Reestablishment of former wintering grounds by New Zealand southern right whales

MARINE MAMMAL SCIENCE, **(*): ***–*** (*** 2013)© 2013 by the Society for Marine MammalogyDOI: 10.1111/mms.12031

Reestablishment of former wintering grounds by NewZealand southern right whales

EMMA L. CARROLL,1,2 Laboratory of Molecular Ecology and Evolution and Marine Mammal

Ecology Group, School of Biological Sciences, University of Auckland, Auckland 1010, New

Zealand; WILLIAM J. RAYMENT,2 Department of Marine Science, University of Otago, PO

Box 56, Dunedin, New Zealand; ALANA M. ALEXANDER, Marine Mammal Institute and

Department of Fisheries and Wildlife, Hatfield Marine Science Center, Oregon State Univer-

sity, Newport, Oregon 97365, U.S.A.; C. SCOTT BAKER, Laboratory of Molecular Ecology

and Evolution, School of Biological Sciences, University of Auckland, Auckland 1010, New

Zealand and Marine Mammal Institute and Department of Fisheries and Wildlife, Hatfield

Marine Science Center, Oregon State University, Newport, Oregon 97365, U.S.A.;NATHALIE

J. PATENAUDE, Coll�egial International Sainte-Anne, 1300 Boulevard Saint-Joseph, Montreal,

Quebec H8S 2M8, Canada; DEBBIE STEEL, Marine Mammal Institute and Department of

Fisheries and Wildlife, Hatfield Marine Science Center, Oregon State University, Newport,

Oregon 97365, U.S.A.; ROCHELLE CONSTANTINE, Marine Mammal Ecology Group, School

of Biological Sciences, University of Auckland, Auckland 1010, New Zealand; ROSALIND

COLE, New Zealand Department of Conservation, Southland Conservancy Office, PO Box

743, Invercargill 9840, New Zealand; LAURA J. BOREN, New Zealand Department of Con-

servation, Aquatic & Threats Unit, Wellington 6143, New Zealand; SIMON CHILDERHOUSE,Blue Planet Marine, PO Box 613, Kingston, Hobart, Tasmania 7051, Australia.

Abstract

Historically, the range of the southern right whale (SRW) included winter calv-ing grounds around the North and South Islands (mainland) of New Zealand (NZ)and in the NZ subantarctic Auckland and Campbell Islands. Due to extensive whal-ing in the 19th and 20th centuries, no SRW was seen around mainland NZ fornearly four decades (1928–1963). Here we present evidence for the regular use of themainland NZ wintering ground, presumably from a remnant population that per-sisted in the NZ subantarctic Auckland and Campbell Islands. SRWs have beensighted every year around mainland NZ since 1988, with 125 sightings during thefocus of this work: from 2003 to 2010. There were 28 cow-calf pairs sighted aroundmainland NZ from 2003 to 2010, compared with 11 sightings from 1991 to 2002.Furthermore, two females, identified by DNA profiles, were sighted with calvesaround mainland at 4 yr intervals: the first evidence of female site fidelity to themainland NZ calving ground. Individual identification from photographs of natural

1Corresponding author (e-mail: [email protected]).2These two authors contributed equally to the data analysis and preparation of this manuscript.

1

markings and DNA profiles provided information on within-year movements andresidency around the mainland, and further evidence for exchange between the main-land and subantarctic wintering grounds. Despite these promising signs, the distri-bution of NZ SRWs remains primarily concentrated in the NZ subantarctic.

Key words: Eubalaena australis, right whale, sightings data, photo-identification,DNA profiles.

Despite nearly a century of protection, the recovery of southern right whales(SRW; Eubalaena australis) remains spatially heterogeneous worldwide (IWC2001). This has been linked to the fact that female SRWs typically show fidelityto calving grounds: long-term photo-identification studies show females return tothe same areas to calve over several decades (Payne 1986, Rowntree et al. 2001).On an evolutionary timescale, this fidelity acts as an isolating mechanism, creating“matrilineal subpopulations” (Burnell 2001). This is reflected by the significantdifferentiation in mitochondrial DNA haplotype frequencies between NewZealand (NZ), southwest Australian, Argentinean, and South African SRW calv-ing grounds (Baker et al. 1999, Patenaude et al. 2007, Carroll et al. 2011b). Thistype of fidelity can be viewed as a type of cultural memory, and the memory ofthe calving ground can be lost when whales that formerly inhabited such areas areextirpated (Clapham et al. 2008). The absence of SRW recovery in some regions,such as in southeast Australia and Chile-Peru (Reilly et al. 2008, Carroll et al.2011b), is thought to be linked to a loss of this cultural memory (Clapham et al.2008).In contrast to this typically strong fidelity to calving grounds, there is also

