Killer whale (Orcinus orca) occurrence andinteractions with marine mammals off Peru

By Juan Pablo Testino, Andrea Petit, Belén Acorta, Aldo S. PachecoSebastian Silva, Joanna Alfaro-Shigueto, David Sarmiento, JavierQuiñones, Alberto More Eche, Eduardo Motta, Sara Fernandez,Elizabeth Campbell, Geyby Carrillo, Maurice Epstein, Miguel

Llapapasca, Adriana González-Pestana*

AbstractKiller whales (Orcinus orca) are widely distributed in all ocean basins however, their occurrence, distribution and ecology in the southeast Pacific, including Peru, is poorly defined. This study aims to describe the occurrence of killer whales in Peruvian waters, with additional description of predatory behaviors. Between 2003 and 2018 there were 29 reports of killer whales in Peruvian waters in which at least 110 individuals were observed, with pod sizes ranging between 1 and 15 individuals. Most sightings occurred in waters within the continental shelf or in close proximity to the shelf break. During eight of the sightings, killer whales displayed predatory behavior towards other marine mammals, including cetaceans (Megaptera novaeangliae and Balaenoptera musculus), and pinnipeds (Otaria flavescens and Arctocephalus australis). In addition, we present the first photo-analysis of the incidence of killer whale tooth rake marks on humpback whale flukes off northern Peru. Between 2009 and 2017, 897 unique individual humpback whales were photo-identified off northern Peru, of which 19.6% (n= 172) displayed rake marks in their flukes, suggesting that humpback whales in the southeast Pacific are exposed to the attack of killer whales. Our findings suggest that the occurrence of killer whales in Peruvian waters are more common than previously documented and that killer whales are preying marine mammals in this region. Further understanding killer whale distribution, foraging habitats and movement patterns within Peruvian waters will be essential in promoting their conservation.

*Corresponding Author E-mail: adriana@conciencia.org.pe

Pacific Science, vol. 73, no. 2December 5, 2018 (Early view)

Introduction

Killer whales (Orcinus orca) are the most widely distributed marine mammal in the world’s

oceans, commonly associated with areas of high primary productivity in coastal, temperate

waters (Forney and Wade 2006). However, information on this species distribution and foraging

habits in tropical waters remains limited (Kinzey et al. 1999, Jackson et al. 2008). In the

southeastern Pacific, killer whales have been poorly studied, although notable exceptions are the

Galapagos islands (Merlen 1999) and Chilean Patagonia (Häussermann et al. 2013). In Peru,

some records exist (Bini 1951, Grimwood 1969, Dahlheim et al. 1982, Van Waerebeek et al.

1988, Majluf and Reyes 1989, García-Godos 2004), but information regarding their ecology is

limited. García-Godos (2004) presents the most comprehensive and updated information on

killer whales in Peruvian waters with 20 sightings recorded between 1995 and 2003, including

reports of predation on the South American sea lion (Otaria flavescens) and South American fur

seal (Arctocephalus australis) in southern Peru (Van Waerebeek et al. 1988, Majluf and Reyes

1989), where significant rockeries are located (Majluf and Trillmich 1981). Since 2003, no

further observations of killer whales have been reported in Peruvian waters (García-Godos

2004).

Killer whales are top predators in marine ecosystems, and different pods can exhibit foraging

specializations, denoted as specific ecotypes (Heimlich-Boran 1988, Baird et al. 1992, Heise

2003, Mehta et al. 2007). In the northeastern Pacific, three ecotypes have been identified: fish-

feeding residents, mammal-hunting transients, and a fish-feeding offshore ecotype (Ford et al.

1998, Ford and Ellis 2006). Reports of killer whales attacking or harassing cetaceans are widely

documented (Jefferson et al. 1991, Baird et al. 2006, Branch and Williams 2006, Pitman et al.

2007). Yet, these predatory interactions might be more common than currently thought, as

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humpback whales (Megaptera novaeangliae) among others cetaceans, are often found with killer

whale tooth-rake marks on their flukes (Mehta et al. 2007, Pitman et al. 2015). In the

southeastern Pacific, the existence of individual ecotypes remains unclear (Olson and Gerrodette

2008), and reports of killer whales preying on large whales (e.g. sperm whales, baleen whales)

has been elusive to document with some exceptions (Arnbom et al. 1987, Flórez-González et al.

1994, Brennan and Rodriguez 1994, Scheidat et al. 2000, Ford and Reeves 2008, Goddall et al.

