912 resultados para Pond of stabilization
Resumo:
Anthropogenic climate and land-use change are leading to irreversible losses of global biodiversity, upon which ecosystem functioning depends. Since total species' well-being depends on ecosystem goods and services, man must determine how much net primary productivity (NPP) may be appropriated and carbon emitted so as to not adversely impact this and future generations. In 2005, man ought to have only appropriated 9.72 Pg C of NPP, representing a factor 2.50, or 59.93%, reduction in human-appropriated NPP in that year. Concurrently, the carbon cycle would have been balanced with a factor 1.26, or 20.84%, reduction from 7.60 Gt C/year to 5.70 Gt C/year, representing a return to the 1986 levels. This limit is in keeping with the category III stabilization scenario of the Intergovernmental Panel for Climate Change. Projecting population growth to 2030 and its associated basic food requirements, the maximum HANPP remains at 9.74 ± 0.02 Pg C/year. This time-invariant HANPP may only provide for the current global population of 6.51 billion equitably at the current average consumption of 1.49 t C per capita, calling into question the sustainability of developing countries striving for high-consuming country levels of 5.85 t C per capita and its impacts on equitable resource distribution. © Springer Science+Business Media B.V. 2009.
Resumo:
Extensive losses of coastal wetlands in the United States caused by sea-level rise, land subsidence, erosion, and coastal development have increased hterest in the creation of salt marshes within estuaries. Smooth cordgrass Spartina altemiflora is the species utilized most for salt marsh creation and restoration throughout the Atlantic and Gulf coasts of the U.S., while S. foliosa and Salicomia virginica are often used in California. Salt marshes have many valuable functions such as protecting shorelines from erosion, stabilizing deposits of dredged material, dampening flood effects, trapping water-born sediments, serving as nutrient reservoirs, acting as tertiary water treatment systems to rid coastal waters of contaminants, serving as nurseries for many juvenile fish and shellfish species, and serving as habitat for various wildlife species (Kusler and Kentula 1989). The establishment of vegetation in itself is generally sufficient to provide the functions of erosion control, substrate stabilization, and sediment trapping. The development of other salt marsh functions, however, is more difficult to assess. For example, natural estuarine salt marshes support a wide variety of fish and shellfish, and the abundance of coastal marshes has been correlated with fisheries landings (Turner 1977, Boesch and Turner 1984). Marshes function for aquatic species by providing breeding areas, refuges from predation, and rich feeding grounds (Zimmerman and Minello 1984, Boesch and Turner 1984, Kneib 1984, 1987, Minello and Zimmerman 1991). However, the relative value of created marshes versus that of natural marshes for estuarine animals has been questioned (Carnmen 1976, Race and Christie 1982, Broome 1989, Pacific Estuarine Research Laboratory 1990, LaSalle et al. 1991, Minello and Zimmerman 1992, Zedler 1993). Restoration of all salt marsh functions is necessary to prevent habitat creation and restoration activities from having a negative impact on coastal ecosystems.
Resumo:
This report provides baseline biological data on fishes, corals and habitats in Coral and Fish Bays, St. John, USVI. A similar report with data on nutrients and contaminants in the same bays is planned to be completed in 2013. Data from NOAA’s long-term Caribbean Coral Reef Ecosystem Monitoring program was compiled to provide a baseline assessment of corals, fishes and habitats from 2001 to 2010, data needed to assess the impacts of erosion control projects installed from 2010 to 2011. The baseline data supplement other information collected as part of the USVI Watershed Stabilization Project, a project funded by the American Recovery and Reinvestment Act of 2009 and distributed through the NOAA Restoration Center, but uses data which is not within the scope of ARRA funded work. We present data on 16 ecological indicators of fishes, corals and habitats. These indicators were chosen because of their sensitivity to changes in water quality noted in the scientific literature (e.g., Rogers 1990, Larsen and Webb 2009). We report long-term averages and corresponding standard errors, plot annual averages, map indicator values and list inventories of coral and fish species identified among surveys. Similar data will be needed in the future to make rigorous comparisons and determine the magnitude of any impacts from watershed stabilization.
Resumo:
Douglas fir is one of the most important trees in northwestern California. Regional pollen records suggest that it has become prominent only in the late Holocene. The primary cause for this change is probably southward stabilization of the mean airstream.
Resumo:
Small indigenous fish species (SIS) are an important source of essential macro- and micronutrients that can play an important role in the elimination of malnutrition and micronutrient deficiencies in the populations of many South and Southeast Asian countries. Of the 260 freshwater fish species in Bangladesh, more than 140 are classified as SIS and are an integral part of the rural Bangladeshi diet. As many SIS are eaten whole, with organs and bones, they contain high amounts of vitamins and minerals, including calcium, and iron and zinc. Some SIS, such as mola, are also rich in vitamin A. SIS are often cooked with vegetables and a little oil, so they contribute to the food diversity of the rural poor.SIS are recognized as a major animal-source food group, contributing to improved food and nutrition security and livelihoods of the people of South and Southeast Asia. The purpose of this workshop is to bring together policy makers, extension agents, researchers, non-governmental and development organizations to share knowledge about small fish, their contribution to better nutrition, production technologies, and strategies for wider dissemination of pond culture and wetland based-production and conservation technologies. The workshop is expected to generate ideas for further research and development of sustainable technologies for production, management and conservation of SIS for the benefit of the people of Bangladesh as well as the South and Southeast Asian region.