evidence that SRWs display plasticity in their philopatric behavior (e.g., Bestet al. 1993) and can rapidly recolonize areas, such as seen off Santa Catarina,southern Brazil (Groch et al. 2005). These SRWs have been the subject ofirregular (1987–1994) but now annual (1997 onwards) aerial surveys and photo-identification studies (Groch and Flores 2011). The rate of population increasefor this calving area was estimated to be larger than what is biologicallyplausible for the species, based on data collected between 1987 and 2003. Thissuggests immigration from other wintering grounds, such as Peninsula Vald�es,is occurring (Groch et al. 2005). Therefore, SRWs seem capable of both fidelityleading to population structure and exploratory behavior leading to rapidexpansion into former habitat.Here we focus on the recovery of SRWs around New Zealand (NZ), which appears

to be occurring with a range expansion from the NZ subantarctic (Auckland andCampbell Islands) to former wintering grounds around mainland NZ (North andSouth Islands) (Carroll et al. 2011b).After extensive commercial whaling in the 19th century and illegal whaling in the

20th century (Dawbin 1986, Tormosov et al. 1998), the species was not seen aroundmainland NZ for nearly four decades (1928–1963, Gaskin 1964). Given NZ had anactive coastal whaling industry during the first half of the 20th century, and “the ani-mals come so close inshore and move up the coast so close inshore that they are a mostconspicuous object” (Gaskin 1964, p. 118), if the SRWs had been present in the areasthe whalers were operating, it is likely the whales would have been sighted. Despitean increase in the number of sightings between 1988 and 2001, the mainland NZcalving ground was estimated to number fewer than a dozen reproductive females in

2 MARINE MAMMAL SCIENCE, VOL. **, NO. **, 2013

2002 (Patenaude 2003). In contrast, a remnant population persisted in the NZ sub-antarctic and was estimated to number 900 whales in 1998, based on capture-recap-ture modeling of individuals identified from both photographs of natural markingsand DNA profiles (Carroll et al. 2011c).Recent genetic evidence suggests SRWs currently seen around mainland NZ and

the NZ subantarctic represent one stock, as there is no differentiation between thetwo regions based on the analysis of mitochondrial or nuclear loci (Carroll et al.2011b). In addition, comparison of DNA profiles of SRWs sampled around mainlandNZ to those sampled in NZ subantarctic during winter field surveys conducted from1995 to 1998 and 2006 to 2008 showed movement between the wintering groundsbetween years (Carroll et al. 2011b). There is also evidence for within-year movementbetween mainland NZ and the NZ subantarctic based on satellite tag data (Childer-house et al. 2010). Hence, it is now thought that there is currently one NZ popula-tion of SRWs with a range that includes two wintering grounds: the primarywintering ground in the NZ subantarctic and secondary wintering ground of main-land NZ. However, it is not possible to tell if the two areas were historically discretestocks or linked by large-scale migration patterns (Carroll et al. 2011b).To monitor the species around mainland NZ, the NZ Department of Conservation

launched a public awareness campaign in 2003 to encourage the public to reportsightings of SRWs. In addition, the Department of Conservation, in collaborationwith other researchers, has been opportunistically photographing and biopsy sam-pling SRWs seen around mainland NZ since 2003. Here we use these opportunisti-cally collected sightings data to document an increase in the number of sightings ofSRWs around mainland NZ from 2003 to 2010, compared with the previous 20 yrperiod. These data are augmented by the investigation of within- and between-yearmovements of individuals identified through photo-identification and DNA profilesaround mainland NZ. We present the first evidence for site fidelity to the mainlandNZ calving ground, including two reproductive females that returned to calve aroundmainland NZ with 4 yr calving intervals. This is the first time sightings and recap-ture data for the mainland NZ wintering ground have been reported, and suggest theoccurrence of SRWs has moved beyond exploratory movements from a source popula-tion. This work builds on and extends previous work on population structure in thisregion (Baker et al. 1999, Alexander et al. 2008, Carroll et al. 2011b).We also present the first comparison of the mainland NZ and NZ subantarctic

photo-ID catalogs and update the comparison of the DNA profile catalogs betweenthe two wintering grounds reported by Carroll et al. (2011b).

