Search Results (106)

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. Full article

Sharks play a key role in coral reef ecosystems, but Caribbean populations are concerningly low. When monitoring endangered species, it is critical to use minimally invasive tools and protocols that are adequate for local species and the environment. This study investigated the adequate deployment time of baited remote underwater videos (BRUVs) for shark studies in the Cayman Islands and whether the use of photo-identification to recognise individuals (MaxIND) on BRUVs could improve abundance estimates (in comparison to MaxN) and the analysis of shark behaviour. From 2015 to 2018, a total of 557 BRUVs were deployed with recording times ranging from 3.8 to 211.03 min. The results showed that (1) of the total number of individual sharks recorded on videos, 95% of individuals were recorded within the first 110 min (slight variations between species), (2) MaxIND values were 1.1–1.5 times greater than that of MaxN (ratios varying with species) and (3) time of first arrival (Tarrive) was similar for all recorded species but time spent in front of the camera’s field of view (Tvisit) and activity levels (count of entries in camera’s field of view) varied between species. The results provide key information to improve the localised monitoring of rare/endangered species and can inform conservation management. Full article

Coral reefs provide environmental goods and services that support biodiversity and people but face diverse threats. To assess the human factors that might be influencing the status of Cuban coral reefs, we collected and analyzed data from three sources: observations made on a research cruise that circumnavigated Cuba’s waters, expert knowledge, and updated published information. Our results show that small-scale fisheries are predominant among human factors influencing Cuban coral reefs, with more than 97% of the fishing incidents detected in situ during the expedition. Many Cuban reefs are heavily fished, have low levels of contamination, and enjoy high legal protection but experience inadequate enforcement. Tourism occurs on many reefs but could be sustainably increased based on its role in supporting enforcement and compliance and reducing fishing pressure. Densities of marine debris were generally lower in Cuban waters than other Caribbean locations and even lower within protected areas. Many human factors are likely acting synergistically, making management a challenge. This is the first at-sea comprehensive visual survey of human factors in Cuban waters and evaluation of marine debris on Cuba’s reefs, establishing a baseline for future assessments. These findings highlight potential human impacts that must be addressed to safeguard the health of Cuba’s marine ecosystem. Full article

Extreme sea surface temperature (SST) events, such as marine heatwaves (MHWs) and marine cold spells (MCSs), severely affect warm water coral reefs. However, further study is required on their historical and future spatiotemporal patterns, driving mechanisms, and impacts in coral reef regions. This study analyzed the spatiotemporal patterns in MHWs/MCSs for the periods 1982–2022 and 2023–2070 using ten indices based on OISSTv2.1 and CMIP6 data, respectively, identified key MHW drivers via four machine learning methods (Random Forest, Extreme Gradient Boosting, Light Gradient Boosting Machine, and categorical boosting) and SHAP values (Shapley Additive Explanations), and then examined their relationship with coral coverage across ten global marine regions. Our results revealed that (1) MHWs are not only increasing in their average intensity but also becoming more extreme, while MCSs have declined. More MHW days are observed in regions like the Red Sea, the Persian Gulf, and the South Pacific Islands, with increases of up to 28 days per decade. (2) Higher-latitude coral reefs are experiencing more severe MHWs than equatorial regions, with up to 1.24 times more MHW days, emphasizing the urgent need to protect coral refuges. (3) MHWs are projected to occur nearly year-round by 2070 under scenario SSP5–8.5. The area ratio of MHWs to MCSs is expected to rise sharply from 2040 onward, reaching approximately 100-fold under the SSP2–4.5 scenario and 196-fold under the SSP5–8.5 scenario, particularly in the Marshall Islands and Caribbean Sea regions. (4) The coefficient of variation (CV) of annual temperature, annual ocean heat content, and monthly temperature were the top three factors driving MHW intensity. We emphasize that future MHW predictions should focus more on the CV of forecasting indicators rather than just the climate means. (5) Coral coverage exhibited post-mortality processes following MHWs, showing a strong negative correlation (r = −0.54, p < 0.01) with MHWs while demonstrating a significant positive correlation (r = 0.6, p < 0.01) with MCSs. Our research underscores the sustained efforts to protect and restore coral reefs amid escalating climate-induced stressors. Full article

