Epidermis differentiation in Salmo irideus Gilb. development [Translation from: Archo ital.Anat.Embriol. 76, 19-30, 1971]

Recent histochemical and histophysiological research on the skin of fish has posed interesting problems both with regard to the presence of specialized types of cell and with regard to the function of this organ. The present paper intends to study the development and the functional differentiation of the trout's skin, both from the histomorphological and the histochemical point of view. The skin of Salmonids is devoid of specialized cells; the granular cells of Petromyzonti, the serous cells of Selacii and the clavate cells described in many other teleosts and it lacks keratin. As such it can be considered a good working model which can be used to show the eventual histomorphological and histochemical changes occurring both in the transformation from the endovular to the aqueous environment. Histomorphological observations were carried out demonstrate the great structural simplicity of the trout's skin at all stages. The article concludes that glycogen increases greatly when the epidermis thickens and therefore when it becomes necessary to guarantee resistance, amongst which is a support mechanism.

Feeding of Gammarus lacustris Sars under different conditions of habitation [Translation from: [Trophic relations of freshwater invertebrates.] (ed. G. G. Vinberg) pp.94-98. Leningrad, Zool.Inst.AN SSSR, 1980]

The amphipod Gammarus lacustris, a regular representative of lacustrine communities, often plays a significant role in the transformation of matter and energy. The object of the present work was to clarify the quantitative side of the feeding of the amphipod under different conditions of habitation. Experimental works on determination of the rate of consumption of food and its dependence on body-weight were carried out in the summer periods 1975-1978 on three water-bodies of the Krasnoyarsk region, of different conditions of habitation for the amphipods.

Factors influencing the start of development in Daphnia pulex winter eggs [Translation from: Biological Reviews Vol. 13, 24-26, 1951]

The winter eggs of Daphnia pulex, after passing safely through the winter , develop and hatch in the spring, multiplying by themselves, while some males emerging among them with the changes in environment produce fertile eggs, which are universally known as winter eggs . This study researches the factors governing the development of winter eggs through experiments.

Ecology and management of water plants in lowland streams

A review article which discusses the ecology and management of common water plants in lowland streams, with an introduction containing a review of previous studies on the subject. The article covers the significance of seasonal growth, the significance of stand structure (particularly in relation to hydraulic resistence), an assessment of current river management, improvements to plant management techniques (in relation to cutting), and alternatives to the traditional techniques of river plant management. There are a number of accompanying figures.

Factors affecting the susceptibility of salmonid fish to disease

A review article discussing the degree of susceptibility of fish to outbreaks of disease and whether, besides from changes in the physical and chemical characteristics of the environment, this susceptibility is instrumental in determining whether or not pathogenic challenge results in disease. The article summarises a decade of work on this subject at the Windermere laboratory of the Freshwater Biological Association and suggests possible directions for future research. The article covers experimental design, effects of environmental stress (including discussion on the hypothalamic-pituitary-interrenal (HPI) axis in salmonid fish), sexual maturation, research areas for future development and evolutionary considerations. There are a number of accompanying figures and images.

Biological surveillance of chalk-streams

An article reviewing the methods of biological surveillance of chalk-streams developed and commonly used at that time, with a focus on their application to the River Frome catchment in Dorset. In evaluating the surveillance methods, the author looks at sampling methods (including cores and kick-sampling), the level of identification of macroinvertebrates, and temporal and spatial variations. Responses of indices to organic pollution are also discussed. A number of accompanying figures are also included.

The design and development of the Windermere Profiler. An instrument for measuring how various environmental parameters vary with depth in lakes, reservoirs and rivers

A review article detailing the background, development and functionality of the Windermere Profiler, a multi parameter environmental monitoring instrument for use in lakes, reservoirs and rivers. The article explains the requirement for regular data collection by the Freshwater Biological Association at Windermere. The article covers the requirements of a profiling instrument, the design considerations, the electronic circuitry, the computer program, the operation of the computer software, the profiler in use and further developments to the design. A number of figures and images accompany the article.

Information science and the scientist. A look at information requirements and the technologies available to scientists in the pursuit of information

A review article looking at the type of information requirements commonly shared by scientists and their use of traditional information services. Areas covered include primary requirements of IFE (Institute of Freshwater Ecology) staff, pure versus applied research, informal and personal sources of information, and traditional library and information services. It goes on to describe how research into information systems and technology may improve the wider accessibility and use of information to the scientific community. Technologies covered include online databases, telecommunications, gateways, expert systems, optical technology and applications of CDROM.

