Tidal Habitats Support Large Numbers of Invasive Blue Catfish in a Chesapeake Bay Subestuary     

Mary C. Fabrizio  Troy D. Tuckey  Robert J. Latour  Gary C. White  Alicia J. Norris 《Estuaries and Coasts》2018,41(3):827-840

The introduction of a non-native freshwater fish, blue catfish Ictalurus furcatus, in tributaries of Chesapeake Bay resulted in the establishment of fisheries and in the expansion of the population into brackish habitats. Blue catfish are an invasive species in the Chesapeake Bay region, and efforts are underway to limit their impacts on native communities. Key characteristics of the population (population size, survival rates) are unknown, but such knowledge is useful in understanding the impact of blue catfish in estuarine systems. We estimated population size and survival rates of blue catfish in tidal habitats of the James River subestuary. We tagged 34,252 blue catfish during July–August 2012 and 2013; information from live recaptures (n = 1177) and dead recoveries (n = 279) were used to estimate annual survival rates and population size using Barker’s Model in a Robust Design and allowing for heterogeneity in detection probabilities. The blue catfish population in the 12-km study area was estimated to be 1.6 million fish in 2013 (95% confidence interval [CI] adjusted for overdispersion: 926,307–2,914,208 fish). Annual apparent survival rate estimates were low: 0.16 (95% CI 0.10–0.24) in 2012–2013 and 0.44 (95% CI 0.31–0.58) in 2013–2014 and represent losses from the population through mortality, permanent emigration, or both. The tagged fish included individuals that were large enough to exhibit piscivory and represented size classes that are likely to colonize estuarine habitats. The large population size that we estimated was unexpected for a freshwater fish in tidal habitats and highlights the need to effectively manage such species.  相似文献   

A review of the ocean science and technology partnership between US and Korea     

Dong-Oh Cho  Mary Anne Whitcomb 《Marine Policy》2008

In 2001, the National Oceanic and Atmospheric Administration (NOAA) and the Ministry of Maritime Affairs and Fisheries Integrated Coastal and Ocean Resources Scientific and Technical Arrangement was signed to pursue scientific and technical cooperation in integrated coastal and ocean resources management in the mutual interest of the participants. Over the last 6 years, the cooperation has been very beneficial, particularly for advancing marine science and management programs in Korea, such as Deep Sea Aquaculture, Sea Grant College Program, Marine Protected Areas, and Ocean Observations. The benefits to NOAA from the cooperation include Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys, ocean and coastal observations, GEOSS program, and Global Program of Action. Also the cooperation has spillover effects on other ocean science and technological arrangement between US and Korea. This article reviews purpose, obstacles, and achievement of the cooperation and suggests recommendations for the future steps.  相似文献   

Combining pixel and object based image analysis of ultra-high resolution multibeam bathymetry and backscatter for habitat mapping in shallow marine waters     

Daniel Ierodiaconou  Alexandre C. G. Schimel  David Kennedy  Jacquomo Monk  Grace Gaylard  Mary Young  Markus Diesing  Alex Rattray 《Marine Geophysical Researches》2018,39(1-2):271-288

Habitat mapping data are increasingly being recognised for their importance in underpinning marine spatial planning. The ability to collect ultra-high resolution (cm) multibeam echosounder (MBES) data in shallow waters has facilitated understanding of the fine-scale distribution of benthic habitats in these areas that are often prone to human disturbance. Developing quantitative and objective approaches to integrate MBES data with ground observations for predictive modelling is essential for ensuring repeatability and providing confidence measures for habitat mapping products. Whilst supervised classification approaches are becoming more common, users are often faced with a decision whether to implement a pixel based (PB) or an object based (OB) image analysis approach, with often limited understanding of the potential influence of that decision on final map products and relative importance of data inputs to patterns observed. In this study, we apply an ensemble learning approach capable of integrating PB and OB Image Analysis from ultra-high resolution MBES bathymetry and backscatter data for mapping benthic habitats in Refuge Cove, a temperate coastal embayment in south-east Australia. We demonstrate the relative importance of PB and OB seafloor derivatives for the five broad benthic habitats that dominate the site. We found that OB and PB approaches performed well with differences in classification accuracy but not discernible statistically. However, a model incorporating elements of both approaches proved to be significantly more accurate than OB or PB methods alone and demonstrate the benefits of using MBES bathymetry and backscatter combined for class discrimination.  相似文献   

The potential of wetlands in reducing storm surge     

Ty V. Wamsley  Mary A. Cialone  John H. Atkinson 《Ocean Engineering》2010,37(1):59-47

