33 resultados para Tanzania grass

em Aquatic Commons


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As threats to the marine environment continue to remain high, and conventional resource-management techniques have been found wanting, marine protected areas (MPAs) are being seen as a tool to address the abuse and destruction of the environment. This study discusses the social dimensions of MPAs in Tanzania, using the case of the Mafia Island Marine Park and the socioeconomic, political and cultural contexts within which Mafia people live their lives. (54 pp.)

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The effects of the grass carp (Ctenopharyngodon idella Val.)on aquatic plant biomass, water quality, phytoplankton, chlorophyll a, zooplankton and benthic fauna were investigated between May and September 2000 in earthen ponds at Cifteler- Sakaryabasi Aquaculture and Research Station. (PDF has 8 pages)

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This study evaluated longevity and population persistence of 768,500 triploid grass carp (Ctenopharyngodon idella Valenciennes) stocked in the 70,000-ha Santee Cooper system in South Carolina from 1989 through 1996 to control hydrilla (Hydrilla verticillata (L.f.) Royle).

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Approximately 768,500 triploid grass carp ( Ctenopharyngodon idella Valenciennes) were stocked into the Santee Cooper reservoirs, South Carolina between 1989 and 1996 to control hydrilla ( Hydrilla verticillata (L.f.) Royle). Hydrilla coverage was reduced from a high of 17,272 ha during 1994 to a few ha by 1998. During 1997, 1998 and 1999, at least 98 triploid grass carp were collected yearly for population monitoring. Estimates of age, growth, and mortality, as well as population models, were used in the study to monitor triploid grass carp and predict population trends. Condition declined from that measured during a previous study in 1994. The annual mortality rate was estimated at 28% in 1997, 32% in 1998 and 39% in 1999; however, only the 1999 mortality rate was significantly different. Few (2 out of 98) of the triploid grass carp collected during 1999 were older than age 9. We expect increased mortality due to an aging population and sparse hydrilla coverage. During 1999, we estimated about 63,000 triploid grass carp system wide and project less than 3,000 fish by 2004, assuming no future stocking. management, population size Ctenopharyngodon idella, Hydrilla

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Florida’s large number of shallow lakes, warm climate and long growing season have contributed to the development of excessive growths of aquatic macrophytes that have seriously interfered with many water use activities. The introduction of exotic aquatic macrophyte species such as hydrilla ( Hydrilla verticillata ) have added significantly to aquatic plant problems in Florida lakes. The use of grass carp ( Ctenopharyngodon idella ) can be an effective and economical control for aquatic vegetation such as hydrilla. Early stocking rates (24 to 74 grass carp per hectare of lake area) resulted in grass carp consumption rates that vastly exceeded the growth rates of the aquatic plants and often resulted in the total loss of all submersed vegetation. This study looked at 38 Florida lakes that had been stocked with grass carp for 3 to 10 years with stocking rates ranging from < 1 to 59 grass carp per hectare of lake and 1 to 207 grass carp per hectare of vegetation to determine the long term effects of grass carp on aquatic macrophyte communities. The median PAC (percent area coverage) value of aquatic macrophytes for the study lakes after they were stocked with grass carp was 14% and the median PVI (percent volume infested) value of aquatic macrophytes was 2%. Only lakes stocked with less than 25 to 30 fish per hectare of vegetation tended to have higher than median PAC and PVI values. When grass carp are stocked at levels of > 25 to 30 fish per hectare of vegetation the complete control of aquatic vegetation can be achieved, with the exception of a few species of plants that grass carp have extreme difficulty consuming. If the management goal for a lake is to control some of the problem aquatic plants while maintaining a small population of predominately unpalatable aquatic plants, grass carp can be stocked at approximately 25 to 30 fish per hectare of vegetation.

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For a long time, the Tanzanian Fisheries Department has managed Tanzanian fisheries without incorporating other stakeholders within its management framework. On lake Victoria, the persistent use of illegal fishing gear and declining catches have led the government to realize that this system of fisheries management may no longer be viable, and have sought to incorporate fishing communities into the management structure. Through the creation of beach management units (BMUs), the Fisheries Departments have sought to persuade fishing communities to implement and enforce Tanzania's fishing regulations and to monitor the fishery. In this paper we explore a recently gathered data set that yields information on, amongst others, how Tanzanian fishing communities perceive the state of their resource base, how they view their relationship with the Fisheries Department, the efficacy of fishing regulations and other variables. We draw on a series of criteria developed by Ostron (1990) for institutional 'robustness' to explore various areas of institutional development on Lake Victoria, and to try and anticipate how the BMUs will fare. We argue there are many socio-political and economic factors that will determine how communities will receive and perceive their responsibilities towards government-imposed administrative structures at the local level, these will become 'socialized' such that they will vary from place to place. While this may bode well for problems of heterogeneity, it does not necessarily mean that fisheries management objective on Lake Victoria will be met

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This paper is aimed at government, non-government organizations, intergovernmental organizations and the general public as they work toward the development of their individual strategies and action plans. It has been recognized that community-based organizations have a particular relevance to the pursuit of sustainable resource management and may well contribute to the foundations of self-sustenance. Women on Lake Victoria, Tanzania presently face great challenges within the fishery. These include the lack of capital, interference by men, theft of fishing gear, time constraints and socio-cultural problems. In recent years, the fish trading and marketing sectors of the fishery, which have traditionally been dominated by women, have seen large incursions by male entrepreneurs. This move has endangered the role of women within the fishery. This paper focuses on the Tweyambe Fishing Enterprise (TFE), a well-known women's group based in Kasheno village in the Muleba District of Kagera Region in northwestern Tanzania. Inhabitants from the Haya ethnic group who make up some 95% of the population of Kagera Region dominate this village. The TFE has a series of initiatives aimed towards ecologically sound self-development

