60 resultados para trace mineral requirements

em Aquatic Commons


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The Alliance for Coastal Technologies (ACT) Workshop on Trace Metal Sensors for Coastal Monitoring was convened April 11-13, 2005 at the Embassy Suites in Seaside, California with partnership from Moss Landing Marine Laboratories (MLML) and the Monterey Bay Aquarium Research Institute (MBARI). Trace metals play many important roles in marine ecosystems. Due to their extreme toxicity, the effects of copper, cadmium and certain organo-metallinc compounds (such as tributyltin and methylmercury) have received much attention. Lately, the sublethal effects of metals on phytoplankton biochemistry, and in some cases the expression of neurotoxins (Domoic acid), have been shown to be important environmental forcing functions determining the composition and gene expression in some groups. More recently the role of iron in controlling phytoplankton growth has led to an understanding of trace metal limitation in coastal systems. Although metals play an important role at many different levels, few technologies exist to provide rapid assessment of metal concentrations or metal speciation in the coastal zone where metal-induced toxicity or potential stimulation of harmful algal blooms, can have major economic impacts. This workshop focused on the state of on-site and in situ trace element detection technologies, in terms of what is currently working well and what is needed to effectively inform coastal zone managers, as well as guide adaptive scientific sampling of the coastal zone. Specifically the goals of this workshop were to: 1) summarize current regional requirements and future targets for metal monitoring in freshwater, estuarine and coastal environments; 2) evaluate the current status of metal sensors and possibilities for leveraging emerging technologies for expanding detection limits and target elements; and 3) help identify critical steps needed for and limits to operational deployment of metal sensors as part of routine water quality monitoring efforts. Following a series of breakout group discussions and overview talks on metal monitoring regulatory issues, analytical techniques and market requirements, workshop participants made several recommendations for steps needed to foster development of in situ metal monitoring capacities: 1. Increase scientific and public awareness of metals of environmental and biological concern and their impacts in aquatic environments. Inform scientific and public communities regarding actual levels of trace metals in natural and perturbed systems. 2. Identify multiple use applications (e.g., industrial waste steam and drinking water quality monitoring) to support investments in metal sensor development. (pdf contains 27 pages)

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Studies were carried out to assess some macro and trace elements of mineral composition of the male and female Heterobranchus bidorsalis adults exposed to graded concentrations (1.00-8.00m/L-1) of Bonny-light crude oil (BLCO). The experiment was monitored for 4 days (toxicity) and 42days (recovery) periods. Significant decreases (P < 0.05)in the sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), phosphorus (P), zinc (Zn), iron (Fe), vanadium (Va), lead (Pb) and manganese (Mn) contents of the male H. bidorsalis corresponded with the increasing concentrations of BLCO. In contrast, the female fishes recorded significant increases (P < 0.05) in the values of the above elements in their tissues as the concentrations of BLCO increased. Furthermore, the values of Na, K, Mg, Ca, P, Zn, Fe, Va, Pb and Mn recorded in the male fishes where generally lower than those of their female counterparts and the control fish. Increased values of these elements were also recorded during the recovery periods (days 14, 28 and 42) of this study in the magnitudes of 15% at day 14, 20% at day 28 and 20% at day 42. This implied that the removal of crude oil stress during this period improved the quantity of these minerals deposited in the fish tissues. The highest percent proportion of Zn and the lowest proportion of Pb recorded in both male and female H. bidorsalis adults agreed with the report of other workers for other fish species. KEYWORDS: Heterobranchus bidorsalis, Mineral composition, Bonny-light crude oil, Toxicity, Recovery.

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The composition of the minerals in three economically important fish species of Lake Tanganyika was determined. From the analyses there does not appear to be significant difference in the composition for the three species. Beside the major elements: Ca, P, K, Na, Mg, Cl, Fe, Al and Zn, eighteen trace elements were determined. The presence of the bones in the fish is especially nutritionally important for the following elements: Ca, P, Br, Sr, Mn and Mg.

