Chalk rivers: nature conservation and management

This is a handbook about Chalk Rivers Nature Conservation and Management from March 1999 by the Water Research Centre and commissioned by English Nature and the Environment Agency, primarly provides an objective basis for formulating conservation strategies for relevant Site of Special Scientific Interest (SSSIs) and Special Areas of Conservation (SACs). It was also seen as being applicable to chalk rivers more generally and has increasingly been regarded as important to the work of the Biodiversity Action Plan Steering Group on chalk rivers, which is led by the Environment Agency. This report contains information on characteristic wildlife communities, their habitat requirements and the ecological impact of activities that are relevant to the chalk river environment. It provides guidance on setting management objectives, options for mitigating impacts, and measures for the maintaining and enhancing the river channel, riparian and floodplain areas associated. The term `chalk river’ is used to describe watercourses dominated by groundwater discharge from chalk geology, including those that flow over a range of non-chalk surface geologies at various points along their length. England contains numerous examples of this river type, located in and downstream of areas of outcropping chalk in the south, East Anglia and up into Lincolnshire and Yorkshire. Indeed, England has the major part of the chalk river resource of Europe. A number of chalk rivers have been designated as Sites of Special Scientific Interest (SSSIs) and English Nature and Environment Agency work drawing up joint conservation strategies.

The Rivers Avon & Erme SAP Consultation Document

This is the Rivers Avon & Erme Salmon Action Plan Consultation document produced by the Environment Agency in 2003. This document is part of a national initiative to produce action plans for the management of all the main salmon rivers of England and Wales by 2003. The aim of this plan is (i) to assess the status of the salmon stocks and fisheries of the rivers Avon and Erme - including the use of Conservation Limits as part of this process, (ii) to identify factors which may limiting stock and fishery performance and (iii) to propose remedial measures address these factors. The report pays attention on the external consultation of the Rivers Avon & Erme Salmon Action Plan (SAP). While the stocks of both rivers have exceeded their respective conservation limits occasionally in individual years, only the Erme has achieved a period of statistical compliance since 1993. It is possible that this situation is largely normal, due to the steep nature of the rivers, obstructions to migration and dependence on suitable flow conditions occurring at the right time of year. The decline of the spring-running component of the stocks has left the populations dependent on autumn flows for the success of the late running component. Actions required to improve compliance with Conservation Limits are proposed and prioritised. The urgent actions relate to the need to improve the consistency with which adequate numbers of salmon reach and utilise fully all the accessible areas of the river systems. This document is intended to be dynamic, with opportunities for review occurring at regular intervals. For example, as the science of fisheries management improves, particularly in the setting of Conservation Limits, so the targets may be altered to reflect any improved methodology.

The Rivers Avon & Erme SAP Final Plan

This is the Rivers Avon & Erme Salmon Action Plan Final document produced by the Environment Agency in 2004. The Rivers Avon and Erme Salmon Action Plan (SAP) has been produced after consideration of feedback from public consultation. The final plan provides a list of the agreed issues and actions for the next five years to maintain and improve the salmon stocks and fisheries of both rivers. Efforts have been made to identify possible sources of funding, partners and timescales. It indicates how the plan will be managed, including the process for reviewing stock status, issues, actions and progress. Low marine survival is currently a major factor limiting the numbers of salmon returning to spawn in both the Avon and the Erme. Actions to improve the accessibility of spawning areas and to maximise the productivity of spawning and nursery habitats are seen as priorities, which should help to offset the low marine survival. The quality of the information available to assess salmon stocks is recognised as a limiting factor in the management of salmon fisheries. The SAP aims also to promote long term collaboration between the Agency and other interested parties in managing the salmon stocks and fisheries of the Avon and the Erme.

Rivers Taw and Torridge scale reading investigation. 8th annual report for the 1972 season

This is the Rivers Taw and Torridge scale reading investigation: the 8th annual report for the 1972 season produced by Devon River Authority in 1973. The object of the investigation is to examine by means of scale reading the biology of age classes of the salmon populations of the Rivers Taw and Torridge. The report is arranged in sections as previously and tables referred to in the report form an appendix. Scales were collected only from fish taken during the normal open season, which in 1972 was 1st April - 31st August. A weekly close time was in operation for the nets, a period of 60 hours from 6 p.m. on Friday evening to 6 a.m. on the following Monday. Thirty six licences for draft or seine nets were issued for the 1972 season and netsmen submitted samples of scales collected direct.

