Ecological study of the River Lambourn. Report for the period October 1970 to March 1972

A small investigation of the ecology of the river Lambourn was carried out during 1967-70. During this period it became clear that detailed and reliable information could only be obtained by a much larger investigation. The present study was planned to meet the minimum requirements. No pumping is expected during this period and, since the pumping carried out during the pilot scheme was on a small scale, it is reasonable to assume that the river is still relatively unaffected by pumping.The present investigation has two main objectives both of which depend on obtaining a detailed picture of the ecology of the river at the present time. First, it will provide basic information on the state of the river prior to the development of the pumping scheme which will be available for comparison at any later date. Secondly, it may be possible to use some of the data to predict the ecological changes which may occur if the flow of the river is altered by the pumping scheme. This report is part of a series of fives studies on the River Lambourn which were undertaken between 1970 and 1979. [PDF contains 83 pages]

Seventh Annual Report for year ended 31st March, 1972

This is the seventh Annual report of the Cumberland River Authority on information of its activities and responsibilities on river management in its area between the beginning of April 1971, to the end of March 1972. The report contains 5 main sections on water resources, land drainage, fisheries, pollution, and finally the expenditure and income for the 12 month period. The first area that the report deals with is water resources, which includes periodical surveys, hydrometric schemes, acceptable flows, conservation works and a review of rainfall and river flow. The section on land drainage looks at work on improvement schemes, floods, charges and information on maintenance work carried out on rivers including Wampool, Waver, Derwent and Eden. The fisheries section covers 5 districts of the River Eden, Esk, Ellen, Derwent and South West Cumberland. It includes angling information and a general report for salmon and sea trout, brown trout and freshwater fish. Fish disease and fish hatchery are also covered as well as fisheries protection and licence duties. The fourth section on pollution deals with water quality, and the results of samples taken for chemical analysis from rivers Eden, Eamont, Petteril, Caldew, Calder, Irthing, Esk, Irt, Mite, Derwent, Ehen, Wampool and Waver are also given. It also covers information on sewage and trade effluents. The River Authorities preceded the Environment Agency which came into existence in 1996.

Anti-grazing properties of the toxic dinoflagellate Karlodinium veneficum during predator-prey interactions with the copepod Acartia tonsa

Karlodinium veneficum (syn. Karlodinium micrum, Bergholtz et al. 2006; J Phycol 42:170–193) is a small athecate dinoflagellate commonly present in low levels in temperate, coastal waters. Occasionally, K. veneficum forms ichthyotoxic blooms due to the presence of cytotoxic, hemolytic compounds, putatively named karlotoxins. To evaluate the anti-grazing properties of these karlotoxins, we conducted food removal experiments using the cosmopolitan copepod grazer Acartia tonsa. Wild-caught, adult female A. tonsa were exposed to 6 monoalgal or mixed algal diets made using bloom concentrations of toxic (CCMP 2064) and non-toxic (CSIC1) strains of K. veneficum. Ingestion and clearance rates were calculated using the equations of Frost (1972). Exposure to the toxic strain of K. veneficum did not contribute to an increased mortality of the copepods and no significant differences in copepod mortality were found among the experimental diets. However, A. tonsa had significantly greater clearance and ingestion rates when exposed to a monoalgal diet of the non-toxic strain CSIC1 than when exposed to the monoalgal diet of toxic strain CCMP 2064 and mixed diets dominated by this toxic strain. These results support the hypothesis that karlotoxins in certain strains of K. veneficum deter grazing by potential predators and contribute to the formation and continuation of blooms.