The first reported occurrence of the mayfly parasite Spirinella adipophila (Sporozoa) in a British river

During a 2-year survey on the distribution and ecology of mayflies in the upper reaches of the River Wey (a tributary of the River Thames) in Surrey, Spirinella was found in large numbers in the larvae of Ephemera Danica, and in low numbers in larvae of E. ignita and H. lateralis. Samples of E. danica taken from seven other tributaries of the Thames showed that Spirinella is present in most of them and often in high numbers.

Burrowing behaviour of signal crayfish, Pacifastacus leniusculus (Dana), in the River Great Ouse, England

Observations were made on crayfish burrows in five locations on the Great Ouse River. The burrow densities and the relative abundance of crayfish were observed. Also, laboratory experiments were carried out in order to study the characteristics and mechanisms of burrowing.

Water quality objectives as a management tool for sustainability

The aim of this paper is to explore the potential role that quality objectives, particularly when backed by statutory force, may play in the sustainable management of river water quality. Economic valuation techniques are discussed, as well as the theory of "critical natural capital". A brief history of water quality legislation includes the implementation of the National Water Council classification in 1979, and the statutory water quality objectives introduced under the Water Resources Act 1991.

The macroinvertebrate fauna of pools in the floodplain (fadama) of the Anambra River, Nigeria

The Anambra River is the largest tributary of the lower Niger River below Lukoja. Between the months of May and November the river is subject to seasonal flooding from heavy precipitation and land runoff into the drainage system. During the flood phase, pools form on the floodplains (known as the fadama) and these pools receive materials and biota from the main river channel. The biota often includes representatives of freshwater vertebrates (including fishes) and invertebrates. On this brief note, the authors report on the macroinvertebrates found during preliminary studies on four fadama pools during the non-flood season between December 1994 and April 1995. 523 specimens were collected, of which 86% were arthropods, 9% were annelids (mostly Tubifex and Nais) and a few leeches (Hirudo), and 5% were gastropod molluscs of the arthropods, 75% were insects particularly Hemiptera and Diptera.

The River Endrick - then and now, monitoring by photography

A major survey of the River Endrick was carried out in 1959-60. This survey was repeated three decades later in 1989-90 and comparisons were made of the fauna at the two times of sampling. During both surveys, photographs were taken of all the sampling sites and the objective of the present paper is to compare some of these photographs and discuss the value of photography in studies of river ecology. The sites used for photographic comparison were not chosen originally for that purpose but as appropriate places on the river from source to mouth to study its ecology. The pairs of photos now available have proved of interest and value and some lessons have been learned in relation to the selection of sites for any future photographic studies. Ideally photos should be taken in more than one season of the year as much of the river can be obscured by riparian trees and shrubs during the vegetative season. The exact position from which each photograph is taken is also a major factor to be considered.

Habitat use by 0+ cyprinid fish in the River Great Ouse, East Anglia

This study was designed to examine the habitat use of several species of 0+ cyprinid in the regulated River Great Ouse and to determine the reasons for specific habitat use. In general, all fish species were found associated with the marginal zone, with little diel variation. Use of shallow habitats in the presence of macrophytes correlated well with the distribution of zooplankton in the river channel, the preferred food source of 0+ cyprinids. During the early to late larval phase, all species fed upon rotifers and diatoms. Cladocera, particularly Alona spp. and Chydorus spp., and early instar larvae of Chironomidae, then became prevalent in the diet along with small numbers of Copepoda. Models were developed to determine habitat availability over a range of discharges, using the physical habitat simulation (PHABSIM) component of the Instream Flow Incremental Methodology (IFIM). The results of this analysis revealed that habitat suitable for 0+ fishes comprised a relatively small percentage of the main channel and generally decreased with discharge.

The mayflies (Ephemeroptera) of the upper River Sigi, north-east Tanzania

The work reported here results from material collected by the author made during 12 years residence in the East Usambaras in the 1950s and early 1960s, as well as a more recent visit. The faunal list the author has compiled comprises 45 species. As well as named species known to occur in the torrential section of the River Sigi, it includes those that are distinct but insufficiently well defined at present to have been formally described. For the sake of completeness, five species of Cloeon and one of Procloeon known to occur in ponds and pools formed by the damming of end-streams in forest clearings, have been included.

Heavy metal pollution in sediments at shipbreaking area of Bangladesh

The research was carried out to assess the trace metal concentration in sediments of ship breaking area in Bangladesh. The study areas were separated into Ship breaking Zone and Reference Site for comparative analysis. Metals like Iron ( Fe) was found at 11932 to 41361.71µg.g-1 in the affected site and 3393.37 µg.g-1 in the control site. Manganese (Mn) varied from 2.32 to 8.25 µg.g-1 in the affected site where as it was recorded as 1.8 µg.g-1 in the control area. Chromium(Cr), Nickel (Ni), Zinc(Zn) and Lead (Pb) were also varied from 22.89 to 86.72 µg.g-1; 23.12 to 48.6;83.78 to 142.85 and 36.78 to 147.83 µg.g-1 respectively in the affected site whereas these were recorded as 19; 3.98; 22.22 and 8.82 µg.g-1 in the control site. Copper (Cu); Cadmium (Cd) and Mercury (Hg) concentration were varied from 21.05 to 39.85; 0.57 to 0.94 and 0.05 to 0.11 µg.g-1 in the affected site and 33.0; 0.115 and 0.01 µg.g-1 in the control site. It may conclude that heavy metal pollution in sediments at ship breaking area of Bangladesh is at alarming stage.

