17 resultados para periodically poled

em Aquatic Commons


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This document describes the analytical methods used to quantify core organic chemicals in tissue and sediment collected as part of NOAA’s National Status and Trends Program (NS&T) for the years 2000-2006. Organic contaminat analytical methods used during the early years of the program are described in NOAA Technical Memoranda NOS ORCA 71 and 130 (Lauenstein and Cantillo, 1993; Lauenstein and Cantillo, 1998) for the years 1984-1992 and 1993-1996, respectively. These reports are available from our website (http://www.ccma.nos.gov) The methods detailed in this document were utilized by the Mussel Watch Project and Bioeffects Project, which are both part of the NS&T program. The Mussel Watch Project has been monitoring contaminants in bivalves and sediments since 1986 and is the longest active national contaminant monitoring program operating in U.S. costal waters. Approximately 280 Mussel Watch sites are sampled on a biennial and decadal timescale for bivalve tissue and sediment respectively. Similarly, the Bioeffects Assessment Project began in 1986 to characterize estuaries and near coastal environs. Using the sediment quality triad approach that measures; (1) levels of contaminants in sediments, (2) incidence and severity of toxicity, and (3) benthic macrofaunal conmmunities, the Bioeffects Project describes the spatial extent of sediment toxicity. Contaminant assessment is a core function of both projects. These methods, while discussed here in the context of sediment and bivalve tissue, were also used with other matricies including: fish fillet, fish liver, nepheloid layer, and suspended particulate matter. The methods described herein are for the core organic contaminants monitored in the NS&T Program and include polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), butyltins, and organochlorines that have been analyzed consistently over the past 15-20 years. Organic contaminants such as dioxins, perfluoro compounds and polybrominated biphenyl ethers (PBDEs) were analyzed periodically in special studies of the NS&T Program and will be described in another document. All of the analytical techniques described in this document were used by B&B Laboratories, Inc, an affiliate of TDI-Brook International, Inc. in College Station, Texas under contract to NOAA. The NS&T Program uses a performance-based system approach to obtain the best possible data quality and comparability, and requires laboratories to demonstrate precision, accuracy, and sensitivity to ensure results-based performance goals and measures. (PDF contains 75 pages)

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The Cape Canaveral, Florida, marine ecosystem is unique. There are complex current and temperature regimes that form a faunal transition zone between Atlantic tropical and subtropical waters. This zone is rich faunistically and supports large commercial fISheries for fish, scallops, and shrimp. Canaveral is also unique because it has large numbers of sea turtles year-round, this turtle aggregation exhibiting patterned seasonal changes in numbers, size frequency, and sex ratio. Additionally, a significant portion of this turtle aggregation hibernates in the Canaveral ship channel, a phenomenon rare in marine turtle populations. The Cape Canaveral area has the largest year-round concentration of sea turtles in the United States. However, the ship channel is periodically dredged by the U.S. Army Corps of Engineers in order to keep Port Canaveral open to U.S. Navy vessels, and preliminary surveys showed that many sea turtles were incidentally killed during dredging operations. In order for the Corps of Engineers to fulfill its defense dredging responsibilities, and comply with the Endangered Species Act of 1973, an interagency Sea Turtle Task Force was formed to investigate methods of reducing turtle mortalities. This Task Force promptly implemented a sea turtle research plan to determine seasonal abundance, movement patterns, sex ratios, size frequencies, and other biological parameters necessary to help mitigate dredging conflicts in the channel. The Cape Canaveral Sea Turtle Workshop is a cooperative effort to comprehensively present research results of these important studies. I gratefully acknowledge the support of everyone involved in this Workshop, particularly the anonymous team of referees who painstakingly reviewed the manuscripts. The cover illustration was drawn by Jack C. Javech. (PDF file contains 86 pages.)