The hydrocoral Millepora complanata (fire coral) plays a critical role in reef structure and relies on a symbiotic relationship with Symbiodiniaceae algae. Environmental stressors derived from climate change, such as UV radiation and elevated temperatures, disrupt this symbiosis, leading to bleaching and threatening reef survival. To gain insight into the thermal stress response of this reef-building hydrocoral, this study investigates the proteomic response of M. complanata to bleaching during the 2015–2016 El Niño event. Fragments from non-bleached and bleached colonies of the hydrocoral M. complanata were collected from a coral reef in the Mexican Caribbean, and proteomic extracts were analyzed using nano-liquid chromatography–tandem mass spectrometry (nano-LC-MS/MS). Uni- and multivariate analyses were applied to identify significant differences in protein abundance. A total of 52 proteins showed differential abundance, including 24 that showed increased expression and 28 whose expression decreased in bleached fragments. Differentially abundant proteins were associated with amino acid biosynthesis, carbohydrate metabolism, cytoskeleton organization, DNA repair, extracellular matrix composition, redox homeostasis, and protein modification. These molecular alterations reflect critical physiological adaptations that may influence stress sensitivity or tolerance in hydrocorals. The findings indicate that heat stress induces molecular responses involving protein refolding, enhanced vesicular transport, cytoskeletal reorganization, and modulation of redox activity. This contributes to a deeper understanding of the molecular mechanisms underlying bleaching in reef-building hydrozoans and broadens current knowledge beyond the more extensively studied anthozoan corals. Full article

A quantitative literature review of restoration techniques and supporting management strategies used throughout the Caribbean and Western Atlantic from 1998 through 2024 was compiled using references from the Web of Science to highlight those with potential for reef replenishment. From 93 sources listed, 74 publications were relevant and categorized into subtopics based on the most prevalent restoration techniques. Roughly half the studies focused on three general topics: the benefits of restoring Acropora species, studies utilizing micro-fragmentation and fragment nurseries, and outplanting techniques. Other subtopics, each with at least three references, included optimizing substrates and artificial reefs, enhancing larval recruitment, emphasizing the role of herbivory, improving management practices, and addressing the impacts of tourism and community engagement. The information from the references was compiled to determine the overlap among categories and the ways in which techniques and management strategies might be applied simultaneously to enhance restoration outcomes. Additionally, sources were analyzed according to time and location of publication to better visualize the emergence of this area of research and restoration efforts. An increase in publications was observed from 2014 to 2024, associated with the rise in major events impacting coral reefs. The major locations for published research were the Florida reef tract and Puerto Rico, though restoration studies were also reported from the Bahamas and sites around the Caribbean. Criteria to assess the success of techniques included coral survival, recruitment, coral coverage, habitat structure and complexity, and biomass of marine life, including fish and invertebrates that inhabited a restored reef. Most restoration efforts utilized either fragmentation or assisted sexual breeding, followed by cultivation in nurseries or labs. Outplanting success depended on fragment size, attachment style, and site selection, with less-intrusive techniques and intermediate planting densities promoting survival. Tools like GAO maps can guide site selection based on herbivore presence and algal coverage. Monitoring is critical to ensuring coral survival, especially after the first year of outplanting, while community involvement can foster public engagement in reef conservation. Full article

Marine heatwaves (MHWs) are increasingly affecting tropical seas, causing mass coral bleaching and mortality in the wider Caribbean (WC) and eastern tropical Pacific (ETP). This leads to significant coral loss, reduced biodiversity, and impaired ecological functions. Climate models forecast a troubling future for Latin American coral reefs, but downscaled projections for the WC and ETP remain limited. Understanding regional temperature thresholds that threaten coral reef futures and restoration efforts is critical. Our goals included analyzing historical trends in July–August–September–October (JASO) temperature anomalies and exploring future projections at subregional and country levels. From 1940 to 2023, JASO air and ocean temperature anomalies showed significant increases. Projections indicate that even under optimistic scenario 4.5, temperatures may exceed the +1.5 °C air threshold beyond pre-industrial levels by the 2040s and the +1.0 °C ocean threshold beyond historical annual maximums by the 2030s, resulting in severe coral bleaching and mortality. Business-as-usual scenario 8.5 suggests conditions will become intolerable for coral conservation and restoration by the 2030s, with decadal warming trends largely surpassing historical rates, under unbearable conditions for corals. The immediate development of regional and local adaptive coral reef conservation and restoration plans, along with climate change adaptation and mitigation strategies, is essential to provide time for optimistic scenarios to materialize. Full article

