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Ocean warming is increasing the incidence, scale, and severity of global-scale coral bleaching and mortality, culminating in the third global coral bleaching event that occurred during record marine heatwaves of 2014-2017. While local effects of these events have been widely reported, the global implications remain unknown. Analysis of 15,066 reef surveys during 2014-2017 revealed that 80% of surveyed reefs experienced significant coral bleaching and 35% experienced significant coral mortality. The global extent of significant coral bleaching and mortality was assessed by extrapolating results from reef surveys using comprehensive remote-sensing data of regional heat stress. This model predicted that 51% of the world’s coral reefs suffered significant bleaching and 15% significant mortality, surpassing damage from any prior global bleaching event. These observations demonstrate that global warming’s widespread damage to coral reefs is accelerating and underscores the threat anthropogenic climate change poses for the irreversible transformation of these essential ecosystems.

Benthic cyanobacterial mats (BCMs) are becoming increasingly common on coral reefs. In Fiji, blooms generally occur in nearshore areas during warm months but some are starting to prevail through cold months. Many fundamental knowledge gaps about BCM proliferation remain, including their composition and how they influence reef processes. This study examined a seasonal BCM bloom occurring in a 17-year-old no-take inshore reef area in Fiji. Surveys quantified the coverage of various BCM-types and estimated the biomass of key herbivorous fish functional groups. Using remote video observations, we compared fish herbivory (bite rates) on substrate covered primarily by BCMs (> 50%) to substrate lacking BCMs (

Resilience of food systems is key to ensuring food security through crisis. The COVID-19 pandemic presents an unprecedented shock that reveals varying levels of resilience of increasingly interconnected food systems across the globe. We contribute to the ongoing debate about whether increased connectivity reduces or enhances resilience in the context of rural Pacific food systems, while examining how communities have adapted to the global shocks associated with the pandemic to ensure food security. We conducted 609 interviews across 199 coastal villages from May to October 2020 in Federated States of Micronesia, Fiji, Palau, Papua New Guinea, Solomon Islands, Tonga, and Tuvalu to understand community-level impacts and adaptations during the first 5-10 months of the COVID-19 crisis. We found that local food production practices and food sharing conferred resilience, and that imported foods could aid or inhibit resilience. Communities in countries more reliant on imports were almost twice as likely to report food insecurity compared to those least reliant. However, in places dealing with a concurrent cyclone, local food systems were impaired, and imported foods proved critical. Our findings suggest that policy in the Pacific should bolster sustainable local food production and practices. Pacific states should avoid becoming overly reliant on food imports, while having measures in place to support food security after disasters, supplementing locally produced and preserved foods with imported foods when necessary. Developing policies that promote resilient food systems can help prepare communities for future shocks, including those anticipated with climate change.

Scleractinian corals are the host group with the greatest number of species associated with hydroids in the genus Zanclea. There are 34 nominal species and 31 genera of scleractinians reported as Zanclea hosts from a few localities across the Red Sea, Indo-Pacific, and Caribbean. However, little is known about how consistent and cosmopolitan scleractinian-Zanclea relationships are. To test their geographical consistency, we surveyed Fijian corals for Zanclea presence using both field-based surveys and analysis of in situ coral photographs. Surveys targeted 16 species and seven genera of reported Zanclea hosts and five other corals commonly found at the sites. We observed Zanclea hydroids associated with 22 species in seven genera of scleractinian corals with 17 (77%) of the species being newly reported hosts. Our findings suggest that a broad diversity of scleractinian corals hosting Zanclea remains to be documented, and although Zanclea-scleractinian associations are likely cosmopolitan in their distribution across localities, associations with specific coral species may not be.

