AquaticMammals 2003, 29.1, 150–172 New observationsand areviewof killer whale ( Orcinusorca ) sightingsin Papua New Guinea waters IngridN. Visser 1 andFrank J. Bonoccorso 2 1OrcaResearch Trust, P.O.Box 1233, Whangarei, New Zealand 2NationalMuseum & Art Gallery,P.O. Box 5560, Boroko, NCD, Papua New Guinea Abstract Keywords: Killer whale, Orcinusorca , Papua New Guinea,photo-identi cation, foraging, elasmo- Althoughtypically considered a temperateto cold branches, n-sh. waterspecies, killer whales (or orca) ( Orcinusorca ) havebeen reported intermittently in tropical waters. Introduction Whilethe IUCN (IUCN, 2000) does not list the speciesas present in Papua New Guinea waters, Thestatus of Papua New Guinea cetaceans is therecords presented here indicate it is found in largelyunknown. The only systematic study of thearea for at least 10 months of theyear. A total species,or individuals within a species,was con- of94 sightings of killer whales in Papua New ductedin 2001, targeting sperm whales ( Physeter Guineawaters were complied. Thirty-seven sight- macrocephalus )(Bonoccorso,unpublished data). ingsfrom April 1987 to July 2002 were recorded Munday(1994) compiled anecdotal information on withan exact date and location, with a further57 cetaceansin the Kimbe Bay area (New Britain sightingsof unknown date or exact location. Island,Papua New Guinea) for a ‘RapidEcological Twenty-sevenof allrecords had either photographs Assessment’and noted that Orcinusorca had been orvideotape to con rm species identi cation. The observed.However, only approximate timings of earliestreference to killerwhales in this region was sightingsby month or year were given, and only from1956, when they were recorded taking sho V generallocations were stated. In addition,although long-lines.Killer whales from Papua New Guinea killerwhales were listed as ‘ uncommon’, noquan- watershave been observed feeding on four species tication was given for this classi cation (Munday, ofelasmobranchs (scalloped-hammerhea dshark, 1994).Although the IUCN Red Data List (IUCN, Sphyrnalewini ;greyreef shark, Carcharhinus 2000)does not list killer whales as presentin Papua amblyrhynchos ; manta ray, Mantabirostris; and NewGuinean waters, they are known to occur blue-spottedray Dasyatiskuhlii )andfour species intermittentlyin the area (Cousteau & Richards, of n-sh (yellow- n tuna, Thunnusalbacares ; big- 1989;Munday, 1994). eye tuna, Thunnusobesus ;Indo-Pacic sailsh, Therefore,following Aragones et al.(1997),who Istiophorusplatypterus; and sun sh, Mola mola). suggestan order of procedures for cetacean Theseare the rstrecords, worldwide, of killer researchin developing countries (i.e., interviews whalesfeeding on scalloped-hammerhead sharks, followedby actual surveys), a preliminaryKimbe greyreef sharks and blue-spotted rays. Killer BayCetacean Research Project was instigated in whalesin these waters have been reported in associ- April2002. Over a 13-dayperiod, six species were ationwith two species of cetaceans (sperm whales, recorded,including killer whales (Visser, 2002 a). Physetermacrocephalus andspinner dolphins, Detailsfrom that survey, along with other records Stenellalongirostris ).Photo-identi cation images ofthe species in Papua New Guinea waters are werecollected for 14 individuals and a catalogue presentedhere. established.Matches were made for two animals— a femalesighted approximately 30 nmiandtwo days apartand a sub-adultmale sighted in the same Materialsand Methods region16 months apart. Some individual killer whalesfrom these waters have been observed with Recordsand anecdotal sightings greyunder- ukes, in contrast to white, which is Forthis paper, scienti c manuscripts,newspapers, typicallydescribed for this species. divemagazines, books, unpublished newsletters, the ? 2003 EAAM Killerwhale sightings near Papua New Guinea 151 ‘Internet’, anecdotalsightings, and unpublished PapuaNew Guinea waters, i.e., PNG1, PNG2, datawere sourced for details of killer whale sight- PNG3etc. This catalogue was compared to the ings.Records were divided into two types, ‘ com- nearestgeographic population of killer whales for plete’and ‘ data-decient’ . For‘ complete’records whichan identi cation catalogue is held, i.e., New anexact date and an exact location was known Zealand. (Table1, Figure 1), whereas for ‘ data-decient’ recordsonly a monthor year was known, or no Age/sexclassi cation dateat all,and an exactlocation may not havebeen Photo-identied killer whales were grouped by known.Because uncertainty in dates could result in ageand sex, following Bigg (1982) and Bigg confusion,or replication of sightings without dates, et al.