Invertebrate communities in northern Lake Victoria, with reference to their potential for fishery production

The zooplankton and macrobenthic communities of Lake Victoria were sampled by lift net and Ponar grab, respectively. The zooplankton comprised copepods and cladocerans, rotifers and aquatic insect larvae. Most taxa exhibited wide distribution in the lake, with the exception of rotifers which were rare in deep offshore waters. The main components in the macro-benthos were chaoborid and chironomid larvae and molluscs. Caridina nilotica (Roux) and other groups were rare in the samples. Zooplankton density ranged from 100000 or more to 4 million ind. m2 and increased from the shallow inshore to deep offshore waters. Numerical dominance of cyclopoids and nauplius larvae was a common feature at all stations sampled. Most macrobenthic taxa were also widely distributed, although chaoborid and chironomid larvae were rare in the samples. Rastrineobola argentea (Pellegrin) and larval Lates niloticus (L.) ate mainly cyclopoid copepods, while cichlids showed a strong preference for adult insects. High ecological stability of the cyclopoids, and the zooplankton community in general, despite radical ecosystem changes in recent years, coupled with what appears to be high predation pressure, offers good prospects for the pelagic fishery in the lake.

The regulators and the regulated: fisheries management, options and dynamics in Kenya's Lake Victoria fishery

The study divides the history of the fishery into five 'regulatory periods': the pre-colonial fishery (pre-1901), the colonial fishery (1901-1963), the post indipendence fishery (1963-1980), the Nile perch 'boom' years (1980-1989), and finally the fishery in the 1990's. Within each of these periods, the nature of and the relationship between, formal and informal regulations differs and changes with time. In the pre-colonial period, the outcome of formal and informal regulations largely sustained the fishery in a productive and species diverse state. However, at no time since then have formal regulations worked, with the result that the nature of production from the fishery changes over time and is dependent on a number of factors, amongst which the most important are effort level increases, technological introductions, species introductions, changes in regional and national job markets, the change from community-based controls to state-based controls within the fishery, and finally, considerable changes to the fish markets.

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.

Size composition of the catches of the pink shrimp Penaeus duorarum notialis in the shrimp fishery of Sierra Leone

Measurements were taken of size distribution of P. d. notialis collected off Sierra Leone over a period of six months from October 1977 to March 1978. From the frequency distribution curves it is observed that the curves for male shrimps show only one or two major modes, which show prominence between 12.5 and 14.1 cm of total length. Females mostly exhibited size groups with three or four different length ranges and occasional occurrence of 1 to 5 modes. These size groups were observed to show continuous changes. No one group could be said to be permanent. The point of entry into the fishery of male shrimps was found to be at an average total length of 10.5 cm, while females did so at 11 cm. Sex ratios in the different samples were usually 1:1 but in one case the males were more numerous by 2:1 and in four other samples females were significantly preponderent. These departures from the 1:1 ratio may have been artificially created by sorting of the catches on board the ships.

A review of the Japanese longline fishery for tunas and billfishes in the eastern Pacific Ocean, 1993-1997

English: This report reviews the Japanese longline fishery in the eastern Pacific Ocean during the 1993-1997 period, extending the studies for the 1956-1992 period made by other investigators. The spatial and temporal distributions of fishing effort, catch, apparent abundance, sexual maturity, and size composition are examined for the principal species of tunas and billfishes taken by that fishery. Some information on the catches of sharks by the Japanese longline fishery is given. The interactions between the surface and longline fisheries are discussed. Spanish: En este informe se presenta un análisis de la actividad pesquera de buques palangreros japoneses en el Océano Pacífico oriental durante el período de 1993-1997, extendiendo los estudios del período de 1956-1992 realizados por otros investigadores. Se examinan las distribuciones espacial y temporal del esfuerzo de pesca, la captura, la abundancia aparente, la madurez sexual, y la composición por talla de las principales especies de atunes y picudos capturadas por dicha pesquería. Se presenta cierta información sobre las capturas de tiburones por la pesquería palangrera japonesa. Se describen las interacciones entre las pesquerías de superficie y palangrera.

