Quantitative Fisheries Stock Assessment

Hilborn, Ray; Walters, Carl J.

doi:10.1007/978-1-4615-3598-0

Cited by 2,240 publications

(957 citation statements)

References 167 publications

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“…In other words, the degree of resolution for current generation archival tags and resultant geopositions cannot distinguish whether a tuna is associated or away from a FAD. But for many fisheries management related questions weekly geopositions are likely to be adequate (e.g., Hilborn and Walters, 1992;Bakun, 1996). Given reasonable fish speeds, weekly pos itions can easily differ by several degrees of latitude and longitude.…”

Section: Nmt Tagsmentioning

confidence: 99%

Ability of Archival Tags to Provide Estimates of Geographical Position Based on Light Intensity

Musyl

Brill

Curran

et al. 2001

Reviews: Methods and Technologies in Fish Biology and Fisheries

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Abstract:We tested the ability of archival tags and their associated algorithms to estimate geographical position based on ambient light intensity by attaching six tags (three tags each from Northwest Marine Technologies [NMT] and Wildlife Computers [WC]) at different depths to a stationary mooring line in the Pacific Ocean (approx. 166º42'W, 24º00'N), for approximately one year (29-Aug-98 to 16-Aug-99). Upon retrieval, one tag each from the two vendors had malfunctioned: from these no data (NMT) or only partial data (WC) could be downloaded. An algorithm onboard the NMT tag automatically calculated geographical positions. For the WC tags, three different algorithms were used to estimate geographical positions from the recorded light intensity data. Estimates of longitude from all tags were significantly less variable than those for latitude. The mean absolute error for longitude estimates from the NMT tags ranged from 0.29 to 0.35º, and for the WC tags from 0.13 to 0.25º. The mean absolute error in latitude estimates from the NMT tags ranged from 1.5 to 5.5º, and for the WC tags from 0.78 to 3.50º. Ambient weather conditions and water clarity will obviously introduce errors into any geoposition algo-

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Section: Nmt Tagsmentioning

confidence: 99%

Ability of Archival Tags to Provide Estimates of Geographical Position Based on Light Intensity

Musyl

Brill

Curran

et al. 2001

Reviews: Methods and Technologies in Fish Biology and Fisheries

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“…Da mesma forma, a saída de barcos da pesca de Manaus já foi evidenciada (Batista, 1998), entretanto sem informações sobre a razão da saída. Hilborn & Walters (1992) indicam que há perdas de embarcações na pesca por afundamento, depreciação física seguida de abandono, mudança de atividade e mudança de área de atuação na pesca, parecendo ser mais importantes o segundo e terceiro itens na região, segundo pescadores entrevistados.…”

Section: Discussionunclassified

“…A caracterização do explorador e de seus meios de deslocamento são fundamentais para o manejo da pesca, pois possibilitam ao administrador conhecer e compreender o objeto principal de manipulação. Esta discriminação prejudica e mesmo inviabiliza a administração da atividade pesqueira na Amazônia, assim como tem ocorrido mundialmente por causas diversas (Hilborn & Walters, 1992).…”

Section: Introductionunclassified

Caracterização da frota pesqueira de Parintins, Itacoatiara e Manacapuru, Estado do Amazonas

Batista

2003

Acta Amaz.