Fish communities in rivers to be affected by Roadford Reservoir

This is the Fish communities in rivers to be affected by Roadford Reservoir report produced by South West Water Authority in 1978. Surveys were carried, out on the Rivers Wolf, Thrushel, Lew and Lumburn, which are likely to be affected directly and indirectly by the construction and use of Roadford Reservoir. Of the upper reaches of three rivers to be affected directly by water releases, two were found to support abundant stocks of salmon and trout, and the third was found to contain abundant stocks of trout and eels. The River Thrushel will be affected indirectly and in this river salmon and trout stocks were present in slightly lower abundance than in others. Population estimates, densities, mean lengths and approximate biomass values were calculated. Other species were present in all rivers, usually in great abundance.

Characterization of toxic impacts on living marine resources in tidal rivers of the Chesapeake Bay

In 1999, the Chesapeake Bay Program completed a survey of existing data on chemical contaminants and the potential for bioeffects in 38 tidal river systems of Chesapeake Bay. This review led to the identification of 20 areas for which there were insufficient data to adequately characterize the potential for contaminant bioeffects on the Bay’s living resources. The goal of the present study was to estimate the current status of ecological condition in five of these areas and thus help to complete the overall toxics inventory for the Bay. These five systems included the Chester River, Nanticoke River, Pocomoke River, Lower Mobjack Bay (Poquosin and Back Rivers) and the South and Rhode Rivers. This study utilized a Sediment Quality Triad (SQT) approach in combination with additional water-column contaminant analysis to allow for a “weight of evidence” assessment of environmental condition. A total of 60 stations distributed among the five systems, using a probabilistic stratified random design, were sampled during the summer of 2004 to allow for synoptic measures of sediment contamination, sediment toxicity, and benthic condition. Upon completion of all analyses, stations were assigned to one of four categories based on the three legs of the triad. Stations with high sediment quality had no hits on any of the three legs of the triad; those with moderate quality had one hit; those with marginal quality had two hits; and those with poor quality had hits for all three legs of the triad. The Pocomoke River had by far the largest proportion of the total area (97.5%) classified as having high sediment quality, while the Rhode/South system had the highest proportion (11.4%) classified as poor. None of the stations in the Chester River, Nanticoke River, and Lower Mobjack Bay systems were classified as poor. More than 65% of the area of each of the five systems was classified with high to moderate sediment quality. The Rhode/South system had 30.4% of total area classified with marginally to severely poor quality. The results of this study highlight the importance of using multiple indicators and a “weight of evidence” approach to characterize environmental quality and the potential bioeffects of toxic contaminants.

Time series analyses of biological and environmental variables for Suisun Bay and the Sacramento and San Joaquin rivers

EXTRACT (SEE PDF FOR FULL ABSTRACT): Arima analysis was used to compute cross-correlations between principal component axes that described environmental variables, chlorophyll concentration and zooplankton density for the Sacramento and San Joaquin rivers and Suisun Bay. ... Cross-correlations among the time series may provide information about links between environmental and biological variables within the estuary and the possible influence of climate.

Colossal loss of shell and fin-fish larvae during collection of Penaeus monodon (Fab.) fry in the rivers of Satkhira

This study was conducted in five river-estuaries of Satkhira from January to December '96. It was found that during the collection of each Peneaus monodon) post larva (PL), about 45 larvae of other shrimps, 12 individuals of fin-fishes and 530 macro-zooplankters were mercilessly destroyed. It was also recorded that about 11.6 million of P. monodon PLs were harvested annually from the study area. The sh1dy implies that colossal loss of shell and fin-fishes and other plankton resources is done by tiger shrimp fry collectors, and such massive destruction adversely affect the natural productivity and ecological balance of the coastal environment.