Salmon action plan. River Ribble - June 2000

In February 1996 A Strategy for the Management of Salmon in England and Wales was launched by the National Rivers Authority. The strategy concentrates on four main objectives for the management of salmon fisheries in England and Wales: (i) Optimise the number of salmon returning to home water fisheries, (ii) Maintain and improve the fitness and diversity of salmon stocks, (iii) Optimise the total economic value of surplus stocks, (iv) Ensure necessary costs are met by beneficiaries. These four objectives will be addressed through local Salmon Action Plans (SAPs) which will be produced for each of the principle salmon rivers in England and Wales by the year 2001. A consultation report was produced for the River Ribble and released publicly in October 1999. This document determined an egg deposition figure of 8.5 million eggs for the Ribble, that would allow maximum gain from the net and rod fisheries; raised a number of issues which are thought to currently limit salmon production; identified actions which may be undertaken by the Environment Agency and other bodies to improve stocks. This action plan re-addresses the issues raised in the consultation document, taking into account the comments received, and also identifies areas of possible improvement in data gathering that would allow more accurate estimation of the spawning target and compliance in future years. The progress of this plan will be monitored and reported annually.

Salmon action plan. River Ribble - August 2000

In February 1996 A Strategy for the Management of Salmon in England and Wales was launched by the National Rivers Authority. The strategy concentrates on four main objectives for the management of salmon fisheries in England and Wales: (i) Optimise the number of salmon returning to home water fisheries, (ii) Maintain and improve the fitness and diversity of salmon stocks, (iii) Optimise the total economic value of surplus stocks, (iv) Ensure necessary costs are met by beneficiaries. These four objectives will be addressed through local Salmon Action Plans (SAPs) which will be produced for each of the principle salmon rivers in England and Wales by the year 2001. This Salmon Action Plan for the River Ribble reviews the status of the stock and the fisheries, seeks to identify the main factors limiting performance, to draw up and cost a list of options to address these, and to consult with local interest groups.

Salmon action plan: River Kent, July 2001

The report presents the Environment Agency's 5 year Salmon Action Plan for the River Kent for the period from January 2001, providing the background to the plan, responses to the public consultation given, and proposed actions.

River Wyre salmon action plan December 2003

In 1996 a Strategy for the Management of Salmon in England and Wales was launched by the National Rivers Authority setting out objectives for the management of Salmon fisheries. These objectives are to be met through local Salmon Action Plans which are to be produced for each of the 68 principal salmon rivers in England and Wales by December 2003. A consultation document was produced for the river Wyre and released publicly during October 2003. This document: • Determined an egg deposition figure of 1.27 million eggs which would allow maximum gain from the fisheries • Raised a number of issues which are though to limit existing salmon production. • Identified actions which may be undertaken by the Environment Agency and other bodies to improved stocks. The document looks at the issues in the consultation document and also highlights some important changes to historic egg deposition rates following further analysis of the data. Some of the major issues addressed in the plan are: • Severe low flows on specific tributaries • Reduced juvenile production caused by insufficient habitat. • Changes in flow regime resulting in the wash out of gravels and redds. • The impact of man made structures preventing access to suitable spawning areas, and preventing the downstream distribution of spawning gravels.

Proposal and validation of methodologies for the categorisation of continuous variables in the development of prediction models

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River Kent salmon action plan - consultation draft

In February 1996, the National Salmon Management Strategy was launched by the Environment Agency's predecessor the National Rivers Authority (NRA, 1996). The strategy concentrates on four main objectives for the management of salmon fisheries in England and Wales. These are primarily aimed at securing the well being of the stock, but in doing so will improve catches and the associated economic returns to the fisheries. The four main objectives are : (i) Optimise the number of salmon returning to home water fisheries, (ii) Maintain and improve fitness and diversity of salmon stocks. (Hi) Optimise the total economic value of surplus stocks, (iv) Ensure necessary costs are met by beneficiaries

Mathematical models for the prediction of temperature distributions resulting from the discharge of heated water into large bodies of water

Mathematical models for heated water outfalls were developed for three flow regions. Near the source, the subsurface discharge into a stratified ambient water issuing from a row of buoyant jets was solved with the jet interference included in the analysis. The analysis of the flow zone close to and at intermediate distances from a surface buoyant jet was developed for the two-dimensional and axisymmetric cases. Far away from the source, a passive dispersion model was solved for a two dimensional situation taking into consideration the effects of shear current and vertical changes in diffusivity. A significant result from the surface buoyant jet analysis is the ability to predict the onset and location of an internal hydraulic jump. Prediction can be made simply from the knowledge of the source Froude number and a dimensionless surface exchange coefficient. Parametric computer programs of the above models are also developed as a part of this study. This report was submitted in fulfillment of Contract No. 14-12-570 under the sponsorship of the Federal Water Quality Administration.