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All abalones belong to the genus Haliotis sensu latu, family Haliotidae. The 75 species known worldwide (Booloot ian et, al. 1962) are anatomically similar and all are adapted for attachment to hard substrates. Seven species are widely distributed along the coast of California (Cox 1962; Mottet 19781, of which several are important in the comercial and sport fisheries of the Pacific Southwest. (PDF has 19 pages.)

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11 specimens of Coryphaenoides armatus were collected at former dumping sites for radioactive material in the Iberian deep sea at a depth of 4700 m and their muscle tissue was analysed for four trace elements (copper, zinc, cadmium and lead) by differential pulse anodic stripping voltammetry (DPSAV). Concentrations of zinc were typical for fish muscle in general; copper content was somewhat higher than generally found in fish. The cadmium and lead contents were at a level found in fish from the open sea but the lead content of 2 specimens taken in area East-B was found to be higher.

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An examination is made of the current situation regarding fisheries planning in Nigeria, identifying areas where information is required to correct existing imbalances. The artisanal fishery, industrial/commercial fishery and aquaculture sectors and requirements for a comprehensive development policy in each sector are detailed

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Trace metals constitute a major form of water pollutant that can adversely affect fish production. The potentially toxic metals have been identified as lead, zinc, copper, arsenic, antimony, mercury beryllium, barium, cadmium, chromium, nickel, selenium among others. Preliminary laboratory studies have been directed to the determination of traces of lead in the aquatic biota and its toxicity. There are indications that the levels reported in effluents from some of the industries may be above the tolerant limits of local fish species and organisms that make up their food. Metal pollution could become a serious problem to freshwater fisheries in the future as a result of increasing urbanization and industrialization, unless efforts are made to prevent it

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Numerous investigations have utilized various semi-purified and purified diets to estimate the protein and amino acid requirements of several temperate fishes. The vast literature on the protein and amino acid requirements of fishes has continued to omit that of the tropical warm water species. The net effect is that fish feed formulation in Nigeria have relied on the requirement for temperate species. This paper attempts to review the state of knowledge on the protein amino acid requirements of fishes with emphasis on the warm water species, the methods of protein and amino acid requirement determinations and the influence of various factors on nutritional requirement studies. Finally evidence are presented with specific examples on how requirements of warm water fishes are different from the temperate species and used this to justify why fish feed formulation in Nigeria are far from being efficient

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An examination is made of the socio-economic factors associated with the failure of existing approaches to the fishing input requirements of small-scale fisheries in Nigeria. The fishermen and secretaries of the fishermen cooperative societies in three major settlements (Uta-Ewa, Okoroete and Iko) were selected for interviews. The survey showed that the idealogy of the fishermen of the role of cooperative society is wrong and specific programmes need to be directed towards correcting this perception. Thus, for any meaningful support programme for the artisanal small-scale fishermen, the perception of the fishermen about the cooperative organization must first be aligned rightly. It is suggested that the fishing input be determined by type and specification as a preliminary step in the delivery of inputs to the fishermen. Social, economic and cultural variabilities should be related to the requirement by the fishermen. The price level of fishermen will determine the direction and level of government support required

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This profile covers life history and environmental requirements of both alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis), since their distribution is overlapping and their morphology, ecological role, and environmental requirements are similar. The alewife is an anadromous species found in riverine, estuarine, and Atlantic coastal habitats, depending on life cycle stage, from Newfoundland (Winters et al. 1973) to Soutn Carolina (Berry 1964). Landlocked populations are i n the Great Lakes, Finger Lakes, and many other freshwater lakes (Bigelow and Sch roeder 1953; Scott and Crossman 1973). The blueback herring is an anadromous species found in riverine, estuarine, and Atlantic coastal habitats, depending on life stage cycle, from Nova Scotia to the St. Johns River, Florida (Hildebrand 1963)