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Revista de biología marina y oceanografía

versión On-line ISSN 0718-1957

Rev. biol. mar. oceanogr. vol.48 no.1 Valparaíso abr. 2013

http://dx.doi.org/10.4067/S0718-19572013000100007 

Revista de Biología Marina y Oceanografía
Vol. 48, Nº1: 73-85
, abril de 2013
Article

ARTÍCULOS

 

Killer whales in Chilean Patagonia: additional sightings, behavioural observations, and individual identifications

Orcas en la Patagonia chilena: avistamientos adicionales, observaciones de comportamiento e identificaciones individuales

 

Verena Häussermann1,2, Jorge Acevedo3, Günter Försterra1,2, Michelle Bailey4 and Anelio Aguayo-Lobo5

1Huinay Scientific Field Station, Casilla 462, Puerto Montt, Chile
2Escuela de Ciencias del Mar, Facultad de Recursos Naturales, Pontificia Universidad Católica de Valparaíso, Avda. Brasil 2950, Valparaíso, Chile. v.haussermann@gmail.com
3Centro Regional de Estudios del Cuaternario Fuego-Patagonia y Antártica (Fundación CEQUA), 21 de Mayo 1690, Punta Arenas, Chile
4Vancouver, British Columbia, Canada. michelle.marcotte@gmail.com
5Instituto Antártico Chileno, Plaza Muñoz Gamero 1055, Punta Arenas, Chile


RESUMEN

Se conoce muy poco sobre las orcas (Orcinus orca) que frecuentan las aguas de la Patagonia chilena y si los individuos identificados son visitantes o residentes. Se informan 119 observaciones oportunistas recolectadas desde 2001 hasta 2012. Los tamaños de los grupos avistados varían desde un animal hasta tamaños grupales de más de 50 individuos. También se informa sobre el comportamiento observado y se presenta un primer catálogo de individuos para la Patagonia chilena, identificándose 49 individuos, de las cuales 7 han sido observados en más de una ocasión.

Palabras clave: Orcinus orca, región de fiordos chilenos, tamaño grupal, comportamiento de alimentación, catálogo de foto-identificación


ABSTRACT

Very little is known about the killer whales (Orcinus orca) that frequent the waters of Chilean Patagonia. Even information as to whether identified individuals are visitors or residents of the region is unknown. Here, we report on opportunistically collected observations in this region from 2001 through 2012. Killer whales were observed on 119 separate occasions in group sizes ranging from one to groups of over 50 individuals. We also describe observed behaviour and present a first catalogue of individuals in Chilean Patagonia. We identified 49 individuals, only seven of which were sighted more than once.

Key words: Orcinus orca, Chilean fjord region, group size, feeding behaviour, photo-identification catalogue


INTRODUCTION

The killer whale, (Orcinus orca Linnaeus, 1758), is a cosmopolitan species. The populations in the Eastern North Pacific are perhaps the most studied and well known in the world. These populations are divided into 3 genetically distinct ecotypes which differ substantially in diet, behaviour, and social structure: transient killer whales (or mammal-eating form), resident killer whales (or fish-eating form), and offshore killer whales who are thought to eat fish including sharks (Bigg 1982, Bigg 1987, Hoelzel & Dover 1991, Matkin et al. 1999, Baird 2000, Saulitis et al. 2000, Ford et al. 2011). Four ecotypes, type A to D, have recently been described from the Southern Ocean which differ in colouration, diet and size, and possibly represent different species or sub-species (Pitman & Ensor 2003, Pitman et al. 2011).