Prediction and confirmation of seasonal migration of Pacific sardine (Sardinops sagax) in the California Current Ecosystem

During the last century, the population of Pacific sardine (Sardinops sagax) in the California Current Ecosystem has exhibited large fluctuations in abundance and migration behavior. From approximately 1900 to 1940, the abundance of sardine reached 3.6 million metric tons and the “northern stock” migrated from offshore of California in the spring to the coastal areas near Oregon, Washington, and Vancouver Island in the summer. In the 1940s, the sardine stock collapsed and the few remaining sardine schools concentrated in the coastal region off southern California, year-round, for the next 50 years. The stock gradually recovered in the late 1980s and resumed its seasonal migration between regions off southern California and Canada. Recently, a model was developed which predicts the potential habitat for the northern stock of Pacific sardine and its seasonal dynamics. The habitat predictions were successfully validated using data from sardine surveys using the daily egg production method; scientific trawl surveys off the Columbia River mouth; and commercial sardine landings off Oregon, Washington, and Vancouver Island. Here, the predictions of the potential habitat and seasonal migration of the northern stock of sardine are validated using data from “acoustic–trawl” surveys of the entire west coast of the United States during the spring and summer of 2008. The estimates of sardine biomass and lengths from the two surveys are not significantly different between spring and summer, indicating that they are representative of the entire stock. The results also confirm that the model of potential sardine habitat can be used to optimally apply survey effort and thus minimize random and systematic sampling error in the biomass estimates. Furthermore, the acoustic–trawl survey data are useful to estimate concurrently the distributions and abundances of other pelagic fishes.

Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index

Millions of crabs are sorted and discarded in freezing conditions each year in Alaskan fisheries for Tanner crab (Chionoecetes bairdi) and snow crab (C. opilio). However, cold exposures vary widely over the fishing season and among different vessels, and mortalities are difficult to estimate. A shipboard experiment was conducted to determine whether simple behavioral observations can be used to evaluate crab condition after low-temperature exposures. Crabs were systematically subjected to cold in seven different exposure treatments. They were then tested for righting behavior and six different ref lex actions and held to monitor mortality. Crabs lost limbs, showed ref lex impairment, and died in direct proportion to increases in cold exposure. Righting behavior was a poor predictor of mortality, whereas reflex impairment (scored as the sum of reflex actions that were lost) was an excellent predictor. This composite index could be measured quickly and easily in hand, and logistic regression revealed that the relationship between reflex impairment and mortality correctly predicted 80.0% of the mortality and survival for C. bairdi, and 79.4% for C. opilio. These relationships provide substantial improvements over earlier approaches to mortality estimation and were independent of crab size and exposure temperature.

Reflex impairment as a measure of vitality and survival potential of Atlantic cod (Gadus morhua)

A ssur ing the v itality and survival potential of live-caught Atlantic cod (Gadus morhua) is important for improving the sorting of fish before net penning operations designed to hold fish for growth and later market. When Atlantic cod are captured by Danish seine, the most commonly used fishing gear for live-caught fish, they undergo stressors such as forced swimming, net abrasion, and air exposure. Laboratory experiments (at an air temperature of 9°C and water temperature of 8°C) were conducted with the aim of constructing a RAMP (reflex action mortality predictor) curve for prediction of vitality and survival potential in Atlantic cod captured in Danish seines, by varying the levels of these stressors. Atlantic cod exposed to increased duration in air (5–20 min) showed increased reflex impairment and mortality, with 75% mortality at 10 minutes of air exposure. Forced swimming in combination with net abrasion and air exposure did not increase reflex impairment or mortality above that associated with air exposure alone. The Atlantic cod RAMP curves indicated that fish with reflex impairment less than 50% would not show mortality and would likely recover from capture stress.