Resumo:
Post larvae of tiger prawn (Penaeus monodon) of the size 10-12 mm were stocked at the rate of 10 lakhs/ha in a manured cement nursary pond which was initially fertilized with chemical manures. Water exchange was attended once in a week. Artificial feeding was given in the form of minced clam meat. After a month, the pond was harvested. The juveniles which have grown to 40-46 mm size were recovered. The percentage of survival from post larvae to juveniles was 85.45%.
Resumo:
An examination is made of various issues regarding freshwater aquaculture development raised by the IIMA study on inland fish marketing in India. The following topics are discussed: 1)fish production and the resources; 2)desirability for refined methodology for assessment of fish production; 3)pond resource under fish culture; 4)conflicting data and 5)observation on research input for freshwater.
Resumo:
The ascorbic acid turnover from the ocular tissues of 11 species of fishes from a culture pond and the river Godavari (Andhra Pradesh, India) has been studied. The free ascorbic acid and ascorbigen contents were more in the case of bottom or deep dwelling fishes and the least in the case of surface living forms, depending upon the light penetration in the area that each species inhabits. The enzymic utilization and ascorbic acid-macromolecule complex varied among the fishes possibly depending upon individual energy requirements and not upon light intensity. No size-related or sex-related variation was observed. No variation was observed between riverine and pond-reared fishes of the same species.
Resumo:
With the stimulus of the very high international market value of penaeid shrimp, new pond areas for shrimp farming are rapidly being added in Bangladesh. Unfortunately, this expansion is occurring with the loss of some natural mangrove forests and with soils and sediments that are far from ideal for aquaculture. In this study, two representative shrimp farming areas were surveyed and pH, in profile depth, was recorded. It was found that the shrimp farming areas of the Chakaria Sundarban are more acidic than those of the Khulna-Satkhira region due to the acid sulfate soils.
Resumo:
An experiment was conducted in two phases for 45 days each to study the effects of six stocking densities (phase-I: 100, 200 and 300 PL/m² and phase-II: 250, 500 and 750 PL/m²) on growth and survival of Macrobrachium rosenbergii postlarvae (PL) in nylon hapa-nets (1.8m x 1.8m x 1.4m) installed in a pond. Stocking densities of 100, 200 and 300 PL 10/m² resulted in similar (P<0.05) body length (47-48 mm) and survival rate (84-88%), while body weight (0.62g) in PL with 300/m² was significantly lower than that (0.70g) in PL with 100 and 200/m². The growth (body length 47mm and weight 0.64g) and survival (84%) of PL stocked at 250 PL/m² density were significantly higher (P<0.05) than that of PL at 500 and 750/m². Besides the variation in growth and survival in PL at six tests stocking densities, a sharp increase in body weight of PL was observed beginning at the 4th week of rearing.
Resumo:
A 10-weeks culture trial of mud crab, Scylla serrata in brackish water earthen pond was conducted in different stocking densities. The aim of the experiment was to identify a suitable stocking density for optimum production. There were three treatment as 5000 crab lings/ha, 10000 crab lings/ha and 15000 crab lings/ha of each with three replications. The initial mean weight of crab lings were same (5.5 ± 0.13 g). The experimental month was June '95 to August '95. The size of each pond was 500 m². To maintain good water quality water was exchanged in every spring tide. The salinity during the experiment were 2-18ppt. Prepared feed of about 32% protein consisting fish meal, MOC rice bran and wheat flour was used at 5% of their body weight. In terms of production, survival rate, growth and carapace width, the stocking density having 10000/ha showed the best (P
Resumo:
Three different stocking rates in a semi-intensive pilot shrimp project was adopted in duplicates of three treatments designated as T1, T2 and T3 having initial per meter square stocking density of shrimp of 40, 44 and 51 respectively of 0.025g size post larva. The study was conducted for 84 days. Commercial pelleted diets designated as starter - 1, 2, 3 and grower were fed at a satiation level during the study period with a feeding frequency of 4 to 5 times per day. Feed rationing was based on the survivability, body weight and tray checking. 5-25% of the pond water was exchanged daily. Sampling was done for growth after every 2nd week. Monthly sampling was done for mortality in the ponds. Mean weight gain of the shrimp in treatments T1, T2 and T3 were 16.96 ± 1.14, 16.04 ± 1.38 and 14.08 ± 1.17g respectively and T1 with a low stocking density showed a significantly best growth among the treatments. Total mortality in treatments T1, T2 and T3 were as 30.00, 39.77 and 31.37% respectively. Significantly higher feed conversion ratio (FCR) of 1.87 was obtained with shrimp in treatment T3 followed by shrimp in T1 and T2 with FCR values of 1.70 and 1.41 respectively. A positive correlation of growth and salinity was observed during the study. Total production per unit area was the highest in the treatment T3 (4928 kg/ha) and followed by T1 (4747 kg/ha) and T2 (4251 kg/ha). The result show significantly negative correlation between individual growth and density.