The Fiji Islands is an archipelago of more than 330 islands located in the tropics of the South Pacific Ocean. Microbial diversity and biogeography in this region is still not understood. Here, we present the first molecular characterization of fungal, bacterial, and archaeal communities in soils from different habitats within the largest Fijian island, Viti Levu. Soil samples were collected from under native vegetation in maritime-, forest-, stream-, grassland-, and casuarina-dominated habitats, as well as from under the introduced agricultural crops sugarcane, cassava, pine, and mahogany. Soil microbial diversity was analyzed through MiSeq amplicon sequencing of 16S (for prokaryotes), ITS, LSU ribosomal DNA (for fungi). Prokaryotic communities were dominated by Proteobacteria (~ 25%), Acidobacteria (~ 19%), and Actinobacteria (~ 17%), and there were no indicator species associated with particular habitats. ITS and LSU were congruent in β-diversity patterns of fungi, and fungal communities were dominated by Ascomycota (~ 57–64%), followed by Basidiomycota (~ 20–23%) and Mucoromycota (~ 10%) according to ITS, or Chytridiomycota (~ 9%) according to LSU. Indicator species analysis of fungi found statistical associations of Cenococcum, Wilcoxina, and Rhizopogon to Pinus caribaea. We hypothesize these obligate biotrophic fungi were co-introduced with their host plant. Entoloma was statistically associated with grassland soils, and Fusarium and Lecythophora with soils under cassava. Observed richness varied from 65 (casuarina) to 404 OTUs (cassava) for fungi according to ITS region, and from 1268 (pine) to 2931 OTUs (cassava) for bacteria and archaea. A major finding of this research is that nearly 25% of the fungal OTUs are poorly classified, indicative of novel biodiversity in this region. This preliminary survey provides important baseline data on fungal, bacterial, and archaeal diversity and biogeography in the Fiji Islands.

Tropical reefs are commonly transitioning from coral- to macroalgal-dominance, producing abrupt, and often lasting, shifts in community composition and ecosystem function. Although negative effects of macroalgae on corals are well documented, whether such effects vary with spatial scale or the density of macroalgae remains inadequately understood, as does the legacy of their impact on coral growth. Using closely adjacent coral- versus macroalgal-dominated areas, we tested effects of macroalgal competition on the Indo-Pacific corals Acropora millepora and Porites cylindrica. When corals were transplanted to areas of: i) macroalgal-dominance, ii) macroalgal-dominance but with nearby macroalgae removed, or iii) coral-dominance lacking macroalgae, coral growth was equivalently high in plots without macroalgae and low (62-90% less) in plots with macroalgae, regardless of location. In a separate experiment, we raised corals above the benthos in each area and exposed them to differing densities of the dominant macroalga Sargassum polycystum. Coral survivorship was high (≥ 93% after 3 months) and did not differ among treatments, whereas the growth of both coral species decreased as a function of Sargassum density. When Sargassum was removed after two months, there was no legacy effect of macroalgal density on coral growth over the next seven months; however, there was no compensation for previously depressed growth. In sum, macroalgal impacts were density dependent, occurred only if macroalgae were in close contact, and coral growth was resilient to prior macroalgal contact. The temporal and spatial constraints of these interactions suggest that corals may be surprisingly resilient to periodic macroalgal competition, which could have important implications for ecosystem trajectories that lead to reef decline or recovery.

Little published or unpublished information exists concerning the benthic community structure or coral fauna at Wake Atoll in the Central Pacific. Here, we apply multivariate statistical analyses to data acquired in 2005 from several complementary survey methods that operate at different scales of spatial and taxonomic resolution to characterize the coral communities in the fore-reef habitat, which is further stratified by geographic sector and depth zone. Both broad-scale towed-diver surveys and site-specific photoquadrat surveys revealed high dissimilarity in overall benthic composition between the northeast and southwest sectors. Coral cover in the northeast sector is more than 2.5 times greater than in the southwest sector; encrusting and massive growth forms dominate in the northeast sector while encrusting and digitate growth forms dominate in the southwest sector. Coral cover and colony abundances are less dominated by a few key genera in the northeast than in the southwest sector, though the genera Montipora, Pocillopora , and Favia are the most numerically abundant taxa in both sectors. Octocorals account for more than 25% of the total coral cover in the northeast sector but less than 5% of the total coral cover in the southwest sector. The deep northeast stratum showed among the highest diversity of growth forms as well as the highest total coral cover, octocoral cover, and coralline algal cover. We provide a list of 101 anthozoan and hydrozoan corals observed at Wake Atoll during survey activities since the year 1979. Five scleractinian species at Wake are on the IUCN Red List of Threatened Species™. The 80 taxa with well-established species names contain components from the Mariana Islands, northern Marshall Islands, and Hawaiian Islands, but show the closest resemblance to the Mariana Islands. Our spatially widespread surveys that generate independent metrics of benthic cover and coral abundance collectively provide the most comprehensive description of coral communities at Wake Atoll produced to date and also provide an important record by which to monitor the response of this community to changing ocean conditions.

