Download or read book The Influence of Spatial and Temporal Scale in Detecting Offshore Recruitment Signals of Atlantic Cod Gadus Morhua Based on Coastal Juvenile Surveys written by Emma L. L. Cooke and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The moratorium on the Newfoundland Atlantic cod (Gadus morhua) fishery in 1992 motivated studies on the factors influencing population stability and tools to forecast future cod abundance. Unfortunately, short-duration time series compromised most efforts to link life stages. I used coastal seine surveys of juveniles (age-0 and -1) to predict offshore pre-adult (age-3) cod abundance at multiple spatial scales (individual bays to offshore regions), temporal scales (short and long-term time series from 7 to 18 years in length) and environmental and biological factors influencing recruitment signal strength. These analyses detected strong recruitment signals among all early age classes from the Newman Sound Survey (1995 - 2013) and demonstrated interactions between juvenile abundance and environmental variables. In contrast, a strong recruitment signal was only detectable from a single bay using the shorter Fleming Survey (1992 - 1997, 2001). For both surveys, recruitment signal strength varied with distance from the index sites, among management zones, and between areas of known ecological and biological significance. Studies evaluating year-class strength often overlook the value of coastal juvenile surveys. These results demonstrate the utility of using information from long-duration coastal seine surveys when forecasting adult population strength. The implications of my results could help stakeholders prepare for socio-economic implications of poor recruitment years, and can be used in management decision-making.

Download or read book Scale dependent Variation in the Recruitment Signal in Juvenile Atlantic Cod Gadus Morhua written by Charles Yu Feng and published by . This book was released on 2007 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceanic Abstracts written by and published by . This book was released on 1995-02 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seagrasses Biology Ecology and Conservation written by Anthony Larkum and published by Springer Science & Business Media. This book was released on 2007-02-22 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seagrasses are unique plants; the only group of flowering plants to recolonise the sea. They occur on every continental margin, except Antarctica, and form ecosystems which have important roles in fisheries, fish nursery grounds, prawn fisheries, habitat diversity and sediment stabilisation. Over the last two decades there has been an explosion of research and information on all aspects of seagrass biology. However the compilation of all this work into one book has not been attempted previously. In this book experts in 26 areas of seagrass biology present their work in chapters which are state-of–the-art and designed to be useful to students and researchers alike. The book not only focuses on what has been discovered but what exciting areas are left to discover. The book is divided into sections on taxonomy, anatomy, reproduction, ecology, physiology, fisheries, management, conservation and landscape ecology. It is destined to become the chosen text on seagrasses for any marine biology course.

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 World Atlas of Seagrasses written by Frederick T. Short and published by Univ of California Press. This book was released on 2003 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seagrasses are a vital and widespread but often overlooked coastal marine habitat. This volume provides a global survey of their distribution and conservation status.

Download or read book Density of Juvenile Cod in Coastal Newfoundland Habitats Multiscale Analyses of Spatial and Temporal Variation written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spatial Synchronicity in Recruitment of Atlantic Cod Gadus Morhua Stocks Off Newfoundland and Labrador and the Flemish Cap written by Fred Tulk and published by . This book was released on 2018 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Habitat Use and Movement Patterns of Juvenile Atlantic Cod Gadus Morhua in a Coastal Area of Eastern Newfoundland microform written by David Cote and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2002 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interactions of Predators Habitat and Conspecifics on the Coastal Distribution of Age 0 Juvenile Cod Gadus Spp in Newfoundland written by Benjamin Jeffrey Laurel and published by . This book was released on 2003 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Predator and Habitat Related Risk on the Spatial Distribution of Juvenile Atlantic Cod Gadus Morhua written by Jessica L. Anderson and published by . This book was released on 2004 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book North Sea Region Climate Change Assessment written by Markus Quante and published by Springer. This book was released on 2016-08-31 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers an up-to-date review of our current understanding of climate change in the North Sea and adjacent areas, as well as its impact on ecosystems and socio-economic sectors. It provides a detailed assessment of climate change based on published scientific work compiled by independent international experts from climate-related disciplines such as oceanography, atmospheric sciences, marine and terrestrial ecology, using a regional evaluation and review process similar to that of the Intergovernmental Panel on Climate Change (IPCC). It provides a comprehensive overview of all aspects of our changing climate, discussing a wide range of topics including past, current and future climate change, and climate-related changes in marine, terrestrial and freshwater ecosystems. It also explores the impact of climate change on socio-economic sectors such as fisheries, agriculture, coastal zone management, coastal protection, urban climate, recreation/tourism, offshore activities/energy, and air pollution.

Download or read book Density of Juvenile Atlantic Cod Gadus Morhua and Greenland Cod G Ogac with Spatial Expansion and Recovery of Eelgrass Zostera Marina written by Margaret Warren and published by . This book was released on 2007 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Fishery Statistics in the North Atlantic written by George Armytage Rounsefell and published by . This book was released on 1948 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Programs for Digital Signal Processing written by IEEE Acoustics, Speech, and Signal Processing Society. Digital Signal Processing Committee and published by . This book was released on 1979 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: Briefly describes the physical characteristics, the habitat, and the behavior of the Alaskan brown bear.

Download or read book Impacts of climate change on fisheries and aquaculture written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2019-01-06 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report indicates that climate change will significantly affect the availability and trade of fish products, especially for those countries most dependent on the sector, and calls for effective adaptation and mitigation actions encompassing food production.

Download or read book Global Climate Change Impacts in the United States written by U.S. Global Change Research Program and published by Cambridge University Press. This book was released on 2009-08-24 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summarizes the science of climate change and impacts on the United States, for the public and policymakers.