Development and collapse of an Oscillatoria bloom in Loch Leven during July 1994

During 1994, weekly spot-sampling of open water sites on Loch Leven took place from 16th March onwards. Very little difference between spot-sampling sites was observed from 16th March to 5th July. Throughout April and May there was a slow increase in levels of chlorophyll-a, followed by a rapid increase through June, reaching a maximum of 230 micrograms per litre. On 8th July there was a very rapid rise in water temperature, with a corresponding increase in dissolved oxygen and pH. At 0915 hours on 9th July there was a drop in all three variables. These changes were coincident with a marked reduction in chlorophyll-a values falling to 70 micrograms per litre on 12th July. On 16th July evidence of a resurgence of photosynthesis was observed.

River Leven (at Newby Bridge) freeze coring report

This is the River Leven (at Newby Bridge) freeze coring report produced by Lancaster University in 2000. This study looks at fine materials in river Leven that may have to be considered detrimental to successful salmonid spawning. Following an observed decline in quality of salmonid fisheries at the site an investigation was initiated to assess the extent of ingress of fine sediments into the spawning gravels. A broader picture was sought by sampling both above and below the weir and close to both banks of the river. A comparison of the fine sediment from each sample site was undertaken. All the freeze cores used in this report contained distinct horizontal strata down through their length. The cores often penetrated into a highly compacted layer of light grey coloured material. The upper surface of this highly compacted layer is considered as a boundary between fine materials of different origin. Considerable variability was observed in the median grain size (D50) of the gravels from the cores. In addition variability was observed in the thickness of the upper less compacted layers. The role of regulated river flow across the weir in clearing fines from river gravels is briefly considered.

Fish surveys on the Leven and Kent estuaries

This is the Wetland resource evaluation and the NRA's role in its conservation: Resource assessment report produced by North West Water in 1982. In this report data from a variety of sources in river Leven and Leven estuary have been examined to determine if there was any objective foundation for the allegations and for the assertion that poor fish catches were related to discharges of industrial effluent to the estuary. Catches of salmon and sea trout from the Leven did not appear to have suffered any long term declines and year to year fluctuations did not appear to be any more extreme than in other North West rivers. Fish surveys did not show any marked differences in the diversity or distribution of fish between the Kent and Leven estuaries but catches of flounders were consistently lower from the Leven estuary. Analysis of fisheries statistics of landings of fish and shellfish from Morecambe Bay did not show any evidence of localised declines in catches from the Leven estuary. Results of laboratory experiments suggested that populations of bivalve molluscs might be more at risk from the effects of discharges to the Leven estuary than resident or migratory fish.

Leven estuary project. Fisheries Department final report

This is the report on the Leven estuary project: Fisheries Department final report produced by the Environment Agency North West in 1997. This report contains information about Leven estuary, river Leven catchment, river Crake catchment and the Ulverston Discharges. The Leven estuary is characterised by being very shallow, and shares the extremely variable tides and currents that characterize the whole of Morecambe Bay. There was little detailed knowledge of the impact on the Leven estuary, and particularly its fisheries, of the discharges from Ulverston. There has been some concern expressed by the lave netsmen and the general public about the possible harmful effects of the effluents on the biology of the estuary. In the absence of a definite strategy for the protection and management of the estuary was born this project. The project involves water quality monitoring, effluent and estuary toxicity testing, tracking of effluent plumes, and salmonid tagging and tracking. The entire project commenced in June 1995 and was expected to reach a conclusion in March 1997. The information gained from the project was expected to contribute to the creation of a 'mixing zone' for the effluent, and to improve the environmental management of the estuary and protection of its fishery.

On the unknown postlarval stages of the garfish, Tylosurus strongylurus (Van Hasselt) and the seapike, Sphyraena jello Cuvier

Unknown larval stages of Tylosurus strongylurus and Sphyraena jello have been traced from Vellar Estuary, Porto Novo (lat. 11 degree 29'N; long. 79 degree 46' E). Descriptions of different stages (7-17.5 mm T. strongylurus, and 18 and 22.5 mm S. jello) are given. A thorough ichthyoplankton survey for 2 years (Nov. 1977-Oct. 1979) in the estuary revealed that these larvae were very rare in the estuary and were caught on the occasion (Nov. 1978) only.