The changing chemical composition of chalk streams and rivers

The area studied was the River Frome system below Dorchester. The main river has its origins mainly in chalk springs, although some of its tributaries have surface run-off from farm lands and heath-lands. Thus the chemistry of the river is affected by changes in land practice and differences in the geology of the catchment area. Regular chemical analysis of chalk waters started at the River Laboratory in 1964, Regular weekly analyses have been carried out since 1965 at Bere Stream (a small chalk stream) and the River Frome (a large chalk stream); also single samples have been analysed to provide preliminary information. In 1970-71 an attempt was made to discover the contribution each main source made to the flow and chemical composition of the River Frome. Results of these investigations are presented in the paper.

The ecology of phytoplankton in Shropshire and Cheshire meres

This review summarizes the findings of 5 years' research (June 1970-June 1975) on the meres of the Shropshire-Cheshire Plain. A mere is a small, shallow lake; supplied principally by ground water, whose chemical composition is infkuenced by the glacial frift through which it is percolating. The seasonal periodicity of the phytoplankton in the meres involved work mainly in the Grose Mere. Here diatoms were typically dominant in Feb & March, green algae in April & May, blue-green algae in early summer and dinoflagellates in late summer. This pattern is broadly similar from year to year, and has been suggested to be representative of a 'regional type'; it is also similar to that described for many of the world's mildly eutrophic temperate lakes. Vertical distribution of phytoplankton is influenced by their buoyancy (or lack of it) of by their ability to swim. A stylized depth-time distribution of 4 major phytoplankton components in Crose Mere is given diagrammatically.

The production of algae growing on gravel in a chalk-stream

Epilithic algae, ie that growing on the surface of stones, was studied as part of the work on the energy flow of the chalk-stream ecosystem, by the River Laboratory. The study area was on Bere Stream and 2 neighbouring streams. The algal biomass was estimated from analysis of chlorophyll a. In Bere Stream the peak chlorophyll a cover occurred in April, while in the neighbouring streams, which have considerably lower nutrient levels, there was on peak. Assuming that 2% of a diatoms dry wt is chlorophyll a, then even in mid-April the biomass of epilithic algae amounted to no more than 15 g dry wt m Super(-2) of exposed gravel. Annual production was calculated to be > 15 times greater than biomass. The estimation of net primary production is always difficult for benthic floras and comparisons are especially difficult when different methods are used. But these figures contrast sharply with those for Ranunculus (water crowfoot) which has a ratio of annual production to maximal seasonal biomass of 1:16. The accumulation of algal biomass is apparently being prevented. Some organic matter may be excreted; some algae will be washed off the bed of the stream by current and grazing by herbivorous invertebrates will also tend to prevent algal accumulation.

Actinomycetes and actinophage in fresh water

Actinomycetes are a group of micro-organisms which lie, in classification, half-way between the fungi and the bacteria. They may be isolated from the plating of leaf washings, water samples and mud dilutions on to nutrient agar (with incorporated actidione to eliminate fungi). The predominant genus varied with the source of the sample. An attempt was also made to isolate the phages of some Actinomycetes. A search was made in the typical environments of the host, for the virus. In this way actinophage were also isolated; and shown to be capable of being transmitted from one host strain to another host strain within 1 sp or from one host to another within 1 genus; i.e. polyvalent.

The communities of running water in Cumbria

For conservations of nature to be effective. there must be an understanding of what is present to be conserved. Thus in order to conserve the communites of the Cumbrian rivers, there must first be surveys to determine the spp present and their relative numbers. This has been carried out for many years, by a number of workers. It has been shown that the communities present are influenced by the substratum, the flow, the chemicals present, water temp and predation. Findings of the work on the River Lune were given at a seminar on the rivers of north-west Europe, held at Amiens in November, 1975. The proceedings of the seminar are to appear in special numbers of Bulletin francais de Pisciculure.

The ecology of the Gussage, a lined winterbourne

The Gussage, a Dorset winterhourne (intermittent chalk stream), has been used to convey water from a compensation borehole to the River Allen to supplement its flow to meet demand for water. Sections of the Gussage have been lined with chalk, butyl sheeting or polythene sheeting to prevent water loss through the porous bed. The effects of this major environmental modification associated with these abstraction practices in the winterbourne catchments have been studied in the Gussage system since 1973. To compensate for the lack of adequate pre-lining data, comparative studies have been made on 3 small unlined chalk streams of varying flow regimes, ie. the Crichel (a winterbourne), the North Winterbourne and the Tarrant (permanent discharge in the reaches studies). The distribution of macrophytes and invertebrates in winterbournes are compared with that in natural and artificial permanent streams. Statistical analysis showed samples from the winterbourne sites and the unmodified permanent stream sites are quite distinct, despite the fact that no samples were taken from winterbourne sites during the dry phase. This emphasizes the differences between the fauna of an intermittent and a permanent stream and suggests that alteration of the flow regime could be a significant factor. Where flow regime has been altered, as in the Gussage downstream of the borehole, the samples occupy an intermediate position. Within this group of modified sites there is no apparent gross difference between the invertebrates of lined or unlined reaches.