Breckwoldt, A., Dombal, Y., Sabinot, C., Gilbert, D., Riera, L., Ferse, S. and Fache, E. 2022. A social-ecological engagement with reef passages in New Caledonia – connectors between coastal and oceanic spaces and species. Ambio (Special Section, Oceania: A Sea of Connections) 51: 2401-2413. DOI: 10.1007/s13280-022-01762-8
Abstract: Healthy and protected coral reefs help island systems in the tropics thrive and survive. Reef passages link the open ocean to lagoon and coastal areas in these ecosystems and are home to an exceptionally diverse and abundant marine life, hosting emblematic species and fish spawning aggregations. Their multiple benefits for the islands and their peoples (e.g., for transport, fishing, socio-cultural aspects) remain yet understudied. Drawing from qualitative interviews with fishers, scuba divers, and surfers along the coast of Grande Terre in New Caledonia, this study highlights the multi-faceted importance of these keystone places. It shows that reef passages are locally deemed ‘communication zones’ between coastal and oceanic spaces and species, and have significant un(der)explored ecological and socio-cultural roles. Understanding and protecting these ecological and cultural keystone places will strengthen both the reef ecosystems and the people dependent on them.
Breckwoldt, A., Nozik, A., Moosdorf, N., Bierwirth, J., Fache, E., Ferse, S., Ford, A., Mangubhai, S., Pelletier, D. and Piovano, S. 2022. A typology for reef passages. Frontiers in Marine Science 9: 786125. DOI: 10.3389/fmars.2022.786125
Abstract: Coral reefs host exceptionally diverse and abundant marine life. Connecting coasts and sheltered lagoons to the open ocean, reef passages are important yet poorly studied components of these ecosystems. Abiotic and biotic elements ‘pass’ through these reef passages, supporting critical ecological processes (e.g. fish spawning). Reef passages provide multiple social and ecological benefits for islands and their peoples, but are so far neither characterized nor recognized for their multifaceted significance. This study investigated 113 reef passages across nine Pacific islands (Fiji, New Caledonia, Vanuatu). GIS-based visual interpretations of satellite imagery were used to develop criteria to define three distinct types, mainly based on distance to coastline and presence/absence of an enclosed water body. The discussion identifies ways to refine and augment this preliminary typology as part of a research agenda for reef passages. With these next steps, this typology will be extendable to other regions to better document reef passages and their various roles, supporting biodiversity conservation and sustainable fisheries management.
Saulnier, E., Breckwoldt, A., Robert, M. and Pelletier, D. 2025. Remote underwater video for monitoring reef fish spawning aggregations. ICES Journal of Marine Science 82(1): fsae194. DOI: 10.1093/icesjms/fsae194
Abstract: Fish spawning aggregations (FSAs) are critical events in the life cycle of many commercially and ecologically important species, yet FSAs are often exploited and highly vulnerable to fishing due to their predictability in time and space. Although FSAs are increasingly recognized as a conservation and management priority, monitoring these ephemeral dynamic events remains challenging. Here, we assessed the ability of remote underwater video (RUV) to monitor reef FSAs, using blacksaddled coral grouper (Plectropomus laevis) as a case study. We deployed RUV systems monthly on a year-round basis in a reef channel of the New Caledonian barrier reef where P. laevis was assumed to form spawning aggregations. Specifically, we investigated whether RUV could both track spatiotemporal changes in fish abundance and detect spawning signs to validate the purpose of potential gatherings. Our analysis revealed strong seasonal changes in P. laevis abundance, characterized by a 5-fold increase between October and February, and marked variations among sampled habitats. The probability of occurrence of males in courtship colouration showed spatiotemporal patterns fairly similar to those in abundance. Finally, we recorded clear courtship behaviours between November and April, providing evidence that P. laevis aggregate monthly to spawn during a protracted reproductive season. This study advances our understanding of the spawning aggregation dynamics of this understudied grouper, and highlights the potential of RUV to monitor and ultimately inform management of reef FSAs.