Methods

Sightings Data Collection and Analysis

Data on sightings of SRWs around mainland NZ between 2003 and 2010 wereextracted from the NZ Department of Conservation’s marine mammal sighting data-base (Department of Conservation 2012). This time period was chosen as sightingsdata from 1976 to 2002 were previously analyzed by Patenaude (2003) and because2003 coincided with the start of the Department of Conservation’s public awarenesscampaign. Sightings in the database were provided by NZ Department of Conserva-tion staff, researchers, and members of the public. Sightings data contained in thedatabase include details on date, location, group size, and group composition. It

CARROLL ET AL.: RIGHTWHALEWINTERING GROUNDS 3

should be emphasized that the sighting data are strictly opportunistic and no data onsearch effort are available. Therefore no attempt has been made to investigate thetemporal or spatial variations in sighting rates.To ensure correct species identification, only sightings accompanied by biopsy sam-

ples or photographic images clearly identifiable as SRWs were considered for analysis.An individual was classified as a calf if it was less than half the length of an accompany-ing large whale, or was evidently a small whale (<8 m) with poorly developed callosi-ties. The individual consistently closest to the calf was assumed to be its mother. Allother individuals were classified as noncalf whales. Independent sightings from thesame day were considered duplicates if confirmed by photo-ID or DNA profile data(see below), or if they occurred within a distance that could realistically have been trav-elled in the elapsed time between sightings. Duplicate sightings were excluded fromthe analysis. This method results in the possibility of the same individual or groupconstituting two sightings if they were sighted on different days. We chose to retainthese between-day sightings as they provide information about residency time aroundmainland NZ, as well as the number of whales present. The total number of sightings,cow-calf pairs, and groups of �3 noncalf whales sighted per year were tallied.

Photo-ID Catalog and Analysis

Images obtained from sightings were included in the photo-ID analysis if theywere in sharp focus and clearly showed the pattern of callosities on the whale’s head,or other permanent distinguishing marks, such as dorsal blazes or “gray-morph” col-oration (Payne et al. 1983, Schaeff et al. 1999). Comparison of images was facilitatedby classification of each individual according to a suite of 17 distinguishing character-istics (e.g., nature of lip callosity, number of rostral islands, Pirzl et al. 2006). Thesedata were stored in a custom-written database, “BigFish” (Pirzl et al. 2006), whichcould be queried each time a new image was compared to the existing catalog. Imageswere compiled into two separate catalogs of left hand sides (LHS) and right handsides (RHS), with each individual assigned a unique alphanumeric code. Where theLHS and RHS of the same individual could be established from the same sighting,they were linked in the separate catalogs by assigning the same code. It should beemphasized that if the LHS and RHS could not be linked in the same sighting, or ifan individual had its LHS and RHS photographed in different sightings, the sameindividual could occur in each catalog with different codes.Photo-ID capture histories were examined to investigate within-year movements

and site fidelity. To further investigate movement of individuals between winteringgrounds, the mainland photo-ID catalog was also compared with a catalog of SRWimages compiled from sightings around the Auckland Islands. The Auckland Islandscatalog consists of high quality images of SRWs gathered during systematic boat-based photo-ID surveys between 2006 and 2011 and contains 513 unique individu-als. Data associated with the Auckland Islands catalog are stored in a separate BigFishdatabase in order to facilitate multiple comparisons. All photo-ID matches wereconfirmed by at least two experienced researchers.

Biopsy Sampling, DNA Extraction, and DNA Profile Construction

Between 2003 and 2010, skin biopsy samples were collected opportunistically by NZDepartment of Conservation staff during a subset of encounters using a small, stainlesssteel biopsy dart fired from a modified veterinary capture rifle (Kr€utzen et al. 2002).