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How is climate change affecting our coastal environment? How can coastal communities adapt to sea level rise and increased storm risk? These questions have garnered tremendous interest from scientists and policy makers alike, as the dynamic coastal environment is particularly vulnerable to the impacts of climate change. Over half the world population lives and works in a coastal zone less than 120 miles wide, thereby being continuously affected by the changes in the coastal environment [6]. Housing markets are directly influenced by the physical processes that govern coastal systems. Beach towns like Oak Island in North Carolina (NC) face severe erosion, and the tax assesed value of one coastal property fell by 93% in 2007 [9]. With almost ninety percent of the sandy beaches in the US facing moderate to severe erosion [8], coastal communities often intervene to stabilize the shoreline and hold back the sea in order to protect coastal property and infrastructure. Beach nourishment, which is the process of rebuilding a beach by periodically replacing an eroding section of the beach with sand dredged from another location, is a policy for erosion control in many parts of the US Atlantic and Pacific coasts [3]. Beach nourishment projects in the United States are primarily federally funded and implemented by the Army Corps of Engineers (ACE) after a benefit-cost analysis. Benefits from beach nourishment include reduction in storm damage and recreational benefits from a wider beach. Costs would include the expected cost of construction, present value of periodic maintenance, and any external cost such as the environmental cost associated with a nourishment project (NOAA). Federal appropriations for nourishment totaled $787 million from 1995 to 2002 [10]. Human interventions to stabilize shorelines and physical coastal dynamics are strongly coupled. The value of the beach, in the form of storm protection and recreation amenities, is at least partly capitalized into property values. These beach values ultimately influence the benefit-cost analysis in support of shoreline stabilization policy, which, in turn, affects the shoreline dynamics. This paper explores the policy implications of this circularity. With a better understanding of the physical-economic feedbacks, policy makers can more effectively design climate change adaptation strategies. (PDF contains 4 pages)

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With the aid of the German Research Association in the central programme 'Sand movements in the German coastal region', an investigation into the current conditions in the shallow water areas of the coasts of the south-eastern North Sea between Sylt and the Weser estuary was carried out by the author. Foundations of the work are 19 continuous current recordings in five profiles normal to the coast from years 1971 to 1973. Off the coasts of the south-eastern North Sea varying tidal currents impinge; they are currents whose directions may vary periodically through all points of the compass. They are caused by the circulating tides in the North Sea (Amphidromien). The turning flow movement experiences a deformation in the very shallow coastal waters, and as it happens the flow turning movement in the case of high tide continues right up onto the outer flats, while here and in the fore-lying shallow water areas around the time of low water (on account of the small depths of waters), there prevails a more variable current. A result of this hydrodynamical procedure is the development of counter currents. This partial translation of the original paper provides the summary of this study of of the mudflat areas between the Elbe and Weser.

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Atka mackerel (Pleurogrammus monopterygius) is hexagrammid fish that inhabits the temperate and subarctic North Pacific Ocean and neighboring seas (Fig. 1). This highly abundant fish is a critically important prey species (Sinclair and Zeppelin, 2002; Zenger, 2004) that supports a directed commercial trawl fishery (Lowe et al., 2006). Atka mackerel is a demersal spawner and males provide parental care to eggs (Zolotov, 1993). During breeding periods, sexually mature males aggregate on the bottom at nesting sites where they establish territories (Lauth et al., in press). Sexually mature females periodically visit male nesting territories from July to October to spawn batches of demersal egg masses (McDermott and Lowe, 1997; McDermott et al., 2007). Individual nests may consist of multiple egg masses deposited by different females, and males defend nesting territories for a protracted period lasting from the time territories are being established until all eggs within the territory are completely hatched (Lauth et al., 2007). Knowledge about the timing of the reproductive cycle and the use of spawning habitat are important for understanding population structure and the dynamics of stock recruitment, which in turn are important factors in the management of Atka mackerel populations.

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Errors in growth estimates can affect drastically the spawner-perrecruit threshold used to recommend quotas for commercial fish catches. Growth parameters for sablefish (Anoplopoma fimbria) in Alaska have not been updated for stock assessment purposes for more than 20 years, although aging of sablefish has continued. In this study, length-stratified data (1981–93 data from the annual longline survey conducted cooperatively by the Fisheries Agency of Japan and the Alaska Fisheries Science Center of the National Marine Fisheries Service) were updated and corrected for discovered sampling bias. In addition, more recent, randomly collected samples (1996–2004 data from the annual longline survey conducted by the Alaska Fisheries Science Center) were analyzed and new length-at-age and weight-at-age parameters were estimated. Results were similar between this analysis with length-at-age data from 1981 to 2004 and analysis with updated longline survey data through 2010; therefore, we used our initial results from analysis done with data through 2004. We found that, because of a stratified sampling scheme, growth estimates of sablefish were overestimated with the older data (1981–93), and growth parameters used in the Alaskan sablefish assessment model were, thus, too large. In addition, a comparison of the bias-corrected 1981–93 data and the 1996–2004 data showed that, in more recent years, sablefish grew larger and growth differed among regions. The updated growth information improves the fit of the data to the sablefish stock assessment model with biologically reasonable results. These findings indicate that when the updated growth data (1996–2004) are used in the existing sablefish assessment model, estimates of fishing mortality increase slightly and estimates of female spawning biomass decrease slightly. This study provides evidence of the importance of periodically revisiting biological parameter estimates, especially as data accumulate, because the addition of more recent data often will be more biologically realistic. In addition, it exemplifies the importance of correcting biases from sampling that may contribute to erroneous parameter estimates.

