New Caledonian Southern Seamounts and Banks IMMA

Area Size

18 758 km2

Qualifying Species and Criteria

Humpback Whale – Megaptera novaeangliae

Criterion A; B (2); C (1); D (1)

Summary

The Southern Seamounts and Banks of New Caledonia IMMA includes some of the primary reproductive areas of the breeding sub-stock of humpback whales designated by IWC as E2 and considered as endangered by IUCN. Whales specifically concentrate around these offshore shallow structures where they come for breeding and nursing during austral winter. High densities have been recorded in the vicinity of the seamounts, especially near Torche bank, Orme bank, and Antigonia seamount. Both residence time and behaviour suggest the seamounts are critical habitat for this endangered population.

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

The group of humpback whales migrating to New Caledonia belongs to the Oceania subpopulation which is classified as endangered by IUCN (Childerhouse et al 2009).  Humpback whales show a high fidelity to the area, and photo-ID and genetics demonstrate that there are also strong connections between this IMMA and the “New Caledonia main island lagoons IMMA”. Humpback whales were observed in high number during the four surveys undertaken on the Southern Seamounts with an encounter rate ranging between 0.11 to 0.39 whales/km (Garrigue et al 2017b). At least 400 individual whales were identified through photo-ID over a three-year period (233 from the Southern Lagoon IMMA, 126 from Southern Seamounts IMMA, 41 matched from both areas) and analysis showed that humpback whales were almost equally likely to return to either (Southern seamounts or main islands lagoon) area in successive years. Indices of intra-annual exchanges indicates that whales were more likely to travel between the areas in the same year than to return to the same area in a different year (Garrigue et al 2013).

Criterion B: Distribution and Abundance

Sub-criterion B2: Aggregations

The IMMA constitutes aggregation spots for humpback whales within the reproductive breeding grounds of New Caledonia (Garrigue et al. 2015, 2017).  They were observed in high number during the four surveys undertaken on the Southern Seamounts with an encounter rate ranging between 0.11 to 0.39 whales/km (Garrigue et al. 2017b). A switching state-space model (SSSM) using a correlation random walk model showed that whales demonstrate a behaviour qualified as “area-restricted search (ARS)” on Antigonia and La Torche which could be indicative of foraging but also of resting or breeding (Garrigue et al. 2015). SSSM and occupancy time indicate significant use of the IMMA by whales (Garrigue et al. 2015). Behavioural observations during surveys suggest that whales are aggregating within the IMMA for reproduction.

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas

The Southern seamounts of New Caledonia have been identified as a reproductive area based on field-based observation (Garrigue et al. 2011, Derville et al. 2016). The area is used for mating and nursing, and also likely for calving, and it constitutes one of the major breeding grounds for this sub-stock. Boat-based data collected between 1996 and 2017 showed that the proportion of groups with calves was higher in the Southern Seamounts (27%) than in the South Lagoon (16%).

Criterion D: Special Attributes  

Sub-criterion D1: Distinctiveness

New Caledonian humpback whales are the reproductive sub-stock E2 as named by IWC, which is genetically different to the other sub-stocks identified in the South Pacific Ocean (Olavarria et al. 2007). The Southern seamounts includes one of the only known breeding areas for humpback whales located in a purely offshore unsheltered oceanic environment (i.e. no emerged reef structures or land) (Garrigue et al. 2017a). MtDNA of 1112 samples collected over the south Pacific (New Caledonia, Tonga, Cook Islands, French Polynesia, Colombia) and Western Australia revealed 115 unique haplotypes. Significant differentiation, at both the haplotype and nucleotide level (FST = 0.033; ΦST = 0.022), were found among the 6 breeding grounds and for most pair-wise comparisons (Olavarria et al. 2007).

Supporting Information

Bonneville, C., Anderson, M., Baker, S., Bott, N., Schmitt, N., Oremus. M. and Garrigue, C. 2017. Temporal and spatial investigation of genetic diversity in humpback whales (Megaptera novaeangliae) wintering in New Caledonia. 2nd Humpback Whale World Congress, 3rd to 7th of July 2017, La Reunion Island.

Childerhouse, S., Jackson, J., Baker, C.S., Gales, N., Clapham, P.J. and Brownell Jr. R.L. 2009 Megaptera novaeangliae (Oceania subpopulation). In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. www.iucnredlist.org.

