Jesús Ernesto Arias-González

Reef fish assemblages in the Veracruz Reef System National Park (VRSNP) are strongly structured along a pronounced north–south gradient, where environmental conditions, urban proximity, and protection levels interact to shape functional diversity and ecosystem functioning. This gradient creates contrasting ecological conditions between northern and southern reefs, providing a natural framework for evaluating how spatial variation influences resilience. Using a stationary visual census across ten latitudinally distributed reefs, we quantified functional entities based on six ecological traits and calculated functional richness, redundancy, over-redundancy, vulnerability, specialization, and originality. Two-way permutational ANOVA and redundancy analysis were used to detect spatial and temporal patterns and to link functional indices to environmental features. The southern sector displayed the most pronounced functional shifts. Nearshore southern reefs, strongly exposed to sedimentation, nutrient loading, and physical disturbance, exhibited reduced functional richness, fewer functional entities, and high functional vulnerability, indicating strong environmental filtering. Over time, these reefs shifted toward generalist-dominated assemblages with rising redundancy, suggesting functional convergence. In contrast, southern offshore reefs supported higher taxonomic and functional richness, buffered by greater habitat complexity and greater distance from shore, although they showed declining redundancy, likely reflecting sensitivity to regional climatic disturbances. In the northern sector, the gradient was moderated by effective protection, which reshaped functional configurations. Nearshore protected reefs such as Isla Sacrificios and Isla de Enmedio maintained high redundancy, low vulnerability, and high biomass of large-bodied fishes, resembling offshore systems rather than disturbed southern nearshore reefs. The northern offshore reef (Isla Verde) shared some of these attributes but exhibited temporal declines in richness, signaling emerging vulnerabilities along the gradient. Functional originality and specialization aligned with benthic states across the gradient, particularly where macroalgal or calcareous substrates prevailed. Overall, the north–south gradient is the primary axis of functional organization in VRSNP, revealing that resilience emerges from the interplay among reef geomorphology, urban influence, and governance effectiveness.

Ocean warming is increasing the frequency, extent, and severity of tropical-coral bleaching and mortality. During 2014–2017, marine heatwaves caused the Third Global Coral Bleaching Event. We analyze data from 15,066 reef surveys globally during 2014–2017. Across all surveyed reefs, 80% and 35% experienced moderate or greater (affecting >10% of corals) bleaching and mortality, respectively. We assess the global extent of coral bleaching and mortality by applying bleaching response curves calibrated from surveyed reefs to predict bleaching globally, based on comprehensive remote-sensing of heat stress. These models predict that 51% and 15% of the world’s coral reefs suffered moderate or greater bleaching and mortality, respectively, during one or multiple years, surpassing damage from any prior global coral bleaching event. Our findings demonstrate that the impacts of ocean warming on coral reefs are accelerating, with the near certainty that ongoing warming will cause large-scale, possibly irreversible, degradation of these essential ecosystems. With heat stress levels during this event surpassing those observed previously, the National Oceanic and Atmospheric Administration developed more extreme Bleaching Alert levels that are now being used during the ongoing Fourth Global Coral Bleaching Event.

Marine heatwaves (MHWs) have become increasingly frequent and intense, raising concerns about their impacts on fisheries production and economic value. We present a global assessment of MHW-related impacts across 2088 marine fisheries from 1985 to 2022. Using high-resolution satellite data and standardized catch production and catch value, we identified significant reductions in catch and ex-vessel value during years of elevated thermal stress. A total of 322 fisheries (15%) showed statistically significant declines during years with high MHW activity, with regional disparities indicating that the Northeast Atlantic and Southeast Pacific experienced the highest cumulative losses, while country ranking highlighted Norway, China, Japan, and Peru as the most affected. Estimated accumulated global losses since 1985 exceeded 5.6 million tonnes and USD 6.6 billion (2005 USD equivalents), nearly 40% of which occurred during 2013–2022. These findings emphasize the need to incorporate extreme thermal events into fisheries risk assessments and adaptation strategies, especially in highly productive or strategic regions.

