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Marine debris is a global crisis impacting human health, wildlife, and coastal economies. Remote sensing and geospatial technologies are an efficient way to document marine debris across large areas, but the high costs of fieldwork and manual interpretation of debris imagery are major barriers to broader use of these methods. Recent advances in machine learning (ML) have brought rapid automation to many remote sensing domains, including the detection and classification of marine debris. This study evaluates the ability to detect and classify coastline marine debris objects in a real-world setting across a large geographic extent. Three leading ML object detection models were trained to detect and classify large shoreline stranded marine debris from a set of aerial images collected over 1,900 km of Hawaiian coastline. The three models evaluated 1,587 image chips containing 10,703 individual debris labels from 8 debris classes. The SS-MN was both the fastest model and provided the best percentage of accurate predictions, achieving an average precision of 72 %. Nonetheless, this performance was achieved at the expense of missing numerous debris objects, with an average recall of 40 %. The other models provided distinct advantages for certain object classes and use cases. The results show that ML techniques show strong potential to automatically detect and classify certain types of marine debris from aerial surveys. However, there are existing methodological and technical challenges left to overcome before ML methods can outperform human observers in manual interpretation of marine debris from imagery.

Abstract Traditional Hawaiian fishponds, called loko iʻa, are a low‐impact and culturally important aquaculture system that historically produced significant fish yields. To better understand the structure of the contemporary food web of the restored Heʻeia fishpond, a mark‐recapture experiment was conducted to estimate the population abundance of the three dominant predatory fishes, and gut content, genetic barcoding, and stable isotope analyses were used to assess their diets. Great barracuda Sphyraena barracuda had the largest estimated population at 190 individuals, followed by 89 giant trevally Caranx ignobilis and 19 bluefin trevally Caranx melampygus. The three species were caught throughout the pond, with C. ignobilis concentrated in the deeper northwest area near a mangrove island. Diets of the three species consisted mainly of nearshore, estuarine fishes, and crustaceans. Prey taxonomic resolution was greatly improved with the use of genetic barcoding since most fish were too degraded to be visually identified. Trophic level calculations and isotopic niche breadth comparisons indicated that C. ignobilis and S. barracuda occupied similar ecological niches in the fishpond, and stable isotope mixing models revealed that their long‐term diets were mostly comprised glass shrimp (Palaemon sp.), mangrove swimming crab (Thalamita crenata), and an invasive Australian mullet (Osteomugil engeli). The native mullet (Mugil cephalus), a primary food fish species from the fishpond, was not identified in the diets of the predatory fishes in this study nor in a previous diet study decades ago prior to the introduction of Australian mullet. The inclusion of the invasive Australian mullet in the contemporary diets of the predatory fishes demonstrates a shift towards the newly available prey which may benefit the native mullet populations. These findings improve the understanding of food web dynamics in contemporary Hawaiian fishponds and provide an example of native predatory fishes consuming an invasive species as part of their diets.

Data-limited fisheries benefit from using life-history traits as biological indicators of targeted stocks. We used histology-based reproductive analyses to estimate size at maturity, per capita egg production, and the number and biomass of immature individuals in the catch for three common coral reef fishes in Fiji market surveys during 2010–2019. We studied Lutjanus gibbus (Forsskål, 1775), Parupeneus indicus (Shaw, 1803), and Chlorurus microrhinos (Bleeker, 1854), which represent three families: Lutjanidae, Mullidae, and Scaridae, respectively. Fork length comprising 50% mature individuals for females of L. gibbus was 22.7 cm, that of P. indicus was 25.9 cm, attaining 38.0 cm for C. microrhinos. Females were rare or absent in the largest size classes of all three species. Immature fish represented up to 50% by number and 41% by biomass of the catch in market surveys, with P. indicus having the greatest immature number (8%‒50%) and biomass (6%‒41%), followed by C. microrhinos (20%‒30% by count, 11%‒18% by biomass) and L. gibbus (9%‒28% by count, 5%‒14% by biomass). Individuals ≤ 30 cm for L. gibbus and P. indicus and ≤ 45 cm for C. microrhinos were responsible for ≥ 90% of egg production per spawning. Skewed size-specific sex ratios suggested that exploitation of the largest size classes had minimal effect on overall egg production. Decreased catches of immature fishes would increase the reproductive population sizes for these species.

