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

This study analyzes temporal, spatial, environmental, ecological and fishing variables that contributed 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). Sci...

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Autores principales:	González,Andrés, Vega,Rodrigo, Yáñez,Eleuterio
Lenguaje:	English
Publicado:	Universidad de Valparaíso. Facultad de Ciencias del Mar 2015
Materias:	South American sea lion Engraulis ringens Multivariate ENSO Index Purse seine
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-19572015000400007
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spelling	oai:scielo:S0718-195720150004000072016-01-26Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern ChileGonzález,AndrésVega,RodrigoYáñez,Eleuterio South American sea lion Engraulis ringens Multivariate ENSO Index Purse seine This study analyzes temporal, spatial, environmental, ecological and fishing variables that contributed 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 (around midday), thus notably increasing their presence within the nets during sets that are less than 20 nautical miles from the colonies; and 2) during warm periods the presence of downwelling Kelvin waves decreases the availability of anchovies (Engraulis ringens) in the area. This causes the fleet to change target species and focus on jack mackerel (Trachurus murphyi), which is generally captured further from the coast and the colonies, significantly decreasing the interaction with local sea lions.info:eu-repo/semantics/openAccessUniversidad de Valparaíso. Facultad de Ciencias del MarRevista de biología marina y oceanografía v.50 n.3 20152015-12-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-19572015000400007en10.4067/S0718-19572015000400007
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	South American sea lion Engraulis ringens Multivariate ENSO Index Purse seine
spellingShingle	South American sea lion Engraulis ringens Multivariate ENSO Index Purse seine González,Andrés Vega,Rodrigo Yáñez,Eleuterio Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile
description	This study analyzes temporal, spatial, environmental, ecological and fishing variables that contributed 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 (around midday), thus notably increasing their presence within the nets during sets that are less than 20 nautical miles from the colonies; and 2) during warm periods the presence of downwelling Kelvin waves decreases the availability of anchovies (Engraulis ringens) in the area. This causes the fleet to change target species and focus on jack mackerel (Trachurus murphyi), which is generally captured further from the coast and the colonies, significantly decreasing the interaction with local sea lions.
author	González,Andrés Vega,Rodrigo Yáñez,Eleuterio
author_facet	González,Andrés Vega,Rodrigo Yáñez,Eleuterio
author_sort	González,Andrés
title	Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile
title_short	Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile
title_full	Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile
title_fullStr	Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile
title_full_unstemmed	Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile
title_sort	operational interactions between the south american sea lion otaria flavescens and purse seine fishing activities in northern chile
publisher	Universidad de Valparaíso. Facultad de Ciencias del Mar
publishDate	2015
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-19572015000400007
work_keys_str_mv	AT gonzalezandres operationalinteractionsbetweenthesouthamericansealionotariaflavescensandpurseseinefishingactivitiesinnorthernchile AT vegarodrigo operationalinteractionsbetweenthesouthamericansealionotariaflavescensandpurseseinefishingactivitiesinnorthernchile AT yanezeleuterio operationalinteractionsbetweenthesouthamericansealionotariaflavescensandpurseseinefishingactivitiesinnorthernchile
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Operational interactions between the South American sea lion Otaria flavescens and purse seine fishing activities in northern Chile

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