Constantine, R., Garrigue, C., Steel, D., Jackson, J., Burns, D.P.J.C., Hauser, N., Mattila, D., Oremus, M., Poole, M., Robbins, J., Thompson, K. and Baker, C.S. 2010. Abundance of humpback whales in Oceania based on fluke photo-identification and DNA profiling, Report to the Scientific Committee of the IWC, SC/62/SH18

Derville, S., Torres, L. and Garrigue, C. 2016. Social segregation of humpback whales in contrasted coastal and oceanic breeding habitats. Report to the Scientific Committee of the International Whaling Commission, SC/66b/SH03, Bled, Slovenia

Derville S, Aucan J, Le Gendre R, Menkes C, Oremus M, Torres LG, Garrigue C in prep Why do humpback whales aggregate around seamounts in South Pacific tropical waters? New insights from diving behaviour and ocean circulation analyses

Etnoyer, P.J., Wood, J. and Shirley, T.C. 2010. How large is the seamount biome? Oceanography 23, 206–209.

Garrigue, C., Zerbini, A.N., Geyer, Y., Heide-Jørgensen, M.P., Hanaoka, W. and Clapham P. 2010. Movements of satellite-monitored humpback whales from New Caledonia. Journal of Mammalogy 91:109-115

Garrigue, C., Clapham, P., Gales, N., Geyer, Y., Oremus, M. and Zerbini, A. 2011. Oceanic seamounts: a new humpback whale habitat discovered using satellite tagging. Fourth International Symposium on Bio-logging, 14-18 March 2011 Hobart, Tasmania, Australia

Garrigue, C., Albertson, R., Jackson, J.A. 2012. An anomalous increase in the New Caledonia humpback whales breeding sub-stock E2. Report to the Scientific Committee of the IWC, SC/64/SH6

Garrigue, C., Freyer, J., Orgeret, F. 2013. Mixing it up – coastal lagoon and offshore seamounts represent a single population of humpback whale in New caledonia, South pacific 20th Biennial Conference on the Biology of Marine Mammals, Dunedin, New Zealand

Garrigue, C., Clapham, P.J., Geyer, Y., Kennedy, A.S., Zerbini, A.N. 2015. Satellite tracking reveals novel migratory patterns and the importance of seamounts for endangered South Pacific humpback whales. Royal Society Open Science 2

Garrigue, C., Bonneville, C., Derville, S., Dodemont, R., Oremus, M., Pérard, V. 2017. Humpback whale offshore breeding grounds in the South Pacific: unravelling the network. 22nd Biennial on the Biology of Marine Mammals, 23 – 27 October 2017, Halifax, Canada.

Garrigue, C. and Derville, S. 2017a. Spatial distribution of humpback whales in breeding grounds: where should we look? Exploration of New Caledonian remote waters as a case study. 2nd Humpback Whale World Congress, 3rd to 7th of July 2017, La Reunion Island.

Kaschner, K. 2008. Air-breathing visitors to seamounts: marine mammals. In Seamounts: ecology, fisheries & conservation (eds TJ Pitcher, T Morato, PJB Hart, MR Clark, N Haggan, RS Santos) pp. 230–238. Oxford, UK: Blackwell Publishing Ltd.

Morato, T., Varkey, D.A., Damaso, C., Machete, M., Santos, M.B., Prieto, R., Pitcher, T.J., Santos, R.S.
2008. Evidence of a seamount effect on aggregating visitors. Marine Ecology Progress Series 357, 23–32.

Olavarría, C., Baker, C.S., Garrigue, C., Poole, M., Hauser, N., Caballero, S., Flórez-González, L., Brasseur, M., Bannister, J., Capella, J., Clapham, P., Dodemont, R., Donoghue, M., Jenner, J., Jenner, M.N., Moro, D., Oremus, M., Paton, D., Rosenbaum, H., Russell, K. 2007. Population structure of humpback whales throughout the South Pacific and the origin of the eastern Polynesian breeding grounds. Marine Ecology Progress Series 330:257-268

Orgeret, F., Garrigue, C., Gimenez, O., Pradel, R. 2014. Robust assessment of population trends in marine mammals applied to New Caledonian humpback whales. Marine Ecology Progress Series 515:265-273

Pitcher, T.J., Morato, T., Hart, P.J.B., Clark, M., Haggan, N., Santos, R.S. 2008. Seamounts: ecology, fisheries and conservation. Oxford, UK: Blackwell Publishing Ltd.

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