DNAwas extracted and DNA profiles, comprising genetically identified sex, mitochon-drial control region haplotype and multilocus genotype, were used to identify whalessampled around mainland NZ, as previously described by Carroll et al. (2011b). Here weadd 3 samples collected in 2010 to the 61 samples collected between 2003 and 2009 pre-viously analyzed by Carroll et al. (2011b). In addition, we reanalyzed two samples thatdid not previouslymeet quality control standards (for full details see Carroll et al. 2011b).The DNA profile capture histories resulting from individuals biopsied more than

once were examined to investigate within-year movements around mainland NZ andsite fidelity through returns over multiple years. We also update Carroll et al. (2011b)by comparing mainland NZ and NZ subantarctic DNA profile catalogs to (1) includeSRWs biopsy sampled (n = 3) around mainland NZ during 2010 and (2) comparethe mainland NZ catalog to the 191 whales sampled in the 2009 Auckland Islandsexpedition (Carroll et al. 2011a).

Reconciling Photo-ID and DNA Profile Data

Encounters where whales were both biopsied and photographed were examined toattempt to reconcile the two different forms of individual identification. The photo-ID and DNA profile identity of an individual were linked only when it was certainthat the two samples had come from the same whale. The photo-ID and DNA profilecapture histories were then combined.

Results

Sighting Data and Sample Collection

After removing duplicates, the data set included 125 sightings of SRWs aroundmainland NZ between 2003 and 2010. For each sighting, species identification wasconfirmed on the basis of photographs (76% of sightings), biopsy samples (9%) orboth (15%). The number of sightings per year varied from five (2004) to 22 (2009,Table 1). Sightings were recorded in all months of the year except March and Decem-ber, although the majority of sightings (61%) were made in the austral winter (June–August, Fig. 2). Sightings including cow-calf pairs were recorded every year, up to amaximum of six in both 2005 and 2006 (Table 1). The peak in sightings of cow-calfpairs occurred in July (11 reports) and August (8 reports, Fig. 1). The mean reportedgroup size was 1.9 (SD = 1.8; range = 1–15). Six groups were reported to containmore than five whales.Sightings were reported from all around the New Zealand coastline, although the

majority of sightings (66%) were made around the South Island (Fig. 2). The highestconcentrations of sightings were reported from the coastline bordering FoveauxStrait, the Otago Peninsula, and the coast of Northland (Fig. 2). Sightings of groupsincluding cow-calf pairs were also widely distributed, although none were reportedfrom the west coast of the South Island (Fig. 2). Of the North Island sightings, 38%contained cow-calf pairs compared to 14% of South Island sightings.

Individual Identification: Photo-ID Data

Images of sufficient quality for photo-ID analysis were sourced from 38 sightings,resulting in a total of 52 photo-IDs (between 0 and 23 per year, Table 1), of which


Table1.

Num

bersofsightingsofsouthern

rightwhalesaround

mainlandNew

Zealand

from

2003

to2010,includingsightingsofcow-calfpairsand

groups

of�3noncalfwhales.NG(year)isthenumberofunique

individualsidentifiedfrom

DNAprofiledataeach

year,N

G(m

ale)andNG(fem

ale)arenumbers

ofunique

maleandfemalegenotypesidentifiedperyearandNG(CC)isthenumberofunique

genotypesoffemaleswithcalves(subsetofNG(fem

ale)).NID

andNID

(CC)arethenumberofunique

individualsandthenumberofunique

femaleswithcalvesidentifiedby

photo-ID

peryear,respectively.DNApro-

fileinform

ationfor61

samplesrepresenting

43whalessampled

between2003

and2009

wassourcedfrom

Carrolletal.(2011b).

Year

Sightings

Cow

-calfsightings

Group

sightings

Biopsysamples

NG(year)

NG(m

ale)

NG(fem

ale)

NG(CC)

Photo-IDs

NID

NID

(CC)

2003

103

212

95

41

33

02004

51

01

11

00

00

02005

196

05

30

31

00

02006

176

410

74

31

86

12007

191

68

52

31

2321

02008

183

02

21

10

22

02009

223

523

20a

811

49

80

2010

155

03

31

21

75

1Total

125

2817

6447

b22

279

5245

2

a The

sexofoneindividualbiopsied

in2009

wasnotabletobe

identified.

bWithin-

andbetween-yearrecaptureshave

been

reconciled.


nine were resightings. The LHS and RHS catalogs contained 33 and 23 whalesrespectively, of which 13 appeared in both catalogs. Therefore, the minimum numberof unique whales identified around mainland NZ between 2003 and 2010 was 33, orthe number of unique whales identified in the larger, LHS, catalog. The maximumnumber of unique whales identified was 43, or the number in both catalogs less thenumber of known replicates between catalogs (33 + 23 – 13).