High-resolution rocky intertidal environment and life-history of tropical limpets, as determined by secondary ion mass spectrometry stable oxygen isotopic analysis of modern and historical mollusc shells.

Anthropogenic disturbances are posing unprecedented challenges to the persistence of ecosystems worldwide. The speed at which these disturbances reach an ecosystem’s tolerance thresholds will determine the time available for adaptation and conservation. Here, we aim to calculate the year after which a given environmental stressor permanently exceeds the bounds of an ecosystem’s tolerance. Ecosystem thresholds are here defined as limits in a given stressor beyond which ecosystems have showed considerable changes in community assembly and functioning, becoming remnants of what they once were, but not necessarily leading to species extirpation or extinction. Using the world’s coral reefs as a case example, we show that the projected effects of marine heatwaves, ocean acidification, storms, land-based pollution, and local human stressors are being underestimated considerably by looking at disturbances independently. Given the spatial complementarity in which numerous disturbances impact the world’s coral reefs, we show that the timelines of environmental suitability are halved when all disturbances are analyzed simultaneously, as opposed to independently. Under business-as-usual scenarios, the median year after which environmental conditions become unsuitable for the world’s remaining coral reefs was, at worse, 2050 for any one disturbance alone (28 years left); but when analyzed concurrently, this date was shortened to 2035 (13 years left). When analyzed together, disturbances reduced the date of environmental suitability because areas that may remain suitable under one disturbance could become unsuitable by any of several other variables. The significance of co-occurring disturbances at reducing timeframes of environmental suitability was evident even under optimistic scenarios. The best-case scenario, characterized by strong mitigation of greenhouse gas emissions and optimistic human development, resulted in 41% of global coral reefs with unsuitable conditions by 2100 under any one disturbance independently; yet when analyzed in combination up to 64% of the world’s coral reefs could face unsuitable environmental conditions by one disturbance or another. Under the worst-case scenario, nearly all coral reef ecosystems worldwide (approximately 99%) will permanently face unsuitable conditions by 2055 in at least one of the disturbances analyzed. Prior studies have indicated the projected dire effects of climate change on coral reefs by mid-century; by analyzing a multitude of projected disturbances, our study reveals a much more severe prognosis for the world’s coral reefs as they have significantly less time to adapt while highlighting the urgent need to tackle available solutions to human disturbances. An analysis of independent human disturbances shows that, under business-as-usual scenarios, unsuitable environmental conditions will exist for half the world’s remaining coral reefs by 2050 (28 years left), while the combined effects of disturbances yields unsuitable conditions by 2035 (13 years left).

Following the end of over a century of intensive commercial whaling in 1986, the monitoring and assessment of sperm whale populations is essential for guiding management and conservation decisions for their recovery. Species distribution models (SDMs) are a useful tool for examining and predicting cetacean distribution patterns and typically incorporate visual, ship-based observations. However, understanding sperm whale distribution and habitat use based solely on surface visual observations is challenging due to the significant amount of time sperm whales spend foraging at depth. For the endangered sperm whale population occurring in Hawaiian waters, we used visual and passive acoustic data collected during four annual NOAA marine mammal line-transect surveys and a suite of biologically relevant environmental variables to develop SDMs within a generalized additive modeling framework to study the distribution of sperm whale groups throughout the island chain. Additionally, the passive acoustic data allowed us to differentiate sperm whale groups as foraging or non-foraging based on their click types to account for differences in distribution and behavior within the archipelago. Foraging groups were predicted primarily in the northwestern region of the archipelago between Laysan Island and Pearl and Hermes Reef as well as north of Maui and Hawaiʻi in the main Hawaiian Islands. Non-foraging groups were predicted to be more uniformly distributed throughout the archipelago. Foraging whale models selected temperature at 584 m depth, surface chlorophyll, and location, while the only significant variables for non-foraging whale models included the standard deviation of sea surface height and location. Each variable provides insight into the oceanographic processes influencing prey abundance and, thus, sperm whale foraging behavior. This study furthers our understanding of the distribution patterns for the sperm whale population in Hawaiʻi and contributes methods for building SDMs with visual and passive acoustic data that may be applied to other cetacean species.

