904 resultados para Pearl-fisheries


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This survey was the second year of a three year study to examine fish populations in relation to low flows, drought and abstraction in the River Ouse. To fully evaluate the possible effects on fisheries the study set out to encompass fish population surveys from fry to adult stock, analysis of angler catch data, reports from anglers and river reports from Environment Agency Fisheries staff.

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This is a report on monitoring carried out in 2001 specifically in relation to effects of flows and abstractions on fisheries in the River Wharfe. The monitoring is a continuation of that started in relation to the Time Limited Abstraction Licences in 1996 and required by the new licences granted in 1999. It gives information regarding fish populations at a range of sites in the River Wharfe and also two tributary sites. It also gives recommendations for future investigations in relation to both Time Limited Licences and general broader issues.

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Fish population studies in the River Ure have continued for their sixth successive year in order to examine and evaluate the effects of low flows and drought conditions particularly in relation to the Time Limited Licence abstraction at Kilgram Bridge, currently granted to Yorkshire Water Services. This monitoring report looks at the different fish populations and growth rates in the main river and tributaries, comparing the results to previous years. The report also looks at the general findings from angling, the medium term drought impacts, the abstraction impacts, and recommendations for investigations for 2002.

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The purpose of this report is to record key events/data and to outline the activities of the NRA Central Area Fisheries Function during 1994. The Rivers looked at include the Ribble, Lune, Hodder and Wyre. The issues that the report looks at includes Hydrological and meterological data, catch data for salmon and sea trout, fish kills, and fish stocking. It also lists the Micro-tag returns for 1994 and the six key objectives that the Central Area Fisheries Function has set itself for 1995. The report uses a range of different graphs and tables to display their data.

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The purpose of this report is to record key events and achievements of the NRA Central Area Fisheries Function in 1995. Rivers include the Ribble, Hodder and Lune. The report looks at Hydrological and meteorological data, site visits made during the year, communications and reports, Capital works and purchases, Stock assessment, monitoring and specific investigations, Fisheries Management advice, Fish kills and rescues, Fish rearing and stocking. It also looks at rod and net catches for salmon and sea trout, micro-tag returns, the drought, the results of the 1995 objectives set the year before and the key objectives for 1996.

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The purpose of this report is to record key events and achievements of the NRA Central Area Fisheries Function in 1996. Rivers are Ribble, Hodder and Lune. The report looks at Hydrological and meteorological data, site visits made during the year, promotional events that it was involved with; communications and reports, Capital works and purchases, Stock assessment, monitoring and specific investigations, Fisheries Management advice, Fish kills and rescues, Fish rearing and stocking. It also includes catch data for net and rod catches for Salmon and Sea trout; the results of the objectives made last year and key objectives for next year.

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This paper highlights the social and economic importance of coarse and stillwater trout fisheries and explains the UK Environment Agency's aim, its policies and processes, and its powers for managing and regulating these fisheries, concluding with reasoned proposals for change.

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This paper gives the results of the Environment Agency's research into the canal close season to the Salmon and Freshwater Fisheries Review Group. It presents the findings of the research, explains why the research was undertaken and how it relates to the Agency's duties. The background for this report includes that angling representative bodies have long argued that the existing situation in which somecanals have a close season and others do not, is unsatisfactory.

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This report looks at the interests of the Fisheries Department for the Lancashire River Board, focusing on the Liverpool and Leeds Canal Survey. It looks at finding parasites in fish from an electrofishing survey (roach and perch). This was to contribute towards the main survey with a possible view to suggesting whether or not the parasites were one reason for the poor fish population. Methods of finding parasites are given, and results of what parasites that were found in the fish are discussed.

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The report looks at trends developing in the area of the Lancashire River Authority which will, by the turn of the century, bring tremendous pressures to bear on its natural resources, particularly land and water. It looks at difficulties maintaining an environment suitable for all, human or otherwise, including construction of energy plants and increasing population. It explores the scheme of harnessing water on Morecambe Bay, including fishery advantages and disadvantages. The report looks at fish deaths and diseases in Morecambe Bay and the Lancashire area, providing statistics.