Individual Identification: DNA Profile Data

Comparison of the five DNA profiles generated here with the 43 profiles generatedin Carroll et al. (2011b) showed there was one match (see Regional Movements sec-tion below). Therefore 47 individuals were sampled on the mainland NZ calvingground between 2003 and 2010, including six dependent calves. Molecular sex iden-tification showed that 25 females and 22 males were captured across the 7 yr period.This sex ratio is not significantly different from parity (v2 test, P = 0.66). Of the 25females, nine were identified as cows with calves on at least one occasion.Both a biopsy sample and a photo-ID were obtained from five different individuals.

In one instance, combining the photo-ID and DNA profile capture histories addednew data to the individual’s sighting record.

Cow-calf Pairs and Group Sightings

Of the 125 sightings reported around mainland NZ between 2003 and 2010, 28were of cow-calf pairs. A further 17 sightings were reported of groups of �3 noncalfwhales, of which eight were confirmed to contain �3 noncalf individuals withphoto-ID and/or DNA profile data (Table S1). All of these groups were recorded fromthe Otago coast or Foveaux Strait. Molecular sex identification of the biopsy samplesrevealed that four of the groups were of mixed sex: one contained a minimum of fivemales and four females (Table S1).

0

5

10

15

20

25

num

ber o

f sig

htin

gs

month

adult

CC

Figure 1. Monthly variation in numbers of sightings of southern right whales around main-land New Zealand between 2003 and 2010, divided into noncalf whales (adult) and cow-calfpairs (CC).


Figure 2. Locations of confirmed southern right whale sightings around mainland NewZealand, 2003–2010. Circles show sightings of groups containing cow-calf pairs and trianglesshow sightings of other whales. Insets show location of mainland New Zealand with respect tosubantarctic islands and detail of the regions with the most sightings.


Regional Movements and Between-year Recaptures

There were 11 cases of whales recaptured on different days within the same year;six from the matching of DNA profiles and five from the matching of photo-ID pho-tographs (Fig. 3). Inspection of the reconciled photo-ID and biopsy data revealed thatthese 11 instances came from at least nine different individuals. Assuming the whaleswere resident around the mainland for the period between their capture and recap-ture, the maximum residency period detected was 58 d for a cow-calf pair in 2010.This period also resulted in the greatest distance between a capture and recapture of610 km.There were three instances of between-year sampling of the same individual on the

mainland NZ wintering ground. Two females, identified based on DNA profiles,were recaptured between-years: the first was captured in both 2005 and 2009 and thesecond was captured in both 2006 and 2010. Both females were with calves in theyears captured around mainland NZ, and were captured between July and September.On two occasions, photographs accompanied the biopsy sample and showed that thecalves associated with the females were relatively young (less than half the length ofthe mother, with abundant orange cyamids on the head). The third instance of abetween-year sampling of the same individual on the mainland was of an adult whaleof unknown sex that was photographed in both 2007 and 2009.

Comparison of Mainland and NZ Subantarctic Photo-ID and DNA Profile Catalogs

Comparison of the mainland NZ and NZ subantarctic photo-ID catalogs revealedeight matches. One of these matches involved a whale sighted at the two locationswithin the same year: in the Auckland Islands, NZ subantarctic, in August 2010 andthen 600 km away off the Otago Coast 16 d later. This represents an average travelspeed of at least 1.56 km/h.The remaining seven whales were sampled at the two locations in different years.

Of particular interest is a female that was sighted in a mixed sex group off the Otagocoast in 2007 and then with a calf in the Auckland Islands in both 2008 and 2011.Comparison of DNA profiles from the mainland NZ data set (n = 47) and the

DNA profiles constructed from SRWs sampled around the Auckland Islands duringthe 2009 field season (n = 191) produced three matches not previously reported.Two females were captured once around mainland NZ in 2005 and 2006, respec-tively, and then again in the Auckland Islands in 2009: neither of these females wereseen as cows with calves in either location. The third match was a male that was sam-pled around mainland NZ as a calf in 2006 and then at the Auckland Islands in 2007and 2009. Combined with the DNA profile matches previously reported by Carrollet al. (2011b), this means there are 10 matches of nine individuals between the tworegions; seven females and two males. The matches were supported by an average of11 microsatellite loci, mtDNA haplotype, and genetically identified sex, and had aprobability of identity (Paetkau et al. 1995) of � 2.91E–12 (Table S2).