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CARACTERIZAÇÃO DA FROTA PESQUEIRA DE PARINTINS, ITACOATIARA E MANACAPURU, ESTADO DO AMAZONAS.RESUMO -A frota pesqueira de Manacapuru, Itacoatiara e Parintins foi analisada em suas características físicas e comparada com a frota Manaus através de dados coletados diretamente nos portos de desembarque e de dados secundários obtidos junto à órgãos federais e a Federação de Pescadores. Foi encontrado que as canoas isoladas variaram de tamanho entre os centros analisados, sendo as maiores encontradas em Manacapuru e Itacoatiara. Os barcos de pesca de Parintins foram significativamente menores que os barcos de pesca de Manaus, Manacapuru e Itacoatiara. O motor Yanmar predominou em todos os municípios, havendo uma relação linear entre a potência deste motor e o tamanho do barco. Manacapuru apresenta barcos mais velhos, seguido da frota de Itacoatiara. As frotas de Parintins e Manaus foram as mais jovens, tendo esta última maior amplitude de idades. Foram encontrados entre 5-6 pescadores por barco de pesca e 2-3 por canoa isolada. A duração das pescarias efetuadas pelos barcos de pesca é crescente descendo o rio, mas não difere para as canoas isoladas entre os centros urbanos. O rendimento da pesca foi menor para os barcos de pesca de Parintins, sendo o rendimento por pescador dos barcos de pesca melhor que o das canoas no período de safra. A partir dos resultados concluiuse que há diferenciação nas características da frota que desembarca em Parintins (Médio Amazonas) em relação aquela desembarcando em Itacoatiara e Manacapuru e que a pesca efetuada com canoas isoladas deve ser tratada diferenciadamente daquela efetuada com barcos de pesca. Palavras-chave: pesca artesanal, frota pesqueira, Amazônia central Chacterization of the commercial fishing fleet from AmazonasStates, Brazil ABSTRACT -The physical characteristics of the Manacapuru, Itacoatiara and Parintins fishing fleets were analyzed and compared with the Manaus fleet, using data collected from the landing ports along with secondary data obtained from federal institutions and the Amazonas Association of Fishermen. It was found that the size of individual canoes varied according to the center analyzed, with the larger ones found in Manacapuru and Itacoatiara. The size of the Parintins fishing vessels was significantly smaller than those in Manaus, Manacapuru and Itacoatiara. Yanmar engines predominated in all municipal districts. There was a linear relationship between the engine power and size of the vessel. The oldest vessels were found in the Manacapuru fleet, followed by the fleet of Itacoatiara. The Parintins and Manaus fleets were the newest, although the latter had the greatest age range. Fishing boats tend usually to have 5 to 6 fishermen and individual canoes 2 to 3. While fishing vessels working down river make longer trips, no difference in trip length was found for individual canoes in the different municipalities analyzed. Parintins fishing boats produced less fish than those of Manacapuru and Itacoatiara. Yield per fisherman during the height of the f...

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“…This contrasts strikingly with the positive feedback (increased fishing intensity) that often occurs in western cultures at times when fish populations begin to decline (Francis 1990). For example, supply-and-demand economics and government subsidies often maintain or increase fishing intensity in response to declining fish populations (Ludwig et al 1993, Hilborn et al 1995, Pauly and Christensen 1995, as in the Pacific sardine and Peruvian anchovy fisheries (Hilborn and Walters 1992), rather than decreasing predation pressure, as would be the typical population response of natural predators (Francis 1990). These policies that promote fishing in response to declining stocks act as positive feedbacks and have repeatedly caused collapse of boreal fisheries.…”

Section: Social Systemsmentioning

confidence: 97%

Sustainable Development of the Boreal Forest: Interaction of Ecological, Social, and Business Feedbacks

Chapin¹,

Whiteman²

1998

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Quantitative Fisheries Stock Assessment

Abstract: Hilborn, Raymond, 1947 -Quantitative lisheries stock assessment : choice, dynamics and uncertainty. I. Title fi. Wallers, Carl J., 597.0524 ISBN 978-1-4020-1845-9 ISBN 978-1-4615-3598-0 (eBook)

Cited by 2,240 publications

References 167 publications

Ability of Archival Tags to Provide Estimates of Geographical Position Based on Light Intensity

Ability of Archival Tags to Provide Estimates of Geographical Position Based on Light Intensity

Caracterização da frota pesqueira de Parintins, Itacoatiara e Manacapuru, Estado do Amazonas

Sustainable Development of the Boreal Forest: Interaction of Ecological, Social, and Business Feedbacks

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