This study presents updated stock assessments and risk analyses of overexploitation for the aggregate small pelagic fish complex and the dominant genus of the complex, Decapterus, for improving the management of the small pelagic fishery in Fisheries Management Area (FMA) 715. The analyses herein used non-equilibrium biomass dynamics models with available data on annual catch and catch per unit effort for 2005 to 2016. Fishing effort was standardised into the number of 20-meter length overall purse-seine vessels. The analyses show that the maximum sustainable yield (MSY) of the aggregate fish was about 121,600 tonnes, caught by 876 purse-seiners, while the MSY of the mackerel scad, Decapterus macarellus (Cuvier, 1833), was about 67,900 tonnes, caught by 805 purse-seiners. Since the mackerel scad and the aggregate fish stocks have been overexploited, a rebuilding strategy would be necessary to restore the stocks to a level capable of producing MSY (BMSY). After achieving the BMSY, it is recommended that a target reference point be implemented for the catch level with the maximum overexploitation risk level of 50 % in 10 years. The catch level meeting this requirement for mackerel scad would equal 80 % of its MSY, which could be achieved by controlling fishing effort at 427 purse-seiners. At this effort level, the fishery would produce 95,800 tonnes of aggregate fish catch with 54,300 tonnes of mackerel scad. These reductions in fishing efforts will be needed to maintain the future sustainability of the fish stocks in FMA 715.

Cetaceans are ecologically important marine predators, and designating individuals to distinct populations can be challenging. Passive acoustic monitoring provides an approach to classify cetaceans to populations using their vocalizations. In the Hawaiian Archipelago, three genetically distinct, sympatric false killer whale (Pseudorca crassidens) populations coexist: a broadly distributed pelagic population and two island-associated populations, an endangered main Hawaiian Islands (MHI) population and a Northwestern Hawaiian Islands (NWHI) population. The mechanisms that sustain the genetic separation between these overlapping populations are unknown but previous studies suggest that the acoustic diversity between populations may correspond to genetic differences. Here, we investigated whether false killer whale whistles could be correctly classified to population based on their characteristics to serve as a method of identifying populations when genetic or photographic-identification data are unavailable. Acoustic data were collected during line-transect surveys using towed hydrophone arrays. We measured 50 time and frequency parameters from whistles in 16 false killer whale encounters identified to population and used those measures to train and test random forest classification models. Random forest models that included three populations correctly classified 42% of individual whistles overall and resulted in a low kappa coefficient, κ = 0.15, indicating low agreement between models, and the true population. Whistles from the MHI population showed the highest correct classification rate (52%) compared to pelagic and NWHI whistles (42 and 36%, respectively). Pairwise random forest models classifying pelagic and MHI whistles proved slightly more accurate (62% accuracy, κ = 0.24), though a similar pelagic-NWHI model did not (56% accuracy, κ = 0.12). Results suggest that the time-frequency whistle characteristics are not suitable to confidently classify encounters to a specific false killer whale population, although certain features of whistles produced by the endangered MHI population allow for overall higher classification accuracy. Inclusion of other vocalization types, such as echolocation clicks, and alternative whistle variables may improve correct classification success for these sympatric populations.

Globally, an increasing recognition of the importance of ecosystem-based management (EBM), Indigenous resource management (IRM), and Indigenous-led research and management is emerging; yet, case studies within scholarly literature illustrating comprehensive application of these theories and philosophies are scarce. We present the collaborative management model for the Heʻeia National Estuarine Research Reserve (NERR) as a contemporary Indigenous Community and Conserved Area (ICCA) that has synergistically operationalized these principles, as well as one that approaches research as a reciprocal collaboration with the Indigenous people and local community (IPLC) of place. The Heʻeia NERR was designated in 2017 through a process led by IPLC members in Hawaiʻi. This research framework is aimed at informing EBM within social-ecological systems. It, therefore, serves as an example of a program designed to demonstrate and provide practical solutions for adaptive resource management. The framework of the Heʻeia NERR embraces the values, perspectives, and IRM strategies that have been foundational for the people of the Pacific to thrive sustainably in the context of limited resources for millennia. As a program, the Heʻeia NERR aims to build bridges between coexisting worldviews as a means of informing policy in the realms of conservation and sustainability. We do this by weaving together conventional and Indigenous science to collaboratively develop research and collaboratively produce new knowledge. We examine these issues through the lens of holistic ecosystem services that consider both the reciprocal benefits that humans provide to nature as well as the full range of existential benefits that humans gain from nature. Research collaborations between the Heʻeia NERR and its partners (University of Hawaiʻi, state and federal agencies, and Indigenous-led NGOs operating in the community) are grounded in Indigenous and local knowledge (ILK) with applications that will guide a future of enhanced ecosystem services in a changing world.

