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International audience; Long-term monitoring is a prerequisite to understanding and protecting long-lived species such as cetaceans. In New Caledonia, South Pacific, an endangered sub-population of humpback whales (Megaptera novaeangliae) seasonally congregates for mating and nursing during the austral winter. For more than two decades, dedicated surveys have been conducted at sea and from land to monitor humpback whale presence in a coastal breeding site, the South Lagoon. Methods were developed to investigate space use patterns and their temporal variations over the long term using a joint dataset of boat-based and land-based observations (1995-2017). A total of 2651 humpback whale groups were observed, including 1167 from land and 1484 at sea (of which 30% were initially detected by the land-based observers). Humpback whales displayed a persistent space use pattern over this 23 year period, consistent social composition over the years, and an increase in the group encounter rates from land and at sea. The core area of use by humpback whales was characterized in the austral winter by stable and relatively low sea surface temperature (22°C). Whales consistently occupied nearshore waters from 10 to 200 m deep and open to the ocean. Waters surrounded by dense coral reefs were avoided. Although humpback whale distribution patterns were persistent and occurrence was found to increase over two decades, a mismatch between humpback whale critical habitat and marine protected areas was revealed. In the context of growing anthropogenic pressure from tourism and industrial development, these findings should be incorporated into local management efforts to protect the endangered Oceania humpback whale in one of its main breeding sites.

Obtaining direct measurements to characterise ecosystem function can be hindered by remote or inaccessible regions. Next-generation satellite tags that inform increasingly sophisticated movement models, and the miniaturisation of animal-borne loggers, have enabled the use of animals as tools to collect habitat data in remote environments, such as the Southern Ocean. Research on the distribution, habitat use and recovery of Oceania’s humpback whales (Megaptera novaeangliae) has been constrained by the inaccessibility to their Antarctic feeding grounds and the limitations of technology. In this multi-disciplinary study, we combine innovative analytical tools to comprehensively assess the distribution and population structure of this marine predator throughout their entire migratory range. We used genotype and photo-identification matches and conducted a genetic mixed-stock analysis to identify the breeding ground origins of humpback whales migrating past the Kermadec Islands, New Zealand. Satellite tracking data and a state-space model were then used to identify the migratory paths and behaviour of 18 whales, and to reveal their Antarctic feeding ground destinations. Additionally, we conducted progesterone assays and epigenetic aging to determine the pregnancy rate and age-profile of the population. Humpback whales passing the Kermadec Islands did not assign to a single breeding ground origin, but instead came from a range of breeding grounds spanning ∼3500 km of ocean. Sampled whales ranged from calves to adults of up to 67 years of age, and a pregnancy rate of 57% was estimated from 30 adult females. The whales migrated to the Southern Ocean (straight-line distances of up to 7000 km) and spanned ∼4500 km across their Antarctic feeding grounds. All fully tracked females with a dependent calf (n = 4) migrated to the Ross Sea region, while 70% of adults without calves (n = 7) travelled further east to the Amundsen and Bellingshausen Seas region. By combining multiple research and analytical tools we obtained a comprehensive understanding of this wide-ranging, remote population of whales. Our results indicate a population recovering from exploitation, and their feeding ground distribution serves as an indicator of the resources available in these environments. The unexpected Kermadec Islands migratory bottle-neck of whales from several breeding grounds, variable distribution patterns by life history stage and high pregnancy rates will be important in informing conservation and management planning, and for understanding how this, as well as other whale populations, might respond to emerging threats such as climate change.

International audience; Seven Longman’s beaked whales (Indopacetus pacificus) stranded together in southern New Caledonia on 16 November 2013 (one adult male, two adult females, two subadult females, one calf, and one unknown). At this time, we have no evidence to suggest that this event was an “atypical” mass stranding associated with active naval sonar or other anthropogenic activities. The adult females were slightly larger (618–640 cm) than the adult male (590 cm). The length of the calf (ca. 300 cm) suggests it was less than a year old. Five of the whales were sampled for mitochondrial (mt) DNA analysis to confirm species identification. All shared the same haplotype over 680 bp of the mtDNA control region. High concentrations of Hg, Fe, Se, Zn (all in the liver), and Cd (in the kidneys) were detected. Necropsies revealed plastic debris in the stomach of two of the whales. One of these same whales had chronic gastritis while the other had acute pleurisy and also tested positive for morbillivirus. This infection may have been a major factor behind this mass stranding event.

Most known concentrations of humpback whales in the southern hemisphere were exploited by commercial whaling operations, first on tropical breeding grounds during the 19th cen- tury and then in Antarctic feeding areas and along migratory corridors during the 20th century. How- ever, whaling logbooks of 19th century whalers show almost no records of catches in some regions of current concentration, notably eastern Polynesia, suggesting that humpback whales were formerly absent from these regions or that the locations of their primary concentrations were unknown to early whalers. Here we investigate the population structure of humpback whales across the South Pacific and eastern Indian oceans, with an interest in the origins of whales in eastern Polynesia, using an extensive collection of mitochondrial DNA (mtDNA) sequences obtained from living whales on 6 breeding grounds: New Caledonia, Tonga, Cook Islands, eastern Polynesia (Society Islands of French Polynesia), Colombia and Western Australia. From a total of 1112 samples we sequenced 470 bp of the mtDNA control region, revealing 115 unique haplotypes identified by 71 variable sites. We found significant differentiation, at both the haplotype and nucleotide level (FST = 0.033; ΦST = 0.022), among the 6 breeding grounds and for most pair-wise comparisons. The differentiation of the eastern Polynesia humpback whales is consistent with the hypothesis of a relic subpopulation, rather than vagrancy or colonization from known neighboring breeding grounds. Regardless of their origin, it seems probable that islands of eastern Polynesia are now the primary breeding grounds for hump- back whales feeding in management Area VI (170 to 120° W) of the Antarctic, as defined by the Inter- national Whaling Commission.