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Trawl surveys to assess the stocks of Lake Victoria (Tanzania) for estimates of biomass and yield, together with the establishment of exploitation patterns, are being undertaken under the Lake Victoria Fisheries Research Project. Preliminary surveys to establish the sampling stations and strategy were carried out between October 1997 and February 1998. Three cruises to cover the whole of Tanzanian waters were undertaken with 133 sampling stations. Data on each rates, species composition, and distribution were collected. Three sampling areas were designated: area A, B and C. In each area, almost the same distribution pattern over depth was found. Lates niloticus (L) formed over 90% of the total catch. Most L. niloticus were from 5-40 cm TL. Abundance decreased with depth, few fish were found deeper than 40m and most fish were caught at <20 m deep. Catch rates varied considerably between stations and areas. Area A had the highest catch rates with little variation over the stations. There is an indication of recovery of species diversity compared with the surveys of RV Kiboko(1985 and 1989)

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The Tanzania Coastal Management Partnership (TCMP) works to implement the National Integrated Coastal Environmental Management Strategy (ICEMS) in Tanzania’s coastal landscapes and seascapes, funded in large measure by the U.S. Agency for International Development. The overarching goal of the Sustainable Coastal Communities and Ecosystems in Tanzania (SUCCESS Tanzania) initiative is to conserve coastal and marine biodiversity while improving the well being of coastal residents through implementation of the Tanzania ICEMS and related ICM policies and strategies. It does this by focusing on three key results: -Policies and Laws that Integrate Conservation and Development Applied -Participatory Landscape Scale Conservation Practiced -Conservation Enterprises Generate Increased and Equitable Benefits from Sustainable Use An additional result sought in the program is gender equity and HIV/AIDS preventive behaviors promoted through communicating HIV/AIDS, environment, and equity messages. (PDF contains 3 pages)

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The work reported here results from material collected by the author made during 12 years residence in the East Usambaras in the 1950s and early 1960s, as well as a more recent visit. The faunal list the author has compiled comprises 45 species. As well as named species known to occur in the torrential section of the River Sigi, it includes those that are distinct but insufficiently well defined at present to have been formally described. For the sake of completeness, five species of Cloeon and one of Procloeon known to occur in ponds and pools formed by the damming of end-streams in forest clearings, have been included.

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Two landing sites were chosen in Tanzania for the 4-beaches survey. The former, Ihale, is a large one with an avarage of 120 boats and direct connections to the fish processing factories. The latter, Mwasonge, is one of the smallest landing sites in the Mwanza region with totally different characteristics. This book section aims to analyse the results from these two sites in the context of the co-management potentialities in Tanzania and more generally on the Lake Victoria region.

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Trawl surveys to assess the stocks of Lake Victoria for estimates of biomass and yield, together with the establishment of exploitation patterns, are being undertaken under the Lake victoria Fisheries Research Project. Preliminary surveys to establish the sampling stations and strategy were carried out between October 1997 and February 1998. Three cruises to cover the whole of the Tanzanian waters were undertaken with a total of 133 sampling stations. Data on catch rates, species composition and distribution were collected.

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Ihale is a large landing site lying approximately 65 km. from Mwanza along the main Mwanza-Musoma highway. Ihale Beach was selected as a potential candidate for the 3-beaches study because of its proximity to Mwanza, and hence suitability for frequent monitoring; and because it is served by a road accessible during the rainy seasons. As with the first training Participatory Rural Appraisal (PRA) on Kiumba Beach on Kenya's Rusinga Island, the objectives with this PRA were as follows: (a) To identify and understand Ihale's community-based organizations and institutions which have a role in the lake's fishery. (b) To consider the key issues which arise from this study for the involvement of communities and community-based organizations and/or institutions such as those at Ihale Beach, in the co-management of Lake Victoria's fishery.

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This paper comprises part of the so-called "3-beaches Survey" of the LVFRP. In Tanzania, this study has developed to examine two landing sites (Mwasonge and Ihale), and to chart the progress of the newly established Beach Management Units (BMU) at each beach, comparing one BMU against the other. The over-arching objective of this survey was to develop an understanding of the context in which Mwasonge's fishery exists. The study does so by examining the community's history, culture and beliefs, various other socio-cultural factors, their resources, society and economy, wealth and the community's perceptions of wealth. Importantly, the survey examines the community's institutions and its perceptions of fishing rules and changes within the fishery. All of these facets of community life are examined with the use of participatory Rural Appraisal tools, and the images that the study generated are reproduced herein.

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Three commercially important fish species, Lates niloticus (L.), Rastrineobola argentea (Pellegrin) and Oreochromis niloticus (L.) that are fished by artisanal fishermen of Lake Victoria, Tanzania part, were studied in Kagera, Mwanza and Mara beaches from October 1997 to July 1999. Catches, effort, exploitation and stock structure were investigated. Beaches for sampling were selected based on importance for landing the above named fish species. The number of boats found on beach that day, the number that lay idle and their means of propulsion were recorded. As many boats as possible were sampled for gear type and gear size. The catches were sorted into species and measured. Variation in the species and size composition of landings was observed between regions, between months and between gears used. The implications of the findings to management are discussed.