18 resultados para Model basic science research

em Aquatic Commons


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Nowadays, risks arising from the rapid development of oil and gas industries are significantly increasing. As a result, one of the main concerns of either industrial or environmental managers is the identification and assessment of such risks in order to develop and maintain appropriate proactive measures. Oil spill from stationary sources in offshore zones is one of the accidents resulting in several adverse impacts on marine ecosystems. Considering a site's current situation and relevant requirements and standards, risk assessment process is not only capable of recognizing the probable causes of accidents but also of estimating the probability of occurrence and the severity of consequences. In this way, results of risk assessment would help managers and decision makers create and employ proper control methods. Most of the represented models for risk assessment of oil spills are achieved on the basis of accurate data bases and analysis of historical data, but unfortunately such data bases are not accessible in most of the zones, especially in developing countries, or else they are newly established and not applicable yet. This issue reveals the necessity of using Expert Systems and Fuzzy Set Theory. By using such systems it will be possible to formulize the specialty and experience of several experts and specialists who have been working in petroliferous areas for several years. On the other hand, in developing countries often the damages to environment and environmental resources are not considered as risk assessment priorities and they are approximately under-estimated. For this reason, the proposed model in this research is specially addressing the environmental risk of oil spills from stationary sources in offshore zones.

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Executive Summary: For over three decades, scientists have been documenting the decline of coral reef ecosystems, amid increasing recognition of their value in supporting high biological diversity and their many benefits to human society. Coral reef ecosystems are recognized for their benefits on many levels, such as supporting economies by nurturing fisheries and providing for recreational and tourism opportunities, providing substances useful for medical purposes, performing essential ecosystem services that protect against coastal erosion, and provid-ing a diversity of other, more intangible contributions to many cultures. In the past decade, the increased awareness regarding coral reefs has prompted action by governmental and non-governmental organizations, including increased funding from the U.S. Congress for conservation of these important ecosystems and creation of the U.S. Coral Reef Task Force (USCRTF) to coordinate activities and implement conservation measures [Presidential Executive Order 13089]. Numerous partnerships forged among Federal agencies and state, local, non-governmental, academic and private partners support activities that range from basic science to systematic monitoring of ecosystem com-ponents and are conducted by government agencies, non-governmental organizations, universities, and the private sector. This report shares the results of many of these efforts in the framework of a broad assessment of the condition of coral reef ecosystems across 14 U.S. jurisdictions and Pacific Freely Associated States. This report relies heavily on quantitative, spatially-explicit data that has been collected in the recent past and comparisons with historical data, where possible. The success of this effort can be attributed to the dedication of over 160 report contributors who comprised the expert writing teams for each jurisdiction. The content of the report chapters are the result of their considerable collaborative efforts. The writing teams, which were organized by jurisdiction and comprised of experts from numerous research and management institutions, were provided a basic chapter outline and a length limit, but the content of each chapter was left entirely to their discretion. Each jurisdictional chapter in the report is structured to: 1) describe how each of the primary threats identified in the National Coral Reef Action Strategy (NCRAS) has manifested in the jurisdiction; 2) introduce ongoing monitoring and assessment activities relative to three major categories of inquiry – water quality, benthic habitats, and associated biological communities – and provide summary results in a data-rich format; and 3) highlight recent management activities that promote conservation of coral reef ecosystems.

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The Pond Dynamics/Aquaculture Collaborative Research Support Program (PDA/CRSP) is a global research network to generate basic science that may be used to advance aquaculture development. One of a family of research programs funded by the United States Agency for International Development (USAID), the CRSP focuses on improving the efficiency of aquaculture systems. The PDA/CRSP began work in 1982 in Thailand, and subsequently in the Philippines, Honduras, the US and, until recently, Rwanda. At all the sites, the goal is the same: to identify constraints to aquaculture production, and to design responses that are environmentally and culturally appropriate. The research network's global experiment has focused on tilapia (Oreochromis niloticus), although some sites have devoted attention to marine shrimp and other locally significant species. Impact of the network's investigations with tilapia is examined in this article.

