Download or read book Acoustic Tracking of Reef Fishes to Elucidate Habitat Utilization Patterns and Residence Times Inside and Outside Marine Protected Areas Around the Island of St John USVI written by Alan Marc Friedlander and published by . This book was released on 2007 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: This technical memorandum describes a developing project under the direction of NOAA's Biogeography Branch in consultation with the National Park Service and US Geological Survey to understand and quantify spatial patterns and habitat affinities of reef fishes in the US Virgin Islands. The purpose of this report is to describe and disseminate the initial results from the project and to share information on the location of acoustic receivers and species electronic tag ID codes. The Virgin Islands Coral Reef National Monument (VICRNM), adjacent to Virgin Islands National Park (VIIS), was established by Executive Order in 2000, but resources within the monument are poorly documented and the degree of connectivity to VIIS is unknown. Whereas, VICRNM was established with full protection from resource exploitation, VIIS has incurred resource harvest by fishers since 1956 as allowed in its enabling legislation. Large changes in local reef communities have occurred over the past several decades, in part due to overexploitation. In order to better understand the habitat utilization patterns and movement of fishes among management regimes and areas open to fishing around St, John, an array of hydroacoustic receivers was deployed while a variety of reef fish species were acoustically tagged. In July 2006, nine receivers with a detection range of ca. 350 m were deployed in Lameshur Bay on the south shore of St. John, within VIIS. Receivers were located adjacent to reefs and in seagrass beds, inshore and offshore of these reefs. It was found that lane snappers and bluestriped grunts showed diel movement from reef habitats during daytime hours to offshore seagrass bed at night. Timing of migrations was highly predictable and coincided with changes in sunrise and sunset over the course of the year. Fish associated with reefs that did not have adjacent seagrass beds made more extensive movements than those fishes associated with reefs that had adjacent seagrass habitats. In April 2007, 21 additional receivers were deployed along much of the south shore of St. John (ca. 20 km of shoreline). This current array will address broader-scale movement among management units and examine the potential benefits of the VICRNM to provide adult 'spillover' into VIIS and adjacent harvested areas. The results from this work will aid in defining fine to moderate spatial scales of reef fish habitat affinities and in designing and evaluating marine protected areas.
Download or read book The State of Coral Reef Ecosystems of the United States and Pacific Freely Associated States written by and published by . This book was released on 2005 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecological Connectivity among Tropical Coastal Ecosystems written by Ivan Nagelkerken and published by Springer Science & Business Media. This book was released on 2009-09-23 with total page 617 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mangrove forests, seagrass beds, and coral reefs are circumtropical ecosystems that are highly productive, and provide many important biological functions and economic services. These ecosystems cover large surface areas in the shallow tropical coastal seascape but have suffered from serious human degradation, especially in the last few decades. Part of their diversity, productivity, and functioning seems to be based on their juxtaposition. Especially in the last decade significant advances have been made on new insights into their ecological connectivity. This authoritative book provides a first-time comprehensive review of the major ecological interactions across tropical marine ecosystems that result from the mutual exchange of nutrients, organic matter, fish, and crustaceans. A group of leading authors from around the world reviews the patterns and underlying mechanisms of important biogeochemical and biological linkages among tropical coastal ecosystems in 15 chapters. Included are chapters that review cutting-edge tools to study and quantify these linkages, the importance of such linkages for fisheries, and how tropical ecosystems should be conserved and managed for sustainable use by future generations. The book uses examples from all over the world and provides an up-to-date review of the latest published literature. This book is a ‘must read’ for professionals working on the conservation, management, and ecology of mangrove, seagrass and coral reef ecosystems.
