19 resultados para Specialized didactics

em Aquatic Commons


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Common salvinia (Salvinia minima Baker) is an exotic floating fern that has been in the U.S. from at least 1928(Small 1931). Its pest status in Florida is less clear perhaps due to the presence of the specialized herbivore Cyrtobagous salviniae (Coleoptera: Curculionidae). Our objective was to sample populations of adult C. salviniae in south Florida in order to assess temporal abundance and estimate density on common salvinia. (PDF has 4 pages.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This technical memorandum documents the design, implementation, data preparation, and descriptive results for the 2006 Annual Economic Survey of Federal Gulf Shrimp Permit Holders. The data collection was designed by the NOAA Fisheries Southeast Fisheries Science Center Social Science Research Group to track the financial and economic status and performance by vessels holding a federal moratorium permit for harvesting shrimp in the Gulf of Mexico. A two page, self-administered mail survey collected total annual costs broken out into seven categories and auxiliary economic data. In May 2007, 580 vessels were randomly selected, stratified by state, from a preliminary population of 1,709 vessels with federal permits to shrimp in offshore waters of the Gulf of Mexico. The survey was implemented during the rest of 2007. After many reminder and verification phone calls, 509 surveys were deemed complete, for an ineligibility-adjusted response rate of 90.7%. The linking of each individual vessel’s cost data to its revenue data from a different data collection was imperfect, and hence the final number of observations used in the analyses is 484. Based on various measures and tests of validity throughout the technical memorandum, the quality of the data is high. The results are presented in a standardized table format, linking vessel characteristics and operations to simple balance sheet, cash flow, and income statements. In the text, results are discussed for the total fleet, the Gulf shrimp fleet, the active Gulf shrimp fleet, and the inactive Gulf shrimp fleet. Additional results for shrimp vessels grouped by state, by vessel characteristics, by landings volume, and by ownership structure are available in the appendices. The general conclusion of this report is that the financial and economic situation is bleak for the average vessels in most of the categories that were evaluated. With few exceptions, cash flow for the average vessel is positive while the net revenue from operations and the “profit” are negative. With negative net revenue from operations, the economic return for average shrimp vessels is less than zero. Only with the help of government payments does the average owner just about break even. In the short-term, this will discourage any new investments in the industry. The financial situation in 2006, especially if it endures over multiple years, also is economically unsustainable for the average established business. Vessels in the active and inactive Gulf shrimp fleet are, on average, 69 feet long, weigh 105 gross tons, are powered by 505 hp motor(s), and are 23 years old. Three-quarters of the vessels have steel hulls and 59% use a freezer for refrigeration. The average market value of these vessels was $175,149 in 2006, about a hundred-thousand dollars less than the average original purchase price. The outstanding loans averaged $91,955, leading to an average owner equity of $83,194. Based on the sample, 85% of the federally permitted Gulf shrimp fleet was actively shrimping in 2006. Of these 386 active Gulf shrimp vessels, just under half (46%) were owner-operated. On average, these vessels burned 52,931 gallons of fuel, landed 101,268 pounds of shrimp, and received $2.47 per pound of shrimp. Non-shrimp landings added less than 1% to cash flow, indicating that the federal Gulf shrimp fishery is very specialized. The average total cash outflow was $243,415 of which $108,775 was due to fuel expenses alone. The expenses for hired crew and captains were on average $54,866 which indicates the importance of the industry as a source of wage income. The resulting average net cash flow is $16,225 but has a large standard deviation. For the population of active Gulf shrimp vessels we can state with 95% certainty that the average net cash flow was between $9,500 and $23,000 in 2006. The median net cash flow was $11,843. Based on the income statement for active Gulf shrimp vessels, the average fixed costs accounted for just under a quarter of operating expenses (23.1%), labor costs for just over a quarter (25.3%), and the non-labor variable costs for just over half (51.6%). The fuel costs alone accounted for 42.9% of total operating expenses in 2006. It should be noted that the labor cost category in the income statement includes both the actual cash payments to hired labor and an estimate of the opportunity cost of owner-operators’ time spent as captain. The average labor contribution (as captain) of an owner-operator is estimated at about $19,800. The average net revenue from operations is negative $7,429, and is statistically different and less than zero in spite of a large standard deviation. The economic return to Gulf shrimping is negative 4%. Including non-operating activities, foremost an average government payment of $13,662, leads to an average loss before taxes of $907 for the vessel owners. The confidence interval of this value straddles zero, so we cannot reject, with 95% certainty, that the population average is zero. The average inactive Gulf shrimp vessel is generally of a smaller scale than the average active vessel. Inactive vessels are physically smaller, are valued much lower, and are less dependent on loans. Fixed costs account for nearly three quarters of the total operating expenses of $11,926, and only 6% of these vessels have hull insurance. With an average net cash flow of negative $7,537, the inactive Gulf shrimp fleet has a major liquidity problem. On average, net revenue from operations is negative $11,396, which amounts to a negative 15% economic return, and owners lose $9,381 on their vessels before taxes. To sustain such losses and especially to survive the negative cash flow, many of the owners must be subsidizing their shrimp vessels with the help of other income or wealth sources or are drawing down their equity. Active Gulf shrimp vessels in all states but Texas exhibited negative returns. The Alabama and Mississippi fleets have the highest assets (vessel values), on average, yet they generate zero cash flow and negative $32,224 net revenue from operations. Due to their high (loan) leverage ratio the negative 11% economic return is amplified into a negative 21% return on equity. In contrast, for Texas vessels, which actually have the highest leverage ratio among the states, a 1% economic return is amplified into a 13% return on equity. From a financial perspective, the average Florida and Louisiana vessels conform roughly to the overall average of the active Gulf shrimp fleet. It should be noted that these results are averages and hence hide the variation that clearly exists within all fleets and all categories. Although the financial situation for the average vessel is bleak, some vessels are profitable. (PDF contains 101 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coral reefs exist in warm, clear, and relatively shallow marine waters worldwide. These complex assemblages of marine organisms are unique, in that they support highly diverse, luxuriant, and essentially self-sustaining ecosystems in otherwise nutrient-poor and unproductive waters. Coral reefs are highly valued for their great beauty and for their contribution to marine productivity. Coral reefs are favorite destinations for recreational diving and snorkeling, as well as commercial and recreational fishing activities. The Florida Keys reef tract draws an estimated 2 million tourists each year, contributing nearly $800 million to the economy. However, these reef systems represent a very delicate ecological balance, and can be easily damaged and degraded by direct or indirect human contact. Indirect impacts from human activity occurs in a number of different forms, including runoff of sediments, nutrients, and other pollutants associated with forest harvesting, agricultural practices, urbanization, coastal construction, and industrial activities. Direct impacts occur through overfishing and other destructive fishing practices, mining of corals, and overuse of many reef areas, including damage from souvenir collection, boat anchoring, and diver contact. In order to protect and manage coral reefs within U.S. territorial waters, the National Oceanic and Atmospheric Administration (NOAA) of the U.S. Department of Commerce has been directed to establish and maintain a system of national marine sanctuaries and reserves, and to monitor the condition of corals and other marine organisms within these areas. To help carry out this mandate the NOAA Coastal Services Center convened a workshop in September, 1996, to identify current and emerging sensor technologies, including satellite, airborne, and underwater systems with potential application for detecting and monitoring corals. For reef systems occurring within depths of 10 meters or less (Figure 1), mapping location and monitoring the condition of corals can be accomplished through use of aerial photography combined with diver surveys. However, corals can exist in depths greater than 90 meters (Figure 2), well below the limits of traditional optical imaging systems such as aerial or surface photography or videography. Although specialized scuba systems can allow diving to these depths, the thousands of square kilometers included within these management areas make diver surveys for deeper coral monitoring impractical. For these reasons, NOAA is investigating satellite and airborne sensor systems, as well as technologies which can facilitate the location, mapping, and monitoring of corals in deeper waters. The following systems were discussed as having potential application for detecting, mapping, and assessing the condition of corals. However, no single system is capable of accomplishing all three of these objectives under all depths and conditions within which corals exist. Systems were evaluated for their capabilities, including advantages and disadvantages, relative to their ability to detect and discriminate corals under a variety of conditions. (PDF contains 55 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The health and continued existence of coral reef ecosystems are threatened by an increasing array of environmental and anthropogenic impacts. Coral disease is one of the prominent causes of increased mortality among reefs globally, particularly in the Caribbean. Although over 40 different coral diseases and syndromes have been reported worldwide, only a few etiological agents have been confirmed; most pathogens remain unknown and the dynamics of disease transmission, pathogenicity and mortality are not understood. Causal relationships have been documented for only a few of the coral diseases, while new syndromes continue to emerge. Extensive field observations by coral biologists have provided substantial documentation of a plethora of new pathologies, but our understanding, however, has been limited to descriptions of gross lesions with names reflecting these observations (e.g., black band, white band, dark spot). To determine etiology, we must equip coral diseases scientists with basic biomedical knowledge and specialized training in areas such as histology, cell biology and pathology. Only through combining descriptive science with mechanistic science and employing