Acropora palmata, a keystone Caribbean coral species, is currently subject to intense restoration efforts across the region. Despite its known annual broadcast spawning, in situ monitoring of 33 colonies in Cozumel, Mexico, from 2018 to 2025 revealed a near-complete absence of spawning activity. While “setting” was occasionally observed, no simultaneous spawning events occurred among colonies, impeding assisted fertilization. This eight-year effort, involving academic institutions, government, NGOs, and the community, highlights the breakdown in reproductive synchrony of A. palmata. We discuss possible contributing factors, including artificial light, sedimentation, thermal anomalies, water quality and direct human impact. These findings demand immediate regional attention and investigation to identify the underlying causes of this reproductive failure.

Coral reefs are threatened by multiple stressors that have driven a decline in the cover of reef-building coral species, resulting in a loss of reef structure and function. Restoration reef science provides useful conservation tools to preserve and restore the key species and ecological functions of these ecosystems. However, gaps remain in restoration at large scales. This study provides a guide of how to invest and apply innovative solutions and immediate action strategies from the tourism-hotel sector in alliance with academia and key stakeholders, through the development and implementation of a multi-species restoration program at two sites in the Mexican Caribbean: Manchoncitos Reef, Riviera Maya and La Francesita Reef, Cozumel. We have identified effective propagation and outplanting techniques for key critically endangered species, as well as genotypes resistant to temperature stress and Stony Coral Tissue Loss Disease (SCTLD), based on pre-restoration nursery trials. We include a comparative analysis over time (2020–2022) showing increased coral cover, structural complexity and fish biomass. Baseline assessment of the study areas will allow adaptation of repopulation techniques not only for hard corals, but also to advance in the comprehensive restoration of the ecosystem, incorporating new elements to the reef, such as fish, crab or sea urchin post larvae. These organisms could accelerate herbivory functions and in turn could improve the natural processes of the coral reefs. Our results improve the understanding of the use of restoration as a tool for climate change adaptation led by the private sector.

A wide range of fish species are caught in reef fisheries. However, fishing efforts tend to be highly selective in favor of large species, which generally have low population growth rates, making them more vulnerable to overfishing. When the decline of large predators occurs, fishing efforts start to focus on catching species from lower trophic levels, which can cause a trophic cascade effect. The objective of this research was to detect changes in the density and biomass of fish communities in areas with different fishing intensity in the study area. This study was carried out in the Banco Chinchorro Biosphere (BCBR) in the Mexican Caribbean and analyze the effect of fishing intensity on fish density and biomass, comparing data obtained from visual censuses with dependent information of the fishery. Evidence was found of a relationship between high fishing exploitation and low levels of density and biomass for Epinephelus striatus, E. guttatus and Lachnolaimus maximus. The decline of predators had no evident effect on the density and biomass of non-commercially important species. The density and biomass of commercially important fish species were influenced by the presence of algae, octocorals, hydrocorals and by variations in their catch per unit of effort (CPUE). This study detected that density and biomass have decreased in some species belonging to the Serranidae and Lutjanidae families in areas with high fishing intensity. On the other hand, little evidence was found that the density and total biomass of families of noncommercially important species increased through the decline of their predators. These results are consistent with previous work documenting how fishing activity affects fish species with high trophic levels. The information generated will help the Reserve’s managers make decisions towards better management and conservation of fishery resources.

Coral bleaching, a consequence of stressed symbiotic relationships between corals and algae, has escalated due to intensified heat stress events driven by climate change. Despite global efforts, current early warning systems lack local precision. Our study, spanning 2015–2017 in the Mesoamerican Reef, revealed prevalent intermediate bleaching, peaking in 2017. By scrutinizing 23 stress exposure and sensitivity metrics, we accurately predicted 75% of bleaching severity variation. Notably, distinct thermal patterns—particularly the climatological seasonal warming rate and various heat stress metrics—emerged as better predictors compared to conventional indices (such as Degree Heating Weeks). Surprisingly, deeper reefs with diverse coral communities showed heightened vulnerability. This study presents a framework for coral reef bleaching vulnerability assessment, leveraging accessible data (including historical and real-time sea surface temperature, habitat variables, and species composition). Its operational potential lies in seamless integration with existing monitoring systems, offering crucial insights for conservation and management.