Download or read book Movements of Reef Fish Across the Boundary of the Virgin Islands Coral Reef National Monument in Coral Bay St John USVI written by Matthew S. Kendall and published by . This book was released on 2016 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Virgin Islands Coral Reef National Monument (VICRNM) was created to expand the protection of the marine ecosystems around St. John. Monument boundaries were not designed using ecological criteria, but were instead the result of historical land ownership and the Territorial Submerged Lands Act of 1974. This study used acoustic telemetry to investigate movements of reef fish relative to the boundary of the Coral Bay portion of the Monument and the protection that this Marine Protected Area (MPA) could offer. In this approach, acoustic transmitters are implanted into fish and their movements are logged on battery-powered acoustic-receivers (n=38) positioned within, outside, and along the boundary of the Monument. Specifically, we quantify residence time of reef fish within VICRNM, the frequency of movements across the VICRNM boundary, and locations of concentrated fish activity. The National Park Service (NPS) manages the entire reef fish community within the Monument. Therefore, we set fish traps in various habitats throughout VICRNM to capture a diversity of species for tagging. Uniquely coded transmitters with a ~376 day battery life were implanted into 75 fish between August and December 2013. Minimum fish size was ~20 cm to accommodate tags. The fish tagged were from 17 species in 7 families with snappers (n = 38 fish) and grunts (n = 24) being the most common. Receivers were downloaded March 2015. Data were summarized to convey basic information about fish movements including: the timespan of detections, number of detections, percent of days detected, number of receivers visited, number and frequency of VICRNM boundary crossing events, proportion of detections inside versus outside VICRNM, and location of day versus night detections"--Executive Summary. [doi:10.7289/V5/TM-NOS-NCCOS-216 (http://dx.doi.org/10.7289/V5/TM-NOS-NCCOS-216)]
Download or read book Spatial Patterns and Habitat Associations of Targeted Reef Fish in and Around a Marine Protected Area in St Croix U S Virgin Islands written by Jamie M. Kilgo and published by . This book was released on 2012 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: As marine protected areas (MPAs) become an increasingly popular method to address global declines of coral reef ecosystems, understanding how to gauge no-take reserve effectiveness through both simple metrics and spatially quantitative methods is imperative for robust design and management. In order to be an effective fisheries management tool, it must be shown that MPAs do not simply displace fishing effort, but can actually increase the biomass or density of fish in adjacent fisheries. Net export of adult fish to surrounding waters, termed the spillover effect, is one way MPAs may function to replenish fish stocks. The ability to detect the spillover effect using simple metrics of abundance and biomass for five highly targeted species was tested for an MPA in the US Virgin Islands. Moreover, it is equally important for managers to understand linkages between reef fish biomass patterns and associated habitat at multiple scales. Habitat characteristics that influence distribution patterns of targeted reef fish can be explored through spatial statistics and spatial multivariate models. In this study, the specific aim was to further evaluate seascape and local site habitat metrics to find how spatial scales of habitat composition and configuration can be used together cohesively to understand reef fish distribution patterns. In addition, global and local spatial regression models were compared to determine if there is non-stationarity of ecological processes across management zones. Results of this study reinforce the complexities of fish-habitat interactions, which make detection of spillover difficult using simple metrics. However, using a combination of both multi-scale spatial habitat metrics and local regression methods can aid in MPA management and design.