Discussion

Regular Use of Mainland NZ Wintering Habitat by SRWs

Here we present evidence that SRWs are now regular visitors to mainland NZ,consistent with previous work (Carroll et al. 2011b). The region appears to have


Figure 3. Within-year movements around mainland New Zealand of individual southernright whales identified by photo-ID and/or DNA profile matching from 2003 to 2010. Circlesshow capture and recapture locations of cow-calf pairs and triangles show locations for otherwhales. Each arrow represents a separate within year movement. Arrow labels represent period ofresidency assuming whales did not leave mainlandNew Zealand between capture and recapture.


increased in importance for cow-calf pairs and, potentially, reproductive groups asshown by the mixed-sex groups of � 3 noncalf whales. We also increased the numberof matches between the NZ subantarctic and mainland NZ wintering grounds usingindividuals identified by photo-ID and DNA profiles. Based on these data, it seemslikely we are witnessing the recolonization of previous calving habitats around main-land NZ by a range expansion from the NZ subantarctic, as first hypothesized byCarroll et al. (2011b).In total, 28 sightings of female SRWs with calves were reported around mainland

NZ between 2003 and 2010. In contrast, no cow-calf pairs were sighted around themainland from 1976 to 1991 and only 11 were reported between 1992 and 2002(Patenaude 2003). Our individual recapture data suggest that cow-calf pairs may beresident around the NZ mainland during the winter calving season. The sighting his-tory for one individual spanned 58 d and there were three other instances of cow-calfpairs sighted on multiple occasions within the same winter. We also documented apossible geographic trend, with a larger number of cow-calf pairs sighted around theNorth Island than the South Island, consistent with previous work (Patenaude 2003).Systematic surveys would be required to investigate this spatial variation in distribu-tion or if there has been an increase in the use of the mainland NZ wintering groundover time.We also present the first evidence for calving site fidelity to the mainland NZ win-

tering ground, as shown by two females that were observed in two different yearsaround the mainland with calves. Given the timing of the observations in the peakcalving period for SRWs (July to September; Best 1994, Patenaude 2000) and thevery young appearance of the calves, we consider the most likely explanation is thatthe calves were born around mainland NZ. However, we cannot rule out the possibil-ity that the mothers gave birth at the subantarctic islands and migrated to the main-land shortly afterwards. A whale of unknown sex was also recaptured in 2007 and2009, adding further evidence of fidelity to this region. These observations suggestthat the occurrence of SRWs around mainland NZ is something beyond exploratorymovements from a source population. This work demonstrates the value of collatingopportunistic sightings data, and the value of combining photo-ID and DNA profiledata to provide insights into the recovery of a previously exploited population.Between 2003 and 2010, eight groups containing three or more unique noncalf

individuals were sampled. DNA profile data showed that five of these containedwhales of both sexes, indicating that the groups may have had some reproductivefunction. The largest of these groups was recorded in Foveaux Strait in August 2009and contained at least five males and four females. Previously, only one potentiallyreproductive group had been reported around mainland NZ: a group of 8–12 whalessighted over a 2 mo period in Foveaux Strait during the winter of 1990 (Patenaude2003). All potentially reproductive groups have been sighted in the southern part ofthe South Island between June and September, suggesting this might be an impor-tant habitat. It is therefore plausible that mating could be occurring around mainlandNZ during these mixed sex aggregations. In line with this hypothesis, one femalewas seen on the Otago Coast in a mixed sex group of four whales the year prior tocalving at the Auckland Islands. This observation is particularly significant given thatfemales are rarely seen at the Auckland Islands in the year prior to calving (Carroll2011). Although very little is known about the timing and location of conception inSRWs generally (Payne 1986, Best et al. 2003), this finding is consistent with arecent paternity study showing that SRWs returning to the NZ calving ground arereproductively self-sustaining on a generational timescale (Carroll et al. 2012).