The abundance and reproductive autonomy of humpback whales from the New Caledo- nia (South Pacific) wintering grounds were investigated using capture-recapture models and pater- nity inference based on nuclear microsatellite genotyping, mitochondrial DNA sequencing, molecu- lar sex identification and photographs of natural markings (photo-identification). The analyses included records of 213 individuals (excluding 16 calves used in paternity inference) identified by genotypes (9 loci), and 210 identified by fluke photographs, collected from 1995 to 2001. By compar- ing records of 175 individuals identified using both genotypes and photographs, a small number of errors were detected (and corrected) in the photo-identification catalogue and in the field and labora- tory notes of the genotypes. Using the weighted mean of the Petersen capture-recapture model, the estimate of abundance based on genotyping (N = 533, CV = 0.15) was larger than the estimate based on photo-identification (N = 327, CV = 0.11). Sex-specific estimates of abundance based on genotypes were similar for males and females although the variance of the female estimate was greater than the male (N f = 248, CV = 0.30; Nm = 288, CV = 0.18, respectively). The paternity of 5 calves from 16 sam- pled cow/calf pairs was inferred from the total sample of 133 non-calf males (one offspring each). The 16 sampled cow/calf pairs and the 5 inferred paternities were used for an alternate 'gametic recap- ture' estimate of male abundance. This gametic recapture estimate (Nm = 379, CV = 0.30) was similar to the sex-specific estimate based on the organismal recapture using a 2-sample model (Nm = 382, CV = 0.22). The close agreement of the organismal and gametic recapture estimates support the as- sumption that this humpback whale wintering ground represents an autonomous population unit that is relatively closed to demographic and reproductive interchange. The current low abundance of the New Caledonian breeding unit highlights the slow recovery of this and some other regional popu- lations in the Southern Hemisphere following intensive 20th century commercial and illegal whaling.

In Garrigue et al. (2004) we present multiple lines of evidence to suggest that humpback whales Megaptera novaeangliae from the winter grounds around New Caledonia (NC) form a small autonomous population unit that is relatively closed to demographic and reproductive interchange with other populations in the South Pacific. Our evidence included a 7 yr database of sighting–resighting records for both individual identification photographs (photo-identification) and microsatellite genotypes from small skin samples collected with a biopsy dart. From these we derived estimates and 95% confidence intervals (CI) of abundance for the non-calf population and for the sex-specific components of the population using standard closedpopulation, capture-recapture models (Fig. 1). The low coefficient of variation (CV) of these estimates, reflecting a high proportion of recapture for individuals across the 7 yr study, and the limited interchange documented with other breeding grounds (Garrigue et al. 2002) supported our conclusion that the population was small and closed demographically. From the total sample of 133 non-calf males, we also inferred the paternity of 5 calves from a total sample of 16 calves (representing about 42% of all cow–calf pairs sighted in the small population over 7 yr). Following the logic of capture-recapture models, we used the proportion of inferred paternities as a male ‘gametic’ recapture estimate of abundance for comparison to the male ‘organismal’ recapture estimate. These 2 estimates were essentially identical (Fig. 1), suggesting that the population of males wintering near NC were likely to be the fathers of the calves. Formally stated, we were unable to reject the null hypothesis that the number of paternities inferred from the sample of calves was greater or less than expected given the estimated number of males in the local population. This finding was unusual, as the success rate of paternity assignments in populations of marine mammals is generally below expectations, even when sampling of males is considerably more complete than in the case of the NC humpback population (e.g. WorthingtonWilmer et al. 1999, Gemmell et al. 2001, Krutzen et al. 2004). We considered that the evidence of relative

International audience; Liver, muscle and blubber tissues of two short-finned pilot whales (Globicephala macrorhynchus) and two pygmy sperm whales (Kogia breviceps) stranded on the coast of New Caledonia have been analysed for 12 trace elements (Al, Cd, Co, Cr, Cu, Fe, organic and total Hg, Mn, Ni, Se, V, and Zn). Liver was shown to be the most important accumulating organ for Cd, Cu, Fe, Hg, Se, and Zn in both species, G. macrorhynchus having the highest Cd, Hg, Se and Zn levels. In this species, concentrations of total Hg are particularly elevated, reaching up to 1452 μg g−1 dry wt. Only a very low percentage of the total Hg was organic. In both species, the levels of Hg are directly related to Se in liver. Thus, a molar ratio of Hg:Se close to 1.0 was found for all specimens, except for the youngest K. breviceps. Our results suggest that G. macrorhynchus have a physiology promoting the accumulation of high levels of naturally occurring toxic elements. Furthermore, concentrations of Ni, Cr and Co are close to or below the detection limit in the liver and muscles of all specimens. This suggests that mining activity in New Caledonia, which typically elevates the levels of these contaminants in the marine environment, does not seem to be a significant source of contamination for these pelagic marine mammals.