Largest baleen whale mass mortality during strong El Niño event is likely related to harmful toxic algal bloom

Facultad de Ciencias Naturales, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
GeoBio-Center, Munich, Germany
Huinay Scientific Field Station, Puerto Montt, Region de los Lagos, Chile
Area de Patrimonio Natural, Consejo de Monumentos Nacionales, Santiago, Región Metropolitana, Chile
Red Paleontológica U-Chile, Laboratorio de Ontogenia y Filogenia, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Región Metropolitana, Chile
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, United States
Scottish Association for Marine Science, Oban, Scotland, UK
Centro de Investigación e Innovación para el Cambio Climático, Universidad Santo Tómas, Santiago, Chile
Centro de Investigación Eutropia, Santiago, Región Metropolitana, Chile
Centro de Estudios Avanzados en Zonas Aridas (CEAZA), La Serena, Chile
Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California, United States
Instituto de Ecología y Biodiversidad (IEB), Facultad de Ciencias, Universidad de Chile, Santiago, Chile
Departamento de Geofísica, Universidad de Concepción, Concepción, Chile
Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Chile
Department of Zoology, Ludwig-Maximilians-University, Munich, Germany
DOI
10.7287/peerj.preprints.2707v1
Subject Areas
Conservation Biology, Ecosystem Science, Marine Biology, Paleontology, Zoology
Keywords
Chilean Patagonia, red tide, El Niño, sei whales, drift models, Balaenoptera borealis, paralytic shellfish poison, Balaenopteridae, taphonomy, climate change
Copyright
© 2017 Häussermann et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Häussermann V, Gutstein CS, Beddington M, Cassis D, Olavarria C, Dale AC, Valenzuela-Toro AM, Perez-Alvarez M, Sepúlveda HH, McConnell KM, Horwitz FE, Försterra G. 2017. Largest baleen whale mass mortality during strong El Niño event is likely related to harmful toxic algal bloom. PeerJ Preprints 5:e2707v1

Abstract

While large mass mortality events (MMEs) are well known for toothed whales, they have been rare in baleen whales due to their less gregarious behaviour. Although in most cases the cause of mortality has not been conclusively identified, some baleen whale mortality events have been linked to bio-oceanographic conditions, such as harmful algal blooms (HABs).In southern Chile, HABs can be triggered by the ocean-atmosphere phenomenon El Niño. The frequency of the strongest El Niño events is increasing due to climate change. In March 2015, by far the largest reported mass mortality of baleen whales took place in a gulf in southern Chile. Here we show that the synchronous death of at least 343, primarily sei, whales can be attributed to HABs during a building El Niño. Although considered an oceanic species, the sei whales died while feeding near to shore in previously unknown large aggregations. This provides evidence of new feeding grounds for the species. The combination of older and newer remains of whales in the same area indicate that MMEs have occurred more than once in recent years.Large HABs and reports of marine mammal MMEs along the north-east Pacific coast may indicate similar processes in both hemispheres. Increasing MMEs through HABs may become a serious concern in the conservation of endangered whale species.

Author Comment

This is a submission to PeerJ for review.