8 resultados para 3-16

em Aquatic Commons


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This publication gives the results of the bottom trawlings made during the cruises Togo 3 and logo 4 by the oceanographic research vessel "Andre NIZERY" on the continental shelf of Togo during the estimation program of halieutic resources. The report includes: 1 - The report of the cruises Togo 3 and Togo 4 2 - Some information on the presentation of the results 3 - The trawl recording cards for the 2 cruises 4 - The length frequency distributions of the measured samples.

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The fishery ministers of the EU agreed in their yearly pre-Christmas marathon session on 18th and 19th Dec. 1997 on next year’s TACs and country quota. Main decision was the increase of the TAC for North sea cod and a smaller than feared cut of cod TACs in the West of Scotland zone, the Irish Sea and the English Channel. For the first time ministers set country quota for horse mackerel; until 1997 there had been - with the exception for Portugal and Spain - only a common quota. Also for the much disputed sandeel fishery a TAC of 1 mio. t was finally established, as well as for bluefin tuna and swordfish in the Atlantic and Mediterranean. For 1998 the EU member countries dispose of a total catch quota of 4.46 mio. t in EU waters, and together with quota in third country waters of 5.2 mio. t. Of this total quota, 3.16 mio. t are fish for human consumption and 2.1 mio. t fish for industrial purposes.

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The hatching rates of African catfish (Clarias gariepinus) eggs on four natural substrates: the roots of Nile cabbage (Pistia stratiotes), water hyacinth (Eichhornia crassipes), pond weed (Ceratophyllum dermasum) and green grass leaves (Commelina sp.), and four artificial substrates: sisal mats, nylon mats, papyrus mats and kakaban mats, was assessed. Concrete slabs were used as control. The natural substrates performed better than the artificial ones. Pistia roots gave the best mean hatching rate of 66.2 ± 3.62%. Green grass leaves were second with a mean rate of 54.0 ± 3.46%, water hyacinth was third with 49.7 ± 3.16% and Ceratophyllum fourth with a mean of 13.0 ± 2.37%. Concrete slabs gave a mean rate of 18.6 ± 2.8%, sisal mats 18.6 ± 2.0%, papyrus 12.2 ± 1.2% and kakaban 11.8 ± 1.9%. Nylon mats were the last, with a mean rate of 4.0 ± 0.7%. The best performing natural substrates were those with the ability to float and thin fibrous roots that seemed to allow higher aeration of the eggs during incubation. The cost of using natural substrates was minimal.

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Charles Henry Gilbert (1859-1928) was a pioneering ichthyologist who made major contributions to the study of fishes of the American West. As chairman of the Department ofZoology at Leland Stanford Junior University in Palo Alto, Calif., during 1891-1925, Gilbert was extremely devoted to his work and showed little patience with those ofa different mindset. While serving as Naturalist-in-Charge of the U.S. Fish Commission Steamer Albatross during her exploratory expedition to the Hawaiian Islands in 1902, Gilbert engaged in an acrimonious feud with the ship's captain, Chauncey Thomas, Jr. (1850-1919), U.S.N., over what Gilbert perceived to be an inadequate effort by the captain. This essay focuses on the conflict between two strong figures, each operatingf rom different world views, and each vying for authority. Despite the difficulties these two men faced, the voyage of the Albatross in 1902 must be considered a success, as reflected by the extensive biological samples collected, the many new species of animals discovered, and the resulting publication of important scientific papers.

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A clean and healthy environment is paramount to human existence. While pesticide use has successfully sustained agricultural and food production in our lifetime as well as safeguarded human health by controlling insect pests, it has also caused many tragedies including population declines in our wildlife, fatalities in workers exposed to pesticides in its manufacture and use, and the increasing incidence of dreaded human illnesses such as cancer. A delicate balance should be achieved to mitigate the adverse impact of pesticide use to the environment and at the same time ensuring short- and long-term agricultural productivity. Endosulfan has been effectively used as a pesticide, but much evidence on its chronic and sub-lethal effects on humans and wildlife have been gathered in recent years. More research still needs to be done to determine its effects from long-term exposure at very low levels. Endosulfan is highly toxic to fish and other aquatic animals and, thus, not recommended for use in aquatic ecosystems. However, in some countries, it has been incorrectly used as a molluscicide in rice paddies, which could have an adverse impact on the rice-fish farming systems and on other surrounding aquatic ecosystems. It is clear that such practices should be stopped and users must strictly observe the recommended application methods. Agricultural productivity should be achieved with less pesticide by using integrated pest management programs which make use of biological, cultural, and physical control agents and lower doses of safer pesticide on a need only basis. The benefits of biotechnology should also be used to develop more effective and safer products and techniques. This is a valid approach and one that will require a unified and concerted effort among suppliers and users of pesticides in order to ensure that resources are used to our best advantage with minimal risk.

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CONTENTS: From resource user to resource manager: a significant change story, by Ruperto Aleroza as told to Jocel Pangilinan and Ronet Santos. Significant change with Cambodian provincial livelihoods study teams, by Bun Hay Chheng, Tan Someth Bunwhat, Mey Chanthou and Bun Puthy. The Community Fisheries Development Office: one year on, by Matt Fox. CFDO open for business, by Louise Mackeson-Sandbach. Stakeholders and institutional involvement in aquaculture management and development, by M. Krishnan and Pratap S. Birthal. Fish seed production for aquaculture in southeast Cambodia: decentralization, the way to go, by Olivier Delahaye Gamucci, Graham C. Mair and Harvey Demaine.