Download or read book Spawning Dynamics Seasonal Movements and Population Structure of Atlantic Cod Gadus Morhua in the Gulf of Maine written by Douglas Robert Zemeckis and published by . This book was released on 2016 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atlantic cod (Gadus morhua) have been a principal target species in New England's ground fish fishery since the 17th century. In recent decades, the Gulf of Maine cod stock has experienced substantial declines in abundance, and many historical spawning components have been depleted, reducing stock productivity and stability. Managing stock rebuilding has been difficult because of many uncertainties in population dynamics. Therefore, to support stock rebuilding efforts, the objective of this dissertation was to improve our understanding of the spawning dynamics, seasonal movements, and population structure of Atlantic cod in the Gulf of Maine. An interdisciplinary review of the scientific literature demonstrated that the cod population off New England can be described as a metapopulation that includes genetically-distinct spring- and winter spawning subpopulations which are comprised of many finer-scale spawning components. Available information indicates that current management unit boundaries do not accurately represent the biological population structure. Therefore, a modification of current management units is recommended to provide a more accurate representation of the underlying biological population processes. Review of the cod spawning literature indicated that cod spawn in multiple locations and seasons, and the complex cod mating system can be described as a "lek". The aspects of cod spawning dynamics most important for consideration by fishery managers are the spatial and temporal extent ofspawning, the behavior of spawners, and the reproductive contributions of older age-classes. The application of spawning closures as part of a multidisciplinary approach to fisheries management is recommended to prevent disruption of spawning and extirpation of semi-discrete spawning components. Spawning site fidelity contributes to the formation and maintenance of the observed metapopulation structure and delays the recolonization of abandoned spawning sites by limiting reproductive connectivity. Acoustic telemetry was used to document prevalent, fine-scale spawning site fidelity with respect to an inshore spawning site in the western Gulf of Maine. Movements away from the inshore spawning site were studied using conventional tags, acoustic telemetry, and geolocation utilizing data from archival data storage tags. Connectivity was documented among multiple inshore spawning sites, which is apparently sufficient to promote gene flow within the western subpopulation. Cod were primarily residential within the western Gulf of Maine. After spawning inshore, cod moved to offshore feeding grounds from summer to early winter. Deep offshore basins served as overwintering habitat before initiation of an inshore spring spawning migration. Results from this dissertation have been valuable for informing fishery managers in the development of regulations to protect cod spawning aggregations. Findings are contributing to ongoing processes to investigate cod population structure and reevaluate current management units. This dissertation provides a more holistic understanding of cod population dynamics, which is expected to contribute to the development of future fishery management plans and stock assessment models that work towards achieving stock rebuilding.
Download or read book Homing Population Structure and Management of Atlantic Cod Gadus Morhua with Emphasis on Spawning at Bar Haven in Placentia Bay Newfoundland written by Dave Robichaud and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atlantic Cod written by George A. Rose and published by John Wiley & Sons. This book was released on 2018-12-13 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive handbook, covering all aspects of the Atlantic cod including the biology, ecology, life histories, behaviour, commercial exploitation and conservation Not only is Atlantic cod one of the most valuable food fish in the world’s oceans, it is an important component of North Atlantic ecosystems and has been subject to much research into its biology, ecology and exploitation. After hundreds of years of exploitation, overfishing in the last half of the 20th Century caused many stocks to collapse, most famously the Northern cod stock off Newfoundland and Labrador, Canada. Since then, most cod stocks have been better researched and managed, but remain in a variety of states, from fully recovered to continued decline. This book, written by world experts, describes that research and management, and the importance of cod and its fisheries on North Atlantic cultures and economies, with impacts well beyond the range of the species. Atlantic Cod: Bio-Ecology of the Fish offers insightful chapter coverage of cod nomenclature, taxonomy, phylogeny and morphology; physiology and ecophysiology; reproduction and spawning behavior; early life history and pre-recruitment processes; migrations, movements and stock identity; feeding, growth and energetics; the place of cod in the ecosystem; the exploitation of cod through history and present day commercial fisheries and precautionary management for sustainable fisheries; impacts of climate change on cod biology and ecology; and the future of the species and its fisheries. Discusses the major commercial importance of Atlantic cod through history Provides a comprehensive treatment of the bio-ecology of the most researched and highly exploited fully marine species Examines how the decline (and recovery) of cod stocks is of great political and scientific interest An essential purchase for marine fisheries scientists Atlantic Cod: Bio-Ecology of the Fish is a vital book for all fisheries scientists, managers and fish biologists.