the synthesis epizootiology provides will we be able to gain insight into causation and become equipped to handle the pending crisis. One of the critical challenges faced by coral disease researchers is to establish a framework to systematically study coral pathologies drawing from the field of diagnostic medicine and pathology and using generally accepted nomenclature. This process began in April 2004, with a workshop titled Coral Disease and Health Workshop: Developing Diagnostic Criteria co-convened by the Coral Disease and Health Consortium (CDHC), a working group organized under the auspices of the U.S. Coral Reef Task Force, and the International Registry for Coral Pathology (IRCP). The workshop was hosted by the U.S. Geological Survey, National Wildlife Health Center (NWHC) in Madison, Wisconsin and was focused on gross morphology and disease signs observed in the field. A resounding recommendation from the histopathologists participating in the workshop was the urgent need to develop diagnostic criteria that are suitable to move from gross observations to morphological diagnoses based on evaluation of microscopic anatomy. (PDF contains 92 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Alliance for Coastal Technologies (ACT) Workshop on Towed Vehicles: Undulating Platforms As Tools for Mapping Coastal Processes and Water Quality Assessment was convened February 5-7,2007 at The Embassy Suites Hotel, Seaside, California and sponsored by the ACT-Pacific Coast partnership at the Moss Landing Marine Laboratories (MLML). The TUV workshop was co-chaired by Richard Burt (Chelsea Technology Group) and Stewart Lamerdin (MLML Marine Operations). Invited participants were selected to provide a uniform representation of the academic researchers, private sector product developers, and existing and potential data product users from the resource management community to enable development of broad consensus opinions on the application of TUV platforms in coastal resource assessment and management. The workshop was organized to address recognized limitations of point-based monitoring programs, which, while providing valuable data, are incapable of describing the spatial heterogeneity and the extent of features distributed in the bulk solution. This is particularly true as surveys approach the coastal zone where tidal and estuarine influences result in spatially and temporally heterogeneous water masses and entrained biological components. Aerial or satellite based remote sensing can provide an assessment of the aerial extent of plumes and blooms, yet provide no information regarding the third dimension of these features. Towed vehicles offer a cost-effective solution to this problem by providing platforms, which can sample in the horizontal, vertical, and time-based domains. Towed undulating vehicles (henceforth TUVs) represent useful platforms for event-response characterization. This workshop reviewed the current status of towed vehicle technology focusing on limitations of depth, data telemetry, instrument power demands, and ship requirements in an attempt to identify means to incorporate such technology more routinely in monitoring and event-response programs. Specifically, the participants were charged to address the following: (1) Summarize the state of the art in TUV technologies; (2) Identify how TUV platforms are used and how they can assist coastal managers in fulfilling their regulatory and management responsibilities; (3) Identify barriers and challenges to the application of TUV technologies in management and research activities, and (4) Recommend a series of community actions to overcome identified barriers and challenges. A series of plenary presentation were provided to enhance subsequent breakout discussions by the participants. Dave Nelson (University of Rhode Island) provided extensive summaries and real-world assessment of the operational features of a variety of TUV platforms available in the UNOLs scientific fleet. Dr. Burke Hales (Oregon State University) described the modification of TUV to provide a novel sampling platform for high resolution mapping of chemical distributions in near real time. Dr. Sonia Batten (Sir Alister Hardy Foundation for Ocean Sciences) provided an overview on the deployment of specialized towed vehicles equipped with rugged continuous plankton recorders on ships of opportunity to obtain long-term, basin wide surveys of zooplankton community structure, enhancing our understanding of trends in secondary production in the upper ocean. [PDF contains 32 pages]

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The importance of fishing gear in fishing cannot be over-emphasized; as without it fish cannot be obtained. The method used to catch fish affects the condition in which the product is landed. This means that a bad-catching method would produced bad fish to the consumer. To achieve the goal of self-sufficiency in fish production in Nigeria, there is need to address the lingering problems of fishing gear and craft technology, especially in terms of availability of materials and their cost. The sale and making of fishing gear materials are two areas of fisheries, which are yet to be exploited by the general public as forms of businesses for livelihood. The study is conducted in villages around the lower part of Kainji Lake, towards the dam, including New Bussa. It reveals that only the fishermen themselves are involved in making their own fishing gears while those involved in the selling of fishing gear materials like the sheet netting, ropes, twines, floats, sinkers etc are business men and women who may not have any experience of fishing. Also considered in the study is the art of making fishing crafts like the canoe and gourd. Very few entrepreneurs are involved and they are so skilled that each is specialized in the making of only one kind of craft or gear

