857 resultados para Restoration and conservation
Resumo:
This is the report on the Effect of Abstraction on Fish and Fisheries presented at the 24th IFM Annual Study Course, The Changing Face of Fisheries September 1993 at Cardiff. Water is abstracted from rivers for a wide variety of uses and causing potential for conflicts between abstracters, fisheries and conservation interests, especially during natural low flows. It looks at the potential effects that flow reduction has over various stages of salmonids at various stages of their life history. The flow at the time of smolt migration has been found to be positively correlated with the number of returning adults, and flow is considered to be one of the most important environmental factors inducing salmonids to enter fresh water and ascend rivers. The importance of time series data on fish stocks and angling success together with models which ultimately relate discharge to standing stock are discussed in relation to the setting up of Minimum Acceptable Flows.
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This is the NRA's role in wetland conservation report produced by the National Rivers Authority in 1995. This document is the third of a series of three R&D Notes produced as part of an integrated research programme addressing aspects of the NRA's role in wetland management and conservation. Chapter 1 considers the nature of the wetland resource and its definition. Chapter 2 presents the NRA's current legislative and policy framework relating to its role in wetland conservation. National and international legislation and agreements are considered, and particular attention is afforded to the potential implications of the 'Habitats Directive'. Chapter 4 presents key examples of operational casework involving wetlands. Differences in approach and external perceptions of the NRA's current and likely future role in wetland conservation are discussed within Chapter 5. Other issues highlighted in this report are: policy guidance required on NRA’s role in land drainage; standard of flood defence service for wetlands; cost-benefit analysis; strategies for halting and reversing the decline and degradation of wetland resource; and Catchment Management Planning.
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As the earth’s resources continue to face increasing pressure from a variety of human and natural causes, protection of the environment and biodiversity is a matter of contemporary concern, The conservation of coastal and marine resources, in particular, has become a priority for countries around the world. In this context, marine protected areas (MPAs) are being widely promoted as one of the most effective tools for the conservation of coastal and marine resources. Most MPAs are located in coastal areas of great biodiversity, and hence their development has direct impacts on the lives and livelihoods of coastal communities, especially small-scale and traditional fishing communities. Typically, they are the ones who have to bear the costs of conservation practices–lost livelihood options, expulsion from traditional fishing grounds and living spaces, and violation of human/community rights, to name a few. The articles in this dossier, drawn chronologically from the pages of Samudra Report, the triannual publication of ICSF, draw attention to these issues. They show that conservation and livelihoods are closely intertwined, and that top-down, non-participatory models of conservation can be counter-productive. Despite being poor and powerless, fishing and coastal communities can be powerful allies in conservation efforts, given their longstanding dependence on natural resources and their traditional ecological knowledge systems. As the examples in this dossier reveal, it is possible for fishing communities to protect and conserve the environment, while continuing with sustainable fishing operations. Clearly, only an integrated approach to fisheries management and conservation will prove successful. This dossier will be useful for policymakers, social scientists, non-governmental organizations and others interested in fisheries, conservation, communities and livelihoods.
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The primary objective of this project, “the Assessment of Existing Information on Atlantic Coastal Fish Habitat”, is to inform conservation planning for the Atlantic Coastal Fish Habitat Partnership (ACFHP). ACFHP is recognized as a Partnership by the National Fish Habitat Action Plan (NFHAP), whose overall mission is to protect, restore, and enhance the nation’s fish and aquatic communities through partnerships that foster fish habitat conservation. This project is a cooperative effort of NOAA/NOS Center for Coastal Monitoring and Assessment (CCMA) Biogeography Branch and ACFHP. The Assessment includes three components; 1. a representative bibliographic and assessment database, 2. a Geographical Information System (GIS) spatial framework, and 3. a summary document with description of methods, analyses of habitat assessment information, and recommendations for further work. The spatial bibliography was created by linking the bibliographic table developed in Microsoft Excel and exported to SQL Server, with the spatial framework developed in ArcGIS and exported to GoogleMaps. The bibliography is a comprehensive, searchable database of over 500 selected documents and data sources on Atlantic coastal fish species and habitats. Key information captured for each entry includes basic bibliographic data, spatial footprint (e.g. waterbody or watershed), species and habitats covered, and electronic availability. Information on habitat condition indicators, threats, and conservation recommendations are extracted from each entry and recorded in a separate linked table. The spatial framework is a functional digital map based on polygon layers of watersheds, estuarine and marine waterbodies derived from NOAA’s Coastal Assessment Framework, MMS/NOAA’s Multipurpose Marine Cadastre, and other sources, providing spatial reference for all of the documents cited in the bibliography. Together, the bibliography and assessment tables and their spatial framework provide a powerful tool to query and assess available information through a publicly available web interface. They were designed to support the development of priorities for ACFHP’s conservation efforts within a geographic area extending from Maine to Florida, and from coastal watersheds seaward to the edge of the continental shelf. The Atlantic Coastal Fish Habitat Partnership has made initial use of the Assessment of Existing Information. Though it has not yet applied the AEI in a systematic or structured manner, it expects to find further uses as the draft conservation strategic plan is refined, and as regional action plans are developed. It also provides a means to move beyond an “assessment of existing information” towards an “assessment of fish habitat”, and is being applied towards the National Fish Habitat Action Plan (NFHAP) 2010 Assessment. Beyond the scope of the current project, there may be application to broader initiatives such as Integrated Ecosystem Assessments (IEAs), Ecosystem Based Management (EBM), and Marine Spatial Planning (MSP).