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Belugas, Delphinapterus leucas, in Cook Inlet, Alaska, represent a unique and isolated marine mammal population that has been hunted for a variety of purposes since prehistoric times. Archeological studies have shown that both Alutiiq Eskimos and Dena'ina Atabaskan Indians have long utilized many marine resources in Cook Inlet, including belugas. Over the past century, commercial whaling and sport hunting also occurred periodically in Cook Inlet prior to the Marine Mammal Protection Act of 1972 (MMPA). During the 1990's, the hunting mortality by Alaska Natives apparently increased to 40-70 whales per year, which led to the decling of this stock and its subsequent designation in 2000 as depleted under the MMPA. Concerns about the decline of the Cook Inlet stock resulted in a voluntary suspension of the subsistenc hunt by Alaska Natives in 1999. The difficulty in obtaining accurate estimates for the harvest of these whales is due to the inability to identify all of the hunters and, in turn, the size of the harvest. Attempts to reconstruct harvest records based on hunters' recollections and interviews from only a few households have been subject to a wide degree of speculation. To adequately monitor the beluga harvest, the National Marine Fisheries Service established marking and reporting regulations in October 1999. These rules require that Alaska Natives who hunt belugas in Cook Inlet must collect the lowere left jaw from harvested whales and complete a report that includes date and time of the harvest, coloration of the whale, harvest location, and method of harvest. The MMPA was amended in 2000 to require a cooperative agreement between the National Marine Fisheries Service and Alaska Native organizations before hunting could be resumed.

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Fishery-independent estimates of spawning biomass (BSP) of the Pacific sardine (Sardinops sagax) on the south and lower west coasts of Western Australia (WA) were obtained periodically between 1991 and 1999 by using the daily egg production method (DEPM). Ichthyoplankton data collected during these surveys, specifically the presence or absence of S. sagax eggs, were used to investigate trends in the spawning area of S. sagax within each of four regions. The expectation was that trends in BSP and spawning area were positively related. With the DEPM model, estimates of BSP will change proportionally with spawning area if all other variables remain constant. The proportion of positive stations (PPS), i.e., stations with nonzero egg counts — an objective estimator of spawning area — was high for all south coast regions during the early 1990s (a period when the estimated BSP was also high) and then decreased after the mid-1990s. There was a decrease in PPS from the mid-1990s to 1999. The particularly low estimates in 1999 followed a severe epidemic mass mortality of S. sagax throughout their range across southern Australia. Deviations from the expected relationship between BSP and PPS were used to identify uncertainty around estimates of BSP. Because estimation of spawning area is subject to less sampling bias than estimation of BSP, the deviation in the relation between the two provides an objective basis for adjusting some estimates of the latter. Such an approach is particularly useful for fisheries management purposes when sampling problems are suspected to be present. The analysis of PPS undertaken from the same set of samples from which the DEPM estimate is derived will help provide information for stock assessments and for the management of purse-seine fisheries.

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Mayan cichlids (Cichlasoma urophthalmus) were collected monthly from March 1996 to October 1997 with hook-and-line gear at Taylor River, Florida, an area within the Crocodile Sanctuary of Everglades National Park, where human activities such as fishing are prohibited. Fish were aged by examining thin-sectioned otoliths, and past size-at-age information was generated by using back-calculation techniques. Marginal increment analysis showed that opaque growth zones were annuli deposited between January and May. The size of age-1 fish was estimated to be 33–66 mm standard length (mean=45.5 mm) and was supported by monthly length-frequency data of young-of-year fish collected with drop traps over a seven-year period. Mayan cichlids up to seven years old were observed. Male cichlids grew slower but achieved a larger size than females. Growth was asymptotic and was modeled by the von Bertalanffy growth equation Lt=263.6(1–exp[–0.166(t–0.001)]) for males (r2=0.82, n=581) and Lt=215.6 (1–exp[–0.197(t–0.058)]) for females (r2= 0.77, n=639). Separate estimates of total annual mortality were relatively consistent (0.44–0.60) and indicated moderate mortality at higher age classes, even in the absence of fishing mortality. Our data indicated that Mayan cichlids grow slower and live longer in Florida than previously reported from native Mexican habitats. Because the growth of Mayan cichlids in Florida periodically slowed and thus produced visible annuli, it may be possible to age introduced populations of other subtropical and tropical cichlids in a similar way.

