The research team, led by Rosa Carmen Sotelo-Casas of the University of Guadalajara, monitored benthic communities in three bay systems: Chamela Bay, the Tenacatita-Barra de Navidad bays, and the Santiago-Manzanillo bays. These locations were chosen because they harbor some of the best-preserved coral ecosystems in the region, each maintaining an average live coral cover of at least 29 percent. Between February 2010 and October 2023, divers combined visual surveys along belt transects with underwater video analysis, extracting forty frames from each recording and overlaying a grid of fifty random points per frame, which yielded two thousand scored points per video. This dual technique allowed the researchers to quantify the cover of reef-building corals, algal turf, fleshy macroalgae, encrusting calcareous algae, and inert substrate with enough precision to track change across thirteen turbulent years.

The reefs themselves are dominated by a single remarkable genus. Pocillopora, the branching coral that forms the structural backbone of these systems, accounted for an average of 30 percent of total benthic cover, dwarfing the contributions of Porites, Pavona, and Psammocora. In total, the team recorded eighteen species of scleractinian coral across the region, with the Santiago-Manzanillo bays supporting the highest richness at sixteen species, followed by Tenacatita-Barra de Navidad with fourteen and Chamela Bay with eight. The rest of the seascape was a dynamic mosaic: algal turf averaged 29 percent, inert substrates 25 percent, encrusting calcareous algae 9 percent, and fleshy macroalgae just 4.5 percent, with sponges, octocorals, bryozoans, and other sessile invertebrates each contributing less than 2 percent.

What makes this region scientifically fascinating is its position at a biogeographic crossroads. The Central Mexican Pacific sits in a transitional zone between the Warm Temperate Northeast Pacific and the Tropical Eastern Pacific ecoregions, bounded to the north by the entrance to the Gulf of California and to the south by the Isthmus of Tehuantepec. The region experiences two sharply contrasting hydroclimatic seasons. From February to June, the equatorward branch of the California Current drives strong wind-powered coastal upwelling, pushing cold, nutrient-rich deep water to the surface and fueling blooms of phytoplankton. From July to January, the poleward Mexican Coastal Current takes over, promoting warm, nutrient-poor conditions. Sea surface temperatures swing from an average of 22.5 degrees Celsius in the dry season to 28.3 degrees in the rainy season, a gradient that can widen by up to 10 degrees when El Niño or La Niña events superimpose their thermal anomalies on the local cycle.

To untangle how these forces shape the reefs, the researchers paired their biological monitoring with satellite-derived environmental data, including sea surface temperature, chlorophyll-a concentration, and the diffuse attenuation coefficient, a measure of water clarity. They then applied a battery of statistical tools rarely seen together in reef ecology: Granger causality tests to determine whether large-scale ENSO indices actually drive local thermal anomalies, periodogram-based dissimilarity measures to compare the rhythms of environmental time series, and beta regression models to link each benthic group’s cover to specific environmental variables with quarterly and semiannual time lags. The results were striking. Of the seven ENSO indices tested, only the Niño 4 index showed consistent and significant causality with local sea surface temperature anomalies at all three sites, indicating that only certain flavors of El Niño genuinely reach these coastal waters.

The interplay between global climate oscillations and local upwelling proved to be the decisive factor in reef survival. When the 2010 to 2012 La Niña event overlapped with the spring 2012 upwelling season, sea surface temperatures plunged below 22 degrees Celsius, thermal anomalies reached roughly minus 4 degrees, chlorophyll-a concentrations climbed above 10 milligrams per cubic meter, and water turbidity hit record values. Conversely, during the 2015 to 2016 El Niño nicknamed Godzilla, the upwelling season kept temperatures below 30 degrees throughout the spring and delayed anomalies exceeding 2 degrees until autumn, effectively buffering the reefs against the worst of the marine heatwave. The timing, the authors conclude, is everything: when an ENSO event opposes the local seasonal cycle, upwelling acts as a stress mitigator, but when the two align, thermal extremes are amplified.