Download or read book Acoustically Monitoring Coral Reef Fishes to Determine Short term Spatial and Temporal Movement and Habitat Utilization Patterns written by Wessley Brandon Merten and published by . This book was released on 2009 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Temporal and Spatial Patterns in Coral Reef Soundscapes and Their Relevance for Larval Fish Orientation written by Erica Staaterman and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Most coral reef fish adults have limited home ranges, but their pelagic larvae have the potential to disperse over great distances. At the end of the pelagic phase, these larvae must seek appropriate settlement habitat. Which environmental signals do they use to find the reef? It has been suggested that fish larvae utilize a combination of visual, olfactory, and acoustic cues at different ontogenetic stages and different distances from the reef. At least ten experiments in the last decade have tested the response of reef fish larvae to sounds of a coral reef, resulting in more than 650 citations. This dissertation focuses on the potential role of acoustic cues in the orientation behavior of larval reef fish from the open ocean. First, a biophysical model was used to examine the consequences of orientation behavior if larvae could detect acoustic signals from 1-10 km from the reef. When larvae oriented early during ontogeny and from larger distances, they greatly increased their settlement success and settled closer to home. These findings suggest that early orientation is critical to the survival of fish larvae, which must be active agents of their own dispersal. Second, a time-series of coral reef soundscapes was conducted for two nearby coral reefs in the Northern Florida Keys. The reef soundscapes were highly variable over daily, lunar, and seasonal time-scales, and the highest amplitudes coincided with new moons of the wet season - the time when the larvae of most coral reef fish species settle. Interestingly, the wind-based contribution to the soundscape also had a lunar period. Third, an acoustic playback experiment was conducted at Dean's Blue Hole in the Bahamas, a relatively "quiet" environment. Larvae from Apogonidae (cardinalfish) and Acanthuridae (surgeonfish) families were exposed to reef sounds recorded in the Bahamas and in Florida and played back at ambient levels. The acanthurid species demonstrated no response to the playbacks, but the apogonids exhibited a disruption of their orientation behavior. This finding suggests that apogonids were able to detect the playbacks, but had no directional response, as was anticipated based on previous studies where sounds were broadcast at higher amplitudes. Finally, an acoustic propagation experiment was conducted in the Upper Florida Keys. Both acoustic pressure and particle acceleration diminished gradually with distance from the reef, but the amplitude of the signal, particularly for particle acceleration, was lower than the detection thresholds of most fish larvae. Furthermore, the particle acceleration field (measured 1-1000 m from the reef) was not highly directional, which may restrict the use of acoustic signals to animals that can detect acoustic pressure. These findings suggest that most fish larvae in the pelagic zone near Florida reefs would have a difficult time locating the reef using acoustic cues alone. However, this may not be the case for species with particularly sensitive hearing (e.g., those that can detect acoustic pressure), and for reefs with higher-amplitude soundscapes. The results of this study challenge research from the past decades that demonstrated a clear attraction of larval fishes to sounds played-back at high amplitudes. Further work is needed, specifically hearing thresholds in other fish larvae, and particle acceleration measurements over longer time periods and near additional coral reefs, to determine whether the trends found in the Florida Keys are consistent with other parts of the world.
Download or read book Hydroacoustics as a Tool for the Assessment of Fishes Within Existing and Candidate Marine Protected Areas MPAs written by Jack Paul Egerton and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydroacoustics is widely used in fisheries research particularly for broad scale investigations such as fish stock assessments. There has, however, only been limited use of such technologies on a smaller scale for estimations of fish abundance, biomass and population size structures inside versus outside marine protected areas (MPAs). Further, within these, understanding the effects of habitat on fish distribution is of high importance especially in movements towards ecosystem based fisheries management (EBFM). The central aim of this study was to use hydroacoustic methods to determine fish distribution in and around existing MPAs and to identify areas which may be suitable for future protection. This was achieved through three field studies described in this thesis. The first study based at multiple locations across The Cayman Islands, examines in a spatial context the protection that MPAs afford to fish spawning aggregations (FSAs) of Nassau grouper (Epinephelus striatus) that they are designed to safeguard. The study found acoustic abundance estimates were similar to those made by divers. The results show the efficacy of hydroacoustic methods for FSA monitoring. The second study was centred on the Cabo Pulmo National Park (CPNP) in Baja California, Mexico. This study details the first application of hydroacoustics for MPA assessment. The results showed that fish abundance and biomass were significantly higher within the CPNP than nearby control areas. Further, the reefs within the CPNP had an order of magnitude greater abundance and biomass, demonstrating the importance of both habitat and protection for fish populations. The third field study was in the waters of the Qatari Gulf, where the hydroacoustic method was used to assess fish abundance values over different habitats to potentially determine areas suitable for protection. The results showed fish abundance, biomass and mean size were greatest over more complex habitats. The final data Chapter examines the data from the three field studies through a size spectra approach. This chapter details the first use of examining hydroacoustically derived fish size spectra in the marine environment. Fish size spectra was more curvilinear over more rugose habitats. This, in combination with examination of the slopes and heights of the spectra has shown that hydroacoustic size spectra approach may be of great value for rapidly assessing the status of fish communities in a non-destructive manner.
