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Author: Clark Raymond Morgan Publisher: ISBN: Category : Marine nurseries -- Florida -- Jacksonville Beach Languages : en Pages :
Book Description
Nearshore marine environments are known to be highly productive systems with relatively high faunal diversity and abundances, but these systems are particularly vulnerable to negative impacts from anthropogenic disturbances that can result in habitat degradation. Despite these challenges, many shark species of various life stages utilize coastal shelf habitats, inshore estuaries, and bays. The inshore habitats of Cumberland and Nassau Sounds in northeast Florida have been proposed as potential nursery grounds by earlier work, but this suggestion did not satisfy all of the standard criteria of shark nursery designation. It has recently been stated that the combination of surveys inside and outside suspected nursery habitats, especially those incorporating mark-recapture studies, would provide a very comprehensive test of the nursery criteria. A primary objective of the present study was to initially describe the composition and abundance of shark populations utilizing the nearshore habitats of northeast Florida, while also comparing them to inshore communities, with emphasis on spatial and temporal variations in assemblages. Fishery-independent longline sampling was conducted across the region and while considerable overlap of species were observed, significant differences in community structure between inshore and nearshore locations were detected. Specifically, the inshore waters of the First Coast support nursery habitat designation for Atlantic sharpnose, blacktip, and sandbar sharks after satisfying the accepted criteria. Given the high amounts of spatial and temporal overlap observed along the First Coast, relative trophic niche dynamics were also investigated via stable isotope analysis of two tissue types. These results revealed varying trophic niche sizes in the long term, but suggest some degree of shared resource use when animals are present on the First Coast. The identification of factors that influence coastal shark habitat utilization, such as competition and resource use, can contribute to understanding and predicting how they may respond to future environmental changes.
Author: Clark Raymond Morgan Publisher: ISBN: Category : Marine nurseries -- Florida -- Jacksonville Beach Languages : en Pages :
Book Description
Nearshore marine environments are known to be highly productive systems with relatively high faunal diversity and abundances, but these systems are particularly vulnerable to negative impacts from anthropogenic disturbances that can result in habitat degradation. Despite these challenges, many shark species of various life stages utilize coastal shelf habitats, inshore estuaries, and bays. The inshore habitats of Cumberland and Nassau Sounds in northeast Florida have been proposed as potential nursery grounds by earlier work, but this suggestion did not satisfy all of the standard criteria of shark nursery designation. It has recently been stated that the combination of surveys inside and outside suspected nursery habitats, especially those incorporating mark-recapture studies, would provide a very comprehensive test of the nursery criteria. A primary objective of the present study was to initially describe the composition and abundance of shark populations utilizing the nearshore habitats of northeast Florida, while also comparing them to inshore communities, with emphasis on spatial and temporal variations in assemblages. Fishery-independent longline sampling was conducted across the region and while considerable overlap of species were observed, significant differences in community structure between inshore and nearshore locations were detected. Specifically, the inshore waters of the First Coast support nursery habitat designation for Atlantic sharpnose, blacktip, and sandbar sharks after satisfying the accepted criteria. Given the high amounts of spatial and temporal overlap observed along the First Coast, relative trophic niche dynamics were also investigated via stable isotope analysis of two tissue types. These results revealed varying trophic niche sizes in the long term, but suggest some degree of shared resource use when animals are present on the First Coast. The identification of factors that influence coastal shark habitat utilization, such as competition and resource use, can contribute to understanding and predicting how they may respond to future environmental changes.