Each reef told its own story of loss and recovery. Chamela Bay, the northernmost and deepest site, kept live coral cover above 19 percent throughout the study, dipping to its lowest point in 2017 before steadily recovering to roughly 29 percent by 2023. The Tenacatita-Barra de Navidad bays suffered the harshest blow, losing 28 percent of coral cover between 2013 and 2014, when cover fell to about 14 percent from a starting point above 46 percent in 2010, yet the system rebounded to approximately 38 percent by 2023. The Santiago-Manzanillo bays, which consistently held the highest coral cover, peaked near 52 percent in 2019 before declining 13 percent in 2023, a drop the researchers attribute to the combined effect of the prolonged 2023 El Niño and heated water discharged from a thermoelectric power plant in the Cuyutlán lagoon near the port of Manzanillo.

The beta regression models revealed that every benthic group responds to a distinct set of environmental levers, and that these levers differ from site to site. Coral cover at Chamela Bay was best explained by the previous semiannual chlorophyll-a value, with a negative relationship, while at Tenacatita-Barra de Navidad the key drivers were local sea surface temperature and thermal anomalies, both negative, and at Santiago-Manzanillo it was the previous quarterly thermal anomaly. Algal turf, the great opportunist of reef surfaces, responded to thermal anomalies with site-specific lags, expanding as anomalies rose at the two northern sites but shrinking at Santiago-Manzanillo, a pattern suggesting that turf dynamics are governed less by temperature itself than by the availability of bare space created when corals die. Encrusting calcareous algae peaked at all three sites in 2017, shortly after the Godzilla El Niño, apparently exploiting the combination of moderate irradiance, elevated nutrients, and fresh settlement space left behind by coral mortality.

These findings carry implications that extend far beyond the Mexican coast. Globally, roughly one-third of the planet’s live coral cover has been lost over the past five decades, and during the 2023 El Niño event, reef ecosystems elsewhere in the Mexican Pacific suffered catastrophic losses of up to 90 percent of coral cover. Yet the Central Mexican Pacific reefs persisted, and the study points to two explanations. First, pronounced seasonal upwelling appears to shield corals from the most severe thermal anomalies, preventing local temperatures from exceeding critical thresholds and boosting productivity that buffers heat stress. Second, the historical gauntlet of thermal events these populations have endured may have selected for strains and colonies that are genetically and physiologically more resistant, a process reinforced by recent evidence that corals exposed to repeated bleaching develop metabolomic and epigenetic adaptations in their tissues, symbiotic algae, and bacterial communities.

The study also delivers a sobering caveat. Resilience is not immunity. The 2023 decline at Santiago-Manzanillo demonstrates that when a powerful El Niño synchronizes with local anthropogenic warming, even the region’s most robust reefs can be pushed past their tolerance limits. The researchers caution that long-term genetic monitoring will be needed to determine whether these coral assemblages are undergoing population turnover after each thermal crisis, and they note that classifying algae into functional groups, while useful for detecting broad patterns, may mask species-level differences driving site-specific behavior. Still, in an era when coral reef news is dominated by collapse, the Central Mexican Pacific offers something increasingly precious: a documented case of reefs that bend under environmental pressure, recover with remarkable speed, and may hold the secrets to how corals everywhere might weather the century ahead.

