Analysis of growth layers in the teeth of Tursiops truncatus using light microscopy, microradiography, and SEM

Preliminary results show microradiography and scanning electron microscopy (SEM) to be more accurate methods of accessing growth layer groups (GLGs) in the teeth of Tursiops truncatus than transmitted light microscopy. Microradiography shows the rhythmic deposition of mineral as alternating radiopaque and radiolucent layers. It improves the resolution of GLGs near the pulp cavity in older individuals, better than either SEM or light microscopy. SEM of etched sections show GLGs as ridges and grooves which are easily counted from the micrograph. SEM also shows GLGs to be composed of fine incremental layers of uniform size and number which may allow for more precise age determination. Accessory layers are usually hypomineralized layers within the hypermineralized layer of the GLG and are more readily distinguishable as such in SEM of etched sections and microradiographs than in thin sections viewed under transmitted light. The neonatal line is hypomineralized, appearing translucent under transmitted light, radiolucent in a microradiograph, and as a ridge in SEM. (PDF contains 6 pages.)

Groundwater abstraction and plankton in the druze pool of Azraq oasis, Jordan

The Azraq oasis lies in the Jordanian desert, about 85 km east of Amman. In this brief paper the author summarises his observations from a visit to the oasis in 1991, discusses the effects of pumping groundwater from the oasis to Amman and presents results from a plankton survey.

The Lune catchment abstraction management strategy. Consultation document September 2003

This consultation document sets out the proposed future licensing strategy for the Lune Catchment Abstraction Management Strategy (CAMS) area. Following the three month consultation period, the Environment Agency will determine the final licensing strategy and publish it in the CAMS document. The strategy will provide an indication of whether new abstraction licences are likely to be available and the conditions that should be expected on licences. Water plays a vital role in the Lune catchment, providing water for public supply, supporting recreation, such as angling and canoeing, and providing sustainable flows to preserve numerous designated sites. There is minimal abstraction throughout much of the catchment, apart from the lower reaches of the River Lune. The document is split into five sections relating to the CAMS process. Sections 1 to 4 outline the CAMS process, and Section 5 outlines the proposed licensing strategy for the Lune CAMS areas. It is important to note that this strategy deals with groundwater and surface water abstractions separately; Sections 4 and 5 are split to differentiate between the surface water and groundwater results and strategy.

The fisheries Aspects of North West Water AuthoritySchemes to Increase Water Abstraction in West Cumbria

This is the report on the Fisheries Aspects of North West Water Authority Schemes to Increase Water Abstraction in West Cumbria by the Egremont and District Anglers’ Association. Existing river pollution and water abstraction in the Ennerdale Lake-River Ehen system is shown to have caused a major deterioration in the conditions in the Ehen fishery. This is reflected by the fact that catches of salmon, sea trout and smelts on the Ehen have all fallen to roughly 6% of the 1965 level; wich is far worse than the deterioration shown in salmon catches for S. W. Cumberland as a whole. Recommendations are made, in the light of proposals by North West Water Authority to increase water abstraction in West Cumbria, to prevent further deterioration in the Ehen fishery in the short term and to improve the situation in the longer term. It contains sections on pollution, water abstraction and fisheries background, flow statistics for and discussion of high water-droughts on the River Ehen, effects of droughts on Tidal Water and a discussion of N.W.W.A. Paper entitled `Water Resources in West Cumbria’ in the light of conditions on the River Ehen.

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.