Resumo:
From the 1940s until 2003, portions of the island of Vieques, a municipality within the Commonwealth of Puerto Rico, were used by the US Navy as a base and training facility, resulting in development and zoning history that differ in comparison to other Caribbean islands. The majority of former Navy lands are now under the jurisdiction of the Department of the Interior’s Fish and Wildlife Service as a National Wildlife Refuge, while a smaller percentage of land was transferred to the Vieques municipality and the Puerto Rico Conservation Trust. An analysis of the distribution and status of the marine resources is timely in light of the recent land transfer, increases in development and tourism, and potential changes in marine zoning around the island. To meet this need, NOAA’s Biogeography Branch, in cooperation with the Office of Response and Restoration and other local and regional partners, conducted Part I of an ecological characterization to integrate historical data and research into a synthesis report. The overall objective of this report is to provide resource managers and residents a comprehensive characterization of the marine resources of Vieques to support research, monitoring, and management. For example, knowledge of the spatial distribution of physical features, habitats, and biological communities is necessary to make an informed decision of the establishment and placement of a marine protected area (MPA). The report is divided into chapters based on the physical environment (e.g., climate, geology, bathymetry), habitat types (e.g., reefs and hardbottom, seagrasses, mangroves) and major faunal groups (e.g. fish, turtles, birds). Each section includes five subsections: an overview, description of the relevant literature, methods of analysis, information on the distribution, status and trends of the particular resource, and a discussion of ecological linkages with other components of the Vieques marine ecosystem and surrounding environment. The physical environment of Vieques is similar to other islands within the Greater Antilles chain, with some distinctions. The warm, tropical climate of Vieques, mediated by the northeasterly trade winds, is characterized by a dry season (December-April) and a rainy season (May-November), the latter of which is characterized by the occasional passage of tropical cyclones. Compared to mainland Puerto Rico, Vieques is characterized by lower elevation, less annual precipitation, and higher average temperatures. The amount of annual precipitation also varies spatially within Vieques, with the western portion of the island receiving higher amounts of rainfall than further east. While the North Equatorial Current dominates the circulation pattern in the Greater Antilles region, small scale current patterns specific to Vieques are not as well characterized. These physical processes are important factors mitigating the distribution and composition of marine benthic habitats around Vieques. In general, the topography of Vieques is characterized by rolling hills. Mt. Pirata, the tallest point at 301 m, is located near the southwest coast. In the absence of island wide sedimentation measurements, information on land cover, slope, precipitation, and soil type were used to estimate relative erosion potential and sediment delivery for each watershed. While slope and precipitation amount are the primary driving factors controlling runoff, land use practices such as urban development, military activity, road construction, and agriculture can increase the delivery of pollution and sediments to coastal waters. Due to the recent land transfer, increased development and tourism is expected, which may result in changes in the input of sediments to the coastal environment.
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The phylogenetic relationships among 12 genera of treefrogs (Family, Rhacophoridae), were investigated based on a large sequence data set, including five nuclear (brain-derived neurotrophic factor, proopiomelanocortin, recombination activating gene 1, tyr
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A clear knowledge of the reproductive potential or fecundity of a fish is quite an essential pre-requisite for the proper management and conservation of the resources. The fecundity studies are also undertaken to determine the index of diversity dependent factor affecting the population size (Simpson, 1951). Qasim & Qayyam (1963) have detailed the various pathways by which an understanding of fecundity could be used for fishery biological work. The ability of egg production varies within the individual limits such as length, somatic weight, gonadal weight, volume of fish etc.
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This study describes the molecular identification of sixteen fish species present in processed products imported into Iran for human consumption. DNA barcoding using direct sequencing of about 650 bp of the mitochondrial Cytochrome Oxidase subunit I gene revealed incorrect labeling (31.25%). Substitution of fish species constitutes serious economic fraud, and our results increase concern regarding the trading of processed fish products in Iran from both health and conservation points of view.