Subject of Research: Long-term benthic changes and resilience of coral reef ecosystems in the Central Mexican Pacific in response to ENSO events and upwelling

Article Title: Ten years of coral reef benthic changes in the Central Mexican Pacific

Article References: Sotelo-Casas, R. C., Rodríguez-Zaragoza, F. A., Rodríguez-Troncoso, A. P., Cupul-Magaña, A. L., & Godínez-Domínguez, E. (2025). Ten years of coral reef benthic changes in the Central Mexican Pacific. Discover Ecology, 1(1), Article 14. https://doi.org/10.1007/s44396-025-00017-6

Image Credits: AI Generated

DOI: 10.1007/s44396-025-00017-6

Keywords: coral reefs, Central Mexican Pacific, ENSO, El Niño, upwelling, Pocillopora, algal turf, coral bleaching, benthic cover, sea surface temperature, reef resilience, beta regression

The scientific motivation is sobering. Caribbean reefs have lost roughly 80 percent of their average hard coral cover over three decades, collapsing from around 50 percent in the 1970s to about 10 percent by the early 2000s, driven by a compounding mix of overfishing, nutrient pollution, disease outbreaks, and climate-driven bleaching. The monitoring window for Isla Solarte overlapped the fourth global coral bleaching event, confirmed by NOAA and the International Coral Reef Initiative in 2024, with bleaching-level heat stress recorded across every major ocean basin including the Caribbean. Against that backdrop, sustained and standardized local monitoring is essential to separate natural variability from human-induced decline and to judge whether conservation measures are working. Yet while large programs such as NOAA’s National Coral Reef Monitoring Program cover U.S. jurisdictions, and earlier efforts like CARICOMP monitoring in Bocas del Toro and fifteen years of Smithsonian-affiliated surveys have built an important regional record, recent open datasets integrating multiple survey types at named Isla Solarte sites simply did not exist.

The logistics of the project are as interesting as the ecology. Rather than relying on occasional volunteers, Ankay Conservation ran a residential model: participants lived on site for multi-week stints, completed six to eight days of preparatory training with daily lectures and in-water identification exercises, and then executed intensive survey windows under staff supervision. This schedule produced 175 unique survey dates across roughly two years, with a median interval of just one day between active survey dates and an average of 16.9 surveys per active month, peaking at 42. Between July 2023 and August 2025, 48 trained participants completed the benthic work, while 19 others handled fish surveys after separate training. Benthic teams laid 30-meter transects parallel to the reef contour, holding depth within about two meters, and sampled substrate every 25 centimeters, yielding 120 point observations per transect. At each point they recorded the organism or substrate directly beneath the tape, a classic point-intercept approach adapted from established reef monitoring principles.

Where the transect line crossed live hard coral, observers logged far more than presence. They classified growth form into seven morphotypes, from massive and encrusting to branching, brain-like meandroid, leaf-like plating, solitary, fleshy, and digitate forms, and they recorded the coral’s condition using standardized field codes: healthy, degraded, bleached, dead, or diseased. Degradation was graded as mild when roughly 10 to 50 percent of the visible coral surface showed tissue loss or overgrowth, and heavy beyond that threshold. Bleaching was split into paling, partial, and full categories. Disease observations included yellow band, black band, and white tissue-loss signs coded under a broad white band disease field code, with the authors careful to note that these were visual field observations rather than laboratory-confirmed diagnoses. The Atlantic and Gulf Rapid Reef Assessment protocol, known as AGRRA, served as the terminological and structural backbone, with tighter methodological alignment for the fish surveys than for the benthic design.

Fish teams used a modified belt transect visual census. After laying a 30-meter tape, they waited five minutes for fish behavior to settle, then two divers swam the line in parallel for ten minutes, each independently recording all fishes within a one-meter belt, covering 60 square meters per transect. Every individual was assigned to species and to one of six size classes, from under 5 centimeters to over 40. The target list drew from 17 families plus invasive lionfish, spanning commercially valuable snappers, groupers, and jacks alongside ecologically critical herbivores such as parrotfishes and surgeonfishes. Structural complexity was estimated by measuring maximum relief, the height of the tallest coral or rock above the lowest substratum, at six fixed points along each transect. To keep data honest, staff reviewed at least the first two surveys from each participant, held post-dive sheet checks, and excluded incomplete records, retaining only benthic transects with 115 to 120 valid point observations.