While data sets on northern hemisphere killer whales are comparably large and populations are often recognized on the individual level (Ford et al. 2000), there is very little known about Patagonian populations. In the Western South Atlantic, the only long-term studies on killer whales have been conducted off the Valdes Peninsula, northern Patagonia, Argentina. The killer whales studied here are famous worldwide for intentionally stranding to catch South American sea lions Otaria flavescens (Shaw, 1800) and southern elephant seals Mirounga leonina (Linneaus, 1758), (Lopez & Lopez 1985, Hoelzel 1991, Iñíguez 2001). Information on Chilean killer whale populations however is scarce. Only 2 congress summaries (Canto 19901, Marcotte et al. 20092), one publication (Capella et al. 1999) and 2 reports for the International Whaling Commission (Mikhalev et al. 1981, Dahlheim et al. 1982) deal exclusively with Chilean and South Eastern Pacific killer whales. The species is also described in field guides of Chilean marine mammals (Sielfeld 1983, Cárdenas 1986). In their monograph on Chilean marine mammals, Aguayo-Lobo et al. (1998) briefly summarize the known information on Chilean killer whales; Capella et al. (1999) added new sightings which increased the number of recorded sightings for Chilean Patagonia to a total of 30. Based on the available published information, the latter authors concluded that the species is scarce in Chilean waters. After this determination of scarcity, Chilean killer whales have only been mentioned in 6 further publications (Hucke-Gaete et al. 2004, Hückstädt & Antezana 2004, Aguayo-Lobo et al. 2006, Moreno et al. 2008, Viddi et al. 2010) and one thesis (Olivares-Mancilla 2005). These publications added 29 new records for Chilean Patagonia, primarily from commercial fishing areas for Patagonian toothfish (Dissostichus eleginoides Smitt, 1898).

Very little information is available about the feeding behaviour of Chilean killer whales. Pinnipeds are generally an important prey item of some killer whale populations (Lopez & Lopez 1985, Hoelzel 1991, Jefferson et al. 1991). In Chile, killer whales regularily feed upon the South American sea lion (Capella et al. 1999, Hückstädt & Antezana 2004), and, to a lower extent, on the South American fur seal (Arctocephalus australis Zimmerman, 1783) (Capella et al. 1999). A variety of other prey items have also been reported (Capella et al. 1999). Killer whales have been observed to feed on the catches in fishing fleets for Patagonian toothfish between 53°S and 57°S (Hucke-Gaete et al. 2004, Olivares Mancilla 2005, Moreno et al. 2008), and possibly attack sperm whales in the same fishing areas (Hucke-Gaete et al. 2004).

In this paper we report 119 new killer whale sightings of generally small groups recorded between 2001 and mid 2012. Observations recorded include group size and, where possible, feeding behaviour. A first edition of a dorsal fin and saddle patch photos catalogue for individual identification and some recapture data are presented.

 

MATERIALS AND METHODS

Killer whale sightings have been recorded opportunistically since 2003 by the team of the Huinay Scientific Field Station (HSFS) in the northern Patagonian channels. Sightings were made from a variety of platforms including small vessels (6-11 m length) during year-round transport trips between Hornopirén and the research station, boat trips for non-killer whale related field work in the Comau Fjord, mainly during the austral summer months (up to 10 trips of 4-6 h per month). Photos of individuals were taken if a camera was available, and the type of displayed activity was recorded if obvious to the observer. Since 2006 boat hours and number of trips have constantly been rising with increasing scientific activity at the station.

In the southern Patagonian channels, the sightings of killer whales were recorded opportunistically by Centro Regional de Estudios del Cuaternario Fuego-Patagonia y Antártica (CEQUA) researchers from different vessels (15 and 26 m length) during the sea lion census in the Magellan region and during the humpback whale program carried out during 2001, and between 2003 and early 2012, respectively.

During several sightings, the teams took photos of the dorsal fin, saddle and eye patches for individual identification. A photo catalogue of identified killer whales was prepared for both study areas. New photographs were checked against existing photo-catalogues and also compared between both regions.

In addition, some sightings recorded by locals and some data from social media have been included in this review. Although videos from the internet are less reliable sources compared to regular sightings, we include them here to provide additional information on killer whales and their behaviour in Chilean Patagonia. Further sightings provided by DIRECTEMAR (part of the Chilean Navy) from 2005 to 2012 were also added to our dataset.

