to track fish schools in the Lofoten area by comparing two methods of calculating their track: 1) calculating and tracking the centroid of the school, and 2) calculating the shift of the school between pings to establish its new position. We calculate the speed of schools along theirs tracks and compare it with known cod speeds. We find that the general heading of all the schools investigated here is towards offshore. We suggest that the speed calculated for these small scale schools might aid in identifying a school's species, when lacking other means.

Download or read book Spectral Discrimination of Fish Shoals from Seafloor in the Gulf of Maine During the Ocean Acoustic Waveguide Remote Sensing OAWRS 2006 Experiment written by Eleftherios Kaklamanis and published by . This book was released on 2021 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we perform a spectral discrimination of fish shoals from background returns using statistical techniques. Classification of fish species requires an efficient and solid approach to distinguish fish scattering from seafloor returns. Neyman-Pearson Hypothesis Testing, Kullback-Leibler divergence, Matched Filter and discriminating based on the shape of the spectral dependence, methods originated from Detection theory, are applied in well documented cases from Gulf of Maine during spawning season to distinguish seafloor returns from fish scattering across frequency domain. The discrimination of fish shoals from seafloor returns is achieved by analyzing the absolute levels of scattered returns and the pattern of their frequency response. A generalization of the statistical techniques is developed that enables all frequencies to be tested at once, allowing the spectral discrimination and echolocation of fish shoals from regions dominated by background returns. Conclusions derived from statistical techniques are consistent with physical evidences, such as in situ echosounder measurements and frequency responses. Fish shoals are distinguished from background regions by evaluating the likelihood ratio test, matched filter and analyzing the slope of the frequency dependence of all pixels in an examined ocean acoustic waveguide remote sensing (OAWRS) image.

Download or read book Principles and Applications of Underwater Sound written by United States. Office of Scientific Research and Development. National Defense Research Committee and published by . This book was released on 1969 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reef Fish Spawning Aggregations Biology Research and Management written by Yvonne Sadovy de Mitcheson and published by Springer Science & Business Media. This book was released on 2011-12-10 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reef fish spawning aggregations, ranging from small groups to many tens of thousands of individuals, are spectacular but poorly known natural phenomena whereby fish assemble at specific times and locations to spawn. For some species these large groups may be the only form of reproduction, the high fish numbers briefly giving a false impression of stability and abundance—an ‘illusion of plenty’. They are often a focus for intensive seasonal fishing because of their predictability and because many important commercial fishes form them. Highly vulnerable to overexploitation, many aggregations and their associated fisheries, have disappeared or are in decline. Few are effectively managed or incorporated into protected areas. Aggregations are not well understood by fishery scientists, managers and conservationists and their significance little appreciated by fishers or the wider public. To ensure their persistence to replenish important fisheries in coral ecosystems, maintain their ecosystem function and continue to delight divers, a significant change in perspective is needed to foster protection and management. This book provides comprehensive and practical coverage of the biology, study and management of reef fish aggregations, exploring their how, when, where, and why. It explores ways to better protect, study, manage and conserve them, while identifying key data gaps and questions. The text is extensively illustrated with many unique, never before published, photographs and graphics. Case studies on over 20 interesting and important fishes are included, outlining their biology and fisheries and highlighting major concerns and challenges.

Download or read book The Behaviour of Teleost Fishes written by Tony J. Pitcher and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is about the behaviour of teleosts, a well-defined, highly successful, taxonomic group of vertebrate animals sharing a common body plan and forming the vast majority of living bony fishes. There are weH over 22000 living species of teleosts, including nearly all those of importance in com mercial fisheries and aquaculture. Teleosts are represented injust about every conceivable aquatic environment from temporary desert pools to the deep ocean, from soda lakes to sub-zero Antarctic waters. Behaviour is the primary interface between these effective survival machines and their environment: behavioural plasticity is one of the keys to their success. The study of animal behaviour has undergone revolutionary changes in the past decade under the dual impact of behavioural ecology and sociobiology. The modern body of theory provides quantitatively testable and experi mentaHy accessible hypotheses. Much current work in animal behaviour has concentrated on birds and mammals, animals with ostensibly more complex structure, physiology and behavioural capacity, but there is a growing body of information about the behaviour of fishes. There is now increasing awareness that the same ecological and evolutionary rules govern teleost fish, and that their behaviour is not just a simplified version of that seen in birds and mammals. The details of fish behaviour intimately reflect unique and efficient adaptations to their three-dimensional aquatic environment.

Download or read book Allee Effects in Ecology and Conservation written by Franck Courchamp and published by Oxford University Press. This book was released on 2008-02-14 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt: Allee effects are relevant to biologists who study rarity, and to conservationists and managers who try and protect endangered populations. This book provides an overview of the Allee effect, the mechanisms which drive it and its consequences for population dynamics, evolution and conservation.

Download or read book Fundamentals of Acoustical Oceanography written by Herman Medwin and published by Academic Press. This book was released on 1997-11-05 with total page 739 pages. Available in PDF, EPUB and Kindle. Book excerpt: The developments in the field of ocean acoustics over recent years make this book an important reference for specialists in acoustics, oceanography, marine biology, and related fields. Fundamentals of Acoustical Oceanography also encourages a new generation of scientists, engineers, and entrepreneurs to apply the modern methods of acoustical physics to probe the unknown sea. The book is an authoritative, modern text with examples and exercises. It contains techniques to solve the direct problems, solutions of inverse problems, and an extensive bibliography from the earliest use of sound in the sea to present references.Written by internationally recognized scientists, the book provides background to measure ocean parameters and processes, find life and objects in the sea, communicate underwater, and survey the boundaries of the sea. Fundamentals of Acoustical Oceanography explains principles of underwater sound propagation, and describes how both actively probing sonars and passively listening hydrophones can reveal what the eye cannot see over vast ranges of the turbid ocean. This book demonstrates how to use acoustical remote sensing, variations in sound transmission, in situ acoustical measurements, and computer and laboratory models to identify the physical and biological parameters and processes in the sea.* Offers an integrated, modern approach to passive and active underwater acoustics* Contains many examples of laboratory scale models of ocean-acoustic environments, as well as descriptions of experiments at sea* Covers remote sensing of marine life and the seafloor* Includes signal processing of ocean sounds, physical and biological noises at sea, and inversions* resents sound sources, receivers, and calibration* Explains high intensities; explosive waves, parametric sources, cavitation, shock waves, and streaming* Covers microbubbles from breaking waves, rainfall, dispersion, and attenuation* Describes sound propagation along ray paths and caustics* Presents sound transmissions and normal mode methods in ocean waveguides

Download or read book Reinventing Fisheries Management written by T.J. Pitcher and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Judged by a dismaying track record and a consequent downturn in the reputation of fisheries scientists, fisheries management is certainly a candidate for calls for reinvention, with many of the world leaders in this area holding the view that no fishery has ever been properly understood or managed. With fisheries science in a state of flux, this extremely important book seeks a new paradigm that will place this flux of ideas in perspective and help us to choose those that will make fisheries management work. The book was planned at a symposium of over 100 fishery researchers at the Fisheries Centre, University of British Columbia, Vancouver, Canada and is organized into five parts: Why does Fisheries Science Need Reinventing?; New Policies; The Role of the Social Sciences; Ecology; Modelling. Carefully integrated and edited by three of the world's leading fishery scientists, this stimulating book should find a place on the shelves of all fishery scientists throughout the world. It will be an invaluable reference source to those studying fish biology, fisheries and oceanography and all those involved in fisheries policy decisions in government and university research establishments.