Background: Brown algae from the order Dictyotales are known to produce specialized metabolites with a wide array of biological activities. Studying these compounds is important for understanding their ecological roles, exploring biomedical potential and developing biotechnological applications. Methods: To evaluate the metabolic diversity of brown algae from the shallow habitats of the northern region of San Andrés Island (Colombia, SW Caribbean), a metabolic profiling approach was employed, based on ¹H-NMR spectra taken from organic extracts. Four sampling expeditions were conducted to collect the most abundant species, taking into account the taxonomic identity, growth substrate and collection date. Results: Five species were found and identified as Canistrocarpus crispatus, Stypopodium zonale, Dictyopteris delicatula, Padina gymnospora and Dictyota spp. Multivariate analyses applied to these spectra revealed that S. zonale and C. crispatus differentiated from the other samples mainly due to the signals for meroditerpenes and diterpenes, respectively. S. zonale had differential metabolic production observed when comparing algae collected in rocky bottoms with thalli growing on dead coral. This difference was attributed to changes in concentrations of the meroditerpene atomaric acid (1). Meanwhile, the major metabolite found in C. crispatus samples was dictyol B acetate (2). Conclusions: NMR metabolomics of San Andrés brown algae differentiated species based on lipid content and metabolic complexity. Notably, prenylated-guaiane diterpenes characterized C. crispatus, and meroditerpenoid concentrations varied in S. zonale. Temporal lipid variations were observed in P. gymnospora, while juvenile Dictyota spp. presented a less complex metabolic signature. Full article

The hypothesis that disturbance to coral reefs creates new surfaces that increase the risk of ciguatera is premised upon the increased algal substrates that develop on these surfaces being colonised by high ciguatoxin (CTX)-producing Gambierdiscus species that proliferate and enter the ciguatera food chain. Current evidence indicates that new algal substrates are indeed rapidly colonised by Gambierdiscus. However, the requirement that these Gambierdiscus species include at least one that is a significant (high) CTX-producer is more likely a limiting step. While ambient environmental conditions impact the capacity of Gambierdiscus to bloom, factors that limit the growth of the bloom could influence (typically increase) the flux of CTX entering marine food chains. Additionally, new algal substrates on damaged reefs can be preferentially grazed to funnel ciguatoxins from Gambierdiscus to herbivores in disturbed reef areas. In societies consuming second trophic level species (herbivores, grazers, and detritivores), such funnelling of CTX would increase the risk of ciguatera, although such risk would be partially offset over time by growth (toxin-dilution) and depuration. Here, we review evidence for six potential mechanisms to increase ciguatera risk from disturbance to coral reefs and suggest a hypothesis where ecosystem changes could increase the flux of CTX to groupers through a shift in predation from predominately feeding on planktonic-feeding prey to mostly feeding on benthic-feeding prey, increasing the potential for CTX to accumulate. Evidence for this hypothesis is stronger for the Pacific and Indian Oceans, and it may not apply to the Caribbean Sea/Atlantic Ocean. Full article

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. Full article

The tropical coral Siderasterea radians is typically found in mangrove areas, seagrass beds, and environments tolerated by few other scleractinians in the Caribbean and South Florida. Siderastrea radians experience bleaching stress in Buttonwood Sound in Florida Bay during April–May, a time when the seawater is below bleaching temperatures. Stress first appears as a pink coloration due to the presence of fluorescent pigments protecting the coral tissue and algal symbionts from exposure to excessive sunlight/UV light. Surveys of S. radians in areas frequented by parrotfish showed that up to 38.5% of the corals were pink, with about a quarter of all the corals having bite marks. In areas not frequented by parrotfish, only 3.2% of the corals were pink, and none had bite marks. A seasonal analysis in parrotfish-frequented seawater showed S. radians contained among the lowest tissue biomass and density of symbiotic algae during April–May 2010–2017, often looking pink. It is hypothesized that seawater temperature is not the cause of bleaching in Buttonwood Sound during April–May but rather predation by the rainbow parrotfish Scarus guacamaia. Full article