A critical component of flood protection in some coastal areas is expected to be the potential contribution of wetlands to the lowering of surges as they propagate inland from the coast. Consequently, an accurate method to quantify the effect of wetlands on coastal surge levels is required. The degree to which wetlands attenuate surge is the subject of debate and difficult to assess. The potential of wetlands to reduce storm surge has typically been expressed as a constant attenuation rate, but the relationship is much more complex. A numerical storm surge model was applied to assess the sensitivity of surge response to specified wetland loss. Results suggest that wetlands do have the potential to reduce surges but the magnitude of attenuation is dependent on the surrounding coastal landscape and the strength and duration of the storm forcing. Numerical models that simulate the relevant physical processes can provide valuable information on how to best integrate wetlands into coastal protection plans. However, while the model applied for this study has displayed skill in estimating surges over wetlands, the formulations are missing key processes and model advancements are necessary.  相似文献   

The effects of trophic interactions and spatial competition on algal community composition on Hawaiian coral reefs     

Mark J. A. Vermeij  Meghan L. Dailer  Sheila M. Walsh  Mary K. Donovan  Celia M. Smith 《Marine Ecology》2010,31(2):291-299

Much of coral reef ecology has focused on how human impacts change coral reefs to macroalgal reefs. However, macroalgae may not always be a good indicator of reef decline, especially on reefs with significant sea urchin populations, as found in Kenya and Hawaii. This study tests the effects of trophic interactions (i.e. herbivory by fishes and sea urchins) and spatial competition (between algae and coral) on algal community structure of reefs surrounding two Hawaiian Islands that vary in their level of human impacts. Reef‐building organisms (corals and crustose coralline algae) were less abundant and turf algae were more abundant on Maui as compared to Lanai, where human impacts are lower. In contrast to previous studies, we found no evidence that macroalgae increased with human impacts. Instead, low turf and macroalgal abundance were best explained by the interactive effects of coral cover and sea urchin abundance. Fishing sea urchin predators appeared to have cascading effects on the benthic community. The absence of sea urchin predators and high sea urchin densities correspond to a disproportionately high abundance of turf and crustose coralline algae. We propose that high turf algal abundance is a better indicator of reef decline in Hawaii than high macroalgal abundance because turf abundance was highest on reefs with low coral cover and few fish. The results of this study emphasize that understanding changes in community composition are context‐dependent and that not all degraded reefs look the same.  相似文献   

Guiding ecological principles for marine spatial planning     

Melissa M. Foley  Benjamin S. Halpern  Fiorenza Micheli  Matthew H. Armsby  Margaret R. Caldwell  Caitlin M. Crain  Erin Prahler  Nicole Rohr  Deborah Sivas  Michael W. Beck  Mark H. Carr  Larry B. Crowder  J. Emmett Duffy  Sally D. Hacker  Karen L. McLeod  Stephen R. Palumbi  Charles H. Peterson  Helen M. Regan  Mary H. Ruckelshaus  Paul A. Sandifer  Robert S. Steneck 《Marine Policy》2010

The declining health of marine ecosystems around the world is evidence that current piecemeal governance is inadequate to successfully support healthy coastal and ocean ecosystems and sustain human uses of the ocean. One proposed solution to this problem is ecosystem-based marine spatial planning (MSP), which is a process that informs the spatial distribution of activities in the ocean so that existing and emerging uses can be maintained, use conflicts reduced, and ecosystem health and services protected and sustained for future generations. Because a key goal of ecosystem-based MSP is to maintain the delivery of ecosystem services that humans want and need, it must be based on ecological principles that articulate the scientifically recognized attributes of healthy, functioning ecosystems. These principles should be incorporated into a decision-making framework with clearly defined targets for these ecological attributes. This paper identifies ecological principles for MSP based on a synthesis of previously suggested and/or operationalized principles, along with recommendations generated by a group of twenty ecologists and marine scientists with diverse backgrounds and perspectives on MSP. The proposed four main ecological principles to guide MSP—maintaining or restoring: native species diversity, habitat diversity and heterogeneity, key species, and connectivity—and two additional guidelines, the need to account for context and uncertainty, must be explicitly taken into account in the planning process. When applied in concert with social, economic, and governance principles, these ecological principles can inform the designation and siting of ocean uses and the management of activities in the ocean to maintain or restore healthy ecosystems, allow delivery of marine ecosystem services, and ensure sustainable economic and social benefits.  相似文献   

Differential effects of salinity changes on two estuarine fishes,Leiostomus xanthurus andMicropogonias undulatus     

Mary L. Moser  Lawrence R. Gerry 《Estuaries and Coasts》1989,12(1):35-41

Salinity fluctuation has been proposed as an important determinant of estuarine fish distribution. To test this idea, we compared distribution, behavioral preference and physiological sensitivity of two juvenile estuarine fishes, spot (Leiostomus xanthurus) and croaker (Micropogonias undulatus), with respect to salinity change. In field collections, spot: croaker ratios were positively correlated with salinity variation. Subsequent behavioral observations revealed that croaker tend to cross a 10‰ salinity gradient less often than spot. We proposed that energetic costs of salinity adaptation may be higher for croaker, resulting in the observed avoidance behavior. Oxygen consumption rates over rapid salinity fluctuations showed no significant differences in metabolic response between species, although there was some indication that sensitivity changes with fish size. Apparently, juvenile spot and croaker are well-equipped to withstand extreme changes in salinity. We conclude that environmental factors correlated with salinity change may be responsible for distribution differences between these two abundant species.  相似文献   