 

RESULTS AND DISCUSSION

One hundred and nineteen new sightings of killer whales from Chilean Patagonia are presented here (Table 1); 29 are from Comau Fjord, Northern Patagonian Zone, 14 from the Marine Protected Area (MPA) Francisco Coloane, Southern Patagonian Zone and 15 from other areas in Chilean Patagonia (Fig. 1), (Map was created using Quantum GIS (QGIS), software SIG open source)3. Fifty-six sightings were reported by the DIRECTEMAR, the remaining 5 were based on videos: one made by an artisanal fisherman and 4 videos were obtained from internet social media sources (Table 1). All the observed killer whales had similar colouration to killer whales seen worldwide, with a medium-sized eye patch oriented parallel to the body axis, and no dorsal cape. No yellowish or brown staining could be distinguished, as has been recorded from some Antarctic whales (Pitman et al. 2003). The individuals resemble the `type A' form in colouration (see Pitman et al. 2003).

 

Figure 1. Map of Chilean Patagonia with the new killer whale sighting locations

Figura 1. Mapa de la Patagonia chilena con los nuevos avistamientos de orcas

 

The great number of new incidental sightings recorded, primarily from 2 restricted areas of Chilean Patagonia (Comau Fjord, MPA Francisco Coloane) and from the few places where the Chilean navy operates regularly, indicates that killer whales may be more common in Chilean waters than previously assumed (another 27 sightings from the Chilean coast north of Puerto Montt and Antarctica are not mentioned here). The probable reason for few reported sightings is likely due to the remoteness of most areas of Chilean Patagonia, the absence of dedicated local marine mammal research, and the lack of a public sighting database.

 

Feeding behaviour and group sizes

During 14 of the 119 sightings, the killer whales were observed displaying active predatory behaviour: 10 times they were hunting and/or feeding on South American sea lions, twice on southern fur seals, once they were filmed attacking a sei whale Balaenoptera borealis Lesson, 1828) and once a killer whale was filmed swallowing an imperial shag Phalacrocorax atriceps King, 1828 (see Table 1). Once a killer whale was observed tail-slapping in Comau Fjord. Fishermen have also observed small groups of killer whales feeding on gull species and Magellan penguins Spheniscus magellanicus (Forster, 1781) during the summer seasons, and removing fish from the lines of artisanal fishermen outside the AMCP Coloane. These sightings are not included in Table 1 because the sighting locations are not provided with certainty. In 3 instances, adult killer whales were observed encircling South American sea lions or fur seals without attacking, while the young calves appeared to be practicing attacks.

The observed attack of a killer whale on a sei whale is the third instance recorded (both times in Tierra del Fuego, see Ford & Reeves 2008 and Goddall et al. 2007). The filmed whale is seen moving heavily and slapping its tail, which may be interpreted to be an attempt to deter the attacking killer whales4. However, baleen whales have been classified as flight species (in contrast to fight species) when being attacked by killer whales (Ford & Reeves 2008): no whale of the genus Balaenoptera has been documented defending itself from a killer whale attack. The only recorded observation that could be interpreted as an attempt to defend itself was a Bryde's whale Balaenoptera edeni Anderson, 1878 which `forcefully wave[d] its tail laterally' once during an hour and a half attack (Silber et al. 1990). Thus we believe the behaviour of this sei whale most probably represents a panicking response by the animal trying to swim away.

In Comau Fjord, killer whales were observed preying on South American sea lions but never on other marine mammals, birds or fish. The MPA Francisco Coloane shelters moderate numbers of pinnipeds, penguins and humpback whales during the summer and fall seasons, however predation behaviours were observed on few occasions. Although humpback whales are also a common marine mammal species in MPA Francisco Coloane, they were not observed being attacked by killer whales.

The group sizes varied between one and 60 individuals, with a mean group size of five. The large group sizes of 30 and 60 individuals were outliers in the data, being the only large aggregations reported. Excluding these outliers, the mean group size was 4.2 individuals, ranging between one and 15 individuals.

The report of a large group of approximately 60 killer whales close to Puerto Montt and the DIRECTEMAR report of another group of 30 killer whales south of Cape Horn are only the second and third records for a group of killer whales larger than 15 animals in Southern Chile. The first record reported 25 killer whales feeding on fish close to Puerto Natales (Capella et al. 1999). It is possible that 2 ecotypes (fish-eaters and mammal-eaters) are present in Chilean waters or that Chilean killer whales are feeding on mammals as well as on fish. Following consumption records and metabolic calculations of Northern Hemisphere transient killer whales (Williams et al. 2004), Chilean Patagonia killer whales may have an important impact on the local sea lion populations and may represent an important regulatory factor. An increase in sample size of observed kills is needed to better understand their feeding behaviour. Analytical techniques (such as identification of fatty acids, stable isotopes) coupled with field observations may prove useful to obtain a more complete picture of the feeding habits of killer whales.