2007, Alava et al. 2013, Häussermann et al. 2013). In Peru, a single report exists of recently

wounded sperm whales (Physeter macrocephalus), which were likely attacked by killer whales

(Dufault and Whitehead 1995). Furthermore, only two records of killer whales attacking

common bottlenose dolphin (Tursiops truncatus) and short-finned pilot whale (Globicephala

macrorhynchus), exist for Peruvian waters (García-Godos 2004)

Despite the high marine productivity and potential for foraging areas for higher trophic-level

consumers in Peruvian waters (Chavez and Messie 2009, Pompa et al. 2011), little is known

regarding the distribution, occurrence and predation habits of killer whales. Moreover, no direct

observation of a predatory interaction exists between a killer whale and large whales, even

though the neritic waters of northern Peru are breeding areas for humpback whales (Pacheco et

al. 2009, Guidino et al. 2014). In this study we present new sightings of killer whales in Peruvian

waters from 2003 to 2018, with associated observations of predatory behavior. We also present a

photo-analysis of humpback whale flukes from northern Peru, as an indication of the prevalence

of killer whale attacks.

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MATERIALS AND METHODS

Killer whale sightings

Sightings of killer whales in Peruvian waters between 2003 and 2018 were gathered from

opportunistic and research-based observations. For each sighting, the date, location, group size,

and behavior were recorded. Sources included: pelagic surveys conducted by the National

Institute of the Peruvian Sea (IMARPE, Spanish acronym) during 2008 and 2014, commercial

tourism vessels (including whale-watching vessels where trained researchers were on-board for

data collection), and opportunistic observation by trained researchers. Given the limited amount

of research conducted on killer whale in Peru, additional occurrence records were compiled from

local news reports, and social media channels (filtering posts for the words “orcas” and

“Peru”). Information from the National Oceanic and Atmospheric Administration (NOAA) was

also included from their surveys in the Eastern Tropical Pacific Ocean (Jackson et al. 2008).

During 35 days, 154 pelagic transects- perpendicular to the coast with a separation of 28 km-

were conducted along the majority of the Peruvian coast by IMARPE between 5 November and

24 December 2008 (05°00´S-17°40´S; 1.8 to 555 km offshore) (IMARPE, 2008), and between

24 February and 11 April 2014 (03°23’S-18°20’S; 1.8 to 148 km offshore) (IMARPE, 2014).

One to three observers sighted cetaceans from the vessel deck at 15 m above the sea level during

daylight hours (06:00-18:00 h) (García-Godos 2004).

Marine-based tourism vessels (i.e. North shore expeditions, Pacifico Adventures and Las

Cherelas) operate in northern Peru (Piura and Tumbes) during the morning (06:00-11:00 h)

between five to seven days per week during the whale-watching or humpback whale breeding

season (July-October), and between three to five days during the rest of the year. The number of

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observers (i.e. land and boat based) are between two to three. The years surveyed varied

according to the tourism operators: North shore expeditions (2012-2018), Pacifico Adventures

(2009-2018) and Las Cherelas (2016-2018).

Humpback whale fluke analysis

To evaluate the prevalence of rake marks on flukes of humpback whales, photo catalogues were

recorded along the coast of Piura and Tumbes during the humpback whale breeding season

yearly between July to October (2009-2017) by marine-based tourism vessels (i.e. North shore

expeditions, Pacifico Adventures and Las Cherelas). Photographs of individual whales were

examined for predatory tooth rake marks. Rake shaped scars result from attacks by killer whales

and are not created by some other source (e.g. false killer whales). This assumption is supported

by work conducted by Schevchenko (1975), and more recently by Mehta (2004).

Photographs were selected using three criteria: i) proportion of the fluke that was visible (more

than 50% of the fluke), ii) fluke angle (visibility of the ventral side), iii) photograph quality

(appropriate focus, lighting and exposure). Photographs that did not meet these criteria were

excluded from the analysis. The five categories established by Steiger et al. (2008) were used for

the analysis (Table 1), in which a rake mark is defined by a set of three or more parallel lines or

marks in close proximity. The prevalence of rake marks on flukes of humpback whales off the

northern coast of Peru was estimated from the total number of photo-identified humpback whales

between the years 2009 and 2017. Then this percentage was extrapolated to the southeastern

Pacific humpback whale stock (Breeding Stock G) to calculate the number of individuals that are

exposed to killer whale attacks. For this analysis, the latest estimation of their stock size was

used which is 6,504 individuals (95% CI: 4,270–9,907) (Félix et al. 2011).