Consistent with previous observations (Patenaude 2003), our data suggest therewere a greater number of sightings of noncow-calf pairs around the southern coast ofthe South Island. The highest concentrations of sightings were in areas that were his-torically important whaling sites, such as the Otago coast and Foveaux Strait (Daw-bin 1986). The species’ return to regions of traditional importance is not surprisinggiven that habitat selection by SRWs in winter is most likely determined by static,physiographic parameters such as bathymetry and shelter from prevailing wind andswell (Elwen and Best 2004a, b).Opportunistic data collection has proved effective for assessing movements around

mainland NZ and connectivity with the NZ subantarctic. As there is now informa-tion on the distribution of SRWs around mainland NZ, it seems timely to initiatededicated, systematic surveys in areas highlighted by multiple sightings as importanthabitats.

Further Evidence for Connectivity Between the NZ Subantarctic and Mainland NZ

The mainland NZ and NZ subantarctic calving grounds represent a single popula-tion of SRWs that is distinct from populations in Australia, based on a study of bothnuclear and mitochondrial genetic markers (Carroll et al. 2011b). The connectionbetween the two areas has previously been supported by the direct movementbetween the habitats of seven individuals identified with DNA profiles (Carroll et al.2011b). Here we add a further eight photo-ID matches and three DNA profilematches between the two areas. We also provide evidence for within-year movementbetween the NZ subantarctic and mainland NZ, based on the matching of a photo-identified whale. This is consistent with previous satellite tag data showing themovement of a SRW between the NZ subantarctic and the South Island of NZ in thewinter of 2009 (Carroll et al. 2011b).

Conclusion

The mainland NZ wintering habitat appears to be increasing in importance forNZ SRWs. Sightings of cows with calves are now recorded every year, and we provideevidence of short-term residency by cow-calf pairs, as well as fidelity to the calvingground over multiple years. In addition we provide further evidence of connectivitybetween the NZ mainland and subantarctic wintering grounds, building on previouswork (Carroll et al. 2011b).

Acknowledgments

We thank all individuals who contributed sighting data and images. We thank RebeccaPirzl (Skadia Pty Ltd) and Saras Kumar (South Australia Department of Environment & Heri-tage) for use of BigFish and Laura Wakelin (New Zealand Department of Conservation) forproviding access to the sightings database and images. Thank you to Trudi Webster for con-firming photo-ID matches. Biopsy sample collection around mainland New Zealand (NZ) wasmade possible by Dan Engelhaupt and NZ Department of Conservation staff, including JimFyfe, Pete McClelland, Paul Brady, Jamie Quirk, Don Neale, Brian Williams, Mike Morrissey,and Mike Ogle. Lab work was funded by the Marsden Fund of New Zealand (to CSB), NZDepartment of Conservation, the Heseltine Trust and an OMV New Zealand Ltd. Scholarship(to EC). EC was supported by a Tertiary Education Commission Top Achiever Scholarship and


a University of Auckland PBRF writing grant. WR was supported by a Foundation forResearch, Science and Technology post-doctoral fellowship.

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Received: 11 September 2012Accepted: 12 February 2013


Supporting Information

The following supporting information is available for this article online: http://onlinelibrary.wiley.com/doi/10.1111/mms.12031/suppinfo.Table S1. Details of encounters with groups of � 3 noncalf southern right whales

made around mainland New Zealand between 2003 and 2010, in which at least onewhale was either biopsied or identified photographically. The table includes the num-ber of biopsies collected (Nbiopsy) and the number of individual whales(Nwhales), males(Nmale), and females (Nfemale) identified from DNA profile data. The number of indi-vidual whales identified through photo-identification is also shown (NID).Table S2. DNA profiles for southern right whales captured (A) on the mainland

wintering ground in two separate years and (B) matches between the mainland NewZealand (NZ) southern right whale DNA profile catalog and the Auckland Islands,NZ subantarctic DNA profile catalog for the 2009 field season. DNA profiles com-prise genetically identified sex (Sex), mitochondrial control region haplotype(mtDNA: haplotype code as described in Carroll et al. 2011b) and multilocus geno-type. The probability of identity (PID) and number of matching loci are also given insupport of the match. The mainland NZ and the Auckland Islands DNA profile cata-log for the 1995–1998 and 2006–2008 field seasons were previously compared byCarroll et al. (2011b). Missing data at a locus are denoted by 0/0.


Reestablishment of former wintering grounds by New Zealand southern right whales

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