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The object of this study was to determine the value of physical, bacteriological and chemical tests used to find out and compare the indices of quality of prawns stored at 0°C and at 18°C. pH value, nature of drip, the total bacterial count, presence or absence of tryptophan, trimethylamine content, glycogen, lactic acid, vitamins such as thiamin, riboflavin and niacin were estimated periodically to evaluate the quality of prawns stored at 0°C, whereas in addition to organoleptic changes, pH, bacterial count, nature of growth in peptone water, soluble protein in salt solution and loss of moisture, glycogen, lactic acid, and changes in vitamin B contents were noted periodically for prawns stored at -l8°C. Riboflavin and niacin were not affected appreciably but the retention of thiamin in prawns was very low.

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Since the year 1925, attention has been focused periodically on the stagnation in the local fishing industry, and those who have studied the subject have been unanimous about the need to introduce modern fishing craft which are capable of working more fishing gear. This report outlines the stages through which the evolution of more effective fishing operations has progressed, both in the gradually increasing use of mechanical propulsion for boats and in the adoption of more modern gear and techniques by local fishermen. No reference is made in this report to the operation of deep-sea trawlers (Sivalingam, 1956) a phase of development which has hitherto not influenced the local fishing industry to any appreciable extent.

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A study of supplementary feeding was conducted on children with a protein food (edible fish powder in the form of 'chutney') for 35 days and the effect assessed periodically. The most noticeable effect was gain in weight and mid arm circumference in children. 35% children showed a weight gain of 1 kg, 27% 0.5 kg, 21% 1.5 kg and 2.5% 2.5 kg. 48% children registered an increase in their mid-arm circumference by 0.5 cm, 16% 1 cm and 2.5% 1.5 cm. 10% children did not gain weight. However, these children had intercurrent infections like measles, whooping cough and asthma.

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Scatophagus argus argus (Green Scat) is a pretty aquarium fish. Its hard spines are venomous and can cause painful injury. In this study 60 specimens of Green Scat were collected periodically from coastal waters of Boushehr (south of Iran) from May 2011 to April 2012. Anatomical features of venomous spines were investigated. Scat venom was extracted from the spines in a new manner for keeping the specimens alive. The nature of venom was tested by SDS-PAGE. Ethical issues and animal welfare principles such as rapid and instantaneous anesthetizing, post operation disinfection and fast recovery of the specimens was practiced in order to minimize the complications. This method enhanced the purity and quantity of venom as demonstrated by 12 separated proteins in electrophoresis. New ethical issues were developed to surviving the specimens and prolong viability as well.

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The effect of betel leaf (Piper betle Linn.) extract on control of autoxidation of fat in dry fish has been studied. Oil sardine has been selected for experiments since it contains very high amount of fat. The treatments were given with 5% (w/v) betel leaf extract in water at different stages of salt curing. FFA, PV and TVN values of the samples were determined periodically to assess the keeping quality and autoxidation. The sample, prepared by dipping the fish in the extract immediately after salting and then drying as usual, was found to have better keeping qualities.

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96h acute toxicity tests were performed using commercial grade metasystox on the marine wedge clam, Donax cuneatus during summer 1985. The behaviour and mortality rates were recorded periodically. Most of the dams responded in opening the shell valves and extending the siphons quicker in low test concentrations (0.004-0.0052 p.p.m) but this was slow and late in high concentrations (0.0056-0.008 p.p.m). Mortality began to occur in 0.008 p.p.m. from 12 h, whereas, in 0.0052 p.p.m. from 60 h onwards. The observed LC sub(0) value was 0.004 p.p.m. and LC sub(50) 0.0064 p.p.m. The regression equation established was Y = 79.0891 + 33.4523 X. The rate of oxygen concentration increased at LC sub(0) and LC sub(50) values compared to control indicating the disturbed physiological adjustment. The results are correlated with physico-chemical parameters of seawater and discussed in the light of pesticide toxicity to the dam.