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RESULTS

Killer whale sightings

Between 2003 and 2018, killer whale sightings were recorded on 29 separate occasions off the

coast of Peru (Figure 1, Table 2). The total number of individuals sighted was at least 110, with

an average group size of 4 individuals (range: 1-15 individuals). In these sightings, each

individual was not uniquely identified; thus, it cannot be determined that the 110 individuals

sighted were unique or resighted individuals. Killer whales were sighted at an average distance

of 55 km (range: 0-148 km) from the coast. Sightings (n=14 groups) were most frequently within

the continental shelf or in close proximity to the shelf break -where the seafloor transitions to the

continental slope- in which these 14 sightings occurred at an average distance of 9 km (range: 0-

30 km) from the continental shelf break. Sightings were registered year-around, with the

exceptions of April and May.

Behavioral observations

During eight sightings, killer whales displayed predatory interactions with cetaceans, such as

blue whale (Balaenoptera musculus), humpback whale and common dolphins (Delphinus sp.),

and pinnipeds, such as South American sea lions and South American fur seals. Two

observations were first time records of killer whales preying on pinnipeds in the northern Peru

region (i.e. Lobos de Tierra and Lobos de Afuera islands; Figure 1).

Predatory interactions with cetaceans

On November 27, 2008, seven killer whales were observed chasing a group of approx. 3000

common dolphins off northern Peru. On August 3, 2016, two killer whales were seen harassing

an unidentified species of whale by swimming very close (less than a meter) and following the

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whale. Furthermore, this interaction was registered close to an artisanal boat off southern Peru.

On November 3, 2016, ten killer whales were observed flanking a blue whale very closely (less

than a meter) off southern Peru.

On September 7, 2016 at 06:30 am a single male killer whale (Figure 2) followed along the

seaward side of a mother and calf pair of humpback whale off Punta Sal (Tumbes, Peru; -3.9777,

-80.9768) traveling southwards at approximate speed of 7-9 km/h. and approximately 30 m from

shore. The calf was positioned close to the shoreline with the adult whale seaward. The killer

whale swam approximately 4-5 m away from the humpback whales. Then the killer whale

changed position and launched three attacks at the calf, striking with its caudal fin. There were 3-

5 minutes between each attack. It could not be confirmed whether the killer whale attacked with

mouth open or closed, therefore it could not be determined whether the killer whale was biting or

ramming. The killer whale remained 4-5 m away from the humpback whales on the seaward

side, and at times approached within 1 m of the whales. When this happened the adult humpback

whale raised its caudal fin towards the killer whale. The humpback whales were constantly

breaching to breath, possibly due to exhaustion. The killer whale’s breathing was less frequent.

When the humpback whales came within 20 m of a purse seine they changed direction to south-

west; the killer whale continued to follow them but from a greater distance (approximately 20m).

The last record of the killer whale following the humpback whales was at 08:12 am (-4.0005527,

- 81.0004194), and no further information was recorded. The observers observed the event for a

total time of 102 minutes. Video footage of the attack is available in supplemental material

https://www.instagram.com/p/BWJfsqCAJSs/?taken-by=northshoreperu

Predatory interactions with pinnipeds

7

Off northern Peru, two sightings were reported of killer whales chasing South American sea

lions close to their rockeries: on December 1, 2015, one killer whale was observed chasing a sea

lion on Lobos de Tierra island, and on November 1, 2016, two killer whales were observed

chasing a group of sea lions on Lobos Afuera island. In both sightings, sea lions were seen

jumping out of the water close to the mouth of killer whales. Off southern Peru, two sightings

were made of killer whales chasing pinnipeds close to their rockeries: on January 1, 2003, two

killer whales were seen chasing South American fur seals on San Juan de Marcona, and on

December 1, 2016, three killer whales were observed chasing a group of South American sea

lions on Punta Coles.

Humpback whale tooth rake marks: prevalence of killer whale attacks

A total of 897 photo-identified humpback whales were registered between 2009 and 2017 off the

north coast of Peru, and 871 were found appropriate for rake mark analysis. From the 871

humpback whale flukes analyzed, 19.6% (n=172 individuals) showed tooth-rake marks. From

this group 2% (18 ind.) showed damage on their flukes with missing pieces associated with the

rake mark (Category 1, Figure 3), 2% (18 ind.) showed severe scarring with three or more sets of

rake marks (Category 2, Figure 3), and 15.6% (136 ind.) had at least one set of rake marks

(Category 3, Figure 3). Many whales presented scars (41.6%, 363 ind.), but these did not meet

the definition of rake marks (Category 4, Figure 3), and 38.5% (336 ind.) had no visible rake

marks or scars on their flukes (Category 5, Figure 3). When extrapolating the percentage of rake

marks found in humpback whales in the coast of northern Peru (19.6%) to the southeastern

Pacific humpback whale stock (6,504 individuals; 95% CI: 4,270–9,907; Félix et al. 2011), at

least approximately 1,275 (95% CI: 837–1,942) (19.6%) individuals of the southeastern Pacific

stock presented tooth-rake marks on their flukes.

