Analysis of groundfish survey abundance data: combining the GLM and delta approaches

Stefánsson, Gunnar

doi:10.1006/jmsc.1996.0079

Cited by 284 publications

(227 citation statements)

References 18 publications

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“…S3). We modeled the data in two parts using a δ-lognormal GLM (44). In the first (binomial) part we modeled the probability of catching any of the species in a set.…”

Section: Methodsmentioning

confidence: 99%

Seamounts are hotspots of pelagic biodiversity in the open ocean

Morato

Hoyle

Allain

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

319

231

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The identification of biodiversity hotspots and their management for conservation have been hypothesized as effective ways to protect many species. There has been a significant effort to identify and map these areas at a global scale, but the coarse resolution of most datasets masks the small-scale patterns associated with coastal habitats or seamounts. Here we used tuna longline observer data to investigate the role of seamounts in aggregating large pelagic biodiversity and to identify which pelagic species are associated with seamounts. Our analysis indicates that seamounts are hotspots of pelagic biodiversity. Higher species richness was detected in association with seamounts than with coastal or oceanic areas. Seamounts were found to have higher species diversity within 30-40 km of the summit, whereas for sets close to coastal habitat the diversity was lower and fairly constant with distance. Higher probability of capture and higher number of fish caught were detected for some shark, billfish, tuna, and other by-catch species. The study supports hypotheses that seamounts may be areas of special interest for management for marine pelagic predators.by-catch | fisheries | longline | pelagic predators | seamount conservation

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“…S3). We modeled the data in two parts using a δ-lognormal GLM (44). In the first (binomial) part we modeled the probability of catching any of the species in a set.…”

Section: Methodsmentioning

confidence: 99%

Seamounts are hotspots of pelagic biodiversity in the open ocean

Morato

Hoyle

Allain

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

319

231

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“…GLMs are an extension of linear models that allow the incorporation of non-normal distributions of the response variable and its transformation to linearity (McCullagh and Nelder 1983). As LPUE data consist of positive values, log-normal or gamma distributions may be appropriate to the response variable (Stefánsson 1996). However, gamma distribution has been considered more suitable for fisheries data (Maynou et al 2003;Myers and Pepin 1990).…”

Section: Discussionmentioning

confidence: 99%

Are Portuguese coastal fisheries affected by river drainage?

Gamito

Vinagre

Teixeira

et al. 2016

Aquat. Living Resour.

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-The Portuguese coast is particularly adequate for studies on the impact of climate change on fisheries, as it has faced an increase in both air and sea surface temperature and a decrease in intensity and frequency of rainfall. Ecological responses to climate change have already been observed in Portuguese waters, with consequences in fisheries. Regional climate models have predicted a further decrease in rainfall in Portugal by the end of the century, which will have a strong impact on the runoff into coastal areas. River drainage affects the physical, chemical and biological properties of coastal ecosystems, regulating habitat availability and favouring their productivity. The present study analysed the influence of river drainage on landings of coastal ports in the vicinity of four hydrologically distinct estuaries. Unlike previous results obtained for the Mediterranean, no significant relationships between river drainage and landings were found. Relationships between drainage and landings can be inconsistent among regions and dependent on how strongly a food web relies on nutrients and organic matter of river origin. In the Portuguese coast, an upwelling regime is of particular importance for the richness and diversity of the coastal ecosystem and for fisheries. The complexity of the coastal upwelling phenomenon together with a possible interaction of several other smaller scale factors acting on recruitment of commercial species may mask the effects of river drainage on landings. Nevertheless, as accentuated decreases in rainfall have been predicted for Portugal, the resulting reduction in river drainage may still strongly impact fisheries in the future.

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“…En este tipo de pesquerías la CPUE es afectada por la disponibilidad de otras especies y principalmente por la decisión de los pescadores en dirigir su esfuerzo sobre una especie en particular. Sin embargo, las capturas nulas pueden constituir una importante fuente de información sobre la condición del stock, a la vez de ser un posible indicador de menor abundancia (Stefánsson, 1996). En este tipo de pesquerías habitualmente se captura más de una especie objetivo en cada lance de pesca, de esta forma la posible obtención de capturas nulas de alguna de las especies puede ser un indicador de menor abundancia para una determinada zona de pesca y/o temporada.…”

Section: Consecuencias De La Estandarización De La Cpue Por Medio De unclassified

“…La eliminación de los registros de ceros produce que los datos asuman generalmente una distribución muy cercana a la log-normal o gamma para los registros de captura positivos, mientras que la incorporación de capturas nulas genera una distribución residual del tipo binomial negativa (Stefánsson, 1996). Sin embargo, la eliminación sistemática de las capturas nulas puede ser también una fuente importante de error, particularmente en los casos donde la serie de datos muestra una disminución del stock a evaluar producto de sobrepesca.…”

Section: Consecuencias De La Estandarización De La Cpue Por Medio De unclassified

Tasas de captura estandarizadas como índice de abundancia relativa en pesquerías: enfoque por Modelos Lineales Generalizados

Gatica

Hernández²

2003

Investig. mar.

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Analysis of groundfish survey abundance data: combining the GLM and delta approaches

Cited by 284 publications

References 18 publications

Seamounts are hotspots of pelagic biodiversity in the open ocean

Seamounts are hotspots of pelagic biodiversity in the open ocean

Are Portuguese coastal fisheries affected by river drainage?

Tasas de captura estandarizadas como índice de abundancia relativa en pesquerías: enfoque por Modelos Lineales Generalizados

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