Here, we expand on the term "ecomimicry" to be an umbrella concept for an approach to adaptive ecosystem-based management of social-ecological systems that simultaneously optimizes multiple ecosystem services for the benefit of people and place. In this context, we define ecomimicry as a strategy for developing and managing cultural landscapes, built upon a deep understanding of the structure and function of ecosystems, that harnesses ecosystem processes for the purpose of balancing and sustaining key ecosystem services, rather than maximizing one service (e.g., food production) to the detriment of others. Ecomimicry arises through novel, place-based innovations or is adopted from elsewhere and adapted to local conditions. Similarly, precontact Hawaiian social-ecological systems integrated a variety of ecomimicry schema to engender a complex system of adaptive resource management that enhanced biocultural diversity and supported resilient food systems, ultimately sustaining a thriving human population. In addition to presenting a synopsis of how ecomimicry was employed in the design and management of Hawaiian social-ecological systems, we identify and characterize specific ecomimicry applications. Within this context, we explore a revival of ecomimicry for biological conservation, biocultural restoration, resilience, and food security. We conclude with a discussion of how revitalizing such an approach in the restoration of social-ecological systems may address issues of conservation and sustainability in the Anthropocene.

Predictive habitat suitability models are powerful tools for cost-effective, statistically robust assessment of the environmental drivers of species distributions. The aim of this study was to develop predictive habitat suitability models for two genera of scleractinian corals (Leptoserisand Montipora) found within the mesophotic zone across the main Hawaiian Islands. The mesophotic zone (30–180 m) is challenging to reach, and therefore historically understudied, because it falls between the maximum limit of SCUBA divers and the minimum typical working depth of submersible vehicles. Here, we implement a logistic regression with rare events corrections to account for the scarcity of presence observations within the dataset. These corrections reduced the coefficient error and improved overall prediction success (73.6% and 74.3%) for both original regression models. The final models included depth, rugosity, slope, mean current velocity, and wave height as the best environmental covariates for predicting the occurrence of the two genera in the mesophotic zone. Using an objectively selected theta (“presence”) threshold, the predicted presence probability values (average of 0.051 for Leptoseris and 0.040 for Montipora) were translated to spatially-explicit habitat suitability maps of the main Hawaiian Islands at 25 m grid cell resolution. Our maps are the first of their kind to use extant presence and absence data to examine the habitat preferences of these two dominant mesophotic coral genera across Hawai‘i.

The structure and dynamics of coral reef environments vary across a range of spatial scales, with patterns of associated faunal assemblages often reflecting this variability. However, delineating drivers of biological variability in such complex environments has proved challenging. Here, we investigated the assemblage structure and diversity of parrotfishes—a common and ecologically important group—across 6° of latitude on the Northern Great Barrier Reef (GBR), Australia. Parrotfish abundance and biomass were determined from stereo-video surveys across 82 sites spanning 31 reefs and assessed against geographic, biophysical, and management-related factors in a multivariate framework to determine major drivers and associated scales of assemblage structure. Large cross-shelf variation in parrotfish assemblages pervaded along the entire Northern GBR, with distinct assemblages associated with sheltered and exposed reefs. Species abundances and diversity generally decreased with decreasing latitude. The gradient of explicit predator biomass associated with management zoning had no effect on parrotfish assemblage structure, but was positively correlated with parrotfish diversity. Our results highlight the ubiquitous presence of cross-shelf variation, where the greatest differences in parrotfish community composition existed between sheltered (inner and mid shelf) and exposed (outer shelf) reef systems. Prior attempts to explain linkages between parrotfishes and fine-scale biophysical factors have demonstrated parrotfishes as habitat generalists, but recent developments in nutritional ecology suggest that their cross-shelf variation on the GBR is likely reflective of benthic resource distribution and species-specific feeding modes.

