Incidence of ulcer disease in African catfish (Clarias gariepinus Burchell) and trial for its chemotherapy

Young Clarias gariepinus cultured in an artificial tank were severely affected by an ulcer type of disease where 77% fish died within 5 weeks. From the lesions and kidney of affected fish Aeromonas, Pseudomonas, Flavobacterium, Micrococcus and Staphylococcus were isolated where Aeromonas was observed as the dominant bacteria. Among them, an A. hydrophila isolate AGK 34 was detected as a pathogen by the experimental challenge test. In order to find out a suitable remedial measure of the disease, four different chemotherapeutants were applied to the affected fish in 6 different ways under laboratory condition. Affected fish were recovered from the disease in different treatments. But the best result was obtained by a successive bath in 1-2% NaCl and subsequent oral treatment with commercial oxytetracycline at a dose of 75 mg/kg body weight of fish.

Illustrated key to the genera of free-living marine nematodes of the Order Enoplida

A pictorial key to US genera of free-living marine nematodes in the order Enoplida is presented. Specific morphological and anatomical features are iUustrated to facilitate use of the key. The purpose of this work is to provide a single key to the genera of enoplid nematodes to facilitate identification of these organisms by nematologists and marine biologists working with meiofauna. (PDF file contains 32 pages.)

Ecological effects of trial pumpings in the Upper Lambourn: Stage 1 group pumping test Upper Lambourn group, September - November 1975

This report to the Thames Water Authority and Central Water Planning Unit is on research carried out in conjunction with the Stage 1 Group Pumping Test of five boreholes in the upper Lambourn Group for a period of three months in September, October and November 1975. The aim of the study was to assess the ecological effects of the pumpin g of five bore-holes in the upper Lambourn. That is, to determine how the seasonal sequence of ecological events in the river differed from what would hav e occurred had no pumping taken place. Since this 'experiment' has no control it is not possible to make a direct assessment. Nevertheless, by careful monitoring of ecological events before, during and after the pumping it is possible to document changes in th e river and by reference to the data already available for the Rive r Lambourn, normal seasonal changes in the flora and fauna can be separated from changes which may be attributable to the pumping and subsequent events.

Evaluation of the nutrient composition of some unconventional feedstuffs

A trial was carried out to evaluate the nutrient composition of some unconventional feedstuffs to ascertain their suitability for incorporation into fish feed. Pawpaw seed, mudskipper meal, water melon seed, almond kernel and groundnut husk were processed and analyzed for their proximate and mineral composition using internationally established procedure. The results obtained showed that the experimental feed stuffs had percentage crude protein that ranged from 7.38% to 55.85%. The highest level (55.85%) was found in mudskipper meal while the lowest (7.38%) was found in groundnut husk. The experimental feed stuffs had appreciable levels of calcium, potassium and phosphorus ranging from 0.29% to 1.87%, 0.17 to 1.26 and 0.06 to 0.97 respectively. Almond kernel can be used to replace soybean meal in aqua feed. Also, mudskipper meal can be used to replace fish meal in order to produce a cheaper fish feed; but it was recommended that feeding trials should be conducted to ascertain the inclusion level at which they can be effectively incorporated. The potentials of some of these feedstuffs in fish feed formulation seem high.

Report on the 2001 stock assessment of the River Darwen catchment

The River Darwen is a highly impacted Lancashire river with very little known about its fishery interest above the impassable weir at Salmesbury Bottoms. Below the weir there are populations of coarse fish around the confluence with the River Ribble. To the knowledge of local bailiff staff, prior to 1996 the fish population in the middle and upper River Darwen had never been surveyed by electric fishing. In order to address this lack of knowledge, a survey was undertaken during the summer of 1996 with the aim of evaluating the salmonid and cyprinid fish population in the river. Twenty two sites were surveyed by electric fishing between June 11th and July 11th 1996. Information was gathered on the presence and density of fish populations in the river catchment, and analysed according to the National Fisheries Classification Scheme in order to determine how these populations compare nationally with sites of similar habitat features. From this report, recommendations were made to improve and develop the fishery potential in relation to water quality and habitat prioritising areas classed as being Ashless. It was recommended that juvenile coarse fish should be stocked in the Houghton Bottoms area. This area has excellent fishery habitat and was found to contain a minor coarse fish population. Water quality in this stretch of river was thought to be good enough to establish a major coarse fish population. Fish were introduced for the first time in 1998 at Houghton Bottoms from the Agency's Leyland Fish Farm. 3000 each of Roach, Chub and Dace were introduced. Further fish introductions occurred in 2000 with the stocking of 1000 Chub, again from the Agency's Leyland Fish Farm in the Lower Darwen and Witton areas of the main river on a trial basis.

The proposed Lune net limitation order 1999 and associated byelaws

The River Lune rises in the hills around Tebay in thje North of England and runs through rural farming country to Morecambe bay. It is generally considered as a river of high purity and unspoiled nature. The salmon fishery was at one time considered amongst the best in England and Wales, with very high catches to both rod and net fishermen. During the late 1960's the disease UDN decimated the stock. Since then there has been a recovery of the stock, but this is considered by most anglers and netsmen to be a partial recovery of some of the previous stock components. In recent years anglers and netsmen have voiced their concerns over the Lune stock and have lobbied for action to improve the Lune fishery. This net limitation order (NLO) and the separate byelaw in conjunction with habitat improvement are proposed as part of the strategy for future conservation and management of this salmon fishery. The fishery is currently exploited by 37 licensed netsmen, the highest number of any single estuary in England and Wales. There are 26 haaf, 10 drift and 1 seine nets available. Current estimates of the rod fishery are that 1100 to 1400 anglers fish 14 000 days per year. The River Luhe is one of the few rivers within England and Wales that has the benefit of an accurate fish counter. The counter is at Forge Weir approximately 4 km upstream of the tidal limit. The counts, together with records of the catches from the rod and net fishery, enable a reasonably accurate assessment of both rod and net exploitation. Extensive surveys of the juvenile population, carried out in 1991 and 1997, provide additional information. The purpose of this document is to describe and explain the current state of the salmon population in the River Lune and in doing so, demonstrate the current need for stock conservation. A second purpose is to demonstrate that the proposed NLO and byelaw package should allow the salmon population to reach its conservation target (spawning escapement target).

Culture of mola (Amblypharyngodon mola) in polyculture with carps: experience from a field trial in Bangladesh

Studies were carried out during May 1997 to January 1998 in Kishoregani district in Bangladesh to investigate the production potential of carp polyculture in combination with Amblypharyngodon mola in seasonal ponds. The preliminary results indicate that A. mola can be successfully cultured in small seasonal ponds in polyculture with carp. This practice can result in an increase in the households' consumption of small fish which have a very high content of calcium, iron and vitamin A. In addition to the nutritional benefits, it can also provide additional income through sale of carp and surplus small fish.