Levesque J.C.,CSA International Inc
Wildlife Biology in Practice | Year: 2010
Natural Resource management is evolving toward ensuring sustainable ecosystems rather than sustainable yields. Understanding how a species interacts with its environment is fundamental for sound ecosystem management. If we are progressing toward an ecosystem management approach, then we must first understand how a species interacts with its environment and how the environment affects a species population dynamics. Ladyfish (Elops saurus) are a valuable commercial and recreational species; however, limited information is available describing the importance of their habitat. To date, only a few studies have noted the environmental conditions during ladyfish field-collections, and only one study has investigated ladyfish nursery habitats in any detail. Given the economic importance of ladyfish in Florida (USA), the objective of this investigation was to define, for the first time, juvenile ladyfish relative abundance in association to environmental conditions and habitat use at multiple Florida estuaries. In addition, this investigation re-examined some of the scientific findings and conclusions of previous ladyfish studies; incorporated additional data sets; and evaluated available ladyfish data at a finer scale of phenomena. Overall, juvenile ladyfish were collected in waters with wide-ranging environmental conditions having a sandy bottom, but preferred specific locations with particular dissolved oxygen, pH, water temperature, and salinity levels according to their size.
Dungan C.F.,Cooperative Oxford Laboratory |
Carnegie R.B.,Virginia Institute of Marine Science |
Hill K.M.,Virginia Institute of Marine Science |
Hill K.M.,Smithsonian Institution |
And 6 more authors.
Diseases of Aquatic Organisms | Year: 2012
To assess potential benefits and liabilities from a proposed introduction of Asian Suminoe oysters, susceptibilities of exotic Crassostrea ariakensis and native C. virginica oysters were compared during exposures to pathogens endemic in temperate, mesohaline waters of Chesapeake Bay and sub-tropical, polyhaline Atlantic waters of southern Florida, USA. Cohorts of diploid, sibling oysters of both species were periodically tested for diseases while reared in mesocosms receiving ambient waters from the Choptank River, Maryland (>3 yr) or the Indian River Lagoon, Florida (10 to 11 mo). Haplosporidium sp. infections (e.g. MSX disease) were not detected in oysters from either site. Perkinsus sp. infections (dermo disease) occurred among members of both oyster species at both sites, but infections were generally of low or moderate intensities. A Bonamia sp. was detected by PCR of DNAs from tissues of both oyster species following exposure to Florida waters, with maximum PCR prevalences of 44 and 15% among C. ariakensis and C. virginica oysters respectively during June 2007. Among C. ariakensis oysters sampled during April to July 2007, a Bonamia sp. was detected in 31% of oysters by PCR (range 11 to 35%) and confirmed histologically in 10% (range 0 to 15%). Among simultaneously sampled C. virginica oysters, a Bonamia sp. was detected in 7% by PCR (range 0 to 15%), but histological lesions were absent. Although this is the first report of a Bonamia sp. from Florida waters, sequences of small subunit (SSU) rDNA and in situ hybridization (ISH) assays both identified the Florida pathogen as Bonamia exitiosa, which also infects oysters in the proximate waters of North Carolina, USA. © Inter-Research 2012.
Levesque J.C.,CSA International Inc
ICES Journal of Marine Science | Year: 2011
Marine resource managers designate marine protected areas (MPAs) to conserve, protect, and enhance fragile marine resources. A form of MPAs sometimes used by resource managers in the United States is a national marine sanctuary (NMS), and for all MPAs, managers need to use updated information during sanctuary management plan reviews (MPRs). In 2006, the Flower Garden Banks NMS (FGBNMS) began its first MPR by conducting public hearings and soliciting comments. Some 66% of comments were about the potential impacts fisheries posed to the sanctuary, so a description of commercial fishery activity in the NW Gulf of Mexico can help guide resource managers make sound, informed decisions. Despite limitations on data and knowledge of fishing effort spatially for the FGBNMS, commercial landings vary by Gulf state, area, and fishing gear, with most landings from the Louisiana and Texas coasts taken with trawls and nets. The main species landed from the NW Gulf of Mexico are shrimp, yellowfin tuna, and red snapper. Some conservation measures proposed for the FGBNMS will likely impact some commercial fisheries (hook and line, bottom longline), but not others (otter trawl, pelagic longline). © 2011 International Council for the Exploration of the Sea.
Levesque J.C.,CSA International Inc
Reviews in Fisheries Science | Year: 2011
Understanding a species life history is fundamental for managing and conserving a population. Despite the importance of this type of information, research attention is often directed at species with the highest economic value. This funding approach is problematic for preserving diversity and rarely considers ecological systematic functions; it prevents resource agencies from allocating funds for studying lower-valued species. For example, the ladyfish (Elops saurus) is a valuable commercial and recreational species in Florida, but in comparison to tarpon (Megalops atlanticus) and bonefish (Albula vulpes), ladyfish have received less funding and research attention. To date, comparably little biological information and no recent reviews are available for ladyfish; research interest is almost non-existent. First, a new review of ladyfish information is provided, and second, statistical evidence is presented and discussed that suggests that there is more published information for tarpon and bonefish than ladyfish because their socio-ecological values are greater. This study’s findings confirm that there are significantly more published articles on tarpon than ladyfish, and the number of articles on ladyfish has declined with time. The number of articles on tarpon and bonefish were positively correlated with time, while the number of articles on ladyfish was negatively correlated with time. Natural resource management is shifting from a sustainable yield to a sustainable ecosystem perspective. Given this shift in management approach, successful ecosystem management requires substantial biological information on a variety of species within a given system, regardless of their socio-economic status. It is important to understand that although some species have been ranked higher than others, in terms of economic importance, ecosystems are functioning systems that do not discriminate or have any jurisdictional boundaries. © Taylor and Francis Group, LLC.
Csa International Inc. | Date: 2012-08-15
An apparatus comprises at least one cutting jet configured to inject a fluid into a first layer of soil below a surface layer of underwater soil in a first region. At least one soil extractor is configured to remove at least a portion of the injected fluid and a portion of the first layer of soil in the first region. A mixing manifold is provided for mixing the removed portion of the injected fluid and the removed portion of the first layer of soil. A discharge is provided for depositing the mixed fluid and soil over the surface layer of underwater soil.