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DISCUSSION

Our study presents the most complete and up-to-date information regarding killer whales in Peru.

This study documents a further 29 sightings of killer whales in Peruvian waters, in which eight

sightings showed predatory interaction with another marine mammal. This study reports the first

direct observation of a killer whale attacking baleen whales in Peru, and notably, 19.6% of

humpback whales examined presented an indication of a killer whale attack. This study also

represents the first observation of a killer whale hunting pinnipeds off northern Peru. These

findings indicate that in Peruvian waters killer whales are preying on marine mammals.

Distribution of killer whales off Peru

Within the southeastern Pacific, the presence of killer whales has been documented primarily in

the Galapagos islands and the waters of Chilean Patagonia (Merlen 1999, Häussermann et al.

2013). Yet, in other areas within the region (i.e. continental Ecuador and Colombia), their

presence has been poorly documented (Flórez-González et al. 1994, Scheidat et al. 2000). In

Peru, most of the sightings reported by García-Godos (2004) were oceanic; whereas in this study,

most sightings were associated with the continental shelf or the shelf break (Figure 1). Coastal

areas within the continental shelf are known for their high marine productivity and high

concentrations of marine mammals (Ryther 1969, Pompa et al. 2011). Furthermore, irregularities

of the sea floor can alter water flow above them, enhance mixing, and promote upwelling of

nutrient-rich waters (Springer et al. 1996, Connolly 2012). As a result, areas above or in close

proximity to the shelf break are foraging areas for higher trophic-level consumers, including

species predated upon by killer whales, such as pinnipeds and other cetaceans (Payne and

Heinemann 1993, Springer et al. 1996, Cañadas et al. 2002, Roberts et al. 2016). In addition,

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breeding areas of humpback whales are located in neritic waters. Therefore, the area above or in

close proximity to the shelf break off Peru might be a suitable area of prey availability for killer

whales.

Predation interactions on marine mammals

In Chilean Patagonia killer whales are regularly observed harassing and predating upon

pinnipeds (i.e. Otaria flavescens, Arctocephalus australis) (Capella et al. 1999, Huckstadt and

Antezana 2004, Häussermann et al. 2013). In Peru, this predatory behavior appears uncommon

however, occurrences have been observed at significant rockeries of pinnipeds in southern Peru

(i.e. San Fernando and San Juan) (Majluf and Trillmich 1981, Van Waerebeek et al. 1988,

Majluf and Reyes 1989, García-Godos 2004). This study represents the first record of a killer

whale preying on South American sea lions and South American fur seals off northern Peru

which is located within an area of exceptional primary productivity (7–8ºS; Moron 2000, Chavez

and Messie 2009). This in turn supports the abundance of higher-trophic level organisms that are

potential prey for killer whales, such as pinnipeds. Since northern Peru represents two of the

most important rockeries of pinnipeds (i.e. Lobos de Tierra and Lobos de Afuera; Majluf and

Trillmich,1981), this area may represent an area of prey availability for killer whales.

In the southeastern Pacific few records exist of killer whales attacking or harassing cetaceans.

Off Chilean Patagonia three observations indicate killer whales attacking sei whales

(Balaenoptera borealis) (Ford and Reeves 2008, Goddall et al. 2007, Alava et al. 2013), and in

the Galapagos islands, killer whales were recorded attacking sperm whales and Bryde’s whales

(Balaenoptera edeni) (Arnbom et al. 1987, Brennan and Rodriguez 1994). In Ecuador and

Colombia, killer whales have been observed attacking humpback whales (Flórez-González et al.

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1994, Scheidat et al. 2000). In Peru, there are two records of killer whales attacking delphinids

(García-Godos 2004) and one presumed attack on sperm whales by killer whales (Dufault and

Whitehead 1995). Thus, this study represents the first direct evidence of a killer whale attacking

large cetaceans in Peru.