 

Seasonality of killer whale sightings

Between 2006 and 2012, 29 groups of killer whales were observed in Comau Fjord. The groups were present briefly (generally one or 2 days) as it is known for mammal-eating killer whales from the North Pacific who remain in one area for a relatively short period of time before moving on to avoid sensitization of prey (Saulitis et al. 2000).

Although observer effort (boat hours) in Comau Fjord is consistently higher during the austral summer, and is increasing every year, reported sightings within summer months (December to March) have been rare until summer 2011/2012. Over all the years, sightings have been quite equally distributed over the seasons (see Table 1). However, it is notable that there were no winter sightings in 2010 and 2011 (Table 1). This apparent absence of killer whales in the winters 2010 and 2011 coincides with the disappearance of the South American sea lions from Lilihuapi Island, the larger of 2 principal non- breeding colonies in Comau Fjord (Lilihuapi Island, before 2010 typically between 400 and 1500+ sea lions year round and Cahuelmó, before 2010 between 100 and 300 sea lions). The sea lion colony at Lilihuapi Island was greatly reduced in early 2009, and practically disappeared in 2010, presumably due to feral dog presence: at least 9 recently born pups were first spotted on the island in December 2008 (Häussermann & Försterra, unpublished data). Since 2012, the colony in Cahuelmó has been increasing significantly to up to 2000 animals. In the neighbouring Reñihué fjord, in which killer whales were spotted nearly every year in winter, there were no winter sightings in 2011 and 2012. In Reñihué the sea lion colony (approx. 200 animals) was greatly reduced in early 2011, and never recovered to its original size. The resulting low densities of sea lions in the Comau and Reñihué Fjord area may have been insufficient to satisfy the high metabolic requirements of killer whales.

In the southern Patagonian channels, 51 new killer whales sightings were made. Of these, 15 groups were observed inside AMCP Francisco Coloane in different years, but particularly in the 2011 summer season, where groups of killer whales were observed each month between January and May. Although survey effort in this area is highest during summer and autumn, groups of killer whales have also been observed year round in the Magellan region. Most of the encounters were in summer (34%), followed by autumn (25%), winter (21%) and spring (20%). When comparing the monthly distribution, at least 2 peaks are denoted, the first in February-March (28%), and the second in June-July (21%). The increase in sightings during summer is likely linked to the breeding cycles of pinnipeds and Magellan penguins.

Very little is known about the movements of killer whales from Antarctic waters, however many animals have been recorded to migrate to lower latitudes during the austral winter for feeding (Mikhalev et al. 1981, Kasamatsu & Joyce 1995). In particular, type A killer whales head north during the winter following the departure of their primary prey, the minke whale (Balaenoptera acutorostrata Lacépède, 1804 and/or B. bonaerensis Burmeister, 1867) in autumn (Budylenko 1981, Mikhalev et al. 1981, Berzin & Vladimirov 1983, Kasamatsu & Joyce 1995). Further research is required to fill in data gaps regarding the seasonality of killer whale occurrence in southern South American and Antarctica.

 

Killer whale photo database

In this paper, a first version of a Chilean killer whale catalogue is presented. Photographs of sufficient quality of dorsal areas from 12 of the observed killer whales in Comau fjord during 6 sightings events (2006, 2007, 2008 and 2010) and from 37 killer whales in southern Patagonian channels, including AMCP Coloane during eleven sightings events between 2006 and 2011 were collected. The identification guide presents 49 distinct individuals from Chile (Fig. 2). A large male killer whale (HUINAY005) was positively identified from 2 separate sightings in August and November, 2008, and another large male (HUINAY007) from 2 separate sightings in November, 2008, and March, 2010 (see Table 1). The individual HUINAY001 of unknown sex, photographed in July 2006 was likely re-sighted in November 2008 (HUINAY009). Roberto Winkler (Pumalín Foundation) saw a large male with a smaller individual in Renihué Fjord on November 17, 2012, and again on November 21, 2012 close to Cahuelmó in Comau Fjord.