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Rastrineobola argentea, local name.s Mukene (Uganda) Omena (Kenya) and Dagaa (Tanzania) occurs in lakes Victoria, Kyoga and Nabugabo (Greenwood 1966). Until the decline of the native fishes especially the haplochromines, R. argentea was of little economic importance to the fisheries of these lakes. The stocks of this species have now increased and commercial catches on Lake Victoria account for over 30%. Fishing for R. argentea is currently still restricted to inshore areas and within the fringing islands of Lake Victoria. This fishery is not yet established on Lakes Kyoga and Nabugabo although the species is quite abundant in these lakes (Proude 1963). On moonless nights, kerosene pressure lamps are exposed on the lake to attract the fishes. These fishes are then fished out using fine meshed seine, lampara or lift nets
Resumo:
Oreochromis niloticus (the Nile tilapia) and three other ti1apine species: Oreochromis leucostictus, Tilapia zi11ii and T. rendallii were introduced into Lakes Victoria, Kyoga and Nabugabo in 1950s and 1960s. The source and foci of the stockings are given by Welcomme (1966) but the origin of the stocked species was Lake Albert. The Nile tilapia was introduced as a management measure to relieve fishing pressure on the endemic tiapiines and, since it grows to a bigger size, to encourage a return to the use of larger mesh gill nets. Ti1apia zillii was introduced to fill a vacant ,niche of macrophytes which could not be utilised' by the other tilapiines. Tilapia rendallii, and possibly T. leucosticutus could been introduced into these lakes accidently as a consquence of one of the species being tried out for aquaculture. The Nile perch and Nile tilapia have since fully established themselves and presently dominate the commercial fisheries of Lakes Victoria and Kyoga. The original fisheries based on the endemic tilapiines O. escu1entus and o. variabilis have collapsed. It is hypothesized that the ecological and limnological changes that are observed in Lakes Victoria and Kyoga are due to a truncation of the original food webs of the two lakes. Under the changed conditions, O. niloticus to be either playing a stabilizing role or fuelling nutrient turnover in the lakes. Other testable hypotheses point to the possible role of predation by the Nile perch, change in regional climate and hydrology in the lake basins.
Resumo:
There have been considerable changes in fish species composition in Lakes victoria, Kyoga and Nabugabo since the Nile perch were introduced. Populations of most of the native species have declined and many species may have become extinct. The original decline in the fish stocks was due to overfishing but the recent and more drastic decline has been attributed to predation by the Nile perch. Nile perch feeds on invertebrates changing to a piscivorous diet with size. Haplochromine cichlids, which were the most abundant fish in Lakes Victoria just before the Nile perch populations started increasing rapidly have been depleted. As more suitable types of prey were depleted in the new habi tats, Nile perch switched to other prey types to the extent of feeding even on its own young. There are, fears that the Nile perch will overshoot its food supply, resulting in a reduction of its own population and subsequently a collapse in the fishery (FAD 1985).
Resumo:
Lakes Victoria, Kyoga and Nabugabo had a similar native fish fauna of high species diversity. stocks of most of the native species declined rapidly and some completely disappeared after Nile perch was introduced and became well established. Although, overexploitation of the fish stocks, competition between introduced and native tilapiines and environmental degradation contributed to the reduction in fish stocks, predation by the Nile perch has contributed much to the recent drastic reductions in fish stock and could even drive the stocks to a total collapse. Nile perch is also currently the most important commercial species in Lakes victoria, Kyoga and Nabugabo and the stability of its stocks is important in the overall sustainability of the fisheries of these lakes. The question that was to be examined in this paper was whether the fisheries of Lakes Victoria, Kyogaand Nabugabo would stabilize and sustain production in the presence of high predation pressure by the Nile perch or whether the Nile perch would drive the fish stocks including itself to a collapse. I t was assumed that Nile perch driven changes in Lakes Victoria, Kyoga and Nabugabo would be driven to a level beyond which they would not change further. This would be followed by recovery and stability or the changes would continue to a point of collapse. It was assumed that Lake Albert represented the ideal stable state. The changes in the new habitats expected to be driven through a major change due to Nile perch predation to a stage where there would be no further changes. After this, a feedback mechanism would move the driven variable towards recovery. The variables would then stabilize and oscillate will an amplitude which approximates to what would be recorded in Lake Albert. Alternatively, the changes would proceed to a stage where the fishery would collapse. The specific hypothesis was that fish species composition and diversity, prey selection by the Nile perch and life history characteristics of the Nile perch in the new habitats would change and stabilize