Some aspects of the ecology and reproduction of the small pelagic cyprinid, Rastrineobola argentea in Lake Victoria

This study concentrated on the reproductive biology of the small pelagic cyprinid Rastrineobola argentea. The results indicate that this fish is an inshore spawning species, which agrees with other recent studies. It was also found that in areas where fishing intensity was likely to be relatively high, the size at first maturity of R. argentea was reduced, which is likely to be an effect of the fish altering its reproductive strategy according to life history theory. The CPUE results showed a general trend of decreasing with distance from shore, however areas less than one kilometer from the shore were not sampled. Evidence was also found suggesting that the cestode parasite, Ligula intestinalis had an adverse effect on the maturation and fecundity of R. argentea. Some management options concerning the findings in this study are also briefly discussed. (PDF has 82 pages)

An overview of the challenges and prospects in developing an aquaculture industry in Lagos State, Nigeria

Macroeconomic growth and the development of sustainable business activities are interrelated. In Lagos State, aquaculture is a marginal economic activity thriving mainly on a semi-intensive level. Notwithstanding the available potentials for the development of successful commercial aquaculture enterprises in the state, the transformation to a full-flagged industry continues to be undetermined by certain critical factors. Feasible development strategies may be sought in increasing all stakeholders' capacity in the formulation of policies, plans and regulations, a complete separation of aquaculture from the capture fisheries in administrative structure and policy; the adoption of precautionary approach; provision of economic incentives to enhance private investments and increase output,respectively

Fish diversity of the wild and aquaculture water bodies in Singida Region

Tanzania Fisheries Research Institute being currently the only fisheries research institute in Tanzania has sole responsibility of marking the presence and distribution of fish species in the country. This work is expected to be completed by the year 2005. In order that this work can be accomplished, both published works and field observations (including geographical location using GPS) have to be compiled. Since the institute has centers in all the Great Lakes and one along the Indian Ocean coast, it is expected that field observations and identifications will be obtained and incorporated into the document to be produced by 2005. (PDF contains 15 pages)

Structure of the limbs and its significance for the ecology and systematics of the family Chydoridae. [Translation of: Voprosy Gidrobiologii, p385, 1965]

For an explanation of the dynamics of numbers of chydorids, appearing a massive group in the littoral of fresh water bodies, the structure of the limbs of 29 species was studied.

Investigations of certain eco-physiological characteristics of the broad and long-pincered crayfish in connection with their interspecific relationships. [Translation from: Lietuvas TSR Mokslu Akademijos Darbai, C Serija 2(40), 279-286, 1966.]

The results are described of eco-physiological investigations of the broad-pincered (Astacus astacus L.J.) crayfish and the long-pincered (Astacus astacus Esch.) crayfish, conducted in 1963—64 in the Institute of Zoology and Parasitology of the Academy of Science of the Lithuanian SSR, for the purpose of studying the interspecific relationship of these two species. In the course of the investigation were determined: the influence of the temperature of the environment on the consumption of oxygen by full grown individuals of both species and on the respiratory movements of the scaphognathites, the threshold temperatures and the saturation of the water by oxygen, the diel activity in the winter period.

On the ecology of species belonging to the genus Mesocyclops Sars (Crustacea, Copepoda) dwelling in the water-bodies of the Urals and Pri-Ural territory. [Translation from: Zoologicheskie Zhurnal 44(1) 127-130, 1965. ]

In the waterbodies of central Russia, the Urals and western Siberia four species of Crustacea, related to the genus Mesocyclops, are widely distributed: M. (s.str.) leuckarti (Claus), M. (Thermocyclops) oithonoides Sars, [M.](Th.) crassus (Fisch.) and M. (Th.) dybowskii (Lande). Numbers and biomass of Mesocyclops oithonoides in the pelagic water of various water-bodies of the Urals are presented and observations on the above mentioned species are discussed.

Preliminary surveys of the fish and fisheries of the Nzoia, Nyando and Sondu Miriu rivers, Kenya

Three Lake Victoria rivers were sampled to assess fish abundance and distribution in preparation for assessment of catches from the river systems. Preliminary fish abundance data indicate that fishing potential upstream is negligible but that important commercial species are present in the downstream floodplain areas. Three catfish species were recorded in the Nzoia river system that have not been found previously in the Kenyan sector of the Lake Victoria system, together with possibly two undescribed Barbus species.

