CSIRO PUBLISHING | Pacific Conservation Biology

The warm-temperate region of the Pacific Ocean is a vast area encompassing a range of habitats and oceanographic influences. There is a wide variety of marine mammal taxa found in the Pacific including dugong, pinnipeds and 34 known species of cetacean many of which are at risk from fisheries interactions, ship-strike, pollution, climate change, and/or emerging threats such as deep-sea mining. Despite the species diversity, known threats and often strong cultural connections between Pacific peoples and marine mammals, governments are constrained in their ability to survey and monitor their large Exclusive Economic Zones. The importance of the Pacific region has been recognised in international initiatives such as the designation of several IUCN Important Marine Mammal Areas (IMMA https://www.marinemammalhabitat.org/immas/) and Convention on Biological Diversity. The South Pacific Regional Environment Programme has developed initiatives to protect marine mammals including Action Plans, Whale Watch Guidelines and fisheries mitigation efforts, but there are ongoing challenges with ensuring these are research informed, that Indigenous and other forms of knowledge are readily available, and that protection measures are enforced.

This collection of papers reflects the challenges with working on marine mammals in the Pacific and the value of multidisciplinary approaches when faced with sparse or patchy datasets. Some papers are the result of decades of research on stranded cetaceans or cryptic species that are opportunistically sighted and challenging to study. The research scales from small, defined coral reef habitats for dugong through to aerial surveys describing the distribution of marine mammals, seabirds and turtles throughout 2.5 million km² of ocean in the southwest and central Pacific. This new knowledge may facilitate the identification of new IMMAs and support the designation of Key Biodiversity Areas. This collection has filled several knowledge gaps, providing critical information for governments and international agencies to ensure these species and their habitats are identified and protected in the future throughout this vast ocean region.

Collection Editors
Rochelle Constantine (University of Auckland - Waipapa Taumata Rau)
Claire Garrigue (Institute for Research and Development)

Last Updated: 07 Oct 2024

PC23036Temporal changes in habitat use by dugongs in a spatially restricted coral reef environment

Christophe Cleguer

, Claire Garrigue

, Mariana M. P. B. Fuentes, Mark Hamann, Claude Payri and Helene Marsh

The dugong’s (Dugong dugon) habitat use in small coral reef lagoon systems, constrained by tides, is poorly understood, hindering adaptive management. Through aerial surveys, we examined seasonal and tidal variations in dugong utilisation in a high conservation value coral reef lagoon. This study reveals significant temporal variations in dugong habitat use, influenced by tides and seasons. It underscores the importance of outer reef habitats devoid of seagrass for the species. Additionally, it contributes evidence of behavioural thermoregulation in dugongs.

This article belongs to the Collection Marine Mammals in the Pacific.

PC23027Long-term strategies for studying rare species: results and lessons from a multi-species study of odontocetes around the main Hawaiian Islands

Robin W. Baird

, Sabre D. Mahaffy

, Brittany Hancock-Hanser, Tori Cullins, Kristi L. West, Michaela A. Kratofil, Daniel M. Barrios, Annette E. Harnish and Paul C. Johnson

Rarely-encountered species of odontocetes often get little research attention or funding to study them. We describe an approach to maximise information from these species while undertaking studies of more common ones, and illustrate this approach with information on pygmy killer whales, a poorly-known and rarely-encountered delphinid in Hawai‘i.

This article belongs to the Collection Marine Mammals in the Pacific.

PC23023Who lives in the open sea? Distribution and densities of surfacing marine megafauna in three subregions of the South Pacific (New Caledonia, Wallis and Futuna, and French Polynesia)

Sophie Laran

, Olivier Van Canneyt

, Ghislain Dorémus

, Claire Garrigue

, Tristan Berr

, Hugo Bourgogne, Mathieu Genu

, Jérôme Spitz

and Vincent Ridoux

This study simultaneously describes the spatial distribution and densities of 22 distinct taxonomic groups of marine mammals, sea turtles, elasmobranchs and seabirds over three large oceanic subregions of the western and central South Pacific Ocean. It demonstrates the value of multi-taxa monitoring applied to aerial surveys of offshore marine megafauna, and provides a baseline for future conservation measures.

This article belongs to the Collection Marine Mammals in the Pacific.

PC23021Diversity and distribution of cetaceans in the Republic of Palau

Olive Andrews

, Tiare Holm, Daniel Burns, Cory Ann Hom-Weaver, Carlos Olavarria, David Orrukem, Rechelluul Percy and Rob Williams

The first investigation into the diversity and distribution of cetaceans in the Republic of Palau was conducted. It resulted in a cetacean species inventory confirming the presence of 15 species and identifying seven as either probable or likely present. The study contributes to the management of cetaceans in Palau National Marine Sanctuary and Protected Area Network.

This article belongs to the Collection Marine Mammals in the Pacific.

PC23016Marine mammal strandings recorded in New Caledonia, South West Pacific Ocean, 1877 to 2022

Claire Garrigue

, Solène Derville

, Claire Bonneville, Maële Brisset, Paco Bustamante

, Christophe Cleguer

, Eric E. G. Clua, Willy Dabin, Sylvie Fiat

, Jean-Lou Justine

, Pauline Machful

, Tepoerau Mai, Patrice Plichon, Annie Portal, Christine Sidobre, Debbie Steel, Jean-Christophe Vivier and Elodie Vourey

Map of strandings in New Caledonia; people gathered around a stranded whale; four commonly stranded species.

Conservation of marine mammals in Oceania is limited by a lack of understanding of these relatively rare, yet emblematic species. Here, we report on significant biological and ecological data acquired from several decades of monitoring strandings in New Caledonia. This increased knowledge may help guide management measures locally and regionally. Photograph by Marine Mammal Stranding Center.

This article belongs to the Collection Marine Mammals in the Pacific.