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The Hawai'i Coral Reef Assessment and Monitoring Program (CRAMP) was established in 1999 to describe spatial and temporal variation in Hawaiian coral reef communities in relation to natural and anthropogenic factors. In this study, we analyzed changes over a 14-yr period (1999 to 2012) based on data from 60 permanent reef stations at 30 sites in the main Hawaiian Islands. Overall mean statewide coral cover, richness, and diversity did not vary significantly since the initial surveys, although local variations in coral cover trends were detected. The greatest proportion of stations with significant declines in coral cover was found on the island of Maui (0.4), and Hawai'i Island had the highest proportion of stations with significant increases (0.67). Trends in coral cover at some stations varied over time due to acute (e.g., crown of thorns outbreak) and chronic (e.g., sedimentation) disturbances. Stations with increasing coral cover with the potential for recovery from disturbances were identified for possible management actions in the face of future climate change. The Hawaiian archipelago, located in the center of the subtropical Pacific, has experienced a temporary reprieve from steadily increasing temperatures over the past several decades due to a downturn of temperatures at the end of the last cycle of the Pacific Decadal Oscillation (PDO) in 1998. In 2014, however, temperatures increased dramatically in Hawai'i, resulting in a major coral bleaching event with associated mortality. Temperature models predict severe bleaching events to increase in frequency and intensity in coming decades with concomitant decline in Hawaiian corals. Trends reported in this study provide a baseline that can later be used to test this predicted decline associated with future warming. [ABSTRACT FROM AUTHOR]

Coral transplantation was used to evaluate the response of corals to trampling by determining growth and mortality at sites that ranged along a gradient of human use. Human use was measured with observational sampling. A clear progression of coral survivorship along the gradient was evident. Survivorship dropped from 70% at the low impact site to 55% at the medium impact site. Total loss (0% survivorship) was reported from the high impact site after only 8 months, equivalent to less than 200,000 total visitors or 63 people in the water per hour. Where transplanted corals survived, there was no difference in growth, presumably due to the control of activities of people in the water at those sites. [Copyright &y& Elsevier]

Nearshore fisheries in Hawai'i have been steadily decreasing for over a century. Marine protected areas (MPAs) have been utilized as a method to both conserve biodiversity and enhance fisheries. The composition of resource fishes within and directly outside of the recently established Hā'ena Community Based Subsistence Fishing Area (CBSFA) on the island of Kaua'i were assessed to determine temporal and spatial patterns in assemblage structure. In situ visual surveys of fishes, invertebrates, and benthos were conducted using a stratified random sampling design to evaluate the efficacy of the MPA between 2016 and 2020. L50 values—defined as the size at which half of the individuals in a population have reached reproductive maturity—were used as proxies for identifying reproductively mature resource fishes both inside and outside the CBSFA. Surveys between 2016 and 2020 did not indicate strong temporal or spatial changes in overall resource fish assemblage structure; however, some species-specific changes were evident. Although overall resource species diversity and richness were significantly higher by 2020 inside the MPA boundaries, there is currently no strong evidence for a reserve effect. [ABSTRACT FROM AUTHOR]

Many corals and reef-dwelling organisms are susceptible to the impacts of storm events, which are typically characterized by large inputs of freshwater, sediment, and nutrients. The majority of storm effects are focused on shallow, nearshore reef flats, as low salinity and sedimentation tend to dissipate with depth and distance from shore. In April 2018, record rainfall on the northern coast of Kaua'i caused extensive flooding and landslides, introducing large amounts of freshwater and sediment into nearshore reefs. Using benthic and fish transects from 2016–2019 and temperature, sediment, and rainfall data gathered pre- and post-flood, this study aimed to quantify and explicate the effects of flooding on the various biotic populations of two reef habitats at Pila'a and Hā'ena, Kaua'i. Results from the shallow Pila'a reef suggest sediment and freshwater-associated declines in mean urchin abundance (−52.0%) and increases in mean coral bleaching (+54.5%) at the flood-prone eastern sector. Additionally, decreases in mean urchin (−65.7%) and fish (−42.3%) populations were observed at shallow Hā'ena transects, but not deep sites, supporting the occurrence of depth-specific affliction. Multivariate community-level analyses affirmed much of these results, showing a significant shift in community structure before and after the flood at both Pila'a and Hā'ena. The outcomes of this study are pertinent to strategic design and solution development by local aquatic resource managers, especially as anthropogenic climate change continues to increase the frequency, duration, and intensity of storm events. [ABSTRACT FROM AUTHOR]