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The U.S. Fish Commission was initiated in 1871 with Spencer Fullerton Baird as the first U.S. Fish Commissioner as an independent entity. In 1903 it became a part of the new U.S. Department of Commerce and Labor and was renamed the Bureau of Fisheries, a name it retained when the Departments of Commerce and Labor were separated in 1912. The Bureau remained in the Commerce Department until 1941 when it was merged with the Biological Survey and placed in the Department of Interior as the U.S. Fish and Wildlife Service. It was a scientific agency with well conceived programs of action, and it provided knowledge, advice, and example to state governments and individuals with fisheries interests and needs. Its efforts were supported by timely international agreements which constituted the precedent for Federal interest in fishery matters. The Fisheries Service earned stature as an advisor through heavy emphasis on basic biological research. The lack of such knowledge was marked and universal in the 1870’s, but toward the end of that decade, strong steps had been taken to address those needs under Baird’s leadership. USFC research activities were conducted cooperatively with other prominent scientists in the United States and abroad. Biological stations were established, and the world’s first and most productive deepsea research vessel, the Albatross, was constructed, and its 40-year career gave a strong stimulus to the science of oceanography. Together, the agency’s scientists and facilities made important additions to the sum of human knowledge, derived principles of conservation which were the vital bases for effective regulatory legislation, conducted extensive fish cultural work, collected and disseminated fisheries statistics, and began important research in methods of fish harvesting, preservation, transportation, and marketing.

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Caspian Sea with its unique characteristics is a significant source to supply required heat and moisture for passing weather systems over the north of Iran. Investigation of heat and moisture fluxes in the region and their effects on these systems that could lead to floods and major financial and human losses is essential in weather forecasting. Nowadays by improvement of numerical weather and climate prediction models and the increasing need to more accurate forecasting of heavy rainfall, the evaluation and verification of these models has been become much more important. In this study we have used the WRF model as a research-practical one with many valuable characteristics and flexibilities. In this research, the effects of heat and moisture fluxes of Caspian Sea on the synoptic and dynamical structure of 20 selective systems associated with heavy rainfall in the southern shores of Caspian Sea are investigated. These systems are selected based on the rainfall data gathered by three local stations named: Rasht, Babolsar and Gorgan in different seasons during a five-year period (2005-2010) with maximum amount of rainfall through the 24 hours of a day. In addition to synoptic analyses of these systems, the WRF model with and without surface flues was run using the two nested grids with the horizontal resolutions of 12 and 36 km. The results show that there are good consistencies between the predicted distribution of rainfall field, time of beginning and end of rainfall by the model and the observations. But the model underestimates the amounts of rainfall and the maximum difference with the observation is about 69%. Also, no significant changes in the results are seen when the domain and the resolution of computations are changed. The other noticeable point is that the systems are severely weakened by removing heat and moisture fluxes and thereby the amounts of large scale rainfall are decreased up to 77% and the convective rainfalls tend to zero.

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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)

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The 800 km coastline of Nigeria is a huge gateway to a supply of food and raw materials. But while immense fishery resource is perceived by many, its full exploitation is obstructed by how little is understood of the ocean processes necessary for effective utilisation. Much basic oceanographic research is needed as a prerequisite to evolving successful strategies for full application of Nigeria's marine fisheries resources

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A brief account is given of some of the discussions presented at a workshop regarding reservoir fisheries in Asia held in Hangzhou, China in Oct 1990. The presentations covered the range of reservoir fisheries management options, from basic limnological research and capture fisheries to intensive cage culture. Particular reference is made to the situation in China, describing current techniques used for stocking and developing reservoir fisheries.

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John Nathan Cobb (1868–1930) became the founding Director of the College of Fisheries, University of Washington, Seattle, in 1919 without the benefit of a college education. An inquisitive and ambitious man, he began his career in the newspaper business and was introduced to commercial fisheries when he joined the U.S. Fish Commission (USFC) in 1895 as a clerk, and he was soon promoted to a “Field Agent” in the Division of Statistics, Washington, D.C. During the next 17 years, Cobb surveyed commercial fisheries from Maine to Florida, Hawaii, the Pacific Northwest, and Alaska for the USFC and its successor, the U.S. Bureau of Fisheries. In 1913, he became editor of the prominent west coast trade magazine, Pacific Fisherman, of Seattle, Wash., where he became known as a leading expert on the fisheries of the Pacific Northwest. He soon joined the campaign, led by his employer, to establish the nation’s first fisheries school at the University of Washington. After a brief interlude (1917–1918) with the Alaska Packers Association in San Francisco, Calif., he was chosen as the School’s founding director in 1919. Reflecting his experience and mindset, as well as the University’s apparent initial desire, Cobb established the College of Fisheries primarily as a training ground for those interested in applied aspects of the commercial fishing industry. Cobb attracted sufficient students, was a vigorous spokesman for the College, and had ambitions plans for expansion of the school’s faculty and facilities. He became aware that the College was not held in high esteem by his faculty colleagues or by the University administration because of the school’s failure to emphasize scholastic achievement, and he attempted to correct this deficiency. Cobb became ill with heart problems in 1929 and died on 13 January 1930. The University soon thereafter dissolved the College and dismissed all but one of its faculty. A Department of Fisheries, in the College of Science, was then established in 1930 and was led by William Francis Thompson (1888–1965), who emphasized basic science and fishery biology. The latter format continues to the present in the Department’s successor, The School of Aquatic Fisheries and Science.