Fisheries surveys over broad spatial areas are crucial in defining and delineating appropriate fisheries management areas. Yet accurate mapping and tracking of fishing activities remain largely restricted to developed countries with sufficient resources to use automated identification systems and vessel monitoring systems. For many countries, the spatial extent and boundaries of fishing grounds are not completely known. We used satellite images at night to detect fishing grounds in the Philippines for fishing gears that use powerful lights to attract coastal pelagic fishes. We used nightly boat detection data, extracted by U.S. NOAA from the Visible Infrared Imaging Radiometer Suite (VIIRS), for the Philippines from 2012 to 2016, covering 1713 nights, to examine spatio-temporal patterns of fishing activities in the country. Using density-based clustering, we identified 134 core fishing areas (CFAs) ranging in size from 6 to 23,215 km2 within the Philippines’ contiguous maritime zone. The CFAs had different seasonal patterns and range of intensities in total light output, possibly reflecting differences in multi-gear and multi-species signatures of fishing activities in each fishing ground. Using maximum entropy modeling, we identified bathymetry and chlorophyll as the main environmental predictors of spatial occurrence of these CFAs when analyzed together, highlighting the multi-gear nature of the CFAs. Applications of the model to specific CFAs identified different environmental drivers of fishing distribution, coinciding with known oceanographic associations for a CFA’s dominant target species. This case study highlights nighttime satellite images as a useful source of spatial fishing effort information for fisheries, especially in Southeast Asia.

The effects of tides on littoral marine habitats are so ubiquitous that shorelines are commonly described as ‘intertidal’, whereas waves are considered a secondary factor that simply modifies the intertidal habitat. However mean significant wave height exceeds tidal range at many locations worldwide. Here we construct a simple sinusoidal model of coastal water level based on both tidal range and wave height. From the patterns of emergence and submergence predicted by the model, we derive four vertical shoreline benchmarks which bracket up to three novel, spatially distinct, and physically defined zones. The (1) emergent tidal zone is characterized by tidally driven emergence in air; the (2) wave zone is characterized by constant (not periodic) wave wash; and the (3) submergent tidal zone is characterized by tidally driven submergence. The decoupling of tidally driven emergence and submergence made possible by wave action is a critical prediction of the model. On wave-dominated shores (wave height ≫ tidal range), all three zones are predicted to exist separately, but on tide-dominated shores (tidal range ≫ wave height) the wave zone is absent and the emergent and submergent tidal zones overlap substantially, forming the traditional “intertidal zone”. We conclude by incorporating time and space in the model to illustrate variability in the physical conditions and zonation on littoral shores. The wave:tide physical zonation model is a unifying framework that can facilitate our understanding of physical conditions on littoral shores whether tropical or temperate, marine or lentic.

The risk of global extinction of reef-building coral species is increasing. We evaluated extinction risk using a biological trait-based resiliency index that was compared with Caribbean extinction during the Plio-Pleistocene, and with extinction risk determined by the International Union for Conservation of Nature (IUCN). Through the Plio-Pleistocene, the Caribbean supported more diverse coral assemblages than today and shared considerable overlap with contemporary Indo-Pacific reefs. A clear association was found between extant Plio-Pleistocene coral genera and our positive resilience scores. Regional extinction in the past and vulnerability in the present suggests that Pocillopora, Stylophora and foliose Pavona are among the most susceptible taxa to local and regional isolation. These same taxa were among the most abundant corals in the Caribbean Pliocene. Therefore, a widespread distribution did not equate with immunity to regional extinction. The strong relationship between past and present vulnerability suggests that regional extinction events are trait-based and not merely random episodes. We found several inconsistencies between our data and the IUCN scores, which suggest a need to critically re-examine what constitutes coral vulnerability. [ABSTRACT FROM AUTHOR]

