miguel araya

Parental care and early development of the labrisomid blenny Labrisomus philippii (Labrisomidae) from northern Chile

Journal of Applied Ichthyology

Mass‐effect: Understanding the relationship between age and otolith weight in fishes

Fish and Fisheries

Biphasic growth modelling in elasmobranchs based on asymmetric and heavy-tailed errors

Environmental Biology of Fishes, 2021

Growth in fishes is usually modelled by a function encapsulating a common growth mechanism across... more Growth in fishes is usually modelled by a function encapsulating a common growth mechanism across ages. However, several theoretical works suggest growth may comprise two distinct mechanistic phases arising from changes in reproductive investment, diet, or habitat. These models are termed two-state or biphasic, where acceleration in growth typically changes around some transition age. Such biphasic models have already been successfully applied in elasmobranch species, where such transitions are detectable from length-at-age data alone, but where estimation has assumed normally distributed errors, which is inappropriate for such slow-growing and long-lived fishes. Using recent advances in growth parameter estimation, we implement a biphasic growth model with asymmetric and heavy-tailed errors. We use data from six datasets, encompassing four species of elasmobranchs, to compare the performance of the von Bertalanffy and biphasic models under normal, skew-normal, and Student-t error distributions. Conditional expectation maximization estimation proves both effective and efficient in this context. Most datasets analysed here supported asymmetric and heavy-tailed errors and biphasic growth, producing parameter estimates different from previous studies.

Isotopic niche and niche overlap in benthic crustacean and demersal fish associated to the bottom trawl fishing in south-central Chile

Journal of Sea Research, 2021

Habitat coupling writ large: pelagic-derived materials fuel benthivorous macroalgal reef fishes in an upwelling zone

Ecology, Jan 20, 2017

Coastal marine upwelling famously supports elevated levels of pelagic biological production, but ... more Coastal marine upwelling famously supports elevated levels of pelagic biological production, but can also subsidize production in inshore habitats via pelagic-benthic coupling. Consumers inhabiting macroalgae-dominated rocky reef habitats are often considered to be members of a food web fuelled by energy derived from benthic primary production; conversely, they may also be subsidized by materials transported from pelagic habitats. Here, we used stable isotopes (δ(13) C, δ(15) N) to examine the relative contribution of pelagic and benthic materials to an ecologically and economically important benthivorous fish assemblage inhabiting subtidal macroalgae-dominated reefs along ~1,000 km of the northern Chilean coast where coastal upwelling is active. Fish were isotopically most similar to the pelagic pathway and Bayesian mixing models indicated that production of benthivorous fish was dominated (median 98%, range 69-99%) by pelagic-derived C and N. Although the mechanism by which these ...

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Alimentaci�n y relaciones tr�ficas de peces costeros de la zona norte de Chile

Investigaciones Marinas, 2004

La zona norte de Chile se caracteriza por la abundancia de peces costeros y alta diversidad de es... more

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Estudio biológico pesquero sobre el recurso jurel en la zona norte (Regiones I y II)

Informes Técnicos FIP-IT/ …, 1995

Estudio biológico de tiburones (marrajo dentudo, azulejo y tiburón sardinero) en la zona norte y central de Chile

Otolith Weight as an Estimator of the Age of Seriola lalandi Valenciennes, 1833 (Carangidae), in the Southeastern Pacific

Animals

The age and growth of fish populations is a critical issue for stock assessment, population dynam... more The age and growth of fish populations is a critical issue for stock assessment, population dynamics and fishery management. Spawner biomass, mortality, growth, recruitment and age at maturity can be misconstrued if the age estimator is inaccurate. Age can be estimated by annuli count, but this requires expertise and is expensive. Otolith weight (OW) is a good indicator of how long a fish has lived, because OW increases during an individual’s life. Seriola lalandi is a migratory fish and is an important resource for local fishermen in northern Chile. Aspects of its biology, i.e., age and growth, remain unknown, at least for the population annually arriving in northern Chile. Fish of a known age (n = 105; from 5.5 to 25.7 cm in FL) from yellowtail aquaculture facilities at Universidad de Antofagasta allowed us to estimate the growth rate of OW, and fish obtained from local fishermen (n = 71; from 37.9 to 109 cm in FL) allowed us to estimate the age and growth of S. lalandi from the a...

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Otolith Weight as an Estimator of the Age of Seriola lalandi Valenciennes, 1833 (Carangidae), in the Southeastern Pacific

Animals

The age and growth of fish populations is a critical issue for stock assessment, population dynam... more The age and growth of fish populations is a critical issue for stock assessment, population dynamics and fishery management. Spawner biomass, mortality, growth, recruitment and age at maturity can be misconstrued if the age estimator is inaccurate. Age can be estimated by annuli count, but this requires expertise and is expensive. Otolith weight (OW) is a good indicator of how long a fish has lived, because OW increases during an individual’s life. Seriola lalandi is a migratory fish and is an important resource for local fishermen in northern Chile. Aspects of its biology, i.e., age and growth, remain unknown, at least for the population annually arriving in northern Chile. Fish of a known age (n = 105; from 5.5 to 25.7 cm in FL) from yellowtail aquaculture facilities at Universidad de Antofagasta allowed us to estimate the growth rate of OW, and fish obtained from local fishermen (n = 71; from 37.9 to 109 cm in FL) allowed us to estimate the age and growth of S. lalandi from the a...

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Efecto de la Temperatura en la Supervivencia Embrionaria y Primeros Estadios Larvales de Psetta maxima

International Journal of Morphology, 2012

Effect of Increased Temperature, Frequency and Feed Ration on Growth of Juvenile Turbot Psetta maxima

Temperature Effect on Embryonic Survival and Early Larval Stages of Psetta maxima

Optimization of Broodstock Management to Increase the Production of Eggs and Larvae of Psetta maxima (Linneaus, 1758)(Turbot)

Dinámica de poblaciones explotadas

Short communication Age, growth and retrospective stock assessment of an economically extinct sparid fish, Polysteganus undulosus, from South Africa JR Chale-Matsau, A. Govender and LE Beckley (Durban, South Africa)................................ 87

Retrocálculo del peso promedio a la edad:¿ Es necesario

Monitoreo de la pesquería artesanal de bacalao de profundidad entre la VIII y XI Regiones

Estimaciones empíricas de mortalidad natural en el bacalao de profundidad (Dissostichus eleginoides Smitt, 1898)

Revista de biología marina y oceanografía, 2007

The instantaneous natural mortality rate is estimated for toothfish (Dissostichus eleginoides) us... more The instantaneous natural mortality rate is estimated for toothfish (Dissostichus eleginoides) using empirical models, with the emphasis on an evaluation of the precision of the estimates. The results are compared with estimates obtained per age classes and obtained through an analytical model. The growth parameters and the size at first maturity available for toothfish are used in order to consider the error in the input parameters, and after the prediction error in the variance computation of the estimates. The M values were estimated with low precision, with coefficients of variation ranging between 41 y 60%, and confidence intervals at 95% fluctuating between 0.04 y 0.39 yr -1 . The median of the estimates ranged between 0.1 and 0.14 yr -1 , and they were closed to the average of the M values obtained per age classes (M = 0.11 yr -1 ). It is recommended to use M = 0.1 yr -1 for stock assessment models applied to the resource, since centesimal values make no sense for an imprecise parameter.

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Optimización en el Manejo de Reproductores para una Mayor Producción de Huevos y Larvas de Psetta maxima (Linneaus, 1758)

International Journal of Morphology, 2013

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