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The ennoblement of human resources has become a prime issue in the philosophy of sustainable aquaculture development in the new millennium.Being the planners, designers, conductors and philosophers of sustainable aquaculture, human beings always demand their further improvement at level best from their current positions to bring supreme success in the sector. As sustainable aquaculture is socio-economic –cum-environmental in concept, its operation and management requires constant interplay of various human knowledge for ensuring its smooth direction and for achieving its goal. So, the arrangement of different types and levels of training and education are the great need for the development of personnel involved in sustainable aquaculture route and also for growing awareness of environmental issues. The modus operandi of training and education has to be changed systematically to answer the calls of the needs of the new millennium. In the developing and developed countries where aquaculture plays a vital role in promoting production of aquatic organisms, alleviating of poverty, ensuring environmental compatibility, replenishing and improving the natural stocks, increasing socio-economic upliftment through integrated development approach, developing and managing the aquatic resources, maintaining gene banks and preserving the diversity of fish stocks, it has been already proved that Human resources development (HRD) is inevitable to bring sustainable aquaculture and plays a great role in the flourishment of the system . Different types and levels of training of personnel required for sustainable aquaculture in the new millennium are brought forward in the study. The importance of human resources development (HRD) through specialized training to the personnel is also depicted.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The behaviour in the feeding process and the functional morphology of Lathonura rectirostris O.F. Muller - one of the widely distributed species of macrothricids - is studied. The current work is an attempt at morpho-functional analysis of the apparatus of the trunk appendages of Lathonura rectirostris O.F. Muller. This highly specialized species, the method of feeding of which basically comes to the mechanical scraping-off and collection of epiphytic single-celled algae and particles deposited on the surface of aquatic plants.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In the skin of Salmo irideus the production of mucus is due to one type of cell specialized as a mucus cell. The histochemical research presented in this paper describes the mucous cells of Salmo irideus and demonstrates observable variation in such cells during the fish's development.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Recent histochemical and histophysiological research on the skin of fish has posed interesting problems both with regard to the presence of specialized types of cell and with regard to the function of this organ. The present paper intends to study the development and the functional differentiation of the trout's skin, both from the histomorphological and the histochemical point of view. The skin of Salmonids is devoid of specialized cells; the granular cells of Petromyzonti, the serous cells of Selacii and the clavate cells described in many other teleosts and it lacks keratin. As such it can be considered a good working model which can be used to show the eventual histomorphological and histochemical changes occurring both in the transformation from the endovular to the aqueous environment. Histomorphological observations were carried out demonstrate the great structural simplicity of the trout's skin at all stages. The article concludes that glycogen increases greatly when the epidermis thickens and therefore when it becomes necessary to guarantee resistance, amongst which is a support mechanism.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Founded in 1959, the Centre de Recherches Océanographiques is now twenty years old. During its existence, its administrative structure and its internal organization have considerably changed. It is now a research center placed under the supervision of the State Secretary for Scientific Research but, for management, it has been committed to the care of Orstom, a French organization specialized into scientific and technological research in the developing countries. Orstom also partially finances the research work, whose aims are decided by special commissions, which in their choices take into account the fundamental options of the plans of development of the government of Côte d'Ivoire.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Feeding habits and feeding strategy of red rockfish (Sebastes capensis) were studied from fish captured along most of the range of this species in coastal waters of South America. Stomach contents of 613 individuals, collected during 2003, were analyzed. Fish were obtained from six locations along the Chilean (23°S to 46°S) and Argentinian (43°S) coasts. The main prey items were Mysidacea (75.06% IRI), Osteichthyes (6.29% IRI),and Rhynchocinetes typus (6.03% IRI). Predator sex and size did not significantly affect the diet, but significant differences were found between locations. Four geographical areas, discriminated by prey occurrence and frequencies, were determined: three on the Pacific coast and one on the Atlantic coast. These areas correspond roughly with biogeographic zones described for the Chilean and southern Argentinian coasts. The feeding strategy index (FSI) indicated a specialized feeding strategy for S. capensis for most of its range. However, the FSI does not include the behaviour of a predator, and the FSI must be interpreted carefully for fishes like S. capensis that are passive ambush feeders. The abundance and availability of different prey may