Behaviour of Southern sea lions in presence of killer whales during fishing operations in Central Chile
The killer whale is an opportunistic top-predator of ecosystems worldwide and its diet varies locally and seasonally, which is reflected in diverse feeding behaviours associated with its prey. We report the occurrence of killer whales presumably predating on southern sea lions associated with the ja...
| Published in: | Scientia Marina |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Consejo Superior de Investigaciones Científicas
2004
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| Subjects: | |
| Online Access: | https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/369 https://doi.org/10.3989/scimar.2004.68n2295 |
| Summary: | The killer whale is an opportunistic top-predator of ecosystems worldwide and its diet varies locally and seasonally, which is reflected in diverse feeding behaviours associated with its prey. We report the occurrence of killer whales presumably predating on southern sea lions associated with the jack mackerel fishing fleet in central Chile. The presence of killer whales was recorded during 4 fishing sets. All sightings consisted of 3-5 individual pods of females and calves. The number of sea lions was not significantly affected by the presence of killer whales, but their behaviour was, by reducing the number of behavioural displays, as they stopped feeding and resting activities and stayed close to the hull of the vessel after net retrieval ended. We propose that killer whales could be using the fishery as an indirect source of prey to benefit from the aggregation of sea lions around the vessel, far away from land. La orca es un depredador tope de hábitos oportunistas que habita diversos ecosistemas de todo el mundo y cuya dieta varía en forma local y estacional, lo que se refleja en la diversidad de comportamientos alimentarios asociados con sus presas. En este trabajo, reportamos la presencia de orcas presumiblemente cazando lobos marinos comunes del sur, en asociación con la flota pesquera de jurel en Chile Central. Se registró la presencia de orcas en cuatro lances de pesca. Todos los avistamientos fueron de grupos compuestos por 3-5 individuos, hembras y crías. Si bien la presencia de orcas no afectó significativamente el número de lobos marinos, si tuvo un efecto en el comportamiento de los lobos marinos reduciendo el número de conductas, cesando las actividades de alimentación y descanso y permaneciendo cercanos al casco del barco pesquero hasta después de finalizada la recuperación de la red. Se propone que las orcas podrían estar utilizando la pesquería como una fuente indirecta de presas, beneficiándose así de la agregación de lobos marinos alrededor del barco pesquero, lejos de tierra. |
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