Download or read book Atlantic Cod written by George A. Rose and published by John Wiley & Sons. This book was released on 2019-02-26 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive handbook, covering all aspects of the Atlantic cod including the biology, ecology, life histories, behaviour, commercial exploitation and conservation Not only is Atlantic cod one of the most valuable food fish in the world’s oceans, it is an important component of North Atlantic ecosystems and has been subject to much research into its biology, ecology and exploitation. After hundreds of years of exploitation, overfishing in the last half of the 20th Century caused many stocks to collapse, most famously the Northern cod stock off Newfoundland and Labrador, Canada. Since then, most cod stocks have been better researched and managed, but remain in a variety of states, from fully recovered to continued decline. This book, written by world experts, describes that research and management, and the importance of cod and its fisheries on North Atlantic cultures and economies, with impacts well beyond the range of the species. Atlantic Cod: Bio-Ecology of the Fish offers insightful chapter coverage of cod nomenclature, taxonomy, phylogeny and morphology; physiology and ecophysiology; reproduction and spawning behavior; early life history and pre-recruitment processes; migrations, movements and stock identity; feeding, growth and energetics; the place of cod in the ecosystem; the exploitation of cod through history and present day commercial fisheries and precautionary management for sustainable fisheries; impacts of climate change on cod biology and ecology; and the future of the species and its fisheries. Discusses the major commercial importance of Atlantic cod through history Provides a comprehensive treatment of the bio-ecology of the most researched and highly exploited fully marine species Examines how the decline (and recovery) of cod stocks is of great political and scientific interest An essential purchase for marine fisheries scientists Atlantic Cod: Bio-Ecology of the Fish is a vital book for all fisheries scientists, managers and fish biologists.
Download or read book Stock Identification Methods written by Steven X. Cadrin and published by Academic Press. This book was released on 2013-10-04 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stock Identification Methods, 2e, continues to provide a comprehensive review of the various disciplines used to study the population structure of fishery resources. It represents the worldwide experience and perspectives of experts on each method, assembled through a working group of the International Council for the Exploration of the Sea. The book is organized to foster interdisciplinary analyses and conclusions about stock structure, a crucial topic for fishery science and management. Technological advances have promoted the development of stock identification methods in many directions, resulting in a confusing variety of approaches. Based on central tenets of population biology and management needs, this valuable resource offers a unified framework for understanding stock structure by promoting an understanding of the relative merits and sensitivities of each approach. - Describes 18 distinct approaches to stock identification grouped into sections on life history traits, environmental signals, genetic analyses, and applied marks - Features experts' reviews of benchmark case studies, general protocols, and the strengths and weaknesses of each identification method - Reviews statistical techniques for exploring stock patterns, testing for differences among putative stocks, stock discrimination, and stock composition analysis - Focuses on the challenges of interpreting data and managing mixed-stock fisheries
Download or read book The Behaviors Habitat Preferences and Ecology of Distinct Atlantic Cod Phenotypes in the Gulf of Maine written by Christian W. Conroy and published by . This book was released on 2016 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diversity in spatial behaviors and associated divergence of phenotypes are common across fish taxa. Behavior and phenotype are shaped by geology, oceanography, climate, prey availability, predation, competition, and the cumulative effects of these factors on past generations. In stochastic natural systems, diversity may enhance stability, resilience, and even productivity of populations and population complexes. Among the behaviors of fish that vary between and within populations is migration. Migration is most often related to travel between spawning and feeding grounds and is integral to population productivity. However, members of the same species and even population may adopt vastly different migratory strategies, including long-distance migration and strict site residence. Across taxa, these strategies are often correlated with metabolism, growth, fecundity, and productivity. In the context of fisheries management, the spatial and physiological variance associated with different migratory strategies may lead to complicated or unexpected responses by managed stocks to disturbance. Understanding the processes that lead to the adoption and maintenance of migratory strategies, how these behaviors affect habitat use, and how behavior and habitat are related to phenotype, are necessary to the development of effective fisheries management policies and regulations. Atlantic