In western Australia, humpback whales have been recorded being attacked by killer whale pods

with a median group size of 6 (range 3–11) (Pitman et al. 2015). This contrasts with the attack

described in this study, where only one individual was observed attacking a humpback calf.

Moreover, killer whales have mainly been observed targeting the calves of humpback whales,

during their migration to their feeding or breeding grounds (Clapham 2001, Mehta et al. 2007,

Pitman et al. 2015). During this migration mothers and calves maintain a shallow-coastal

distribution (Flórez-González 1991, Félix and Haase 2005, Guidino et al. 2014, Oña et al. 2016),

which can be a behavioral strategy (Pitman et al. 2015) to reduce potential predation from killer

whales (Corkeron and Connor 1999). In this study, the mother and calf were observed very close

to shore; this coupled with the mother interposing her body between the killer whale and the calf

might have been a behavior to protect the calf from the killer whale (Pitman et al. 2015).

Humpback whale tooth-rake marks: prevalence of killer whale attacks

Mehta et al. (2007) reviewed baleen whale photo-identification catalogues from around the

world and found that rake-marked humpback whales range from 0 to 40% of the population and

are globally widespread with rates varying according to region. In eastern Australia 17% of 1436

humpback whales possessed some form of predatory scarring (Naessig and Lanyon, 2004). In the

western North Atlantic rake marks were found in 14% of 3365 humpbacks (Katona et al. 1988).

In the North Pacific region, 15% of 3650 humpbacks presented unambiguous, discernable rake

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marks (Steiger et al. 2008). Off Gabon, 17.3% of 682 humpback whale flukes showed evidence

of killer whale tooth-rake marks (Weir et al. 2010). Rake marks were found in 11.86% of 3042

humpback whales assessed in the south eastern Pacific (i.e. Panama, Colombia, Ecuador, Chile

and Antarctic waters) (Capella et al. 2018). The results found in Peruvian waters (19.6%) are

within the percentage ranges of tooth-rake marks found in other studies worldwide, including in

the south eastern Pacific. These findings in conjunction with Capella et al. (2018) suggest that

humpback whales in the southeast Pacific are more exposed to the attack of killer whales than

previously recognized. Yet, this estimation should not be used to understand the limiting

population growth factors facing this humpback whale stock. Scarring should be considered

evidence of either the prey’s ability to escape, or the predator’s inefficiency, or both, rather than

as a direct indication of predation rate (Schoener 1979). Yet, attacks can have a successful

outcome for killer whales; in Western Australia, killer whales attacked and killed humpback

whale calves in 22 events (64% of attack outcomes observed) (Pitman et al. 2015).

The location and timing of these predation events remains to be revealed. It is possible that at

least some of this scarring occurred in the humpback whales’ Antarctic feeding grounds (Pitman

and Ensor, 2003); yet, in the Magellan Strait, southern Chile, no attacks on humpback whales

have been observed (Capella et al. 2014). Most killer whale attacks occur on young animals,

primary calves, in breeding sites or during their first migration to feeding areas (Mehta et al.

2007, Capella et al. 2018). Furthermore, in the south eastern Pacific, the highest overlap between

the distribution of humpback whales and killer whales occurs off Peru, southern Ecuador and the

Galapagos islands (Capella et al. 2018). Therefore, in this area the highest number of predation

events is expected. In this study, direct evidence indicates that these attacks can happen in

humpback whale breeding areas. The percentage of humpbacks with tooth-rake marks for the

12

southeastern Pacific stock might be an underestimation of attack rates since this result does not

include the unknown number of calves that are presumably killed.

This study suggests that killer whales occurring in Peruvian waters are preying on marine

mammals (i.e. pinnipeds and cetaceans); yet, further research is needed to determine if killer

whales in Peruvian waters present a specialized ecotype. Future research efforts should include

the recording of photographs to develop a killer whale photo-identification catalogue for

Peruvian waters which can clarify their behavioral and movement patterns. Understanding the

presence, distribution, abundance and habitat use of cetaceans is essential for their conservation,

especially since Peru has been identified as a hotspot for marine mammals (Pompa et al. 2011,

Kaschner et al. 2011).

Acknowledgments

We thank the Oficina de Investigaciones de Depredadores Superiores of IMARPE for the data

collected between 2004-2017. Phil Jones, Michael Mcmaster, Robert Pitman and an anonymous

reviewer are thanked for their suggestions and comments on the manuscript. The humpback

whale photo ID catalog is available upon request to A.S.P. Pacifico Adventures thanks their crew

for the effort in collecting humpback whale photographs every year.