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While an overwhelming majority of sub-Saharan African countries exhibit serious weaknesses in statistics pertaining to crop and livestock sectors, the deficiencies in terms of nationally representative data on the fishery sector are even more acute. The very little data available on the sector are essentially derived from case studies of selected fisheries, and the limited nationally representative data available are generally derived from a few questions included in the livestock section of household surveys. These do not permit the detailed characterization of the fishery production systems. As a consequence in many countries the decision-makers and planners lack the most basic information about the role and importance of the fisheries sector to their national economy. As part of an initiative called the Living Standards Measurement Study-Integrated Surveys on Agriculture (LSMS-ISA) project, a collaboration was developed between the World Bank and the WorldFish Center to address this situation. This report provides detail on pilot testing of a fisheries module for living standards measurement surveys.

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Many highly exploited ecosystems are managed on the basis of single-species demographic information. This management approach can exacerbate tensions among stakeholders with competing interests who in turn rely on data with notoriously high variance. In this case study, an application of diet and dive survey data was used to describe the prey preference of lingcod (Ophiodon elongatus) in a predictive framework on nearshore reefs off Oregon. The lingcod is a large, fast-growing generalist predator of invertebrates and fishes. In response to concerns that lingcod may significantly reduce diminished populations of rockfishes (Sebastes spp.), the diets of 375 lingcod on nearshore reefs along the Oregon Coast were compared with estimates of relative prey availability from dive surveys. In contrast to the transient pelagic fishes that comprised 46% of lingcod diet by number, rockfishes comprised at most 4.7% of prey items. Rockfishes were the most abundant potential prey observed in dive surveys, yet they were the least preferred. Ecosystem-based fisheries management (EBFM) requires information about primary trophic relationships, as well as relative abundance and distribution data for multiple species. This study shows that, at a minimum, predation relative to prey availability must be considered before predator effects can be understood in a management context.

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Sablefish (Anoplopoma fimbria) are often caught incidentally in longline fisheries and discarded, but the extent of mortality after release is unknown, which creates uncertainty for estimates of total mortality. We analyzed data from 10,427 fish that were tagged in research surveys and recovered in surveys and commercial fisheries up to 19 years later and found a decrease in recapture rates for fish originally captured at shallower depths (210–319 m) during the study, sustaining severe hooking injuries, and sustaining amphipod predation injuries. The overall estimated discard mortality rate was 11.71%. This estimate is based on an assumed survival rate of 96.5% for fish with minor hooking injuries and the observed recapture rates for sablefish at each level of severity of hook injury. This estimate may be lower than what actually occurs in commercial fisheries because fish are likely not handled as carefully as those in our study. Comparing our results with data on the relative occurrence of the severity of hooking injuries in longline fisheries may lead to more accurate accounting of total mortality attributable to fishing and to improved management of this species.

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Research on assessment and monitoring methods has primarily focused on fisheries with long multivariate data sets. Less research exists on methods applicable to data-poor fisheries with univariate data sets with a small sample size. In this study, we examine the capabilities of seasonal autoregressive integrated moving average (SARIMA) models to fit, forecast, and monitor the landings of such data-poor fisheries. We use a European fishery on meagre (Sciaenidae: Argyrosomus regius), where only a short time series of landings was available to model (n=60 months), as our case-study. We show that despite the limited sample size, a SARIMA model could be found that adequately fitted and forecasted the time series of meagre landings (12-month forecasts; mean error: 3.5 tons (t); annual absolute percentage error: 15.4%). We derive model-based prediction intervals and show how they can be used to detect problematic situations in the fishery. Our results indicate that over the course of one year the meagre landings remained within the prediction limits of the model and therefore indicated no need for urgent management intervention. We discuss the information that SARIMA model structure conveys on the meagre lifecycle and fishery, the methodological requirements of SARIMA forecasting of data-poor fisheries landings, and the capabilities SARIMA models present within current efforts to monitor the world’s data-poorest resources.

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The present report was prepared for the Water and Food Challenge Program project “Optimizing the management of a cascade of reservoirs at the catchment level” (MK3). It constitutes the baseline assessment of fish and fisheries in the Sesan River Basin. The objective of the MK3 project is to contribute knowledge and recommendations so that cascades of reservoirs corresponding to hydropower dams in the Mekong Basin are managed in ways that are more fair and equitable for all water users. This project seeks to understand at the catchment scale the cumulative upstream and downstream consequences of management decisions taken for multiple reservoirs. Revised rules for water storage infrastructure management will in particular take into account fisheries and agricultural potential as well as hydropower gen