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Cymo andreossyi is found both in the live and dead branching corals of coral Pacillopora, Acropora and Montipora. Compared to the occurrence its compatriot C. melanodactylus, this species found in large numbers. The relationship is mutualistic, with the species occupying a niche similar to that occupied by the more colorful Trapezia species.

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Labroides dimidiatus, is one of several species of cleaner wrasses found on coral reefs from Eastern Africa and the Red Sea to French Polynesia, for the first time from Iran (Persian Gulf, Kish Island). Like other cleaner wrasses, it eats parasites and dead tissue off larger fishes’ skin in a mutualistic relationship that provides food and protection for the wrasse, and considerable health benefits for the other fishes. Some fish mimic cleaner wrasses. For example, a species of blenny called Aspidontus taeniatus has evolved the same behavior to tear small pieces of flesh from bigger fish. Cleaner wrasses are usually found at cleaning stations. Cleaning stations are occupied by different units of cleaner wrasses, such as a group of youths, a pair of adults, or a group of females accompanied by a dominant male. When visitors come near the cleaning stations, the cleaner wrasses greet the visitors by performing a dance-like motion in which they move their rear up and down. The visitors are referred to as "clients". Blue streak cleaner wrasses clean to consume ectoparasites on client fish for food. The bigger fish recognise them as cleaner fish because they have a lateral stripe along the length of their bodies and by their movement patterns.

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The Striped Catfish can be recognized by its striped coloration, barbels around the mouth, and its body shape which tapers to a point posteriorly. Small juveniles are black and large adults may be less distinctly striped. Plotosus lineatus can reach a maximum length of 32 cm (13 in) and about 40cm in Persian Gulf. The body is brown with cream-colored or white longitudinal bands. The most striking feature of this species is in the fins; in fact the second dorsal, caudal and anal are fused together as in eels. In the rest of the body is quite similar to a freshwater catfish: the mouth is surrounded by four pairs of barbells, four on the upper jaw and four on the lower jaw. The first dorsal and each of the pectoral fins have a highly venomous spine. They may even be fatal. Juveniles of P. lineatus form dense ball-shaped schools of about 100 fish, while adults are solitary or occur in smaller groups of around 20 and are known to hide under ledges during the day. Adult P. lineatus search and stir the sand incessantly for crustaceans, mollusks, worms, and sometimes fish. Striped eel catfish is an oviparous fish; this species has demersal eggs and planktonic larvae. This species has evolved long ampullary canals in its electrosensory organs.

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Electric rays, thought to be the most primitive of the skates and rays, have stout tails but have rather expansive disc. This group is distinguished by the presence of powerful electric organs, derived from branchial muscles in head region. Torpedo sinuspersici found inshore in sandy bottoms, and well offshore from the surf zone down to 200 m. Also on or near coral reefs (like Kish Island in Persian Gulf). Common in shallow sandy areas. Occasionally hooked by anglers, more often seen by divers; can deliver a strong shock. Flesh is edible. T. sinuspersici can survive for hours after being stranded on the beach. Little is known of the life history of the Gulf torpedo. It is a sluggish predator of bony fishes. At night it actively hunts for food, sculling slowly through the water about a meter above the bottom; during the day it usually rests on the bottom and opportunistically ambushes unwary prey. It uses its broad pectoral fins to envelop the target fish before delivering an electric shock to stun it. Usually solitary, they may form groups during the mating season. Reproduction is a placental viviparous, with the developing embryos initially surviving on their yolk sacs, and then on enriched uterine fluid produced by the mother. Litters of 9-22 young are birthed in the summer. Newborns measure about 10 cm wide; males mature at a disc width of 39 cm and females at 45 cm.

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Chrysiptera unimaculata, an algivorous species also living on the coral reef flat and being territorial but not considered as a strict farmer in this location. Maximum length is 8 cm in Persian Gulf. It is living in close association with macrophytes. Adults are found solitarily or in small groups among coastal algal reefs, rubble or over open beach-rock of reef flats exposed to moderate surge and feeds mainly on benthic algae. C. unimaculata is oviparous, distinct pairing during breeding. Eggs are demersal and adhere to the substrate. Males guard and aerate the eggs.