No-take marine protected areas (MPAs) are commonly applied in community-based management schemes to sustain and enhance coral-reef fisheries. However, many MPAs in Fiji and the South Pacific are relatively small ("641 km2), and few data exist regarding the effects of these MPAs on populations of exploited species. We used hook-and-line fishing surveys to assess whether 4 relatively small (

Miller et al. (2007; Mar Ecol Prog Ser 335:227-231, this volume) dispute the ability of visual surveys to distinguish between colonies of Acropora palmata formed by sexual and asexual processes. They argue that approaches that do not consider genetic diversity are not appropriate for assessing population recovery. Visual surveys are clearly not reliable for distinguishing colony origin; however, the significance of the findings in Miller et al. (2007) for assessment of population recovery is not clear. While genetic diversity may indeed be important for population survival and species per- sistence, our study (Grober-Dunsmore et al. 2006; Mar Ecol Prog Ser 321:123-132) assessed popula- tion recovery by temporally sampling demographic attributes which are critical for ecosystem func- tion (e.g. topographic complexity) over shorter ecological timescales. Ideally, genetic studies should be contextualized with demographic and other environmental and ecological data to improve our understanding of processes that lead to population persistence. However, without having historical genetic data from A. palmata populations, or being able to distinguish which genets are more or less resilient, or being able to identify source-sink dynamics, genetic tools presently offer limited infor- mation for assessing population recovery of A. palmata.

Populations of Acropora palmata in the Caribbean were decimated in the 1970s and 1980s, with little apparent signs of recovery until the late 1990s. Here, we document an increase in A. palmata colonies between 2001 and 2003 at 8 of 11 monitoring sites in waters adjacent to the island of St. John, US Virgin Islands. The shallow waters along the NW coast of the island exhibited the greatest increase in colony abundance, perhaps due to greater larval supply and/or conditions that favor settlement and subsequent survivorship. Of concern, however, is the lack of survival of large colonies (at all sites), which are most frequently affected by stressors (e.g. Coralliophila abbreviata, damselfishes, active disease) and are most likely to be remnants (colonies with discontinuous, living coral-tissue over an existing coral framework). Predation by C. abbreviata and active coral disease may directly contribute to the development of these remnant colonies. In addition, we recorded damage to colonies attributed to damselfishes and raise the possibility that these territorial reef- inhabitants act as vectors in the transmission of coral disease. While the incidence of disease around St. John is generally low, it may persist as a ubiquitous, chronic stress. Finally, because stressors are more prevalent on large colonies and in high-density stands, they have the potential to inhibit the recovery of A. palmata populations to their historic condition.