cod (Gadus morhua) adopt a range of spatial behaviors across the North Atlantic, with effects on productivity and growth. As in other fish taxa, resident cod have lower growth rates and fecundity than conspecific migrants. Many identified groups of cod residents are physically isolated from nearby migrants, offering little insight to many of the important questions surrounding these behavioral strategies. In the Gulf of Maine, sympatric resident and migrant cod have been identified from a number of locations. This research focused on the interactions between behavior, habitat use, and phenotype of cod in the Gulf of Maine. A visually distinct cod phenotype found at several locations throughout the region features red pigmentation and a deeper body than the familiar form of cod. As is observed elsewhere in the species range, this red phenotype remains in relatively shallow, structured habitats and grows at lower rates compared to the familiar migrant olive phenotype. The connection between low growth, resident behavioral strategy, and body morphology (deep vs. fusiform) has been observed in a number of salmonids and may be common among fishes that occupy diverse environments. Red phenotypes were highly selective of certain habitats, and the spatial behaviors of all cod regardless of phenotype changed seasonally, possibly due to the influence of seasonal changes in environmental conditions like temperature. Phenotype-specific behaviors were consistent both inshore and offshore, generally following resident and migrant strategies. Offshore red phenotypes expressed strict site fidelity, but this may in part be due to habitat limitation, as nearshore red phenotypes adhered to shallow depths but moved up and down the coast. Regardless of phenotype, cod utilize shallow, structured habitats at an offshore site, Cashes Ledge, during the warm periods of the summer and fall. Habitat use is focused on the most complex habitats in the shallowest peaks of the ledge, which often are covered in thick macroalgal stands. The shallow structured habitats preferred by red phenotypes and utilized by all cod are not available to widely used groundfishing gear, thus limiting fishing pressure on these important habitats. At the same time, shallow coasts and ledges will be affected by warming surface waters and increased storm activities associated with ongoing climate change. The importance of these habitats and their utilization by cod relative to their adopted migratory strategies may impact population-scale responses of cod to future management activities.
Download or read book Spawning and Life History Information for North Atlantic Cod Stocks written by K. M. Brander and published by . This book was released on 2005 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanisms and Consequences of Variation in the Migratory Behaviour of Atlantic Cod Gadus Morhua L in the Northern Gulf of St Lawrence written by Arnault Le Bris and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis aimed to characterize individual variation in the migratory behaviour of Atlantic cod (Gadus morhua) in the northern Gulf of St. Lawrence, and to assess the consequences of this variation on the structure and management of the population. First, I reviewed interplays between genetic, environmental, and social factors in the evolution and maintenance of individual variation in the migratory behaviour of marine fishes, with an emphasis on Atlantic cod. Evidence of fine-grained responses to environmental changes suggested that phenotypic plasticity is a substantial source of variation in migratory behaviours. However, because the genetic basis of migratory traits has been overlooked, the relative contributions of genetic, environment, and genetic by environment interactions have not been quantified for any marine fishes. Within the cod population from northern the Gulf of St. Lawrence, reconstruction of migration routes of cod equipped with data-storage tags revealed undocumented concurrent presence of resident and migratory individuals. Depth time-series analyses revealed high individual variability in vertical patterns of migration. Consequences of the observed individual variation in migration propensity on the structure of the population were then evaluated. Focusing on the fjord of Bonne Bay where I previously identified resident and homing cod, I assessed the degree of demographic dependency of Bonne Bay cod with Gulf cod. Although local recruitment occurs, Bonne Bay does not harbour an abundance of adult cod and external sources of recruitment are substantial. The bay however provides a nursery and a spawning area for Atlantic cod. Finally, I quantified effects of variation in adult migratory behaviour and population density distribution on the performance of a fishery closed area designed to protect a spawning aggregation. Closed area usage by free-ranging individuals revealed disproportional levels of protection between migratory groups. Estimated population density distributions during two periods of contrasted abundance level suggested that, when a closed area is located on the core of a population distribution, density-dependent contraction of population range increases closed area performance. Both individual closed area usage and population density distribution indicated that a displacement south and a reduction of the enforcement period would improve the performance of the study closed area.