Aspects of the biology and population dynamics of freshwater mussels in Lake Kariba and Lake McIlwaine

The essential aim of this study was to provide a broad foundation of biological knowledge upon which a programme of mussel utilization and management could be built. Results of the study are presented in three main sections. Part 1 describes the stock of Lake Kariba and Lake McIlwaine; part 2 describes various aspects of the breeding biology of the three species; and part 3 presents the results of morphological, biochemical and age analyses - aspects which are used for initial standing crop and production calculations. The final discussion concludes the thesis with a general examination in ecological terms of the factors which have influenced the development and nature of the mussel faunas of the two lakes under consideration.

Length-weight relationship of small pelagic fish species of the southeast and South Brazilian Exclusive Economic Zone

The length-weight relationship (LWR) parameters of 23 small pelagic fish species (belonging to 13 families) from the south-southeast Brazilian Exclusive Economic Zone in 1996 and 1997 are presented. The b values varied between 2.72 and 3.53. The samples for this study were collected during hydroacoustic surveys covering an area of 700 000 square km.

Assessment of the fishing effort level in the shrimp fisheries of the central and southern Gulf of California

In view of the concern caused by the declining trend in the annual shrimp yield in the Central Gulf of California, an attempt was made to analyze the fishing effort level exerted upon the shrimp stocks of the blue (Farfantepenaeus stylirostris) and the brown shrimp (F. californiensis) from 1980 to 1991. For this purpose, both Schaefer and Fox production models were applied. The results from these analyses revealed an economic overexploitation condition, and suggested an imperative need to implement as a regulatory measure, the reduction of the catch per unit of effort level (CPUE) to keep the fishery within acceptable bioeconomic margins of a maximum sustainable yield (Ys). This can only be achieved through the adjustment of the fleet size from 481 vessels down to 250 or 275.

Evaluation of the carcass and commercial characteristics of carps

The role of carcass evaluation techniques in aquaculture research programs, especially in genetics, breeding, production management, feeding and nutrition, cannot be overemphasized. Knowledge of production efficiencies and growth potentials in relation to desired carcass attributes has provided an impetus to improvements in genetic selection techniques and management of aquatic food animals. Accurate, standard and uniform methods of carcass evaluation are critically important. A standard format developed for collection of data on carps is presented in this paper.

William Francis Thompson (1888–1965): a Preeminent Fishery Biologist of the Early and Mid Twentieth Century

William Francis Thompson (1888–1965) was a preeminent fishery scientist of the early to mid twentieth century. Educated at Stanford University in California (B.A. 1911, Ph.D. 1930), Thompson conducted pioneering research on the Pacific halibut, Hippoglossus stenolepis, from 1914 to 1917 for the British Columbia Provincial Fisheries Department. He then directed marine fisheries research for the State of California from 1917 to 1924, was Director of Investigations for the International Fisheries Commission from 1924 to 1939, and Director of the International Pacific Salmon Fisheries Commission from 1937 to 1942. He was also Director of the School of Fisheries, University of Washing-ton, Seattle, from 1930 to 1947. Thompson was the founding director in 1947 of the Fisheries Research Institute at the University of Washington and served in that capacity until his retirement in 1958. He was a dominant figure in fisheries research of the Pacific Northwest and influenced a succession of fishery scientists with his yield-based analysis of fishery stocks, as opposed to studying the fishes’environment. Will Thompson was also a major figure in education, and many of his former students attained leadership positions in fisheries research and administration.

Assessment of the Distribution and Abundance of Coastal Sharks in the U.S. Gulf of Mexico and Eastern Seaboard, 1995 and 1996

During 1995 and 1996, the National Marine Fisheries Service (NMFS), conducted pilot studies to develop survey methodology and a sampling strategy for assessment of coastal shark populations in the Gulf of Mexico and western North Atlantic. Longline gear similar to that used in the commercial shark fishery was deployed at randomly selected stations within three depth strata per 60 nautical mile gridf rom Brownsville, Tex. to Cape Ann, Mass. The survey methodology and gear design used in these surveys proved effective for capturing many of the small and large coastal sharks regulated under the auspices of the 1993 Fisheries Management Plan (FMP) for Sharks oft he Atlantic Ocean. Shark catch rates, species composition, and relative abundance documented in these pilot surveys were similar to those reported from observer programs monitoring commercial activities. During 78 survey days, 269 bottom longline sets were completed with 879 sharks captured.