Environmental variables and fisheries diversity of the Naaf River Estuary, Bangladesh

The Naaf River estuary is one of the large estuaries in the Bangladesh coastal region not to have been affected by extensive human disturbance. This research provides information about the fisheries diversity status by Estuarine Set Bag Net (ESBN) sampling relation to physicochemical variables in both spatio-temporal scales. About 25 km of the lower estuary was divided into six zones for sample collection by considering the accessibility and availability of the ESBN operation, fish landing centers and location of the fishing villages. In total 48 samples have been analyzed which were taken throughout March to October 2006. To quantify the species diversity, all fisheries data were analyzed by using EstimateS and EcoSim software which accounts the different diversity indices viz., species richness, Shannon–Wiener diversity Index, Dominance and Evenness index. The research results demonstrate that the Naaf River estuary is a habitat of 161 (species richness, Sobs=161, Choa 1=162±2.34, ACE=161.73) different species which belong to 98 fin fishes, 23 shrimps and prawns,13 crabs, 11 molluscs, 3 echinoderms, 4 other crustaceans;while 9 remain unidentified. Results on the aquatic environment,mainly salinity and turbidity were found to have a major influence on their occurrence and distribution. All the findings indicated that the Naaf River estuary is a highly productive system and provides a favourable environment for large variety of estuarine species assemblages.

The home range of the signal crayfish in a British lowland river

The signal crayfish Pacifastacus leniusculus (Dana), a native of north-western North America, is now a common resident in some British fresh waters following its introduction to England in 1976 (Lowery & Holdich 1988). In 1984, signal crayfish were introduced into the River Great Ouse, the major lowland river in southern central England, where they have established a large breeding population. This study examines two sites near Thornborough Weir. For the measurement and description of home range a new eletronic microchip system and a modified capture-mark-recapture method were employed. Signal crayfish were marked or tagged to see if they gradually moved away from their burrows. This method proved to be successful for estimating population densities when a section of river is divided into several equidistant linear ”locations”.

A fisheries management plan for the River Tweed in the Scottish Borders

The River Tweed is, in rod-catch terms, the second most important river in Britain for Atlantic salmon, with an annual rod catch of ca.10,000 fish. This article gives an outline of the second edition of the Tweed Fisheries Management Plan, which is defined as "The co-ordination of data collection and analyses with fundamental research into relevant topics to devise management actions that will beneficially affect the future state of fish stocks". Much of the work set down for the present is concerned with setting up recording and measuring systems for fish catches and exploitation rates, and for the operation of monitoring sites for juvenile densities and adult trout and salmon spawning runs. While surveys show the present state of affairs, the collection of records and regular monitoring of sites will mean that in the future, the past will be better known through a longer series of records. Two case histories are described. The first is concerned with setting aims for managing the brown trout of the Tweed and defining the present state of the fishery. The second is an investigation into the spring salmon of the Tweed.

Biodiversity of macrozoobenthos in a large river, the Austrian Danube, including quantitative studies in a free-flowing stretch below Vienna: a short review

The Danube is ca. 2850 km in length and is the second largest river in Europe. The Austrian part of the Danube falls 156 metres in altitude over its 351 km length and, since the early 1950s, the river has been developed into a power-generating waterway, so that the continuity of the river is now interrupted by ten impounded areas. Only two stretches of the original free-flowing river are left, the Wachau region (above river-km 2005, west of Vienna) and the region downstream from the impoundment at Vienna (river-km 1921). Most of the recent theories and concepts related to invertebrates, in the context of the ecology of running waters, are based on studies on small streams, whereas investigations of large rivers have played a minor role for a long time, mainly due to methodological difficulties. The authors' recent detailed studies on macroinvertebrates in the free-flowing section of the Danube below Vienna, provide an excellent opportunity to survey or restate scientific hypotheses on the basis of a large river. In this review the main interest focuses on the investigation of biodiversity, i.e. the number of species and their relative proportions in the whole invertebrate community, as well as major governing environmental factors. The article summarises the species composition, the important environmental variables at the river cross-section and the effect of upstream impoundment on the riverbed and its fauna.

Falling through the cracks: are European directives and international conventions the panacea for freshwater nature conservation?

There are many ways of practising freshwater nature conservation: from strict legislative protection of individual species considered rare or threatened to protecting whole lakes or long stretches of rivers; from practical conservation management at a local scale to integrated catchment management at the river basin scale; and from the encouragement of better habitat management through codes of good practice to statutory control of pollution or abstraction. Whatever the mechanism, an essential pre-requisite is a way of choosing where to put the effort, especially when resources for nature conservation are severely limited. The aim of this article is to review the contribution from four specific international measures to the task of assigning priorities for conservation. The 1990s saw the introduction of two European directives (the Habitats Directive (HD) and the Water Framework Directive (WFD)) and one international convention (the Biodiversity Convention (CBD)) each with the potential for influencing, to a greater or lesser extent, the conservation of freshwater habitats and species. This article also discusses a much older convention – the Ramsar Convention – adopted in 1971 specifically to help tackle the conservation and management of wetlands and aquatic ecosystems. Although the authors have focused mainly on the UK, the subject is relevant to other parts of Europe and beyond. The article explores the degree to which these measures help in identifying the most important fresh waters for conservation, and asks whether or not they present the right conservation message to a wide audience.

The Permanent Okavango River Basin Water Commission annual report 2009

First published annual report of OKACOM, covering first period of Sida-funded three year workplan from 2007 until 2009, during which the Secretariat was established. (PDF contains 32 pages)

The Okavango River Basin Transboundary Diagnostic Analysis: reimagining the river

OKACOM's Transboundary Diagnostic Analysis study used integrated flows analysis to develop scenarios for possible developments in the Okavango River Basin. (PDF contains 2 pages)