The Sensitivity of Four Monitoring Well Sampling Systems to Low Concentrations of Three Volatile Organics     

Ronald Schalla  David A. Myers  Mary Ann Simmons  John M. Thomas  Antony P. Toste 《Ground Water Monitoring & Remediation》1988,8(3):90-96

Four state-of-the-art ground water sampling systems were analyzed to determine their reliability in providing representative samples of the volatile chlorinated hydrocarbons trichloroethylene (TCE), perchloroethylene (PCE), and 1,1,1-trichloroethane (TCA) from a simulated monitoring well. The sampling systems studied represent four commonly used devices, including a stainless steel and Teflon® piston pump, a Teflon bailer, a Teflon bladder pump, and a PVC air-lift pump.
Controlled laboratory sampling experiments were conducted in a tank and well test chamber designed to approximate field conditions. A well purging and sampling procedure was used in the test apparatus to determine the accuracy and precision of each device for detecting low concentrations of the compounds in ground water. The compounds selected are some of the most ubiquitous hazardous contaminants found in shallow aquifers near hazardous waste sites throughout the United States.
No significant statistical difference was found among the four sampling systems in detecting the compounds.  相似文献   

The autecology and production dynamics of eelgrass (Zostera marina L.) in Netarts Bay,Oregon     

Mary E. Kentula  C. David McIntire 《Estuaries and Coasts》1986,9(3):188-199

Changes in biomass, growth form and shoot net primary production in an eelgrass, Zostera marina L., bed were monitored along transects at three tidal heights in Netarts Bay, Oregon, from May 1979 through June 1981. During the growing season, April through October, the mean plastochrone interval was 16.5 d along the low intertidal transect and 11.6 d along the high intertidal transect. The mean export interval was 13.3 d along the low intertidal transect and 11.6 d along the high intertidal transect. The life span of a leaf averaged 48 d along the low intertidal transect and 36 d along the high intertidal transect. Shoot density was positively correlated with mean leaf area index (LAI) until the LAI reached 3.8 to 5.5, above which LAI was negatively correlated with density. The maximum Zostera biomass ranged from 143 (high intertidal transect) to 463 (low intertidal transect) g dry wt m^?2. Maximum values of shoot net production ranged from 4.7 (high intertidal transect) to 13.6 (low intertidal transect) g dry wt m^?2d^?1. Zostera shoot net production was related to light and to the physical damage to the shoots associated with a rapid accumulation of Enteromorpha biomass in the bay. In addition, patterns of biomass accumulation were related to the duration of water coverage, as determined by both tidal height and local impoundments of water. At all transects, biomass sloughed was equal to at least 50% of the shoot net primary production in that area during that time period; sloughed leaves accounted for 25 to 97% of these losses. An estimate of the total annual net primary production of aboveground Zostera in the bed was 17,500 kg, dry wt (SE=3,080 kg dry wt), which was equivalent to a mean annual rate of 383 g C m^?2 (SE=67 g C m^?2)  相似文献   

Iron metal production in silicate melts through the direct reduction of Fe(II) by Ti(III), Cr(II), and Eu(II)     

Henry D. Schreiber  G.Bryan Balazs  Andrew P. Shaffer  P.Lynne Jamison 《Geochimica et cosmochimica acta》1982,46(10):1891-1901

The production of metallic iron in silicate melts by the chemical reactions, 2Ti³⁺_(melt) + Fe²⁺_(melt) → 2Ti⁴⁺_(melt) + Fe⁰_(crystal)2Cr²⁺_(melt) + Fe²⁺_(melt) → 2Cr³⁺_(melt) + Fe⁰_(crystal)2Eu²⁺_(melt)+ Fe²⁺_(melt) → 2Eu³⁺_(melt) + Fe⁰_(crystal) has been demonstrated under experimental conditions in a simplified basaltic liquid, Such reactions may occur in lunar basalts and other reduced systems, and, thus, may aid in the understanding of the reduced nature of lunar basalts. The reactions were studied in a glass-forming Na-Ca-Mg-Al-silicate composition at a melt temperature of 1250°C and an imposed oxygen fugacity at the C/CO buffer (1 atm total pressure). Microtitrations of individually-doped samples were used in the quantitative assessment of their redox ratios and for the calibration of visible and near-infrared spectral absorptions. These spectral absorptions were then applied to the evaluation of the mutual redox interactions in dual-doped samples.  相似文献