Two more individuals seen in Chile were added to the database: one killer whale was photo-identified during the commercial Patagonia toothfish activities in 2002-2003 (see Hucke-Gaete et al. 2004); and one additional photo from a large male was received from Francisco Viddi (WWF Chile).

Of the 37 identified killer whales in the Magellan region, 6 individuals have been positively re-sighted after their first identification (Fig. 2). The individuals CEQUA#016, CEQUA#017 and CEQUA#018 were first photographed in AMCP Francisco Coloane in early February 2011 and re-sighted in the same area during the same month: CEQUA#016 was re-sighted twice, and CEQUA#017 and CEQUA#018 once (in late February). CEQUA#019 was first photographed in March 2011 in Francisco Coloane and then re-sighted in April and October 2011 in the same area. CEQUA#021 was first sighted in a group of 3 individuals in March 2011 in Francisco Coloane and then re-sighted in a group of 15 individuals in the same area in April 2011. CEQUA#011, a young male killer whale, was first photographed at Cape Horn in March 2007 and then re-sighted in Francisco Coloane in April 2011. The individuals accompanying him in the second sighting were not the same photographed at Cape Horn suggesting a change in group composition during these 4 years.

One killer whale (photographed on November 19, 2008) appears to have a healed cookie-cutter shark wound5. Cookie-cutter sharks are common outside the shelf break in warm-temperate waters, indicating killer whales may have travelled quite far equator-ward and off the Chilean coast (Dwyer & Visser 2011).

With the help of the photo-ID guide, re-sighting data over the next years will help to clarify the behavioural and migratory patterns of these killer whales.

 

Conservation of killer whales in Chile

Artisanal fishermen in southern Chile have been reported to shoot at killer whales with fire arms because they believe the whales present a danger to them (Sielfeld 1983). The general perception that killer whales are `man-eaters' is still prevalent in Chile. Increased public education will help to show that killer whales are not a threat to humans. It may help to highlight that killer whales principally eat sea lions, a species fishermen traditionally see as an enemy due to the damage they cause through direct and indirect interference with their fishing activities (Goetz et al. 2008).

We encourage tourism operators and the public to participate in collecting data on killer whales in Chile and submitting it to scientists.

Accordingly, it can be concluded: 1) Killer whales along the Chilean Patagonian coast are considerably more common than previously thought, 2) The absence of re-sightings between CEQUA and HUINAY specimens indicate either a significantly larger population and/or separate subpopulations which occupy different parts of the Chilean fjord region and 3) Observations indicate that the food spectrum of killer whales in Patagonia includes a variety of marine mammals and birds, and fish.

 

ACKNOWLEDGMENTS

This is publication Nº 69 of Huinay Scientific Field Station and Nº 44 of the Marine Mammal Research Program of Fundación CEQUA. We want to thank Reinhard Fitzek, Christoph Mayr, Francisco Viddi, Francisco Martínez, Mathias Hune, Luis Bertea, Cristián González and Daniela Haro for contributing data and photos of killer whales sightings. Thanks to David Bellhoff for providing the map.

 

NOTES

1Canto J, JC Cárdenas & J Yañez. 1990. Distribución y tamaño grupal de Orcinus orca (Linnaeus, 1758) en Chile. En: Resumen 4ª Reunión de trabajo de especialistas en mamíferos acuáticos de América del Sur. Valdivia, Chile. p. 13.
2Marcotte M, V Häussermann, J Biro & G Försterra. 2009. The role of the silent warden: Trophic interactions between killer whales and sea lions in Chilean Patagonia. In: Congreso de Ciencias del Mar. Talcahuano, Chile, p. 104.
3Quantum GIS Development Team. 2012. Quantum GIS Geographic Information System. Open Source Geospatial Foundation Project. http://qgis.osgeo.org
4<http://www.youtube.com/watch?v=dHVr8x4rBkM&feature=youtu.be>
5R. Pitman, pers. comm. 2012. robert.pitman@noaa.gov

 

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Received 29 June 2012 and accepted 22 February 2013
Editor: Claudia Bustos

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