979 resultados para Aquatic resources


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The trawl fishery for pelagic annorhead, Pseuaopentaceros wheeleri(fonnerly referred to as Pentaceros richardsoni), and alfonsin, Beryx splendens, over the central North Pacific seamounts has a relatively short history. Before 1967, fishery scientists were generally unaware of the resources on seamounts; however, the discovery of commercial concentrations of pelagic armorhead on seamounts in the southern Emperor Seamounts by a Russian commercial trawler in November 1967 led to almost immediate exploitation of the species by the Soviets. Unconfinned reports indicated that the schools of pelagic annorhead on the seamounts averaged 30 m thick and catches averaged from 3 to 50 metric tons on 10-20 min hauls (Sakiura 1972). Japanese trawlers entered the fishery in 1969. To assist in the development of this tishery, Japanese research vessels conducted extensive surveys in 1972 on the distribution and potential for development ofthe pelagic armorhead and alfonsin resources. The results of their surveys to the central North Pacific and mid-Pacific seamounts showed that many had summits that were too deep for trawling. Those found suitable were concentrated in the southern Emperor-northern Hawaiian Ridge. (PDF file contains 113 pages.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim of this working paper was to evaluate the potential of different fisheries enhancement and aquacultural systems to benefit marginal farmers who manage small rainfed irrigation systems in the lowland Dry zone of Sri Lanka. Analysis was based on secondary data and key informant interviews with professional fishermen and marginal farmers in N.W Province. [PDF contains 57 pages]

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Describes the routine activities that make up the work day of the University's Natural Resources Institute. Hours at the microscope, data recording, analysis, and publications. Responsible for a broad program of research and conservation education. Its main concern is with fresh and salt water fisheries, seafood processing and marketing, estuarine studies, game animals, forestry, and water pollution problems. (PDF contains 4 pages.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

HIGHLIGHTS FOR FY 2009 1. Completed the second of a two-year Gulf sturgeon population study on the Choctawhatchee River, Florida. The juvenile, sub adult and adult Gulf sturgeon population was estimated at 3,400 fish. 2. Three young of year Gulf sturgeon were collected by Corps of Engineers biologists in the upper Brothers Rivers. 3. Two YCC enrollees spent eight weeks assisting PCFO biologists and Tyndall AFB with various projects. 4. The Gulf Sturgeon 5-Year Summary and Evaluation was completed. 5. Karen Herrington co-authored a peer-reviewed journal article for a striped bass symposium at the annual American Fisheries Society meeting, which will be published in the symposium proceedings. The article reviews the past 25 years of striped bass restoration in the ACF and is titled “Restoration of Gulf Striped Bass: Lessons and Management Implications”. 6. We documented recent purple bankclimber recruitment in the Ochlockonee River for the first time in several years. 7. We provided over 200 genetic samples to Warm Springs Fish Technology Center to compare mussel populations and genetic diversity, rank populations by status, and facilitate recovery actions. 8. We established permanent mussel monitoring locations in Sawhatchee Creek and the Flint River to examine trends in population size, survival, and recruitment. 9. We provided a prioritized list to the Federal Emergency Management Agency of 197 stream crossings that occur near freshwater mussel populations in order to facilitate habitat restoration following major flooding in Alabama, Florida, and Georgia in the spring of 2009.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Alliance for Coastal Technologies (ACT) convened a workshop on Evaluating Approaches and Technologies for Monitoring Organic Contaminants in the Aquatic Environment in Ann Arbor, MI on July 21-23, 2006. The primary objectives of this workshop were to: 1) identify the priority management information needs relative to organic contaminant loading; 2) explore the most appropriate approaches to estimating mass loading; and 3) evaluate the current status of the sensor technology. To meet these objectives, a mixture of leading research scientists, resource managers, and industry representatives were brought together for a focused two-day workshop. The workshop featured four plenary talks followed by breakout sessions in which arranged groups of participants where charged to respond to a series of focused discussion questions. At present, there are major concerns about the inadequacies in approaches and technologies for quantifying mass emissions and detection of organic contaminants for protecting municipal water supplies and receiving waters. Managers use estimates of land-based contaminant loadings to rivers, lakes, and oceans to assess relative risk among various contaminant sources, determine compliance with regulatory standards, and define progress in source reduction. However, accurately quantifying contaminant loading remains a major challenge. Loading occurs over a range of hydrologic conditions, requiring measurement technologies that can accommodate a broad range of ambient conditions. In addition, in situ chemical sensors that provide a means for acquiring continuous concentration measurements are still under development, particularly for organic contaminants that typically occur at low concentrations. Better approaches and strategies for estimating contaminant loading, including evaluations of both sampling design and sensor technologies, need to be identified. The following general recommendations were made in an effort to advance future organic contaminant monitoring: 1. Improve the understanding of material balance in aquatic systems and the relationship between potential surrogate measures (e.g., DOC, chlorophyll, particle size distribution) and target constituents. 2. Develop continuous real-time sensors to be used by managers as screening measures and triggers for more intensive monitoring. 3. Pursue surrogate measures and indicators of organic pollutant contamination, such as CDOM, turbidity, or non-equilibrium partitioning. 4. Develop continuous field-deployable sensors for PCBs, PAHs, pyrethroids, and emerging contaminants of concern and develop strategies that couple sampling approaches with tools that incorporate sensor synergy (i.e., measure appropriate surrogates along with the dissolved organics to allow full mass emission estimation).[PDF contains 20 pages]