Download or read book The Benefits of Marine Protected Areas written by Australian Government - Department of the Environment and Heritage - Environment Australia and published by . This book was released on 2003 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Marine and Coastal Protected Areas written by Rodney V. Salm and published by IUCN. This book was released on 2000 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a new edition of the classic textbook on marine protected area (MPA) management in the tropics, originally produced as an output of the Bali World Parks Congress in 1982. Approaches to planning and managing MPAs have evolved considerably. Major advances include innovative financing mechanisms, partnerships with the private sector and NGOs, and collaborative management between government and coastal communities. These advances have brought new approaches for MPA establishment and management that are more participatory, involving communities through interaction and collaboration rather than prescription. With new case studies and illustrations, the guide comes in a water-resistant cover for field use. It is intended for those who plan individual and/or national MPA systems and gives philosophical context for MPAs along with some basic principles and approaches.
Download or read book Seascape Ecology written by Simon J. Pittman and published by John Wiley & Sons. This book was released on 2017-10-30 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seascape Ecology provides a comprehensive look at the state-of-the-science in the application of landscape ecology to the seas and provides guidance for future research priorities. The first book devoted exclusively to this rapidly emerging and increasingly important discipline, it is comprised of contributions from researchers at the forefront of seascape ecology working around the world. It presents the principles, concepts, methodology, and techniques informing seascape ecology and reports on the latest developments in the application of the approach to marine ecology and management. A growing number of marine scientists, geographers, and marine managers are asking questions about the marine environment that are best addressed with a landscape ecology perspective. Seascape Ecology represents the first serious effort to fill the gap in the literature on the subject. Key topics and features of interest include: The origins and history of seascape ecology and various approaches to spatial patterning in the sea The links between seascape patterns and ecological processes, with special attention paid to the roles played by seagrasses and salt marshes and animal movements through seascapes Human influences on seascape ecology—includes models for assessing human-seascape interactions A special epilogue in which three eminent scientists who have been instrumental in shaping the course of landscape ecology offer their insights and perspectives Seascape Ecology is a must-read for researchers and professionals in an array of disciplines, including marine biology, environmental science, geosciences, marine and coastal management, and environmental protection. It is also an excellent supplementary text for university courses in those fields.
Download or read book Coral Reef Fish Habitat Associations and Implications for Research Monitoring and the Design of Marine Protected Areas written by Benjamin Michael Fitzpatrick and published by . This book was released on 2012 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated abstract] The goal of this work was to investigate the finescale habitat associations and determine the effect of human impacts on coral reef fish assemblages. Initially I investigate how finescale spatial habitat variation influences the distribution and abundance of coral reef fishes. Significant variation in the reef fish assemblage was driven by variation in habitat. Consequently finescale habitat variation needs be accounted for in spatial or temporal surveys of coral fish assemblages. My second question investigated how protection from fishing influences the overall variation in coral reef fish assemblages, while my third question investigated how consistent the differences in protected fish assemblages are through time. Protection from fishing accounted for significantly more variation in fish assemblages than that explained by finescale habitat alone. This was driven by an average abundance and length of target species being higher inside sanctuaries and a response in non-target species indicating that there are some trophic interactions occurring between fishes. I found that both target and non-target species can be more abundant at protected reefscapes through time, consistent with the theory that protected areas can achieve recovery and lasting maintenance of fish assemblage structure relative to adjacent fished locations. I also investigated how fish assemblages within shallow coral reef habitats differ to those of adjacent continental shelf habitats to a depth of 100m. Cross-shelf sampling produced significant new knowledge on the depth and habitat specificity of many species previously only known from shallow coral reef environments. Many target species protected by shallow water protected areas are found as adults in unpotected shelf waters suggesting shallow water protected areas alone may not be effective for all species equally. Expanded depth distributions for many species revealed some refuge at depth from shallow water climate related impacts, though it is uncertain how this might contribute to persistence in populations at a local or regional scale. Many species are confined to one or a few shallow water habitats for their entire post recruitment lifehistory as opposed to others that can range across many. Fish assemblages associated with deeper water habitats are composed of higher order predators and high numbers of unique species, suggesting they will respond very differently to shallow waters when impacted by fisheries. Diversity and unique species associated with deep water habitats approached those found at shallow coral reef habitats. Habitat specialization changes dramatically from species to species and was not easily predicted. This research holds a number of key implications. Firstly the design of coral reef marine protected areas and associated monitoring programs should account for variation in benthic habitat. Fishing and other human impacts affect significantly different elements of coral reef fish assemblages depending upon the biological and physical parameters of the benthic habitat found. Marine protected areas should incorporate this habitat variability wherever practical, as discrete elements of trophic structure were significantly associated with different habitats...