Author: Cheston Thomas Peterson Publisher: ISBN: Category : Ecology Languages : en Pages : 0
Book Description
Drivers of animal movement, including abiotic factors such as environmental conditions or climate and biotic factors such as species interactions and reproduction, are classic topics in ecology and relevant to both basic and applied scientific questions. Understanding phenomena such as seasonal migrations are important in fisheries management, and describing habitat use and ecological interactions is a primary goal in fisheries ecology as the field moves toward holistic, ecosystem-based approaches. Here I present the results of research investigating the drivers of movement in coastal sharks, from scales of seasonal migrations and temporal patterns of abundance to fine-scale movement of a single species as it relates to the distribution and density of its prey and predators. I used a 10 year data set of long-term fishery-independent gillnet and longline surveys to explore the effects of abiotic variables on temporal patterns of community structure of fishes and correlates of migration at two seagrass shoals off the FSU Coastal and Marine Laboratory. I examined community structure using non-metric multidimensional scaling (NMDS) with environmental fitting, compared temporal community structure using permutational multivariate analysis of variance (PERMANOVA) of monthly catch rates in both gear types, and tested for cyclicity in community structure. I also used generalized additive models (GAMs) to explore the effects of environmental variables (e.g. temperature and photoperiod) on immigration and emigration phases of dominant taxa. I found strong seasonality and cyclicity in assemblages captured by both gear types, with depauperate winter communities and diverse assemblages in warmer month - especially late summer and fall. My results suggest temperature may determine the timing of immigration and duration of the residency period of dominant taxa, including the juvenile life stages of some coastal sharks, but photoperiod may cue immigration and emigration in adults when the purpose of those migrations includes predicable reproductive functions (e.g. parturition). I found evidence of partial migration in juvenile life stages of some coastal sharks, and hypothesize that rising temperatures due to climate change may have variable effects on residency patterns over ontogeny. I conducted similar fishery-independent sampling in Apalachicola Bay from 2018 to 2020 during the summer to study habitat overlap in multiple life stages of a group of sympatric coastal sharks. I also used data shared with me by the Florida Fish and Wildlife Conservation Commission to explore the relationship of habitat use in coastal sharks to prey distribution and density. My analyses suggested this relationship may vary among species and life stage, as predation risk or environmental tolerances may drive habitat use in early life stages of some species. Prey distribution may be more important for dietary specialists. Interestingly, habitat use of species life stages with increasing reported dietary overlap appeared to converge. Using acoustic telemetry, I described movement and habitat use of bull sharks (Carcharhinus leucas), bonnetheads (Sphyrna tiburo), and gafftopsail catfish (Bagre marinus) in Apalachicola Bay and St. George Sound. I used linear mixed models (LMM) to integrate the tracking information with blue crab (Calinectes sapidus) density data from the same fishery-independent surveys conducted by FWC to explore the predator-prey dynamics of blue crabs, bonnetheads, and bull sharks. All three fishes were resident throughout the summer and were philopatric. Bull sharks used more of the habitat than bonnetheads or gafftopsail catfish. Bonnetheads mainly used seagrass habitats, while gafftopsail catfish used muddy habitats around freshwater inputs. There were relationships of size and the proportion of the acoustic array each species used, with a positive correlation of size and space used in both species of sharks and a negative correlation in gafftopsail catfish, which may be driven my differences between sexes. Bonnetheads were not detected in habitats where blue crabs were most dense, but the probability of bull shark presence was highest. Results of the LMM analyses suggested a significant negative relationship of bonnethead habitat use and bull shark presence probability, as well as a significant negative relationship of the interaction of bull shark presence and salinity (bull shark presence probability was highest at sites with the lowest average salinities). These results suggest habitat use in bonnetheads may follow predictions of optimal foraging theory and the ideal free distribution under the constraint of predation risk, which may be informative in understanding the roles of predation and prey availability in the habitat use of marine mesopredators.
Author: Jeffrey C. Carrier Publisher: CRC Press ISBN: 1420080482 Category : Nature Languages : en Pages : 748
Book Description
Since the award-winning first volume, The Biology of Sharks and Their Relatives, published in 2004, the field has witnessed tremendous developments in research, rapid advances in technology, and the emergence of new investigators beginning to explore issues of biodiversity, distribution, physiology, and ecology in ways that eluded more traditional
Author: John C. Moore Publisher: Cambridge University Press ISBN: 1107182115 Category : Business & Economics Languages : en Pages : 445
Book Description
This book presents new approaches to studying food webs, using practical and policy examples to demonstrate the theory behind ecosystem management decisions.
