Study Protocol: Interactive Dynamics of Coral Reef Fisheries and the Nutrition Transition in Kiribati.

The Kiribati 2019 Integrated Household Income and Expenditure Survey (Integrated HIES) embeds novel ecological and human health research into an ongoing social and economic survey infrastructure implemented by the Pacific Community in partnership with national governments. This study seeks to describe the health status of a large, nationally representative sample of a geographically and socially diverse I-Kiribati population through multiple clinical measurements and detailed socio-economic surveys, while also conducting supporting food systems research on ecological, social, and institutional drivers of change. The specific hypotheses within this research relate to access to seafood and the potential nutritional and health benefits of these foods. We conducted this research in 21 of the 23 inhabited islands of Kiribati, excluding the two inhabited islands-Kanton Islands in the Phoenix Islands group with a population of 41 persons (2020 census) and Banaba Island in the Gilbert Islands group with a population of 333 persons (2020 census)-and focusing exclusively on the remaining islands in the Gilbert and Line Islands groups. Within this sample, we focused our intensive human health and ecological research in 10 of the 21 selected islands to examine the relationship between ecological conditions, resource governance, food system dynamics, and dietary patterns. Ultimately, this research has created a baseline for future Integrated HIES assessments to simultaneously monitor change in ecological, social, economic, and human health conditions and how they co-vary over time.

Rights and representation support justice across aquatic food systems.

Injustices are prevalent in food systems, where the accumulation of vast wealth is possible for a few, yet one in ten people remain hungry. Here, for 194 countries we combine aquatic food production, distribution and consumption data with corresponding national policy documents and, drawing on theories of social justice, explore whether barriers to participation explain unequal distributions of benefits. Using Bayesian models, we find economic and political barriers are associated with lower wealth-based benefits; countries produce and consume less when wealth, formal education and voice and accountability are lacking. In contrast, social barriers are associated with lower welfare-based benefits; aquatic foods are less affordable where gender inequality is greater. Our analyses of policy documents reveal a frequent failure to address political and gender-based barriers. However, policies linked to more just food system outcomes centre principles of human rights, specify inclusive decision-making processes and identify and challenge drivers of injustice.

Environmental performance of blue foods.

Fish and other aquatic foods (blue foods) present an opportunity for more sustainable diets1,2. Yet comprehensive comparison has been limited due to sparse inclusion of blue foods in environmental impact studies3,4 relative to the vast diversity of production5. Here we provide standardized estimates of greenhouse gas, nitrogen, phosphorus, freshwater and land stressors for species groups covering nearly three quarters of global production. We find that across all blue foods, farmed bivalves and seaweeds generate the lowest stressors. Capture fisheries predominantly generate greenhouse gas emissions, with small pelagic fishes generating lower emissions than all fed aquaculture, but flatfish and crustaceans generating the highest. Among farmed finfish and crustaceans, silver and bighead carps have the lowest greenhouse gas, nitrogen and phosphorus emissions, but highest water use, while farmed salmon and trout use the least land and water. Finally, we model intervention scenarios and find improving feed conversion ratios reduces stressors across all fed groups, increasing fish yield reduces land and water use by up to half, and optimizing gears reduces capture fishery emissions by more than half for some groups. Collectively, our analysis identifies high-performing blue foods, highlights opportunities to improve environmental performance, advances data-poor environmental assessments, and informs sustainable diets.

Depth as an organizing force in Pocillopora damicornis: intra-reef genetic architecture.