Download or read book Reef Fish Movements and Marine Reserve Designs written by Nicholas Alexander Farmer and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Movement patterns and space use by mature fishes are critical in determining the effectiveness of marine reserves in conserving spawning stock biomass and/or providing biomass to adjacent fisheries through 1spillover2. Home range sizes, activity patterns, site fidelity and habitat preferences were determined for acoustically-tagged snappers and groupers using a rigorously-calibrated array of omnidirectional hydroacoustic receivers deployed in the diverse coral reef environments of a no-take marine reserve (NTMR) network in the Dry Tortugas, Florida. An individual-based localizing tendency model of reef fish movement was parameterized from fine-scale acoustic telemetry data and integrated into a Spatial Management Performance Assessment (SMPA) simulation model for reef fish populations developed to quantitatively evaluate performance of no-take marine reserves in the Dry Tortugas, Florida. Spatially-explicit SMPA models were parameterized for three overfished stocks in the lucrative snapper-grouper fishery: red grouper (Epinephelus morio), black grouper (Mycteroperca bonaci), and mutton snapper (Lutjanus analis). SMPA models were used to evaluate the impacts of a variety of life histories, movement strategies and speeds, and management regulations upon long-term stock sustainability, as measured by annual changes in spawning potential ratio (SPR), and long-term stock productivity, as measured by annual changes in fisheries yield-in-weight per recruit (Yw/R). Under assumptions of constant regional fishing pressure, constant recruitment, and 1realistic2 fish movement, SMPA simulation runs from initial conditions in 2000 suggested that by 2014, the Tortugas NTMR network should function to restore red grouper populations to 30% SPR, a Federal management benchmark for sustainability. Mutton snapper were the most mobile of the species investigated; if mutton snapper movements are ignored, their population is predicted to attain 30% SPR by 2014, but given 1realistic2 mobility, they may not attain this target by 2021 without additional protections. Black grouper are currently fished at over 9 times sustainable levels. SMPA simulations suggest coupling an increase in minimum size at capture of 20 6 25 cm with NTMR implementation would result in substantial short term losses in yield, but would restore both black grouper and mutton snapper populations to 30% SPR by 2021 and lead to increased long-term yields. Although marine reserve sites are often chosen opportunistically, these findings strongly suggest that reserve designs (e.g. proper sizes and configurations) must take into account the scales and patterns of movement exhibited by the exploited stocks they are intended to protect. These modeling efforts also suggested reserves are not a panacea; in order to promote sustainability for severely depleted stocks, they must be accompanied by an overall reduction in fishing capacity. Although important questions remain concerning the movements of reef fish in response to habitat and density dependent processes, our analyses of realistic reef fish behaviors suggest that the NTMRs of the Dry Tortugas promote substantial gains in SPR, promoting long-term stock sustainability and enhanced egg production. Increased rates of movement diminish these benefits, but may also mitigate short-term losses in yield associated with NTMR establishment.