The response of corals to future conditions of global warming and ocean acidification (OA) is a topic of considerable interest. However, little information is available on the seasonal interaction between temperature, pCO2, and irradiance under ecologically relevant experimental conditions. Controlled experiments were performed in continuous-flow mesocosms under full solar radiation to describe the direct and interactive effects of temperature, irradiance, and pCO2 on growth of a Hawaiian reef building coral (Montipora capitata) over an annual cycle. Corals were subjected to 12 experimental treatments consisting of two pCO2 levels (present-day levels, 2× present), two temperature regimes (ambient, heated+2°C), and three conditions of irradiance (ambient, 50 and 90% reduction). A multiple polynomial regression model with full factorial fixed factors (temperature, pCO2, irradiance)was developed. Temperature and irradiance were the primary factors driving net calcification (Gnet) rates of M. capitata, with pCO2 playing a lesser role. Gnet showed a curvilinear response to irradiance and temperature, which defines thresholds at the end members. Also, high irradiance regimes under elevated temperatures showed a negative synergistic effect on Gnet. Therefore, decreasing irradiance penetration resulting from greater depth and/or higher turbidity will lower the impact of ocean warming on M. capitata. Results suggest that under future climate conditions, the interaction of environmental parameters may shift seasonal patterns in Gnet and timing of growth optima for M. capitata. Ocean warming in shallow water environments with high irradiance poses a more immediate threat to coral growth than acidification for this dominant coral species. In the future, increased temperature and the interaction between high irradiance and high temperature will be the main factors controlling Gnet with OA playing a less important role. This observation is congruent with other reports that high temperature combined with high irradiance is the main cause of high coral mortality during mass bleaching events. [ABSTRACT FROM AUTHOR]

The Hawaiian Archipelago experienced a moderate bleaching event in 2019—the third major bleaching event over a 6-year period to impact the islands. In response, the Hawai'i Coral Bleaching Collaborative (HCBC) conducted 2,177 coral bleaching surveys across the Hawaiian Archipelago. The HCBC was established to coordinate bleaching monitoring efforts across the state between academic institutions, non-governmental organizations, and governmental agencies to facilitate data sharing and provide management recommendations. In 2019, the goals of this unique partnership were to: 1) assess the spatial and temporal patterns of thermal stress; 2) examine taxa-level patterns in bleaching susceptibility; 3) quantify spatial variation in bleaching extent; 4) compare 2019 patterns to those of prior bleaching events; 5) identify predictors of bleaching in 2019; and 6) explore site-specific management strategies to mitigate future bleaching events. Both acute thermal stress and bleaching in 2019 were less severe overall compared to the last major marine heatwave events in 2014 and 2015. Bleaching observed was highly site- and taxon-specific, driven by the susceptibility of remaining coral assemblages whose structure was likely shaped by previous bleaching and subsequent mortality. A suite of environmental and anthropogenic predictors was significantly correlated with observed bleaching in 2019. Acute environmental stressors, such as temperature and surface light, were equally important as previous conditions (e.g. historical thermal stress and historical bleaching) in accounting for variation in bleaching during the 2019 event. We found little evidence for acclimation by reefs to thermal stress in the main Hawaiian Islands. Moreover, our findings illustrate how detrimental effects of local anthropogenic stressors, such as tourism and urban run-off, may be exacerbated under high thermal stress. In light of the forecasted increase in severity and frequency of bleaching events, future mitigation of both local and global stressors is a high priority for the future of corals in Hawai'i. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lingulids are living fossils well-known for stasis in their evolutionary history. • A global molecular phylogeny of the extant Lingulidae was reconstructed. • Lingulids are substantially more species-rich than previously recognized. • Phylogenetic relationships within Lingula and Glottidia were resolved well. • Time-calibrated tree shows Cretaceous origins of the two extant lingulid genera. The Lingulidae are often considered living fossils, because they have shown little morphological change since the Paleozoic. Limited morphological variation has also made the taxonomic study of living lingulids challenging. We investigated species diversity and phylogenetic relationships of extant lingulids and show that they are substantially more diverse than realized, demonstrating that morphological stasis was commonly accompanied by speciation. Species delimitation based on cytochrome c oxidase subunit I (COI) gene sequences from 194 specimens sampled from East Asia, Australia, Oceania, and the Americas suggested 14–22 species in the lingulids (9–17 species in Lingula and 4–5 species in Glottidia), in contrast to the 11–12 species currently recognized globally in the family. Four-gene phylogenetic analyses supported the sister relationship between Lingula and Glottidia. Within Lingula, L. adamsi , which possesses large, brownish shells, was recovered as sister to all remaining Lingula species, which have more or less greenish shells. Within the greenish Lingula clade, the ' L. anatina' complex was sister to the clade that includes the ' L. reevei ' complex. The ' L. anatina' complex was further separated into two major clades with partly separate ranges centered on (i) temperate East Asia, and (ii) the tropical west-central Pacific. Within Glottidia, Pacific species were nested within Atlantic species. Time-calibrated phylogenetic analyses suggested that Lingula likely originated in the early Cretaceous contrary to a previously proposed hypothesis advocating a Cenozoic origin. The separation of Lingula and Glottidia appears to date from the Mesozoic, not from the Carboniferous, contrary to a previous hypothesis. Overall, our results uncovered substantial cryptic diversity in lingulids, which will form the basis for conservation and further taxonomic revision. [ABSTRACT FROM AUTHOR]