Author: C. Herb Ward Publisher: Springer ISBN: 1493934562 Category : Technology & Engineering Languages : en Pages : 948
Book Description
This book is open access under a CC BY-NC 2.5 license. The Gulf of Mexico is an open and dynamic marine ecosystem rich in natural resources but heavily impacted by human activities, including agricultural, industrial, commercial and coastal development. The Gulf of Mexico has been continuously exposed to petroleum hydrocarbons for millions of years from natural oil and gas seeps on the sea floor, and more recently from oil drilling and production activities located in the water near and far from shore. Major accidental oil spills in the Gulf are infrequent; two of the most significant include the Ixtoc I blowout in the Bay of Campeche in 1979 and the Deepwater Horizon Oil Spill in 2010. Unfortunately, baseline assessments of the status of habitats and biota in the Gulf of Mexico before these spills either were not available, or the data had not been systematically compiled in a way that would help scientists assess the potential short-term and long-term effects of such events. This 2-volume series compiles and summarizes thousands of data sets showing the status of habitats and biota in the Gulf of Mexico before the Deepwater Horizon Oil Spill. Volume 2 covers historical data on commercial and recreational fisheries, with an analysis of marketing trends and drivers; ecology, populations and risks to birds, sea turtles and marine mammals in the Gulf; and diseases and mortalities of fish and other animals that inhabit the Gulf of Mexico.
Author: Babin, Marcel Publisher: UNESCO ISBN: 9231040421 Category : Nature Languages : en Pages : 880
Book Description
The proliferation of harmful phytoplankton in marine ecosystems can cause massive fish kills, contaminate seafood with toxins, impact local and regional economies and dramatically affect ecological balance. Real-time observations are essential for effective short-term operational forecasting, but observation and modelling systems are still being developed. This volume provides guidance for developing real-time and near real-time sensing systems for observing and predicting plankton dynamics, including harmful algal blooms, in coastal waters. The underlying theory is explained and current trends in research and monitoring are discussed.Topics covered include: coastal ecosystems and dynamics of harmful algal blooms; theory and practical applications of in situ and remotely sensed optical detection of microalgal distributions and composition; theory and practical applications of in situ biological and chemical sensors for targeted species and toxin detection; integrated observing systems and platforms for detection; diagnostic and predictive modelling of ecosystems and harmful algal blooms, including data assimilation techniques; observational needs for the public and government; and future directions for research and operations.
Book Description
This manual defines methods for estimating selectivity of gillnet and longline gears, with particular reference to the use of these gears in abundance surveys. The manual illustrates how gear design, the basic concepts of size selection and fish morphometric data can be used to model selectivity. Statistical estimation methods are described in detail, and examples given of their application in spreadsheets. The efficient use of these gears in abundance and research surveys is also discussed. Although the manual concentrates on gillnets and longlines, the methods given are general enough to be relevant to any research involving gear selectivity
Author: Miles Jonathan Furnas Publisher: ISBN: Category : Nature Languages : en Pages : 354
Book Description
This text provides the first comprehensive description of the state of the Great Barrier Reef catchment, modern levels of runoff to the reef and the influence of runoff on coastal reef ecosystems.
Author: John Terborgh Publisher: Island Press ISBN: 1597268194 Category : Science Languages : en Pages : 487
Book Description
Trophic cascades—the top-down regulation of ecosystems by predators—are an essential aspect of ecosystem function and well-being. Trophic cascades are often drastically disrupted by human interventions—for example, when wolves and cougars are removed, allowing deer and beaver to become destructive—yet have only recently begun to be considered in the development of conservation and management strategies. Trophic Cascades is the first comprehensive presentation of the science on this subject. It brings together some of the world’s leading scientists and researchers to explain the importance of large animals in regulating ecosystems, and to relate that scientific knowledge to practical conservation. Chapters examine trophic cascades across the world’s major biomes, including intertidal habitats, coastal oceans, lakes, nearshore ecosystems, open oceans, tropical forests, boreal and temperate ecosystems, low arctic scrubland, savannas, and islands. Additional chapters consider aboveground/belowground linkages, predation and ecosystem processes, consumer control by megafauna and fire, and alternative states in ecosystems. An introductory chapter offers a concise overview of trophic cascades, while concluding chapters consider theoretical perspectives and comparative issues. Trophic Cascades provides a scientific basis and justification for the idea that large predators and top-down forcing must be considered in conservation strategies, alongside factors such as habitat preservation and invasive species. It is a groundbreaking work for scientists and managers involved with biodiversity conservation and protection.
Author: Clark Raymond Morgan
Author: Clark Raymond Morgan
Author: Cheston Thomas Peterson
Author: Jeffrey C. Carrier
Author: John C. Moore
Author: C. Herb Ward
Author: Babin, Marcel
Author: Holger Hovgêrd
Author: Miles Jonathan Furnas
Author: Jose I. Castro
Author: John Terborgh