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The annual estimated total marine fish catch in Nigeria for the period 1971 to 1979 is 0.3299 million metric tons. The differential distribution pattern of the predominant fish groups for the maritime states, the component species, their life habits in relation to hydrographic factors leasing to seasonal fluctuations in the fisheries are highlighted, focussing also on the types of fishing carafts and gear in common use along the coastal states and the fish species obtained from them. The landings by the exploratory and commercial fishing trawlers including the distant water vessels (imports) form about 4.24% of the total marine fish landing

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bibliography and list of resources to accompany Information Literacy presentation by Natalie Wiest, presented at the 20th Annual SAIL meeting.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

One of the objectives of the Terrestrial Initiative in Global Environmental Research is to assess the sensitivity of British plant and animal species to climate change. The first phase of the program involved the identification of criteria for selecting species suitable for the study of effects of projected climate change in the British Isles. Apart from shallow ponds, annual temperature ranges of 0 to 25 C in temperate freshwater habitats are narrower than those in most temperate terrestrial habitats. Although freshwater organisms have to exist within a narrower range than their terrestrial equivalents, few species can survive throughout their life cycle over the whole temperature range. Field studies on the effects of natural and artificial thermal discharges into streams and rivers have shown that increases in water temperature affect aquatic insects at both the species and community level. Although field data provide valuable information, a more productive approach is to determine experimentally the requirements of different species. Although there are just over 1850 species of aquatic insects in the British Isles, detailed quantitative information on the relationship between temperature and development of eggs, larvae and pupa is available for relatively few species. One exception is the egg stage of stoneflies (Plecoptera). The range for egg hatching in stoneflies clearly show that some species could be threatened while others could benefit from a defined increase in water temperature as a result of climate change. A critical review of the available data on this group would produce a set of equations that could be used to predict the ecological effects of climate change on this group of indicator species.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Irrigation in the eleven River Basin Authorities and in particular in the South Chad Irrigation Project and the Baga Polder Project is increasing and demands high yearly investments for aquatic weed control in canals and drains. If the weeds are biologically controlled by the grass carp (Ctenopharyngodon idella Val.), the costs will be turned into profit, particularly when the fish production (resident fish plus grass carp) is harvested and sold for food. The use of irrigation canals and drains for aquaculture in the form of fish polyculture may be a wise step towards increased fish production. This paper highlights the concept of fish production from aquatic weed control and concludes that it is a proven profitable venture in several countries

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Cross River State (Nigeria) marine and freshwater artisanal capture fisheries are divided into 4 categories according to the type of resources being exploited. Schaefer's production model is applied to each of the fisheries to estimate the maximum sustainable yields (Ymax). The total potential yield for all the fisheries in natural waters is 178,650 tonnes/year. This potential is unlikely to be achieved as more fishermen are abandoning the occupation due to the scarcity of boats, outboard engines and nets. Even if the full potentials were realized the production would still be short of what the State should produce by about 30.5%. Investment opportunities which, if effected can help to narrow the gap between the available and the desired level of production are enumerated

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A brief account is given of the demand for ornamental fish, providing also estimates of world trade volume. The major importing countries are the USA, Japan, Germany, the UK and the Netherlands. Present supply patterns are outlined; although Nigeria has vast natural resources of tropical aquatic life and the right climate for breeding, current exports are estimated at only 5% of the total potential. Recommendations for the promotion of exports of tropical aquarium fish in Nigeria are included