Download or read book Migration Ecology of Marine Fishes written by David Hallock Secor and published by JHU Press. This book was released on 2015-06-15 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: A revelatory look at the secrets of marine fish migration. Not since F. R. Harden Jones published his masterwork on fish migration in 1968 has a book so thoroughly demystified the subject. With stunning clarity, David Hallock Secor's Migration Ecology of Fishes finally penetrates the clandestine nature of marine fish migration. Secor explains how the four decades of research since Jones's classic have employed digital-age technologies—including electronic miniaturization, computing, microchemistry, ocean observing systems, and telecommunications—that render overt the previously hidden migration behaviors of fish. Emerging from the millions of observed, telemetered, simulated, and chemically traced movement paths is an appreciation of the individual fish. Members of the same populations may stay put, explore, delay, accelerate, evacuate, and change course as they conditionally respond to their marine existence. But rather than a morass of individual behaviors, Secor shows us that populations are collectively organized through partial migration, which causes groups of individuals to embark on very different migration pathways despite being members of the same population. Case studies throughout the book emphasize how migration ecology confounds current fisheries management. Yet, as Secor explains, conservation frameworks that explicitly consider the influence of migration on yield, stability, and resilience outcomes have the potential to transform fisheries management. A synthetic treatment of all marine fish taxa (teleosts and elasmobranchs), this book employs explanatory frameworks from avian and systems ecology while arguing that migrations are emergent phenomena, structured through schooling, phenotypic plasticity, and other collective agencies. The book provides overviews of the following concepts: • The comparative movement ecology of fishes and birds • The alignment of mating systems with larval dispersal • Schooling and migration as adaptations to marine food webs • Natal homing • Connectivity in populations and metapopulations • The contribution of migration ecology to population resilience
Download or read book Reproductive Potential written by Beth Emily Scott and published by . This book was released on 2003 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stock Structure and Seasonal Movements of Atlantic Cod Gadus Morhua in NAFO Divs 3KL Inferred from Recent Tagging Experiments written by John Brattey and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Movement of Atlantic Cod Gadus Morhua in and Among the Western Gulf of Maine Rolling Closures as Determined Through Mark and Recapture written by Michael Morin and published by . This book was released on 2003 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Homing Mechanisms and Mating Systems of Atlantic Cod written by Matthew J. S. Windle and published by . This book was released on 2006 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Northern Atlantic Cod Gadus Morhua of Eastern Newfoundland and Labrador as a Metapopulation written by R. Kent Smedbol and published by . This book was released on 1999 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seasonal Trends in Spawning Condition and Catch Rates of Atlantic Cod Gadus Morhua in Northern Placentia Bay Newfoundland Over 1995 1999 written by Aline D. P. Bolon and published by . This book was released on 1999 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stock Structure and Seasonal Migration Patterns of Atlantic Cod Gadus Morhua Based on Inshore Tagging Experiments in Divs 3KL During 1995 97 written by John Brattey and published by . This book was released on 1999 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Fish Biology and Fisheries written by Paul J. B. Hart and published by John Wiley & Sons. This book was released on 2008-04-15 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent decades have witnessed strong declines in fish stocks aroundthe globe, amid growing concerns about the impact of fisheries onmarine and freshwater biodiversity. Fisheries biologists andmanagers are therefore increasingly asking about aspects ofecology, behaviour, evolution and biodiversity that weretraditionally studied by people working in very separate fields.This has highlighted the need to work more closely together, inorder to help ensure future success both in management andconservation. The Handbook of Fish Biology and Fisheries has beenwritten by an international team of scientists and practitioners,to provide an overview of the biology of freshwater and marine fishspecies together with the science that supports fisheriesmanagement and conservation. This volume, subtitled Fish Biology, reviews a broadvariety of topics from evolutionary relationships and globalbiogeography to physiology, recruitment, life histories, genetics,foraging behaviour, reproductive behaviour and community ecology.The second volume, subtitled Fisheries, uses much of thisinformation in a wide-ranging review of fisheries biology,including methods of capture, marketing, economics, stockassessment, forecasting, ecosystem impacts and conservation. Together, these books present the state of the art in ourunderstanding of fish biology and fisheries and will serve asvaluable references for undergraduates and graduates looking for acomprehensive source on a wide variety of topics in fisheriesscience. They will also be useful to researchers who needup-to-date reviews of topics that impinge on their fields, anddecision makers who need to appreciate the scientific backgroundfor management and conservation of aquatic ecosystems. To order volume I, go to the box in the top right hand corner.Alternatively to order volume II, go to:http://www.blackwellpublishing.com/book.asp?ref=063206482X or toorder the 2 volume set, go to:http://www.blackwellpublishing.com/book.asp?ref=0632064838. Provides a unique overview of the study of fish biology andecology, and the assessment and management of fish populations andecosystems. The first volume concentrates on aspects of fish biology andecology, both at the individual and population levels, whilst thesecond volume addresses the assessment and management of fishpopulations and ecosystems. Written by an international team of expert scientists andpractitioners. An invaluable reference tool for both students, researchers andpractitioners working in the fields of fish biology andfisheries.