The Coral Reef Assessment and Monitoring Program (CRAMP) of Hawai'i was established in 1998 to monitor long-term changes in coral reef benthic communities around the state. Development of the methodology involved analysis of results from previous monitoring programs in Hawai'i to determine precision and statistical power of various methods to detect change. Additional field trials were conducted to examine factors such as repeatability, appropriate transect length, number of transects, number of samples per transect, cover estimation techniques, observer variation, as well as time and financial constraints. Benthic monitoring methods used previously in Hawai'i generally showed low statistical power for detecting change due to low precision and small sample size. Field trials indicated that repeatability of conventional techniques using transects or quadrats had high variation and consequently low statistical power unless efforts were made to reposition the sampling units with greater precision. Longer transects (e.g., 25 and 50 m) had higher variability than shorter transects (e.g., 10 m), suggesting that smaller sampling units were more appropriate for the habitats sampled. Variability among observers analyzing the same data was low in comparison with other sources of error. Visual estimation techniques showed low initial cost but were inefficient per survey. Digital video required the highest initial monetary investment but yielded the greatest quantity of data per survey with sufficient quality. The cost effectiveness of the digital video method compared with other techniques increased with more surveys and in more remote situations where logistical expenses were incurred. A within-habitat stratified random sampling design was implemented for the CRAMP design. Fixed transects were chosen to reduce temporal variance and allowed efficient resurveying under the high-wave-energy field conditions typically found in Hawai'i. The method was designed to detect an absolute change of 10% in benthic cover with high statistical power using 50 points per frame, 20-30 frames per transect, and 8-10 transects per depth. Fixed photo-quadrats with high precision and high resolution were included in the design to allow detailed monitoring of coral/algal growth, recruitment, and mortality. [ABSTRACT FROM AUTHOR]

Coral reefs are susceptible to climate change, anthropogenic influence, and environmental stressors. However, corals in Kāneʻohe Bay, Hawaiʻi have repeatedly shown resilience and acclimatization to anthropogenically-induced rising temperatures and increased frequencies of bleaching events. Variations in coral and algae cover at two sites—just 600 m apart—at Malaukaʻa fringing reef suggest genetic or environmental differences in coral resilience between sites. A reciprocal transplant experiment was conducted to determine if calcification (linear extension and dry skeletal weight) for dominant reef-building species, Montipora capitata and Porites compressa, varied between the two sites and whether or not parent colony or environmental factors were responsible for the differences. Despite the two sites representing distinct environmental conditions with significant differences between temperature, salinity, and aragonite saturation, M. capitata growth rates remained the same between sites and treatments. However, dry skeletal weight increases in P. compressa were significantly different between sites, but not across treatments, with linear mixed effects model results suggesting heterogeneity driven by environmental differences between sites and the parent colonies. These results provide evidence of resilience and acclimatization for M. capitata and P. compressa. Variability of resilience may be driven by local adaptations at a small, reef-level scale for P. compressa in Kāneʻohe Bay. [ABSTRACT FROM AUTHOR]