Operational interaction between South American sea lions Otaria flavescens and artisanal (small-scale) fishing in Chile: Results from interview surveys and on-board observations

Sepúlveda, Maritza; Pérez, M.J.; Sielfeld, Walter; Oliva, Doris; Durán, L. René; Rodríguez, Laura; Araos, V.; Buscaglia, Marino

doi:10.1016/j.fishres.2006.10.009

Cited by 47 publications

(43 citation statements)

References 17 publications

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“…The result of the variable Distance to the closest colony center is in agreement with the findings of other studies (Szteren & Páez 2002, Smith & Baird 2005, Sepúlveda et al 2007. This inverse correlation is partly explained by the fact that the feeding areas of the sea lions are fundamentally shallow-coastal waters (Hevia 2013, Hückstädt et al 2014, and also the females need to remain close to their offspring (Smith & Baird 2005).…”

Section: Discussionsupporting

confidence: 88%

“…The main operational interactions between sea lions and fisheries reported in Chile are predation of catch, bycatch and incidental mortality of sea lions (Hückstädt & Antezana 2003, Sepúlveda et al 2007, Reyes et al 2013, while the damage to fishing gear is important in artisanal fisheries (Sepúlveda et al 2007). Hückstädt & Antezana (2003) reported an average interaction of 21 sea lions per set while Reyes et al (2013), working with the trawling industrial fleet that operates in the south-central Chile indicates a catch rate of 1.2 sea lion/trawl -1 and a mortality of 14.6%.…”

Section: Introductionmentioning

confidence: 99%

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Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile

González

Vega

Yáñez

2015

Rev. biol. mar. oceanogr.

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Resumen.-Se analizan variables temporales, espaciales, ambientales, ecológicas y pesqueras que contribuyen a la variación del número de lobos marinos comunes (Otaria flavescens) que interactúan con las faenas de pesca de cerco industrial de la flota que opera en el norte de Chile (18°21'-24°00'S). Observadores científicos fueron embarcados en buques cerqueros entre febrero 2010 y diciembre 2011. Los datos fueron modelados usando modelos lineales generalizados (MLG) y modelos lineales generalizados mixtos (MLGM). Los resultados muestran que la variabilidad en el número de lobos marinos atraídos por las operaciones de pesca para alimentarse o intentar hacerlo, se explica por las variables: Hora del lance, Distancia a las colonias de lobos más cercanas, Temperatura superficial del mar, Especie objetivo del lance, Latitud y Número de aves marinas en torno a la embarcación. Luego del análisis detallado de las variables significativas, se puede concluir que los principales mecanismos que estarían actuando sobre la interacción entre lobos marinos y la operación de pesca serían: 1) una estrategia utilizada por los otáridos para disminuir el estrés por calor en el período reproductivo (verano), saliendo al mar en horas de máxima radiación solar (al mediodía), lo que incrementa notablemente su presencia dentro del cerco en lances realizados a menos de 20 millas náuticas de las colonias y 2) durante per íodos cálidos, la presencia de ondas Kelvin descendentes disminuiría la disponibilidad de anchoveta (Engraulis ringens) en la zona, lo que provoca que la flota reoriente sus operaciones hacia el jurel (Trachurus murphyi), recurso que generalmente se captura a mayores distancias de la costa y de las colonias, disminuyendo significativamente la interacción con los lobos marinos. Palabras clave: Lobo marino común, Engraulis ringens, Índice ENSO Multivariado, Pesca de cercoAbstract.-This study analyzes temporal, spatial, environmental, ecological and fishing variables that contr ibuted to variations in the number of South American sea lions (Otaria flavescens) that interacted with the industrial purse seine fishing operations in the north of Chile (18°21'-24°00'S). Scientific observers were placed onboard purse seiners vessels between February 2010 and December 2011. Data were modeled using generalized linear models (GLM) and generalized linear mixed models (GLMM). The results show that the variations in the number of sea lions attracted to fishing operations for feeding or attempting to feed on catches, depends on the following variables: Time of haul, Distance to the closest sea lion colony, Sea surface temperature, Target species of the haul, Latitude, and Number of seabirds circling the vessel. After detailed analysis of the significant variables, it can be concluded that the main mechanisms involved in the interaction between the sea lions and the fishing operations were: 1) a strategy used by the sea lions to decrease heat stress during the breeding period (summer) by entering the water when solar radiation is at its peak...

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile

González

Vega

Yáñez

2015

Rev. biol. mar. oceanogr.

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“…These pinnipeds have a detrimental impact on gillnets and the fish caught, to the point where fishermen from Monte Hermoso are forced to change to longlines and handlines. The same behaviour has also been reported for sea lions of other South American fisheries such as the Uruguayan and Chilean ones (SZTEREN; PÁEZ, 2002;SEPÚLVEDA et al, 2007). Moreover, further studies should include such physical parameters as water temperature in their analyses.…”

Section: Discussionsupporting

confidence: 75%

Bycatch of franciscana dolphins Pontoporia blainvillei and the dynamic of artisanal fisheries in the species' southernmost area of distribution

Negri¹,

Denuncio

Panebianco³

et al. 2012

Braz. j. oceanogr.