Bycatches of sharks in the tuna purse-seine fishery of the eastern Pacific Ocean reported by observers of the Inter-American Tropical Tuna Commission, 1993-2004

Information on bycatches of sharks collected by observers of the Inter-American Tropical Tuna Commission (IATTC) between 1993 and 2004 is presented in this data report. This report contains two sections. The first section summarizes information used by the staff of the IATTC to review and revise IATTC observers’ at-sea species identifications of Carcharhinus falciformis, C. limbatus, and C. longimanus. The revisions were based on 1) data collected on species-specific diagnostic characteristics as part of a special sampling program conducted between March 2000, and March 2001 and 2) a review of observers’ archival field notes for the 1993-2004 period. The second section summarizes the shark bycatches reported by IATTC observers between 1993 and 2004, incorporating the revisions of observers’ at-sea identifications. The IATTC-observed shark bycatch data are summarized as tables with annual tallies of observed bycatches and maps of the spatial distributions of the average bycatches per set and size compositions of the bycatches.

Preliminary report on the coarse fishery status in the River Lune with particular reference to the Lansil Fishery

This study takes a preliminary step towards investigating the reports of poor rod catches of coarse fish in the River Lune. These poor catches and concern over the possible loss of coarse fish from the Lower Lune is investigated, using creel census data from 1991. Historical data is used where available for comparative studies. The conclusion that this report comes to is that there is a problem with the recruitment of coarse fish within the population. Dace, roach and bream all show good growth rates but only poor if any recruitment. Historical investigations suggest that roach and bream may never have successfully recruited without artificial induced conditions. The situation with dace is of more concern as populations in other rivers in Northern England are also in decline, whilst historically they were naturally recruiting.

Linefish resources annual report for the year 2000. Part 3: towards a management plan for the Mozambican line fishery

The dependence of Mozambique on its marine resources is highly significant. There is a need for a plan of action for sustainable use of these important resources, for the benefit of the nation. In this document, some aspects are included, that can be important to take into consideration for a sound action plan for the lin fishery of Mozambique.

Salmon and freshwater fisheries in the Solway Firth. Report of the Working Party of North West Water Authority and the Annan District Salmon Fishery Board.

The Workinq Party of North West Water Authority and the Annan District Salmon Fishery Board's aims were to identify the current problems relating to the salmon and freshwater fisheries in the Solway Firth and its tributaries (embracing the catchments of the Annan, Kirtle Water, Sark, Esk, Eden, Wampool and Waver - and possibly also the Lochar Water and the Nith) to produce agreed outline solutions, and to consider the financial aspects of the future administration of these fisheries.

1994 annual report on fisheries in the North west incorporating the annual summary of fishery statistics.

This report provides national and regional developments, statistics on fisheries finance, including income and expenditure, salmon and sea trout catches, including rod and line, commercial catches, and angler log book returns, monitoring and special projects, including salmon microtagging, salmon egg survival in Swanside Beck, and fish stock assessments, one with hydroacoustics, and one of surveys of different areas in Cumbria. The appendix includes a summary of fish statistics for 1994.

1995 annual report on fisheries in the North west incorporating the annual summary of fishery statistics.

This fisheries report summarises national and regional developments focussing on the North West region of the Environment Agency. The North West region covers around 14,000 square km, from Cheshire in the south to its northern border with Scotland. The report provides statistics on fisheries finance, including income and expenditure, salmon and sea trout catches, including rod and line and net catches, and special projects, including fish stock assessments, and surveys. The appendix includes a summary of fish statistics for 1995.

1998 annual report on fisheries in the North west incorporating the annual summary of fishery statistics.

This fisheries report summarises national and regional developments focussing on the North West region of the Environment Agency. The North West region covers around 14,000 square km, from Cheshire in the south to its northern border with Scotland. This report provides national and regional developments,and special projects, including fish stocking assessments, radiotracking, and Cumbria surveys. Salmon and sea trout catches, including rod and line and net catches appear in the appendix.

1999 annual report on fisheries in the North west incorporating the annual summary of fishery statistics

This fisheries report summarises national and regional developments focussing on the North West region of the Environment Agency. The North West region covers around 14,000 square km, from Cheshire in the south to its northern border with Scotland. The report provides statistics on fisheries finance, including salmon and sea trout catches, including rod and line and net catches, and special projects, including fish stock assessments, radiotracking, and various surveys. The appendix includes a summary of fish statistics for 1999.

Summary of fishery statistics, 1974-77

This fisheries report summarises developments of the years 1974-77 in the region of the North West Water Authority. This report provides catch statistics, rod and line and commercial 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.

Summary of fishery statistics, 1978

This fisheries report summarises developments of the year 1978 in the region of the North West Water Authority. This report provides catch statistics, rod and line and commercial 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.