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Tables and Figures

Table 1. Rake mark scarring categories by Steiger et al. (2008).

Category Criteria1 Rake mark injuries damage the integrity of the

fluke.2 Severe scarring, showing three or more sets of

rake marks.3 One to three sets of rake marks4 Scratches or scars, not in close proximity, not

forming three parallel lines.5 No rake marks present.

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Table 2. Killer whale (Orcinus orca) sightings off Peru, 2003–2018. nd= not detailed

Sighting dateGroup

sizeLatitude Longitude Behavior Source Observations

1 Jan 2003 2Predatoryinteraction

with pinnipeds

Marco Cardeña

San Juan deMarcona, Ica(land-based)

28 Feb 2003 1 −18.322 −70.945IMARPE (online request)

Jun-Jul 2006 6 −6.46666667 −80.8333333Probablyfeeding

Ignacio García Godos

Oct-Nov 2006 ns −11 −86 ndJackson et al.2008

Approximatepoints

Oct-Nov 2006 ns −12 −87 ndJackson et al.2008

Approximatepoints

Oct-Nov 2006 ns −13 −91 ndJackson et al.2008

Approximatepoints

2 Jul 2008 10−15.7000526

2−76.64888202 Swimming

Eduardo Motta

27 Nov 2008 7 −8.298216 −79.60716

Predatoryinteraction

withDelphinus sp.

Ignacio García Godos

12 Dec 2008 1 −12.725 −77.241 SwimmingIMARPE (2008)

5 Nov 2008−24 Dec 2008

2 SwimmingIMARPE (2008)

Atico

29 Jan 2012 7 −3.76089 −81.80937 SwimmingEduardo Motta

19 Aug 2012 2 Swimming Paul Visscher5 km northoff Ilo port

15 Mar 2013 6-8Pacifico Adventures

22 km offOrganos

28 Mar 2013 15

Swimming tosouth close to

artisanalfishery boats,an orca was

feedingpossibly on a

devil ray(Mobula spp.)

Maurice Epstein

1-2 km offPeña Mala,Vichayito

10 Sept 2013 1 −9.344 −79.475IMARPE (online request)

23 Dec 2013 6 −7.6883 −80.22773 Calm, Ignacio

15

swimmingduring seismic

prospectionGarcía Godos

3 Mar 2014 4 −15.415 −75.957 SwimmingIMARPE (2014)

1 Dec 2015 1 −6.46929 −80.837459Predatoryinteraction

with pinnipeds

David Sarmiento

21 Jan 2016 >1 −3.57185 −81.326216 SwimmingJoanna Alfaro

1 Mar 2016 6 Swimming Andrea PetitBanco deMancora

3 Aug 2016 2Predatoryinteraction

with a whaleClint Cabana

South ofPisco

7 Sept 2016 1 −3.9777 −80.9768

Predatoryinteraction

with humpbackwhales

Juan Pablo Testino, Alberto More, GeybyCarrillo, Elizabeth Campbell

30 Oct 2016 4Swimming and

jumpingSara Fernández

18 kmoffshorePunta Sal

1 Nov 2016 2 −6.944444 −80.723333Predatoryinteraction

with pinnipeds

Joanna Alfaro

3 Nov 2016 10 −17.75 −71.5

Predatoryinteractionwith a blue

whale

Published by El Puerto Noticias Ilo

South Ilo

1 Dec 2016 3 −17.233198 −71.5998Predatoryinteraction

with pinnipeds

Joanna Alfaro

6 Oct 2017 1 −4.11242 −81.12 TravelingPacifico Adventures

28 Oct 2017 5 −8.016 −80.2241 ndIMARPE (online request)

25 Jan 2018 2 Swimming Andrea Petit25 km off

Punta Mero

16

Figure 1. Killer whale (Orcinus orca) sighting locations off Peru between 1995 and 2018. Darkgrey color represents the continental shelf. Open circles (O) indicate sightings where non-predatory behavior was registered, rectangles ( �) indicate sightings were predatory behavior wasregistered in this study between 2003 and 2018. Crosses (+) indicate sightings from García-Godos (2004) between 1995 and 2003, and closed circles () indicate major pinnipeds coloniesin Peru (Majluf and Trillmich1981).

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Figure 2. Killer whale registered predating humpback whales on September 7, 2016 off Tumbes,Peru.

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Figure 3. Rake marks in the flukes of humpback whales off northern Peru. Categories (numbers)determined by Steiger et al. (2008).

19

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