explain both the geographic differences in dietary composition and the specialized feeding strategy of S. capensis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Body size at gonadal maturity is described for females of the slipper lobster (Scyllarides squammosus) (Scyllaridae) and the endemic Hawaiian spiny lobster (Panulirus marginatus) (Palinuridae) based on microscopic examination of histological preparations of ovaries. These data are used to validate several morphological metrics (relative exopodite length, ovigerous condition) of functional sexual maturity. Relative exopodite length (“pleopod length”) produced consistent estimates of size at maturity when evaluated with a newly derived statistical application for estimating size at the morphometric maturation point (MMP) for the population, identified as the midpoint of a sigmoid function spanning the estimated boundaries of overlap between the largest immature and smallest adult animals. Estimates of the MMP were related to matched (same-year) characterizations of sexual maturity based on ovigerous condition — a more conventional measure of functional maturity previously used to characterize maturity for the two lobster species. Both measures of functional maturity were similar for the respective species and were within 5% and 2% of one another for slipper and spiny lobster, respectively. The precision observed for two shipboard collection series of pleopod-length data indicated that the method is reliable and not dependent on specialized expertise. Precision of maturity estimates for S. squammosus with the pleopod-length metric was similar to that for P. marginatus with any of the other measures (including conventional evidence of ovigerous condition) and greatly exceeded the precision of estimates for S. squammosus based on ovigerous condition alone. The two measures of functional maturity averaged within 8% of the estimated size at gonadal maturity for the respective species. Appendage-to-body size proportions, such as the pleopod length metric, hold great promise, particularly for species of slipper lobsters like S. squammosus for which there exist no other reliable conventional morphological measures of sexual maturity. Morphometric proportions also should be included among the factors evaluated when assessing size at sexual maturity in spiny lobster stocks; previously, these proportions have been obtained routinely only for brachyuran crabs within the Crustacea.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Indo-Pacific lionfish, Pterois miles and P. volitans, have recently invaded the U.S. east coast and the Caribbean and pose a significant threat to native reef fish communities. Few studies have documented reproduction in pteroines from the Indo-Pacific. This study provides a description of oogenesis and spawn formation in P. miles and P. volitans collected from offshore waters of North Carolina, U.S.A and the Bahamas. Using histological and laboratory observations, we found no differences in reproductive biology between P. miles and P. volitans. These lionfish spawn buoyant eggs that are encased in a hollow mass of mucus produced by specialized secretory cells of the ovarian wall complex. Oocytes develop on highly vascularized peduncles with all oocyte stages present in the ovary of spawning females and the most mature oocytes placed terminally, near the ovarian lumen. Given these ovarian characteristics, these lionfish are asynchronous, indeterminate batch spawners and are thus capable of sustained reproduction throughout the year when conditions are suitable. This mode of reproduction could have contributed to the recent and rapid establishment of these lionfish in the northwestern Atlantic and Caribbean.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Contemporary in-depth sequencing of environmental samples has provided novel insights into microbial community structures, revealing that their diversity had been previously underestimated. Communities in marine environments are commonly composed of a few dominant taxa and a high number of taxonomically diverse, low-abundance organisms. However, studying the roles and genomic information of these “rare” organisms remains challenging, because little is known about their ecological niches and the environmental conditions to which they respond. Given the current threat to coral reef ecosystems, we investigated the potential of corals to provide highly specialized habitats for bacterial taxa including those that are rarely detected or absent in surrounding reef waters. The analysis of more than 350,000 small subunit ribosomal RNA (16S rRNA) sequence tags and almost 2,000 nearly full-length 16S rRNA gene sequences revealed that rare seawater biosphere members are highly abundant or even dominant in diverse Caribbean corals. Closely related corals (in the same genus/family) harbored similar bacterial communities. At higher taxonomic levels, however, the similarities of these communities did not correlate with the phylogenetic relationships among corals, opening novel questions about the evolutionary stability of coral-microbial associations. Large proportions of OTUs (28.7–49.1%) were unique to the coral species of origin. Analysis of the most dominant ribotypes suggests that many uncovered bacterial taxa exist in coral habitats and await future exploration. Our results indicate that coral species, and by extension other animal hosts, act as specialized habitats of otherwise rare microbes in marine ecosystems. Here, deep sequencing provided insights into coral microbiota at an unparalleled resolution and revealed that corals harbor many bacterial taxa previously not known. Given that two of the coral species investigated are listed as threatened under the U.S. Endangered Species Act, our results add an important microbial diversity-based perspective to the significance of conserving coral reefs.