Download or read book Spatio temporal Ecology and Management of Temperate Reef Fish Populations written by and published by . This book was released on 2017 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: The demography of marine reef fishes with a dispersive larval stage can be highly variable, with several processes that govern reproduction, dispersal, and recruitment operating across multiple spatial and temporal scales. Characterizing the patterns of this variation and the underlying processes responsible for them can help guide efforts to conserve and manage human impacts on these species. In this dissertation, I explore how associations between temperate reef habitat and fish reproductive potential may vary across spatial scales, how spatial and temporal variation in larval production can influence spatial management strategies, and how stochastic variation in larval dispersal and settlement may affect the ability to detect the impacts of management actions. Habitat attributes may have both separate and combined effects on the reproductive potential of reef fishes across spatial scales, but the patterns and ecological processes governing these relationships do not necessarily "scale up" from small-scale, in-situ observations to whole reefs and seascapes. In Chapter 1, I combine in-situ dive surveys with high-resolution habitat maps to investigate how associations between reproductive potential of the kelp bass (Paralabrax clathratus) and kelp forest habitat attributes translate between within- and among-reef spatial scales. Macroalgae and benthic rugosity explain the most variation in reproductive potential within reefs, but the configuration of available habitat explains more variation among reefs. I propose that a mismatch between processes operating at different spatial scales is responsible for these results and suggest that future efforts to clarify among-reef relationships are necessary to estimate reproductive potential of fishes on rocky reefs. Marine reserves are an integral management tool to protect biomass and rebuild depleted fisheries, particularly when important locations for larval production are protected. However, given the uncertainty and temporally dynamic nature of spatially-structured populations, rotating closures might provide a more adaptive solution to both conserve and utilize built-up biomass. In Chapter 2, I construct an age-structured population model with spatially-structured larval productivity to compare the relative efficacy of marine reserves and rotating closures at achieving conservation and fishery management goals. Given a population with a static larval production location, rotating closures outperform permanently fishing the larval production location but underperform permanently protecting the larval production location in the source in terms of total biomass and yield. When the location of the larval production varies in time, permanent reserves generally sustain higher biomass but rotating closures allow for higher fishery yield, and these results are robust to uncertainty in the location of the larval production in any given year. Rotating closures may therefore better buffer against spatial uncertainty in production locations while permanent reserves buffer against temporal uncertainty. Many marine populations are subject to considerable interannual variation in critical demographic rates such as larval dispersal and survival, and such variation may obscure short-term population responses to protection by marine reserves. In Chapter 3, I consider an age-structured population with stochastic variation in larval survival and population openness to explore the conditions under which managers might expect to observe population responses contrary to deterministic projections through the first 10 years of reserve protection. While the shape of stochasticity in larval survival does not have a strong effect on the ability to detect population changes due to reserve protection, temporal autocorrelation in survival does increase the risk of failing to detect a reserve effect. The degree of population openness may indirectly affect recovery trajectories by changing intrinsic population growth rates, but resolving overall larval survival matters more to detecting reserve effects than does resolving larval origin.
Download or read book Rocky Reef Fish Connectivity written by Geoffrey Scott Cook and published by . This book was released on 2011 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: The extent to which marine populations are connected by dispersing larvae and the ramifications of this connectivity for population dynamics was investigated for the temperate damselfish, Hypsypops rubicundus, in San Diego County, USA. Surveys identified six source populations for this species: Carlsbad, Cardiff, Torrey Pines, La Jolla, Mission Point, and Zuniga Point. Three of these reefs are within or adjacent to existing marine protected areas. Trace elemental fingerprinting was used to quantify the connectivity of populations in 2008-2009. High-resolution sampling over a protracted spawning season revealed that elemental fingerprints of reefs earlier in the spawning season became indistinguishable from other reefs later in the spawning season, resulting in inaccurate assignment of natal origin of post-dispersal fish. When natal origins of fish were assessed using appropriately binned data, one reef, La Jolla, emerged as the predominant source population, supplying itself and three other reefs with recruits. The northernmost reef, Cardiff was a "pure" sink, in that it unilaterally imported fish. Dispersal trajectories predominantly were in a northerly direction, but sporadic southerly dispersal was documented, corresponding to empirically measured current reversals. On intra-annual time scales this network of reefs resembles a source-sink metapopulation, but over annual time scales it functions as an open metapopulation with a well-mixed larval pool. To assess the demographic significance of observed connectivity patterns, empirically parameterized, stage-based matrix models were coupled with connectivity matrices. Elasticity analyses suggest inter-reef connectivity acts primarily to regulate which vital rates are demographically most significant; at low levels of connectivity adult survivorship has the greatest influence on population growth rate; at high levels of connectivity, juvenile growth is most influential. Quantitative metrics of sources and sinks were developed and node deletion experiments conducted to better characterize reef connectivity within the metapopulation. La Jolla was identified as the most valuable reef within the metapopulation in terms of connectivity; it may regulate how populations of fish at other reefs persist over time, and as such should be a conservation priority. New knowledge of the magnitude, directionality and variability of connectivity, and its roles in regulating local and metapopulation dynamics will aid local marine conservation efforts.