Relative to terrestrial plants, and despite similarities in life history characteristics, the potential for corals to exhibit intra-reef local adaptation in the form of genetic differentiation along an environmental gradient has received little attention. The potential for natural selection to act on such small scales is likely increased by the ability of coral larval dispersal and settlement to be influenced by environmental cues. Here, we combine genetic, spatial, and environmental data for a single patch reef in Kane'ohe Bay, O'ahu, Hawai'i, USA in a landscape genetics framework to uncover environmental drivers of intra-reef genetic structuring. The genetic dataset consists of near-exhaustive sampling (n = 2352) of the coral, Pocillopora damicornis at our study site and six microsatellite genotypes. In addition, three environmental parameters - depth and two depth-independent temperature indices - were collected on a 4 m grid across 85 locations throughout the reef. We use ordinary kriging to spatially interpolate our environmental data and estimate the three environmental parameters for each colony. Partial Mantel tests indicate a significant correlation between genetic relatedness and depth while controlling for space. These results are also supported by multi-model inference. Furthermore, spatial Principle Component Analysis indicates a statistically significant genetic cline along a depth gradient. Binning the genetic dataset based on size-class revealed that the correlation between genetic relatedness and depth was significant for new recruits and increased for larger size classes, suggesting a possible role of larval habitat selection as well as selective mortality in structuring intra-reef genetic diversity. That both pre- and post-recruitment processes may be involved points to the adaptive role of larval habitat selection in increasing adult survival. The conservation importance of uncovering intra-reef patterns of genetic diversity is discussed.

Rise and fall of a hybrid zone: implications for the roles of aggression, mate choice, and secondary succession.

Hybridization can be an important evolutionary force by generating new species and influencing evolution of parental species in multiple ways, including introgression and the consequences of hybrid vigor. Determining the ecological processes underlying evolution in hybrid zones is difficult however because it requires examining changes in both genotypic frequencies over time and corresponding ecological information, data that are rarely collected together. Here, we describe genetic and ecological aspects of a hybrid zone between the Eastern Fence Lizard, Sceloporus undulatus, and the Florida Scrub Lizard, Sceloporus woodi, occurring over at least 23 generations. The hybrid zone, discovered greater than 35 years ago using morphological characters, originally consisted of nearly even proportions of parental species and hybrids. Now, using genetic markers (species-diagnostic mtDNA sites and 6 nDNA microsatellite loci across a total of n = 117 individuals), we confirm not only that hybridization occurred but also that subsequent backcrossing has resulted in highly introgressed hybrids, with many hybrids containing mitochondrial DNA from one species on a nuclear DNA background of the other. Ecological aspects explaining these shifts in genetic composition include female mate choice, changes in habitat associated with secondary succession, and, most strongly, a hierarchy of male territorial advantage-ecological mechanisms likely to be involved in the emergence and disappearance of many animal hybrid zones. Our results suggest that genetic assimilation is not a significant threat to either species and that rather transient hybrid zones such as this may serve to increase genetic diversity and are candidates for causing genetic discordance in phylogeographic analyses.

Genetic relatedness does not retain spatial pattern across multiple spatial scales: dispersal and colonization in the coral, Pocillopora damicornis.

Patterns of isolation by distance are uncommon in coral populations. Here, we depart from historical trends of large-scale, geographical genetic analyses by scaling down to a single patch reef in Kane'ohe Bay, Hawai'i, USA, and map and genotype all colonies of the coral, Pocillopora damicornis. Six polymorphic microsatellite loci were used to assess population genetic and clonal structure and to calculate individual colony pairwise relatedness values. Our results point to an inbred, highly clonal reef (between 53 and 116 clonal lineages of 2352 genotyped colonies) with a much skewed genet frequency distribution (over 70% of the reef was composed of just seven genotypes). Spatial autocorrelation analyses revealed that corals found close together on the reef were more genetically related than corals further apart. Spatial genetic structure disappears, however, as spatial scale increases and then becomes negative at the largest distances. Stratified, random sampling of three neighbouring reefs confirms that reefs are demographically open and inter-reef genetic structuring was not detected. Attributing process to pattern in corals is complicated by their mixed reproductive strategies. Separate autocorrelation analyses, however, show that the spatial distribution of both clones and nonclones contributes to spatial genetic structure. Overall, we demonstrate genetic structure on an intrareef scale and genetic panmixia on an inter-reef scale indicating that, for P. damicornis, the effect of small- and large-scale dispersal processes on genetic diversity are not the same. By starting from an interindividual, intrareef level before scaling up to an inter-reef level, this study demonstrates that isolation-by-distance patterns for the coral P. damicornis are limited to small scales and highlights the importance of investigating genetic patterns and ecological processes at multiple scales.