SCIENTIFIC LONG-TERM MONITORING OF HUMPBACK WHALES OFF PRONY BAY - NEW CALEDONIA

Start date: August 2024

Study site : South lagoon of New-Caledonia

The humpback whales of New Caledonia's South Lagoon have been the subject of long-term monitoring by the Opération Cétacés association since 1995. From July to September, when the breeding season is in full swing and the whales are congregating in the sheltered waters of the lagoon, scientists set out to sea from Prony Bay. Some, stationed on land from the summit of Cap N'Doua, detect the whales' blowing and jumping up to several dozen kilometers away. Others, aboard a zodiac, approach the whales to observe them, photograph them, take tissue samples with a crossbow or record their song.

This long-term monitoring program has made it possible to collect a dataset that is exceptional in terms of its regularity, temporal scope and diversity. It has considerably increased our knowledge not only of humpback whales in New Caledonia, but also of the behavior and biology of this species in general. For example, research resulting from these surveys has shown that humpback whales that gather in New Caledonia during the austral winter form a small sub-stock (BSE2) of the Oceania population, itself classified as "endangered" in 2008. Finally, numerous subjects have been studied in collaboration with researchers from the South Pacific Whale Research Consortium and other international partners: for example, Antarctic feeding grounds, connectivity on an Oceania-wide scale, the evolution and cultural transmission of male song, female natality and male reproductive success, demographic trends, hormonal regulation of reproduction, and the impact of tourism activities.

Today, the PRONYSTIC project aims to continue this long-term monitoring, which is all the more valuable in the context of climate change, where long time series are essential to understanding environmental and anthropogenic forcings. Led by UMR Entropie in partnership with the Opération Cétacés association, the PRONYSTIC project will track the population trend and health status of humpback whales in the Grand Lagon Sud in relation to climate oscillations affecting local and Southern Ocean conditions.

It relies on three traditional monitoring methods - genetics, photo-identification and acoustics - but will also promote the development of emerging methods such as aerial drone photogrammetry. This project is being carried out with the logistical and financial support of the Southern Province, and with the participation of local institutional, associative and private players.

LINKED PublicationS

Allen, J. A., Garland, E. C., Garrigue, C., Dunlop, R. A., & Noad, M. J. (2022). Song complexity is maintained during inter-population cultural transmission of humpback whale songs. Scientific reports, 12(1), 8999. https://doi.org/10.1038/s41598-022-12784-3

Garrigue, C., Derville, S., (2022). Behavioral responses of humpback whales to biopsy sampling on a breeding ground : the influence of age-class , reproductive status , social context , and repeated sampling. Mar. Mammal Sci. 38, 102–117. https://doi.org/10.1111/mms.12848

Chero, G., Derville, S., Pradel, R., Gimenez, O., Bonneville, C., Garrigue, C., Reproductive capacity of an endangered and recovering population of humpback whales in the Southern Hemisphere. Marine Ecology Progress Series (2020), 643, 219-227. https://doi.org/10.3354/meps13329.

Derville, S., Torres, L. G., Dodémont, R., Perard, V., Garrigue, C. From land and sea, long-term data reveal persistent humpback whale breeding habitat in New Caledonia, Aquatic Conservation : Marine and Freshwater Ecosystems (2019), 29(10), 1697-1711. https://doi.org/10.1002/aqc.3127.

Derville, S., Torres, L., Garrigue, C., Social segregation of humpback whales in contrasted coastal and oceanic breeding habitats. Journal of Mammalogy, (2018), 99(1), 41–54. https://doi.org/10.1093/jmammal/gyx185.

Garrigue, C., Dodemont, R., Steel, D., Baker, C.S., 2004. Organismal and “gametic” capture-recapture using microsatellite genotyping confirm low abundance and reproductive autonomy of humpback whales on the wintering grounds of New Caledonia. Mar. Ecol. Prog. Ser. 274, 251–262. https://doi.org/10.3354/meps274251

Garrigue, C., Constantine, R., Poole, M., Hauser, N., Clapham, P.J., Donoghue, M., Russell, K., Paton, D., Mattila, D.K., Robbins, J., Baker, C.S., 2011. Movement of individual humpback whales between wintering grounds of Oceania (South Pacific), 1999 to 2004. J. Cetacean Res. Manag. 3, 275–281.

Garrigue, C., Greaves, J., Chambellant, M., 2001. Characteristics of the New Caledonian Humpback whale population. Mem. Queensl. Museum 47, 69–75.

Garrigue, C., Gill, P., 1994. Observations of humpback whales Megaptera novaeangliae in New Caledonian waters during 1991-1993. Biol. Conserv. 70, 211–218. https://doi.org/10.1016/0006-3207(94)90165-1