The Co-management survey: results of the survey of Fisheries Department personnel

This short book section analyses the role of Fisheries Department personnel in the process of co-management related to the LVFRP.

The Co-management survey: results of the fish processing factory survey

This book section analyses the role of fish processing factories in the process of co-management related to the LVFRP.

Ratio of natural isotopes of nitrogen. I. Primary results: soils of Dombes [Translation from: Revue d'Ecologie et de Biologie du Sol 14, 279-287, 1977]

Utilization of the heavy isotope of nitrogen as a tracer has found numerous applications in soil biology. It allows better definition of different stages of the nitrogen cycle, in particular the immobilization-mineralization cycle. In this work, the authors report the results of calculations of natural isotope ratios of nitrogen in samples of water, soil and vegetation prevailing in Dombes and discuss the possibilities of errors and coefficients of fractionation.

Effects of flow regime on the young stages of Salmonid fishes. Conclusions based on results for 1977-1981

Rivers in Teesdale and its fish population have been monitored for several years. This report briefly describes the life cycle of British salmonid fishes and indicates the main ways in which this life cycle is influenced by discharge and related effects. Some highlights of the research results for 1977 - 1981 are briefly stated and proposals for future research are listed. Some practical implications of the results are discussed. (PDF contains 34 pages)

Effects of flow regime on the young stages of salmonid fishes. Summary and conclusions based on results for 1981-1985

The main British salmonid species spawn in clean gravel in streams and rivers, many of them in the upland areas of Britain. The earliest stages of the life cycle (eggs and alevins) spend some months within the gravel of the river bed. During this period their survival rate can be strongly influenced by flow regime and by related phenomena such as movement of coarse river bed material, changes in water level and the deposition of silt. In recent years human influence upon the flow regimes of upland water courses and upon the sediment inputs to them has increased. In order to conserve and, if possible, enhance the populations of salmonid fishes a deeper understanding of the interrelationships between survival of young salmonids and flow-related phenomena is needed. The acquisition of appropriate information is the main aim of the present project, which included: Studies on silt movement and the infilling of gravel voids by fine sediments, together with initial studies on the relationship between intragravel oxygen supply rate and the survival of intragravel stages of salmonids; studies in the general field of egg washout. The latter investigated the physical background to gravel bed disruption, the examination of the physical characteristics of sites chosen for redds, dimensions of redds and burial depth of eggs relative to the size of the fish constructing the redd and a series of smaller studies on other aspects of egg washout.

On statistical treatment of the results of parallel trails with special reference to fishery research

Parallel trials form a most important part of the technique of scientific experimentation. Such trials may be divided into two; categories. In the first the results are comparable measurements of one kind or another. In the second the data consist of records of the number of times a certain 'event' has occurred in the two sets of trials compared. Only trials of the second category are dealt with here. In this paper all the reliable methods of testing for significance the results of parallel trials of a certain type with special reference to fishery research are described fully. Some sections relate to exact, others to approximate tests. The only advantage in the use of the latter lies in the fact that they are often the more expeditious. Apart from this it is always preferable to use exact methods.

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.

Results of the 1998 frame survey: Lake Kariba, Zimbabwe shore

The findings are presented of a survey conducted on Lake Kariba in order to update the basic statistics of the inshore fishery from a previous survey conducted in 1993 and also to collect some socioeconomic data regarding the artisanal fishery. The 1998 frame survey provided information on fishers both for the whole fishery and per village and changes in numbers; socio-economic characteristics as well as the number of fishing units and gear are included.

Making experiment station results more useful to African fish farmers

Rather than using more or less ideal conditions for setting experimental controls, the use of conditions similar to those likely to be encountered by farmers should produce research results which are realistically achievable on the farm. ICLARM has developed an approach to farmer-led experimentation which utilizes a spreadsheet to collate and analyze data collected from participating farmers. The simulation of actual management practices utilized by farmers produced results in replicated on-station trials which were within 11% of net yields on-farm. In addition to giving researchers a tool for comparing farm and station management practices, giving farmers a realistic indication of what yields will be if a technology is adopted should help overcome the problems of disillusionment often encountered when farm results fall below those expected by researchers on the basis of experiment station studies.

Results of bottom trawl surveys carried out in Vietnamese waters (20-200 m) in 1996-1997

Bottom trawl surveys were conducted in the southwest monsoon season in 1996 (survey 1) and in the northeast monsoon season in 1996-97 (survey 2) throughout Vietnamese waters. The surveys mainly covered the depth zone 50-200 m but in the northeast monsoon season the depth zone 20-50 m was included in the northern and southern areas. Overall, 273 trawl hauls were conducted. The total biomass for Vietnamese waters in the depth zone 20-200 m was estimated at 700 000 t . Biomass estimates are given for the most abundant species. A relatively higher mean catch-per-unit effort (CPUE) was obtained from survey 2 than from survey 1 and in partcular at depth ranges 50-100 and 100-200 m in south Vietnam. Overall, the dominant families were Monacanthidae (34%), Carangidae (15%), Trichiuridae (9%) and Synodontidae (6%).

Catching and rearing postlarval cleaner shrimp for the aquarium trade: results from a WorldFish Center project in Solomon Islands

Between 1999 and 2003, the WorldFish Center in Solomon Islands conducted research into the feasibility of a new fishery based on the capture and culture of postlarval coral reef fish for the live fish trade. The work was carried out in two phases: a research phase from late 1999 to the end of 2002; and a “finetuning” phase in 2003. Most of the species were of value to the marine aquarium trade, with very few live reef food fish recorded. The most valuable ornamentals were the banded cleaner shrimp, Stenopus species. Cleaner shrimp were harvested using crest nets, the method being modified with the addition of a solid, water-retaining cod-end designed to increase survival at capture. Grow-out techniques were improved by rearing the shrimp separately in jars to prevent aggression. The jars were painted black to protect the shrimp from sunlight. An economic model using experimental catch data and farm gate prices indicates that the fishery based on shrimp, supplemented with small numbers of lobster and fish is economically viable. The next step will be setting up a demonstration farm in a village in the Western Province of Solomon Islands.

Preliminary results of a silver carp breeding program in Vietnam

The article describes the silver carp (Hypophthalmichthys harmandi and Hypophthalmichthys molitrix) breeding program in Vietnam.

Blue Marlin, Makaira nigricans, Movements in the Western North Atlantic Ocean: Results of a Cooperative Game Fish Tagging Program, 1954-88

Blue marlin, Makaira nigricans, tag and recapture data are summarized for 1954-1988. During this period, 8,447 fish have been tagged and only 30 (0.35 percent) have been returned. Results of the tagging program indicate that blue marlin not only travel considerable distances (7,OOO km from the U. S. Virgin Islands to the Ivory Coast of West Africa), but have remained at large for up to 8 years. Seasonal movements, however, are difficult to determine accurately.