(1990).These groupings were; ‘ adultmale’ ; ‘data-decient’ records were listed in a separate ‘sub-adultmale’ ; ‘female’; ‘juvenile’; ‘calf’; and table(Table 2, Figure 2). ‘unidentied’ . Althoughspecies identi cation may be uncertain whensuggested by non-specialists, killer whales are Results consideredone of the easiest species of marine mammalto identify at sea based on their size, ‘Complete’and ‘ data-decient’ sightings postocularwhite patch, and the large dorsal Ninety-foursightings of killerwhales in Papua New nson males (Heyning & Dahlheim,1988). In Guineawaters were complied. Twenty-seven of all addition,many observations recorded here were recordshad either photographs or videotape to accompaniedby photographs or videotape, or the conrm species identi cation. Table 1 liststhose observerhad multiple encounters with the species sightingswhere exact date and location were e.g.,M. Benjaminand T. Peluso(Table 1). known.Of these‘ complete’killer whale sightings (n=37),56.7% come from the Kimbe Bay area Photo-identication (WestNew Britain Island). Photo-identication uses photographs to record Table2 lists‘ data-decient’ sightings ( n=57), for individualcongenital and/ oracquiredidenti cation whichexact dates or precise locations could not be marks(Hammond et al.,1990).For killer whales, established.To enable future researchers access to everyindividual can be uniquely identi ed from dataand clarity of the records, all known ‘ data- high-qualityphotographs (Baird, 2000). The dorsal decient’ records are listed here. However, it is nisthe main feature photographed because it is possiblethat some records in Table 2 areduplicates, exposedabove water most often (Bigg, 1982). Some e.g.,sighting No. 10(Table 1) and sighting No. 19 killerwhale research projects use photographs of (Table2) both record killer whales at Bradford onlyone side of the dorsal n,e.g., in the Paci c Shoal,Kimbe Bay in 1994, and both record forag- NorthWest (Ford & Ellis, 1999;Ford et al., 1994) ingon a shark,yet these sightings cannot con- andNorway (T. Similä, pers.comm.). However, clusivelybe shown to be either the same nor whereverpossible during this study, both sides of diVerentevents. thekiller whales were photographed, as pigmenta- tionpatterns can di Verconsiderably on eachside of Sightingsby month and year ananimal (Leatherwood et al.,1984;Visser & Recordsfrom Table 1 and2 (‘complete’and ‘ data- Mäkelä inen, 2000) and a recordof both sides decient’ ) wereplotted by month, where known couldimprove the chances of subsequent matches. (n=52)(Fig. 3). The most sightings were recorded Moreover,this allows photographs from the public in April (n=15),followed by July( n=8).There were (whichmay be takenof eitherside of ananimal)to nosightings recorded for Januaryor February(Fig. bematched (Visser & Mäkelä inen, 2000). 3).For a 15year period (1987– 2002) killer whales Killerwhales can also be photo-identi ed bytheir havebeen sighted each year (with the exception of distinctivesaddle patches (Baird & Stacey,1988; 1989and 1990— Table 1). Bigg,1982), eye patches (Visser & Mäkelä inen, 2000),pigmentation patterns on the underside of Photo-identication thetail (Visser, 2000 b),malformations(Berghan & All killerwhales photographed in Papua New Visser,2000), scars from propellers (Visser, 1999 b; Guinea,with high quality images, were identi able. Visser& Fertl,2000) and other scars such as teeth ThePapua New Guinea killer whale photo- rakemarks (Baird, 2000; Visser, 1998). Therefore, identication catalogue is currently comprised of photographs(including underwater images) and dorsal n,saddle-patch, and eye-patch surface videotapeillustrating any unique features were photographsand side-on, full-body and partial- collected. bodyunderwater photographs (catalogue held by Tocatalogue the killer whales, each animal was Visser).From these images, 14 uniqueanimals were assigneda uniqueconsecutive number, preceded by registeredin the catalogue (PNG1– PNG14). Of theletters PNG, signifying that it was identi ed in these,two are adult males, three are females, one is 152 Table 1. ‘Complete’ records of sightings of killer whales in Papua New Guinea waters (exact date and location known). Location/ Source Latitude & Photographs/ Number of animals Foraging (p.c.=personal Date & Time Longitude Videotape (sex/age) behaviour Other details communication) 1 23 April 1987 Susan’s Reef, Kimbe Underwater Approximately 15 (1 Spy-hopped and looked M. Benjamin1 p.c. 1600–1730 h Bay, West New Britain photographs adult male, calves) at boat. Swimmers Island entered the water and the 05)17*36+S/150)08*17+E killer whales approached within 15 m. 2 26 June 1988 OV Auna Village, No photographs 3 (1 adult male, 2 Dorsal ns, silhouetted in C. Davis2 & L. at sunset Wuvulu Island, females) the distance. Prezelin3 p.c. Bismark Archipelago 01 44 97 S/142 48 95 E ) * + ) * + I. 2 3 27 June 1988 OV Auna Village, Underwater