The reduction in coral cover on many contemporary tropical reefs suggests a different set of coral community assemblages will dominate future reefs. To evaluate the capacity of reef corals to persist over various time scales, we examined coral community dynamics in contemporary, fossil, and simulated future coral reef ecosystems. Based on studies between 1987 and 2012 at two locations in the Caribbean, and between 1981 and 2013 at five locations in the Indo-Pacific, we show that many coral genera declined in abundance, some showed no change in abundance, and a few coral genera increased in abundance. Whether the abundance of a genus declined, increased, or was conserved, was independent of coral family. An analysis of fossil-reef communities in the Caribbean revealed changes in numerical dominance and relative abundances of coral genera, and demonstrated that neither dominance nor taxon was associated with persistence. As coral family was a poor predictor of performance on contemporary reefs, a trait-based, dynamic, multi-patch model was developed to explore the phenotypic basis of ecological performance in a warmer future. Sensitivity analyses revealed that upon exposure to thermal stress, thermal tolerance, growth rate, and longevity were the most important predictors of coral persistence. Together, our results underscore the high variation in the rates and direction of change in coral abundances on contemporary and fossil reefs. Given this variation, it remains possible that coral reefs will be populated by a subset of the present coral fauna in a future that is warmer than the recent past.

Most reef-building corals in the order Scleractinia depend on endosymbiotic algae in the genus Symbiodinium for energy and survival. Significant levels of taxonomic diversity in both partners result in numerous possible combinations of coral-Symbiodinium associations with unique functional characteristics. We created and analyzed the first coral-Symbiodinium networks utilizing a global dataset of interaction records from coral reefs in the tropical Indo-Pacific and Atlantic Oceans for 1991 to 2010. Our meta-analysis reveals that the majority of coral species and Symbiodinium types are specialists, but failed to detect any one-to-one obligate relationships. Symbiont specificity is correlated with a host's transmission mode, with horizontally transmitting corals being more likely to interact with generalist symbionts. Globally, Symbiodinium types tend to interact with only vertically or horizontally transmitting corals, and only a few generalist types are found with both. Our results demonstrate a strong correlation between symbiont specificity, symbiont transmission mode, and community partitioning. The structure and dynamics of these network interactions underlie the fundamental biological partnership that determines the condition and resilience of coral reef ecosystems.

Growth anomalies (GAs) are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA) (n = 304 surveys) and Porites growth anomalies (PGA) (n = 602 surveys) from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies) found on different host genera (Acropora vs. Porites). As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment.

In Hawaii, coral reefs occur across a gradient of biological (host abundance), climatic (sea surface temperature anomalies) and anthropogenic conditions from the human-impacted reefs of the main Hawaiian Islands (MHI) to the pristine reefs of the northwestern Hawaiian Islands (NWHI). Coral disease surveys were conducted at 142 sites from across the Archipelago and disease patterns examined. Twelve diseases were recorded from three coral genera (Porites, Montipora, Acropora) with Porites having the highest prevalence. Porites growth anomalies (PorGAs) were significantly more prevalent within and indicative of reefs in the MHI and Porites trematodiasis (PorTrm) was significantly more prevalent within and indicative of reefs in the NWHI. Porites tissue loss syndrome (PorTLS) was also important in driving regional differences but that relationship was less clear. These results highlight the importance of understanding disease ecology when interpreting patterns of disease occurrence. PorTrm is caused by a parasitic flatworm that utilizes multiple hosts during its life cycle (fish, mollusk and coral). All three hosts must be present for the disease to occur and higher host abundance leads to higher disease prevalence. Thus, a high prevalence of PorTrm on Hawaiian reefs would be an indicator of a healthy coral reef ecosystem. In contrast, the high occurrence of PorGAs within the MHI suggests that PorGAs are related, directly or indirectly, to some environmental co-factor associated with increased human population sizes. Focusing on the three indicator diseases (PorGAs, PorTrm, PorTLS) we used statistical modeling to examine the underlying associations between disease prevalence and 14 different predictor variables (biotic and abiotic). All three diseases showed positive associations with host abundance and negative associations with thermal stress. The association with human population density differed among disease states with PorGAs showing a positive and PorTrm showing a negative association, but no significant explanatory power was offered for PorTLS.