Fish communities and fisheries in Wales's National Nature Reserves: a review

Wales is important for fish conservation in Britain. In much of Wales, atchments are small (median catchment size = 121 km2 ) and frequently eparated by areas of upland (> 600 m altitude), creating a highly agmented habitat for freshwater fish. Consequently, fish communities onsist mainly of diadromous species such as trout, eel and sticklebacks hat were able to recolonise freshwaters via the sea following the retreat of he ice sheets ca. 10 000 years BP. This review aims to (i) update the former work of Lyle and Maitland, taking into account new National Nature Reserves (NNRs)and additional data collected since 1991; (ii) assess the different fish communities represented on Welsh NNRs with respect to their naturalness; (iii) examine the use of NNRs for angling; (iv) evaluate opportunities for expanding the NNR series to conserve fish populations of conservation importance. The paper provides a table of freshwater fish occurrence by water body in Wales.

Active reservoir management: a model solution

Steady-state procedures, of their very nature, cannot deal with dynamic situations. Statistical models require extensive calibration, and predictions often have to be made for environmental conditions which are often outside the original calibration conditions. In addition, the calibration requirement makes them difficult to transfer to other lakes. To date, no computer programs have been developed which will successfully predict changes in species of algae. The obvious solution to these limitations is to apply our limnological knowledge to the problem and develop functional models, so reducing the requirement for such rigorous calibration. Reynolds has proposed a model, based on fundamental principles of algal response to environmental events, which has successfully recreated the maximum observed biomass, the timing of events and a fair simulation of the species succession in several lakes. A forerunner of this model was developed jointly with Welsh Water under contract to Messrs. Wallace Evans and Partners, for use in the Cardiff Bay Barrage study. In this paper the authors test a much developed form of this original model against a more complex data-set and, using a simple example, show how it can be applied as an aid in the choice of management strategy for the reduction of problems caused by eutrophication. Some further developments of the model are indicated.

An analysis of salmon rod catch data from castle fisheries, River Derwent, 1923-1989.

The aim of this study was to investigate the historical catch record from the Castle Fishery on the River Derwent over the period 1923 - 1989, to determine if changes had taken place in the composition of the catch and to examine the influence of flow on the performance of the fishery. The River Derwent is situated in West Cumbria, North West England. It flows from its source on Scafell Pike (NGR NY 229 089) westwards discharging into the Irish sea at Workington, a distance of 52 km. Over its length it receives water from an additional 214 km of stream, 5 large lakes and approximately 30 small tarns. The catchment drains a total area of 663 km2. The study concludes that through the time period there was considerable variation in catch between years. The trend was for the catch to increase steadily over the period 1923 - 1958, declining rapidly in 1959, after which catches increased steadily reaching a peak in the mid-sixties, before declining towards the end of the decade. During the seventies and eighties catches remained relatively stable at between 300 - 600 salmon per year until 1988 when over 2000 salmon were reported caught, the greatest number in any year over the study period.

Bottlenose Dolphins, Tursiops truncatus, Removing By-catch from Prawn-trawl Codends During Fishing in New South Wales, Australia

During a fishing trip to record video footage of fish escaping from a by-catch reducing device located in a commercial prawn trawl, two bottlenose dolphins, Tursiops truncatus, were observed to actively manipulate the codend at the seabed, removing and consuming components of catch (mostly juvenile whiting, Sillago spp.). The observed feeding pattern suggests a well established behavioral response to trawling activities and is discussed with respect to (1) the potential nutritional benefit that dolphins may derive from such activities and (2) the effects that scavenging may have on selectivity of the gear.

Salmonid & freshwater Fisheries statistics England & Wales 1989

This is the Salmonid & Freshwater Fisheries Statistics for England & Wales 1989 produced by the National Rivers Authority (NRA) in 1989. This report is focused on the maintenance, improvement and development of fisheries of England and Wales. This report is the first on salmon and migratory trout catch statistics for England and Wales published by the National Rivers Authority (NRA). From 1989 onwards, these statistics will appear each year as NRA fisheries statistics reports replacing the Data Report Series which was published by the Ministry of Agriculture Fisheries and Food (MAFF) Directorate of Fisheries Research. This report makes a general review of different catches: Northumbria, Yorkshire, Anglian, Thames, Southern, Wessex, South West, Severn-Trent, Welsh and North West.

Salmonid & freshwater Fisheries statistics England & Wales 1990

This is the Salmonid & Freshwater Fisheries Statistics for England & Wales 1990 produced by the National Rivers Authority (NRA) in 1992. This report is focused on the maintenance, improvement and development of fisheries of England and Wales. This report is the second compilation of salmon and migratory trout catch statistics for England and Wales published by the National Rivers Authority (NRA). Before 1989, these statistics were published by the Ministry of Agriculture Fisheries and Food (MAFF) Directorate of Fisheries Research in their Data Report Series. The 1990 data have been presented in a broadly similar format to those of 1989. However, two further NRA regions, four in all, provided effort data for rod fisheries in 1990. This report makes a general review of different catches: Northumbria, Yorkshire, Anglian, Thames, Southern, Wessex, South West, Severn-Trent, Welsh and North West.