The realization that coral reef ecosystem management must occur across multiple spatial scales and habitat types has led scientists and resource managers to seek variables that are easily measured over large areas and correlate well with reef resources. Here we investigate the utility of new technology in airborne laser surveying (NASA Experimental Advanced Airborne Research Lidar (EAARL)) in assessing topographical complexity (rugosity) to predict reef fish community structure on shallow (

Fouha Bay is a 400-m-long funnel-shaped, 10-m-deep, coral-fringed embayment on the southwest coast of Guam. It drains a small catchment area (5 km2) of steeply sloping, highly erodible lateritic soils. River floods are short-lived and the sediment load is very large, with suspended sediment concentration (SSC) exceeding 1000 mg l−1. The resulting river plume is about 1 m thick and is pulsing in a series of 1–2 h-long events, with outflow velocity peaking at 0.05 m s−1. Turbulent entrainment results in an oceanic inflow at depth into the bay. As soon as river flow stops, the plume floats passively and takes 5 days to be flushed out of Fouha Bay. The suspended fine sediment flocculates in 5 min and aggregates on ambient transparent exopolymer particles to form muddy marine snow flocs. In calm weather, about 75% of the riverine mud settles out of the river plume into the underlying oceanic water where it forms a transient nepheloid layer. This mud ultimately settles and is trapped in Fouha Bay. Under typhoon-driven, swell waves, the surface plume is at least 7 m thick and bottom entrainment of mud results in SSC exceeding 1000 mg l−1 for several days. It is suggested that successful management of fringing coral reefs adjacent to volcanic islands may not be possible without proper land use management in the surrounding catchment.

Maintaining coral reef resilience against increasing anthropogenic disturbance is critical for effective reef management. Resilience is partially determined by how processes, such as herbivory and nutrient supply, affect coral recovery versus macroalgal proliferation following disturbances. However, the relative effects of herbivory versus nutrient enrichment on algal proliferation remain debated. Here, we manipulated herbivory and nutrients on a coral-dominated reef protected from fishing, and on an adjacent macroalgal-dominated reef subject to fishing and riverine discharge, over 152 days. On both reefs, herbivore exclusion increased total and upright macroalgal cover by 9–46 times, upright macroalgal biomass by 23–84 times, and cyanobacteria cover by 0–27 times, but decreased cover of encrusting coralline algae by 46–100% and short turf algae by 14–39%. In contrast, nutrient enrichment had no effect on algal proliferation, but suppressed cover of total macroalgae (by 33–42%) and cyanobacteria (by 71% on the protected reef) when herbivores were excluded. Herbivore exclusion, but not nutrient enrichment, also increased sediment accumulation, suggesting a strong link between herbivory, macroalgal growth, and sediment retention. Growth rates of the corals Porites cylindrica and Acropora millepora were 30–35% greater on the protected versus fished reef, but nutrient and herbivore manipulations within a site did not affect coral growth. Cumulatively, these data suggest that herbivory rather than eutrophication plays the dominant role in mediating macroalgal proliferation, that macroalgae trap sediments that may further suppress herbivory and enhance macroalgal dominance, and that corals are relatively resistant to damage from some macroalgae but are significantly impacted by ambient reef condition.

This publication does not have an abstract. The first paragraph of the Introduction is displayed as the abstract. The Mariana Islands are a chain of 16 volcanic peaks stretching over a distance of approximately 2,500km from 13' to 21' N latitude and centered at 145' E longitude (Fig. 19.1). Politically, the area is divided into two jurisdictions, Guam and the Commonwealth of the Northern Mariana Islands. Guam is a US territory located at 13'28' N, 144'45'E and is the southernmost island in the Mariana Archipelago. It is the largest island in Micronesia, with an area of 560km2 and a maximum elevation of approximately 405m above sea level. The northern portion of the island is relatively flat and consists primarily of uplifted limestone. The southern half of the island is primarily volcanic, with more topographic relief, and large areas of highly erodible lateritic soils (Siegrist and Randall 1992; Chapter 18, Riegl et al. ). The island possesses fringing reefs, patch reefs, submerged reefs, offshore banks, and a barrier reef surrounding the southern shores. The reef margin varies in width, from tens of meters along some of the windward areas, to well over 100m. The combined area of coral reefs and lagoons is approximately 69km2 in nearshore waters between 0-3nmi, and an additional 110km2 in federal waters greater than 3nmi offshore (Hunter 1995).