The ecological picture that emerged is one of stressed but spatially patchy reefs. Mean live coral cover across all transects was just 6.45 percent, ranging from zero to 28.3 percent on individual transects, with site means spanning 3.61 percent at Buoy Line to 9.73 percent at Grandma’s Garden. A Kruskal-Wallis test confirmed these site differences were statistically robust, and post-hoc comparisons pinpointed which sites differed. Algae dominated more space still, averaging 14.15 percent cover and reaching 43.3 percent on some transects, with Pandora showing the highest site mean at 19.54 percent. Sponges formed another substantial living category. A PERMANOVA on the full multivariate benthic composition confirmed that the five sites host genuinely distinct communities rather than one uniform reef, a finding the authors argue justifies site-level monitoring, since pooling nearby reefs into a single regional average would erase exactly the differences that matter for management.

Coral health data added a layer of nuance. From 1,778 retained coral-health records, the most common observations were healthy coral points, followed by mild and heavy degradation; acute disease signs were rare, with only isolated yellow band, black band, and white tissue-loss records across all sites and years. Bleaching-related observations, however, told a temporal story: when paling, partial, and full bleaching were combined into a single score, mean values were significantly higher in 2023 than in 2024 or 2025, with sites including Pandora, Buoy Line, and Grandma’s Garden showing elevated signals during the first survey year. Given that 2023 marked the onset of the fourth global bleaching event, the pattern is striking, though the authors urge caution because sampling was unevenly balanced across sites and years, and a point-intercept design can miss transient bleaching episodes entirely.

The fish surveys sketched a community shaped, plausibly, by human pressure. Parrotfishes and grunts were the most frequently recorded groups, while large-bodied predators and mesopredators were uncommon, and most individuals fell into the 6 to 20 centimeter size classes. Herbivores peaked at Casablanca, whereas predators were recorded more often at Pandora, the site with the highest mean maximum relief at 29 centimeters, hinting that structural complexity may bolster refuge availability for larger fish, though site-level relief differences were not statistically significant and no causal test was performed. Correlation analyses among substrate categories reinforced interpretive restraint: hard coral and macroalgae showed only a weak positive association, meaning the data do not demonstrate direct coral-algal competition or replacement, while abiotic substrate correlated negatively with most living categories.

What elevates the work beyond a local dataset is its demonstration of a replicable model. The full dataset is openly available on Zenodo, complete with metadata and R scripts on GitHub for reproducing every figure, and records also feed the Global Coral Reef Monitoring Network. The authors are candid about the limitations: participant backgrounds were not systematically logged, formal inter-observer reliability testing was not conducted, and observer variability, visibility, and uneven sampling effort all remain sources of noise. Yet standardized protocols, simplified field categories, staff audits of early surveys, and aggressive data cleaning appear to have produced numbers coherent enough to detect statistically significant site-level patterns. In an era when professional monitoring budgets cannot cover every reef that needs watching, Isla Solarte’s volunteer divers have made a case that structured citizen science, done rigorously, can fill gaps that would otherwise stay dark, while building the local capacity that long-term conservation ultimately depends on.

Subject of Research: Citizen science monitoring of coral reef condition at Isla Solarte, Bocas del Toro, Panama

Article Title: Citizen science baseline dataset for monitored reef sites around Isla Solarte, Bocas del Toro, Panama (2023–2025)

Article References: Sills, P., & Young, R. (2026). Citizen science baseline dataset for monitored reef sites around Isla Solarte, Bocas del Toro, Panama (2023–2025). Discover Oceans, 3(1), Article 40. https://doi.org/10.1007/s44289-026-00155-z

Image Credits: AI Generated

DOI: 10.1007/s44289-026-00155-z

Keywords: coral reefs, citizen science, Bocas del Toro, Panama, coral bleaching, reef monitoring, benthic cover, fish assemblages, AGRRA, Caribbean, open data, conservation