Essais d'utilisation de "nourrisseur à la demande" pour l'alimentation de Chrysichthys nigrodigitatus en cage-enclos

An experiment using demand feeder was carried out on the catfish Chrysichthys nigrodigitatus reared in cage-enclosure in the lagoon Ebrié (Côte d'Ivoire). The study lasted 5 months, from October to March, and showed that the demand feeder improves the growth rate of the fish and the feed conversion. It was able, as well as the conventional hand feeding, to show monthly variations of performances.

Lune - 1992 surveys. Summary of results

This report summarises the routine monitoring surveys carried out in the River Lune and River Duddon estuaries during 1992. Data includes salinity, chloride, pH, nutrients and heavy metals.

Report on the 1992 stock assessment of the Wyre catchment

The aim of this study was to assess the status of the juvenile salmonid and coarse fish populations of the Wyre catchment. Emphasis was placed on an examination of the distribution of spawning and nursery areas for salmonids within the study area and an assessment of the status of juvenile salmonid stocks. The species distribution and spawning areas for other fish species were also identified where possible and the status of the Wyre coarse fishery, downstream of Churchtown Weir, assessed. This report examines the results of stock assessment surveys carried out in the Wyre catchment between 2/06/92 and 11/08/92. Forty-six sites were surveyed from Tarnbrook Wyre (SD. 598577) and Marshaw Wyre (SD. 614541) downstream to St Michaels (SD. 465411). Flow, habitat and in-river obstructions have been shown to affect juvenile salmonid densities. A habitat description is provided for each site studied during the course of this study.

Swanside Beck, fisheries survey, 22nd September 1992

Swanside Beck is formed from a number of minor tributaries which rise in the Middop area to the west of Barnoldswick. The Beck is approximately 10 km long from the source of its longest tributary (SD. 850445) to the confluence with the River Ribble (SD. 769455). Swanside Beck has one major tributary, Ings Beck, which rises from a number of sources on Twiston Moor and is approximately 6km in length from the source of its longest tributary (SD. 812418) to the confluence with Swanside Beck (SD. 785453). Both Swanside and Ings Becks are important spawning and nursery areas for salmon and sea trout from the River Ribble. In recent years a perceived decline in the migratory fish population of the becks has been reported. This decline has been reported in terms of both adult returns and juvenile production and has been particularly noted in Swanside Beck. The aim of this survey was to assess the likely benefits to Fisheries and Conservation interests of the adoption of a set aside policy for agricultural land adjacent to Swanside Beck. The survey also formed part of an on-going Fisheries study of factors limiting juvenile migratory salmonid production in Swanside Beck. This section of the report deals with the Fisheries aspects of the survey.

Summary document of the work being done in 1992-1993 regarding the migratory salmonid fisheries of the River Ribble catchment

This document lists the work on salmonid fisheries in the River Ribble catchment in the north west of England which was done in 1992-93. The document includes the following: analysis of historical catch data from the River Ribble covering 1937-1991; Ribble and Hodder stock assessment surveys 1992-93 including Swanside Beck; Ribble catch data from game angling log books 1993; results of salmon scale sampling 1993; results of microtagging programme in Hodder and Ribble 1993; Waddow Weir dish counter data 1993; Winkley Hall (Hodder), Locks Weir and Waddow Hall (Ribble) fish counter data 1993; number of fish and ova from Witcherwell Hatchery 1993.

Annual report 1992

An account is given of the activities conducted by the Lake Kariba Fisheries Research Institute during the year 1992, which include the following research programmes: Comparative study of growth of Limnothrissa miodon (Boulanger) in Lake Kariba; Effort calibration for the Kapenta fishery; Pre-recruitment ecology of the freshwater sardine L.miodon (Boulanger) in Lake Kariba; The ecology of the inshore fishery of Lake Kariba - biology of Synodontis zambezensis; Mercury in the tigerfish (Hydrocynus vittatus), green happy (Serranochromis codringtoni) and Tanganyika sardine (L.miodon) from Lake Kariba, Zimbabwe; and, Assessment of the potential development of a Synodontis fishery on Lake Kariba, Zimbabwe.

1992 fisheries statistics, Lake Kariba - Zimbabwe shore

This statistical report covers catch records from the Zimbabwe part of Lake Kariba for the period 1974-1992. Landings, catches and fishing effort statistics are included for both the pelagic and the inshore artisanal fishing sectors.

Summary of fishery statistics 1992

This fisheries report summarises developments of the year 1992 in the North West region of the National Rivers Authority. It provides catch statistics, rod and line and commercial catches for salmon and sea trout, fish culture and hatchery operations, restocking with trout and freshwater fish, upstream fish movement recorded at authority fish counters, counts of salmon and sea trout spawning redds, fish mortalities, licences issued, and prosecutions. Among the streams that are covered in the report are the River Lune, River Kent, River Leven, River Ribble and River Derwent.

Field validation of the 'Logie' fish counter at Forge weir on the River Lune, 1992

The stock assessment task group report (1991) mentions that fish counters could play a key role in providing data on the size of the adult stock, and in particular the migratory salmonid stock. This report assesses the performance of the 'logie' fish counter at Forge Weir on the River Lune. Using video surveillance, a total of 1137 hours time lapse and 15 hours real time were used for validation purposes. This report looks at materials and methods, counting accuracy, sizing ability and environmental conditions, performance across the electrode array and salmonid swimming speed.

Interactions between marine mammals and pelagic longline fishing gear in the U.S. Atlantic Ocean between 1992 and 2004

The U.S. East Coast pelagic longline fishery has a history of interactions with marine mammals, where animals are hooked and entangled in longline gear. Pilot whales (Globicephala spp.) and Risso’s dolphin (Grampus griseus) are the primary species that interact with longline gear. Logistic regression was used to assess the environmental and gear characteristics that influence interaction rates. Pilot whale inter-actions were correlated with warm water temperatures, proximity to the shelf break, mainline lengths greater than 20 nautical miles, and damage to swordfish catch. Similarly, Risso’s dolphin interactions were correlated with geographic location, proximity the shelf break, the length of the mainline, and bait type. The incidental bycatch of marine mammals is likely associated with depredation of the commercial catch and is increased by the overlap between marine mammal and target species habitats. Altering gear characteristics and fishery practices may mitigate incidental bycatch and reduce economic losses due to depredation.

The durability of different fish cage materials and the pros and cons of cage rotation

The procedures described are standard methods used in the European Union to quantify wood quality. Samples used here were smaller than the standards laid down in the DIN system (12 x 12 x 16 cm) as Litsea is a small tree and planks of the required size are unobtainable. The use of quality sized samples means that the results presented here can be compared with each other but unfortunately not with data in the literature. Wood is dried first at ambient temperature in the shade to reduce moisture content to an even 11-12%. Part of the sample was then oven-dried to 0% moisture content and its specific density determined by weighing a subsample of 128 cm super(3) (4 x 4 x 8 cm). Strength of expansion of the wood is determined as the percentage by which the wood sample can be pulled apart parallel and vertical to the grain before it breaks. Compression and bending strengths and elasticity are measured by compressing, bending and pulling wood sample in a machine specially designedto determine the forces required.