Use of a Multiplicative Model to Estimate Catch Rate and Effort from Commercial Data

Gavaris, Stratis

doi:10.1139/f80-273

Cited by 159 publications

(116 citation statements)

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“…However, the lack of linearity, the variation of catchability with abundance or the wide fraction of the variance that is not explained in the relationship between CPUE and abundance (Paloheimo and Dickie, 1964;Cooke, 1985;Shardlow, 1993), can lead to potentially misleading evaluations (Peterman and Steer, 1981;Shardlow, 1993). Since the work of Gavaris (1980), linear models have been increasingly used in order to contemplate these prerequirements, with more information being requested, generating a demand for identifying the variables that explain most of the variance (Vignaux, 1996). This can be done through variables that are relatively easy to follow, such as size of the ships and information about the effort (Palsson and Durrenberger, 1982), even though such variables do not explain an acceptable or significant minimum in some fisheries (Hilborn andLedbetter, 1985, Merona andGascuel, 1993).…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal distribution of fishing resources exploited by the Manaus fishing fleet, Amazonas, Brazil

Batista

Petrere

2007

Braz. J. Biol.

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Fishing resources are important generators of income and food for the rural and urban people in the Amazon. The present paper investigates fishing and environmental variables determining fishing production landed in Manaus and evaluates the relative abundance of commercial fishes in the different sub-systems of the Central Amazon basin. Information collected was used to test the new catch index derived from multiple regressions with the following significant variables: number of fisherman days fishing; distance of the fishing ground from Manaus; amount of ice carried during the trip; and river level. There were no significant differences between mean catch values of the Purus, Madeira and Juruá sub-systems. These results suggest that the tributaries of the right margin were very similar and were the most productive in commercial terms. The actual production varies according to the recent magnitude of fishing effort, environmental variations and operational aspects of fishing, particularly ice consumption.Keywords: distribution, fishes, Amazon, fishing fleet, large rivers.Distribuição espacial e temporal de recursos pesqueiros explorados pela frota pesqueira de Manaus, Amazonas, Brasil ResumoRecursos pesqueiros são importantes fontes de renda e alimento para as populações rurais e urbanas na Amazônia. O presente trabalho avalia a pesca e as variáveis ambientais que determinam a produção de pescarias que desembarcam em Manaus, e avalia também a abundância relativa de recursos pesqueiros em diferentes subsistemas na Amazônia Central. A informação coletada no porto de desembarque de pescado de Manaus foi utilizada para testar um novo índice de captura obtido a partir de um modelo de covariância que apresentou as seguintes variáveis significativas: número de pescadores/dia (dias de pesca vezes número de pescadores por viagem); distância do pesqueiro até Manaus; quantidade de gelo que usou durante a viagem; e nível de rio. Não houve nenhuma diferença significativa entre valores médios de captura entre os subsistemas do Purus, Madeira e de Juruá. Estes resultados sugerem que os tributários da margem direita são similares e mais produtivos em termos comerciais. Concluiu-se que a produção corrente varia de acordo com a magnitude de esforço pesqueiro, por variações ambientais, assim como por aspectos operacionais da pesca, particularmente o consumo de gelo.

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Section: Discussionmentioning

confidence: 99%

Spatial and temporal distribution of fishing resources exploited by the Manaus fishing fleet, Amazonas, Brazil

Batista

Petrere

2007

Braz. J. Biol.

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“…Catch rate, expressed in kg h 1 , was standardized using the multiplicative model (Gavaris, 1980) to correct for variation in vessel tonnage class (related to fishing power) and country. Factors previously recognized as affecting the interpretation of CPUE data are tonnage category, country, area, season, and gear.…”

Section: Methodsmentioning

confidence: 99%

“…Area, season, and gear were not confounding factors for this analysis because our spatial analysis more appropriately Figure 1. Winter distribution of northern Atlantic cod (January to April) averaged over 1980-1991(modified from Wroblewski et al, 1995. The irregular outline of an area stretching from just south of 48 N to 55 N plus two areas on the Grand Banks represents the extent of the observed cod concentrations (where catch rates exceeded 1.5 t h 1 ).…”