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In Argentina, the franciscana dolphin is one of the most vulnerable cetaceans regularly entangled in coastal artisanal fishery nets. The aim of this paper is to estimate the species' incidental mortality on the Southern coast of Buenos Aires province through interviews with the captains of artisanal fishing vessels, in the period 2006-2009. Franciscana bycatch was reported for gillnets and shrimper gear all year round but it occurred more frequently between October and February, at 5 km offshore and 10-20 m depth. The estimated mean annual incidental mortality was 107 dolphins (CI 95% = 87-129), 92 caught in gillnets (CI 95% = 73-112) and 15 in shrimpers' gear (CI 95% = 8-25) with a capture per unit effort of 0.029 dolphins per km of gillnet (CI 95% = 0.023-0.036) and 0.022 per shrimpe r's net (CI 95% = 0.012-0.035). Annual fluctuations were due to differences in the number of gillnetting fishing days. If mortality estimates for the Northern coast are also taken into account, values attain a maximum of 360-539 dolphins bycaught in the entire Buenos Aires province, representing 2.5-3.7% of the species' abundance in Argentina. This will inevitably lead to the decline of franciscana dolphin populations in the near future unless alternative fishing grounds are identified and alternative gearadopted.

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“…La mayoría de las poblaciones de estos mamíferos fueron severamente reducidas en los últimos siglos debido a la actividad pesquera y a la caza indiscriminada (Cabrera and Yepes 1940;Vaz-Ferreria 1982). Además, se menciona a la pesquería como uno de los mayores factores que afectan directamente a la recuperación de las mismas (Crespo et al 1997;Dans et al 2003a,b;Sepúlveda et al 2007;Túnez and Pimper 2014 una gran preocupación para la conservación de dichas especies. Debido a su rol de depredadores tope, los mamíferos marinos suelen morir enmallados incidentalmente en las redes de pesca y, además, compiten por los recursos con las pesquerías (Northridge 1991;Crespo et al 1997Crespo et al , 2000Dans et al 2003 a, b).…”

Section: Nardelli and Ji Túnezunclassified

Aportes de la genética de la conservación al estudio de los mamíferos neotropicales: revisión y análisis crítico

Nardelli

Túnez

2017

Ecol. Austral

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R��.Si bien todos los seres vivos modifican su entorno, nuestra especie ha adquirido la capacidad de hacerlo a una escala espacio-temporal superlativa. Como resultado de la industrialización y del uso de nuevas tecnologías, el impacto antrópico ha ido en aumento en los últimos siglos, lo que causó la disminución de los tamaños poblacionales o la extinción de numerosas poblaciones silvestres. En este sentido, desde el campo de la genética de la conservación, en las últimas décadas se realizaron diversos esfuerzos para aportar conocimientos nuevos que contribuyan a la conservación de poblaciones, especies y hábitats. Las propiedades de los distintos marcadores moleculares han permitido estudiar la variabilidad genética de las especies y cómo esa variabilidad se estructura en las poblaciones y define las llamadas Unidades de Manejo, que son unidades genéticas cuyo nombre deriva de actividades extractivistas. En este artículo revisamos y analizamos críticamente los esfuerzos científicos en el área de la genética de la conservación realizados entre 2006 y 2015 en pos de la conservación de los mamíferos del Neotrópico. También criticamos el concepto de Unidad de Manejo y analizamos las perspectivas a futuro en el campo de la genética de la conservación de los mamíferos neotropicales.[Palabras clave: biología de la conservación, fauna neotropical, especies amenazadas, marcadores moleculares] A��. Contributions of conservation genetics to the study of neotropical mammals: review and critical analysis.Although all living beings modify their environment, our species has acquired the ability to do so on a superlative space-time scale. As a result of industrialization and the use of new technologies, the anthropic impact has been increasing in the last centuries, causing the decrease in population sizes or the extinction of numerous wild populations. In this sense, from the field of conservation genetics, diverse efforts have been made in the last decades in order to provide new knowledge that contributes to the conservation of populations, species and habitats. The properties of the different molecular markers have allowed studying the genetic variability of the species and how it is structured in the populations, defining the so-called Management Units, genetic units whose name derives from extractivist activities. In this article we perform a review and critical analysis of the scientific efforts in the area of conservation genetics carried out between the years 2006 and 2015 for the conservation of mammals of the Neotropics, criticize the concept of Management Unit and analyze future perspectives in the field of conservation genetics of neotropical mammals.

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Operational interaction between South American sea lions Otaria flavescens and artisanal (small-scale) fishing in Chile: Results from interview surveys and on-board observations

Cited by 47 publications

References 17 publications

Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile

Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile

Bycatch of franciscana dolphins Pontoporia blainvillei and the dynamic of artisanal fisheries in the species' southernmost area of distribution

Aportes de la genética de la conservación al estudio de los mamíferos neotropicales: revisión y análisis crítico

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