Mixed stock analysis of juvenile green turtles aggregating at two foraging grounds in Fiji reveals major contribution from the American Samoa Management Unit

Identifying the source rookery of green turtles (Chelonia mydas) found in feeding grounds around the Korean Peninsula

Determining the genetic diversity and source rookeries of sea turtles collected from feeding grounds can facilitate effective conservation initiatives. To ascertain the genetic composition and source rookery, we examined a partial sequence of the mitochondrial control region (CR, 796 bp) of 40 green turtles (Chelonia mydas) collected from feeding grounds around the Korean Peninsula between 2014 and 2022. We conducted genetic and mixed-stock analyses (MSA) and identified 10 CR haplotypes previously reported in Japanese populations. In the haplotype network, six, three, and one haplotype(s) grouped with the Japan, Indo-Pacific, and Central South Pacific clades, respectively. The primary rookeries of the green turtles were two distantly remote sites, Ogasawara (OGA) and Central Ryukyu Island (CRI), approximately 1,300 km apart from each other. Comparing three parameters (season, maturity, and specific feeding ground), we noted that OGA was mainly associated with summer and the Jeju Sea, whereas CRI was with fall and the East (Japan) Sea ground. The maturity did not show a distinct pattern. Our results indicate that green turtles in the feeding grounds around the Korean Peninsula originate mainly from the Japan MU and have genetic origins in the Japan, Indo-Pacific, and Central South Pacific clades. Our results provide crucial insights into rookeries and MUs, which are the focus of conservation efforts of the Republic of Korea and potential parties to collaborate for green turtle conservation.

Conservation status and cultural values of sea turtles leading to (un)written parallel management systems in Fiji

Globally and locally, conservationists and scientists work to inform policy makers to help recovery of endangered sea turtle populations. In Fiji, in the South Pacific, sea turtles are protected by the national legislation because of their conservation status, and are also a customary iTaukei resource. Centered on our interview-based study at Qoma and Denimanu villages, parallel management systems coexist, where both the (written) national legislation and the (unwritten) customary iTaukei rules determine the time and the quantity of sea turtle harvest. In addition, non-governmental organizations and academic institutions may influence local sea turtle management by providing scientific awareness and helping divert the economic values from the meat to the living animal. We suggest that the government and non-governmental organizations emphasize community management of sea turtles, and work alongside the customary chiefs and their fishing clans to understand the real harvest (eventually by allowing quotas) and to monitor the recovery of South Pacific sea turtles in Fijian waters.

"Draw the sea…": Children's representations of ocean connectivity in Fiji and New Caledonia

In the South Pacific region, marine territories and resources play a crucial role for local communities. Children engage with these territories and resources from an early age onwards. As the next ocean stewards, they are a stakeholder group whose understandings of ocean connectivity and fisheries should be given serious consideration in decision-making processes towards the sustainable use and management of coastal seas. This paper analyses 290 children's drawings from Fiji and New Caledonia, created in 2019 in spontaneous response to the instruction: "Draw the sea and what you and others do in the sea". Exploring the webs of connections with and within the sea revealed by these children's drawings and their own interpretations leads us to discuss children's representations of the sea: (1) beyond a land-sea compartmentation, (2) as a locus of both exploitation and conservation of marine life, and (3) as a 'place-full' space connecting human and more-than-human realms.

Soundscape of green turtle foraging habitats in Fiji, South Pacific

The soundscape features of the marine environment provide crucial information about ecosystem health for many species, and they are defined by the local biological, geophysical, and anthropogenic components. In this study, we investigated the soundscape at green turtle neritic foraging habitats in Fiji, South Pacific, with the aims of characterizing the contribution of each component and of comparing the levels of acoustic pressure among sites with different abundances of sea turtles. Four sites were selected at two islands, and one hydrophone was deployed at each site. Generalized additive models highlighted that sound pressure levels (SPLs) at low frequencies (125–250 Hz) were especially affected by wind conditions, while at higher frequencies (>250 Hz) SPLs were mostly influenced by fish and crustacean acoustic activity. Higher abundances of green turtles were found at sites with the highest levels of SPLs and the highest number of acoustic emissions by fishes and crustaceans but were not related to maximum seagrass and macroalgae coverage, or the highest number of fish. The selected coastal habitats have negligible anthropogenic noise, thus this study informs physiological and behavioral studies of the acoustic signatures that sea turtles might target and provides a baseline against which potential impact of soundscape changes on sea turtle spatial abundance and distribution can be evaluated.

Integrating morphological and genetic data at different spatial scales in a cosmopolitan marine turtle species: challenges for management and conservation

Patterns of genetic structure in highly mobile marine vertebrates may be accompanied by phenotypic variation. Most studies in marine turtles focused on population genetic structure have been performed at rookeries. We studied whether genetic and morphological variation of the endangered green turtle (Chelonia mydas) is consistent geographically, focusing on foraging grounds. An association between population genetic structure and body shape variation at broad (inter-lineage) and fine (foraging grounds) scales was predicted and analysed using mitochondrial DNA and geometric morphometrics. Although genetic and phenotypic differentiation patterns were congruent between lineages, no fine-scale association was found, suggesting adaptive divergence. Connectivity among Pacific foraging grounds found here suggests that temperatures of ocean surface currents may influence the genetic structure of C. mydas on a broad scale. Our results suggest that vicariance, dispersal, life-history traits and ecological conditions operating in foraging grounds have shaped the intraspecific morphology and genetic diversity of this species. Considering a range of geographic and temporal scales is useful when management strategies are required for cosmopolitan species. Integrating morphological and genetic tools at different spatial scales, conservation management is proposed based on protection of neutral and adaptive diversity. This approach opens new questions and challenges, especially regarding conservation genetics in cosmopolitan species.