The infraclass Euthyneura (Mollusca, Heterobranchia) exhibits significant diversity in morphology, size, life habits, and color. Several species are important for research in evolution, ecology, chemistry, and pharmacology. Despite Colombia’s expansive Pacific and Caribbean coasts, which host ecosystems such as rocky shores and coral reefs, key habitats for sea slugs and sea hares, the biodiversity of Euthyneura remains largely understudied. This study aims to expand the inventory of Euthyneura diversity in intertidal and shallow subtidal rocky and coral reef environments in Colombia’s Pacific (Uramba Bahía Málaga National Natural Park) and Caribbean (Seaflower Biosphere Reserve) areas. Rapid biodiversity assessments using snorkeling and errant scuba diving at depths of 1–40 m resulted in the documentation of 31 species (14 in Caribbean coral reefs and 17 in Pacific intertidal and shallow subtidal rocky shores and reefs). Eleven species were new records. The family Aplysiidae was the richest with five species, followed by Facelinidae with four, and Aeolidiidae, Discodorididae, Chromodorididae, and Plakobranchidae with three each. Given the limited sampling effort (~40 h in the Caribbean and ~20 h in the Pacific) and the substantial new data collected, it is evident that there is still much to learn about this group in these areas. Increased efforts, combined with detailed morphological and molecular techniques, will enhance our understanding and documentation of Euthyneura diversity in Colombia. Full article

Background: The Merulinidae family belonging to the order Scleractinia is mainly distributed in the Indo-Pacific and Caribbean regions and often constitute the most dominant species of coral reefs. Mitochondrial genome is a key tool for studying the phylogeny and adaptation. Only a few studies have conducted the characteristics analyses of mitochondrial genome in the Merulinidae family. Methods: Therefore, we used high-throughput sequencing technology to describe the mitochondrial genome of Platygyra daedalea, a member of this family. Bioinformatics was used to analyze the composition characteristics of the mitochondrial genome of 10 Merulinidae species. Results: The mitochondrial genome of P. daedalea had a total length of 16,462 bp and a GC content of 33.0%. Thirteen unique protein-coding genes (PCGs), two transfer RNA (tRNA) genes, and two ribosomal RNA (rRNA) genes were annotated. Each species of Merulinidae had 13 unique PCGs in the mitochondrial genome. In contrast, the number of tRNAs and rRNAs significantly varied in Merulinidae species. Collinearity and gene rearrangement analyses indicated that the mitochondrial evolution of species in the Merulinidae family was relatively conserved. Divergence time analysis indicated that Merulinidae originated in the Oligocene, whereas the Platygyra genus originated in the Miocene. The formation and intraspecific divergence of coral species were consistent with geological changes in the ocean. Conclusions: The results of this study help better understand the characteristics of the mitochondrial genome in the Merulinidae family and provide insights into the utility of mitochondrial genes as molecular markers of phylogeny. Full article

The larger benthic foraminifera is a group of marine protists harbouring symbiotic algae, that are geographically confined to shallow tropical and subtropical waters, often associated with coral reefs. The resulting controls on availability of habitat and rates of dispersion make these foraminifers, particularly the genus Amphistegina, useful proxies in the study of invasive marine biota, transported through hull fouling and ballast water contamination in modern commercial shipping. However, there is limited information on the importance of these dispersal mechanisms for foraminifers in the Pre-Industrial Era (pre-1850) for the Atlantic and Caribbean region. This paper examines possible constraints and vectors controlling the invasion of warm-water taxa from the Indo-Pacific region to the Atlantic and Caribbean region. Heterostegina depressa, first described from St. Helena, a remote island in the South Atlantic, provides a test case. The paper postulates that invasions through natural range expansion or ocean currents were unlikely along the possible available routes and hypothesises that anthropogenic vectors, particularly sailing ships, were the most likely means of transport. It concludes that the invasion of the Atlantic by H. depressa was accomplished within the Little Ice Age (1350–1850 C.E.), during the period between the start of Portuguese marine trade with east Africa in 1497 and the first description of H. depressa in 1826. This hypothesis is likely applicable to other foraminifers and other biota currently resident in the Atlantic and Caribbean region. The model presented provides well-defined parameters that can be tested using methods such as isotopic dating of foraminiferal assemblages in cores and genetic indices of similarity of geographic populations. Full article

In this paper, we analyze the serious environmental accident caused by a massive oil spill on 7 February 2024, off the island of Tobago, using two separate algorithms, namely, the established visible near-red index (VNRI) algorithm and the novel IVI visible reflectance ratio index (IVI), both applied to Sentinel-2 satellite images. These algorithms were specifically designed to monitor oil spills in inner waters. In this paper, where the IVI is presented for the first time, its effectiveness in the open sea is also showcased allowing the identification and subsequent monitoring over time of the oily masses that threaten the coral reef of the island. The analysis suggests that with sufficient cloud-free conditions, high temporal revisit multispectral optical satellites could support the timely detection and tracking of oil masses during environmental incidents near natural sanctuaries. Full article