Section: Methodsmentioning

confidence: 99%

“…Third, the schools spread over an increasingly greater range of depths. The greatest density of fish as reflected by high catch rates was generally observed no deeper than 600 m between 1980 and 1988 . By 1989, substantial catch rates were observed as deep as 1100 m, particularly to the north although catches continued to be considerable at the shallower depths.…”

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confidence: 97%

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Recent changes in the winter distribution and movements of northern Atlantic cod (Gadus morhuaLinnaeus, 1758) on the Newfoundland-Labrador Shelf

Kulka

Wroblewski

Narayanan

1995

ICES Journal of Marine Science

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S. 1995. Recent changes in the winter distribution and movements of northern Atlantic cod (Gadus morhua Linnaeus, 1758) on the Newfoundland-Labrador Shelf. -ICES J. mar. Sci., Using catch data collected by fishery observers from the otter trawl fleet, we describe changes in the winter distribution of cod on the Newfoundland-Labrador Shelf between 1980 and 1992. We determined the relative abundance of cod in three areas of winter aggregation: south-east of Hamilton Bank, south-east of Belle Isle Bank and south-east of Funk Island Bank. The principal finding was that the cod, during their reproductive period, exhibited significant changes in distribution and behaviour, well before the stock showed signs of collapse. There were three indicators of these changes. First, there was a progressive disappearance of fish from the north with time. Most of the biomass was located in the Hamilton Bank area before 1984. By 1989, most of the fish were found at the Belle Isle Bank and south-east of Funk Island Bank locations and by 1991, only to the south (Funk Island Bank). Second, movements of the prespawning/spawning schools became more limited. Compared with the extensive along-shelf migrations, often covering distances of about 100 km, observed in earlier years, the fish schools after 1989 exhibited less movement to the north. Density of fish in the schools was highest in 1990. By 1991, the schools remained nearly stationary around 49 30 N, near the southern end of their distribution. Third, the schools spread over an increasingly greater range of depths. The greatest density of fish as reflected by high catch rates was generally observed no deeper than 600 m between 1980 and 1988 . By 1989, substantial catch rates were observed as deep as 1100 m, particularly to the north although catches continued to be considerable at the shallower depths. These changes in distribution and behaviour were generally coincident with the occurrence of anomalously cold ocean temperatures and heavy ice conditions, but no direct link between these changes and the environment was evident.1995 International Council for the Exploration of the Sea

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“…M e a n l n transformed CPUE data were grouped by cells defined by time of day, month and year and were analyzed by a three-way ANOVA (Gavaris, 1980;Anon., 1985), i.e. : Ln (catch per hour…”

Section: Commercial Bottom Trawl Datamentioning

confidence: 99%

Pelagic Occurrence of Greenland Halibut,Reinhardtius hippoglossoides(Walbaum), in West Greenland Waters

Jørgensen¹

1997

J. Northw. Atl. Fish. Sci.

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The extent of pelagic occurrence of Greenland halibut, Reinhardtius hippoglossoides (Walbaum), in Greenland waters was evaluated from four pelagic surveys, two conducted at deep water areas where the commercial fishery takes place and two in areas considered to be important nursery areas. The results from the pelagic surveys are compared to results from bottom trawl surveys conducted in the same areas and at the same time. Pelagic behaviour was further supported by investigations of stomach contents from Greenland halibut sampled during pelagic and bottom surveys, and by analysis of commercial bottom trawl data. One-year-old Greenland halibut were abundant and they undertook vertical feeding migrations at night. Older Greenland halibut were rarely encountered pelagically, and the analysis of commercial trawl data showed that the catchability of Greenland halibut did not vary diurnally.

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Use of a Multiplicative Model to Estimate Catch Rate and Effort from Commercial Data

Cited by 159 publications

References 0 publications

Spatial and temporal distribution of fishing resources exploited by the Manaus fishing fleet, Amazonas, Brazil

Spatial and temporal distribution of fishing resources exploited by the Manaus fishing fleet, Amazonas, Brazil

Recent changes in the winter distribution and movements of northern Atlantic cod (Gadus morhuaLinnaeus, 1758) on the Newfoundland-Labrador Shelf

Pelagic Occurrence of Greenland Halibut,Reinhardtius hippoglossoides(Walbaum), in West Greenland Waters

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