Salmonid & freshwater Fisheries statistics England & Wales 1992

This is the Salmonid & Freshwater Fisheries Statistics for England & Wales 1992 produced by the National Rivers Authority (NRA) in 1994. This report is focused on the maintenance, improvement and development of fisheries of England and Wales. This report is the fourth compilation of salmon and migratory trout catch statistics for England and Wales published by the National Rivers Authority. For the years 1983-88, these statistics were published by the Ministry of Agriculture, Fisheries and Food (MAFF), Directorate of Fisheries Research in their Data Report Series. Other than for rod catches, the 1992 data have been presented in a broadly similar format to those of 1991, Presentation of the rod data however has changed considerably due to the introduction in January 1992 of the first National Rod Fishing Licence. This report makes a general review of different catches: Northumbria, Yorkshire, Anglian, Thames, Southern, Wessex, South West, Severn-Trent, Welsh and North West.

Salmonid & freshwater Fisheries statistics England & Wales 1994

This is the Salmonid & Freshwater Fisheries Statistics for England & Wales 1994 produced by the National Rivers Authority (NRA) in 1995. This report is focused on the maintenance, improvement and development of fisheries of England and Wales. This report is the sixth compilation of salmon and migratory trout catch statistics for England and Wales produced by the National Rivers Authority. For the years 1983-88, these statistics were published by the Ministry o f Agriculture, Fisheries and Food (MAFF), Directorate of Fisheries Research in their Data Report Series. The 1994 data have been presented in a broadly similar format to those of 1993.This report makes a general review of different catches: Northumbria, Yorkshire, Anglian, Thames, Southern, Wessex, South West, Severn-Trent, Welsh and North West.

Salmonid & freshwater Fisheries statistics England & Wales 1996

This is the Salmonid & Freshwater Fisheries Statistics for England & Wales 1996 produced by the Environment Agency in 1997. The principal aim of the Environment Agency in respect of fisheries is to maintain improve and develop fish stocks, the basic fisheries resource, in order to optimise the social and economic benefits from their sustainable exploitation. This report is the second collation of salmon and migratory trout catch statistics for England and Wales produced by the Environment Agency. For the years 1989-94, these statistics were published by the National Rivers Authority (NRA) and the years 1983-88 by the Ministry of Agriculture, Fisheries and Food, Directorate of Fisheries Research in its Data Report series. The 1996 data, have been presented in a broadly similar format to those of 1995. This report makes a general review of different catches: Northumbria, Yorkshire, Anglian, Thames, Southern, Wessex, South West, Severn-Trent, Welsh and North West.

The effect of abstraction on fish and fisheries

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.

Salmonid and freshwater fisheries statistics for England and Wales,1997

This report is the third collation of salmon and migratory trout catch statistics for England and Wales produced by the Environment Agency. For the years 1989-94, these statistics were published by the National Rivers Authority (NRA) and the years 1983-88 by the Ministry of Agriculture, Fisheries and Food, Directorate of Fisheries Research in its Data Report series. This report is designed to be a reference document of declared salmonid catches in England and Wales and is produced in the autumn following the season. Salmon stock assessment data including provisional catches, counter run estimates and some juvenile data are now published in an annual assessment for the International Council for the Exploitation of the Seas (ICES). The first report in this series was published jointly by the Environment Agency and the Centre for Environment, Fisheries & Aquatic Science (CEFAS) in April 1997 (Anon 1998).

Salmonid and freshwater fisheries statistics for England and Wales,1998

This report is the fourth collation of salmon and migratory trout catch statistics for England and Wales produced by the Environment Agency. For the years 1989-94 these statistics were published by the National Rivers Authority (NRA) and for the years 1983-88 by the Ministry of Agriculture, Fisheries and Food, Directorate of Fisheries Research, in its Data Report series. This report is designed to be a reference document of declared salmonid catches in England and Wales. Salmon stock assessment data including provisional catches, counter run estimates and some juvenile data are now published in an annual assessment for the International Council for the Exploitation of the Seas (ICES). The second report in this series was published jointly by the Environment Agency and the Centre for Environment, Fisheries & Aquatic Science (CEFAS) in April 1998 (Anon 1999).

On the stabilisation of turbulent lifted flames

This study explores the stabilisation mechanisms of turbulent lifted flames by examining the scalar dissipation rate (SDR) of both passive and reactive scalars and their cross dissipation (CDR) in the stabilisation region. DNS results of a laboratory scale hydrogen turbulent lifted flame has been used for this analysis. Various definitions of the flame leading edge (FLE) has been compared and differences are illustrated. Time and spatial averaged statistic of SDR and CDR were examined. It was found that the averaged SDR for the mixture fraction at FLE was well below the reference quenching value for stoichiometric mixture. The averaged SDR for the progress variable is in the same order of the unstrained premixed laminar flame value. It was observed that the averaged CDR changed from negative to weakly positive at FLE. The change in sign was explained by a change in the relative alignment of the gradients of mixture fraction and progress variable. It was thus evident that the CDR was a good marker for stabilisation region and an important quantity in stabilisation mechanism.