Download or read book The Galapagos Marine Reserve written by Judith Denkinger and published by Springer Science & Business Media. This book was released on 2014-01-24 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on how marine systems respond to natural and anthropogenic perturbations (ENSO, overfishing, pollution, tourism, invasive species, climate-change). Authors explain in their chapters how this information can guide management and conservation actions to help orient and better manage, restore and sustain the ecosystems services and goods that are derived from the ocean, while considering the complex issues that affect the delicate nature of the Islands. This book will contribute to a new understanding of the Galapagos Islands and marine ecosystems.
Download or read book Use of a Towed Camera System for Estimating Reef Fish Populations Densities on the West Florida Shelf written by Sarah Elizabeth Grasty and published by . This book was released on 2014 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reef fish species tend to reside over high relief habitat which makes them difficult to sample with traditional gears such as nets and trawls. Therefore, implementing and understanding the strengths and weaknesses of new approaches which incorporate acoustic and optical methods has become a priority for reef fish stock assessment. Beginning in June of 2013, a towed camera system known as the Camera-Based Assessment Survey System (C-BASS) has been used to visualize over 500 kilometers of transect and record more than 80 hours of video over several habitats in the Gulf of Mexico. Surveys have been completed on the West Florida Shelf in the Florida Middle Grounds (FMG), Madison-Swanson (MS) and Steamboat Lumps (SL) closed areas. High resolution multibeam bathymetry is available for these areas and was important for the deployment of C-BASS which is towed just above the seafloor (2-3 meters above the bottom). This system can facilitate regular surveys of fishes which inhabit untrawlable bottom types (e.g. reefs, pinnacles, boulders) and within habitats where lethal, extractive techniques are prohibited such as in protected areas. To address potential biases resulting from fish reactions towards C-BASS, observed reactive behavior was analyzed in addition to far-field reactive behavior towards C-BASS using stationary camera pods. Most fish observed on C-BASS imagery exhibited weak negative or neutral behavior at proportions of 49% and 38%, respectively. Of those fish which did negatively react to C-BASS, almost all movement was in the 180° and 0° directions (right and left) relative to the tow body's movement. Preliminary results from the direct observation (far-field) experiments also demonstrated a general lack of reactive behavior as C-BASS was towed nearby with no significant decreases in mean abundance of fishes between the periods before, during and after C-BASS was towed over an area (95% confidence level). Although behavioral reactions are species-specific, results indicate that the system may not greatly deter the species of interest (i.e. snappers, groupers, porgies, lionfish, and amberjacks) in this study. Density estimates and subsequent first-order total abundance estimates were also developed for stratified habitat types in the FMG and MS. Overall abundance estimates were greater in 2014 than in 2013 which likely were a result of increased illumination, improvements to video quality, and lower chlorophyll and turbidity levels in 2014. With minor improvements and further behavior analysis, it is expected C-BASS can provide accurate, precise abundance estimates of target reef fish species for management purposes.
