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  • 1
    Publication Date: 1979-08-01
    Print ISSN: 0029-8549
    Electronic ISSN: 1432-1939
    Topics: Biology
    Published by Springer
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  • 2
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The invertebrate macrofauna of Seal Sands, Teesmouth, is very limited in species composition. Nereis diversicolor has a two-year life cycle; the larger size-class provides the main prey of the birds Pluvialis squatarola, Numenius arquata and Limosa lapponica. Hydrobia ulvae is an important food of P. squatarola and Calidris canutus. Small Carcinus maenas occur in late autumn and are taken by the larger shorebirds. Small Macoma balthica are also taken, but are scarce and not an important bird food. Tadorna tadorna and Calidris alpina subsist chiefly on species of small oligochaetes and polychaetes which occur at very high densities (Gray 1976). Feeding areas of the shorebird species show some segregation, particularly in groups of species taking the same prey. It is calculated that birds removed about 90% of the standing crops of large Hydrobia and Nereis during a single winter. This followed the reclamation of more than half the intertidal land used as feeding grounds by the birds.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2021-05-19
    Description: A survey of demersal fish resources of the Continental Shelf of Ecuador was carried out between October 1980 an July 1985 by the National Fisheries Institute of Ecuador, with British Technical Cooperation. This report deals with the stock assessment part of the work. In the course of seven cruises, 366 valid diurnal hauls were made with a high-opening bottom trawl. The demersal fish resources were estimated by swept area methods and the results are presented. The overall average standing stock of demersal fish was 78 000 t of which 22 000 t was good fish, but 36 000 t were gurnards (Triglidae) and 3 000 t of unusable fish. The main stocks were gurnards, grunts and croakers, sharks and corvinas Cynoscion spp. The southern areas especially the Gulf of Guayaquil had the highest densities of fish (9,6 t.Km-2 or 4,0 t.Km-2 excluding gurnards). There was a massive abundance of the gurnard, Prionotus stephanophys in 1984 and 1985. There was a general decrease and other changes in the demersal stocks due to the effects of the ”El Niño” in 1983.
    Description: Published
    Keywords: Demersal fisheries ; Geographical distribution ; Biomass ; Demersal fisheries ; Geographical distribution ; Abundance ; Biomass
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 4
    Publication Date: 2021-05-19
    Description: Los tiburones son muy abundantes en las aguas ecuatorianas. Son capturados tanto por embarcaciones artesanales como por barcos industriales junto con peces pelágicos grandes (dorado, picudo, atún) y como pesca acompañante en los arrastreros. No existe una pesquería dedicada específicamente a la captura del tiburón. Sin embargo, se capturan grandes cantidades como parte de la pesca acompañante de varias otras pesquerías. Los tiburones más comunes en las capturas son los de la familia Carcharhinidae, los carcharhinidos. Se tiene que considerar que no todos los tiburones capturados se comercializan. A más de la captura de la flota artesanal, una porción muy apreciable del total es realizada por barcos industriales, los atuneros y los palangreros, éstos regresan a los puertos con tiburón solamente cuando no pueden llenar sus bodegas con especies de más alto valor. De lo contrario, simplemente les quitan las aletas que tienen gran valor comercial y desechan los restos del tiburón al mar. Considerando los problemas nutricionales que existen en los sectores marginados de la población se cree que el Ecuador puede beneficiarse con una mayor utilización de la captura existente de tiburón. Este trabajo describe las características de la pesca incidental del tiburón en Ecuador y propone un uso adecuado de los productos que se puedan derivar del mismo, atendiendo al deficit alimentario que existe en el país, fundamentalmente en los sectores de menos recursos. Propone el estudio, se declaren ilegales las prácticas de desechar al mar los tiburones, contando para ello con observadores nacionales que ejerzan un control de la pesca.
    Description: Published
    Keywords: Shark fisheries ; Shark utilization
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 5
    Publication Date: 2021-05-19
    Description: The stock estimates obtained during the demersal fish resources survey in 1980-1985 were used to estimate the potential yields of demersal stocks of the Ecuadorian Continental Shelf. The difficulties of predicting yields for multispecies fisheries are discussed and modified version of the Gulland model was adopted. The potential realizable yields for multispecies fisheries are discussed and a modified version of the Gulland model was adopted. The potential realizable yield was calculated to be between 15,000 t and 20,000 t per year, of which 2,000 t is good quality fish, 5,000 t per year of small and medium fish and 8,000 t of gurnards. The majority of these resources are at present being fished at around their optimum levels and any further developments that would increase the fishing effort on demersal resources which are at present being exploited should be approached with caution. The national fisheries, especially the artisanal sector play a valuable role in the country and care should be taken to see that these are not adversely affected.
    Description: Published
    Keywords: Demersal fisheries ; Continental shelves ; Demersal fisheries ; Continental shelves ; Yield predictions ; Exploitation
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 6
    Publication Date: 2021-05-19
    Description: A study was carried out the white fish landings made by the artisanal fisheries in mainland Ecuador in 1982. There were four main groups of landings: the fishery for large pelagic fish, the demersal longline fishery on hard grounds; the set net fisheries for corvina and other medium and large bottom fish and the landings of shrimp by-catch. The fishes caught and their nomenclature; the gears used, the vessels and the fishing communities are briefly described. The landings of with fish by these fisheries in 1082 are given and discussed. The total landings were between 15.000 t and 20.000 t. Of this about 40% was large pelagic fish; 20-30% shrimp by-catch, 20% good quality demersal fish and 10% shark. It should be possible to increase the landings in some categories, but feasibility studies would be needed any development could be recommended and at present the fishermen are not receiving a good return for their efforts.
    Description: Published
    Keywords: Catch composition ; Pelagic fisheries ; Artisanal fishing ; Catch composition ; Pelagic fisheries
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 7
    Publication Date: 2021-05-19
    Description: 153 experimental sets were made with stackable Antillean fish traps in depths of 5 to 30 m in the waters around the Galápagos Island (Ecuador), between Octobre and April 1983. 1,885 fish were caught of 18 species mainly of the families Pomadasyidae, Acanthuridae, Sparidae and Serranidae. The mean catch rate was 5,5 Kg per lift or 0,4 Kg.h-1, and the mean weight of the fish caught was 0,45 Kg. The optimum set duration was found to be between 2 and 18 hours (possibly indicating a high rate of escape). This study took place during the period of the ”El Niño”, when catches of fish in this area generally were low, and it is not known what effect this had. The catches were good compared with other shallow areas, but the fishes caught were mainly of medium quality. It is thought that significant increases in the quantity and quality of the catch could be obtained with commercial traps in deeper areas, but the efficient use of these would require new vessels and equipment, and the resulting increase in fishing effort could lead to overfishing of the most acceptable species of reef fish. Hence the development of fishery using fish traps is not recommended for Galápagos. A study of the biology of the fish caught was carried out. A bibliography of references on fish traps and their use was compiled and is included.
    Description: Published
    Keywords: Fisheries ; Trap fishing ; Fisheries ; Catch statistics ; Trap fishing
    Repository Name: AquaDocs
    Type: Journal Contribution
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