Universidad Autónoma de Baja California Sur

The global decline in marine biodiversity is accelerating, prompting Mexico’s government to establish marine protected areas to regulate human activities. The objective of this study was to test whether there were differences in fish taxonomic and functional diversity among protected reef sites within Parque Nacional Huatulco and adjacent non-protected (NP) zones, as well as whether the temporal trends in fish diversity, density, and biomass of commercial and non-commercial species differed in relation to these human use levels. It was hypothesized that fish functional diversity would be similar among protected and NP sites, given that fishing and tourism activities persist at protected sites. Concurrently, taxonomic and functional diversity decline was predicted, associated with decreasing commercial species due to increasing human activities in both zones. We collected data from underwater monitoring conducted by SCUBA divers (2006–2020) at 20 coral and rocky reef sites to calculate taxonomic and functional diversity metrics based on six biological traits. Functional diversity metrics were employed to analyze the resemblance among human use levels. Additionally, ecological indicators were incorporated as response variables in linear models to assess temporal changes. The results demonstrated functional diversity resemblance among human use levels, as well as temporal stability in Simpson’s dominance index and significant increases in fish species richness and density at both zones. For protected sites, significant changes in fish functional diversity (increase in functional richness and decrease in divergence and originality), could indicate positive effects of protection, such as functional redundancy increases and the capacity to maintain reef functions over time. Commercial and non-commercial species exhibited stability or increase in density and biomass at both protected and NP sites.

The mother‐of‐pearl oyster Pinctada mazatlanica (Hanley, 1856) obtained full protection from the Mexican government after the fishery collapse in 1939. P. mazatlanica was listed in 1994 as a threatened species in the “Special Protection” category. However, no quantitative assessment of the state of the population has been done so far. Our study is the most comprehensive summer interannual monitoring program conducted so far in the Eastern Pacific using SCUBA diving censuses conducted in 314 sampling sites located along the Mexican Pacific between 1998 and 2021. We propose the hypothesis that although P. mazatlanica had full protection with the NOM‐059, global warming reported in northwest Mexico has caused a decrease in the population abundance along the Pacific coast, which may render the protection effort useless. However, we demonstrate that P. mazatlanica was the numerically dominant macro–mollusk and occupied the 18th ranked abundance place compared with the entire epibenthic macroinvertebrate fauna that included 241 species at rocky reefs of the Mexican Pacific, particularly abundant along the peninsular coast of the Gulf of California. Population frequency size distribution of P. mazatlanica dorsoventral length showed positive population growth and latitudinally similar dorsoventral length range (2–30 cm, mode 14 cm when protandry takes place) along the peninsular coast of the Gulf of California, indicating a stable population in time and space. We observed high abundances in the central Gulf of California (Baja Peninsula), mainly from Loreto to La Paz. We conclude that P. mazatlanica is a stable and healthy population along the rocky reefs of the peninsular coast of the Gulf of California even during prolonged anomalous warm events in 2013–2016. Therefore, the present protection status should be modified accordingly.

Background Streptococcus agalactiae (Group B Streptococcus , GBS) is an important pathogen associated with neonatal sepsis, pneumonia, and meningitis, which can be transmitted from colonized pregnant women to their newborns. This study aimed to determine the prevalence and characterize the genomic features of S. agalactiae isolates from pregnant women attending a referral hospital in Northeastern Mexico. Methods Vaginal-rectal swabs were collected from pregnant women during routine prenatal care between April 2017 and March 2020. Whole-genome sequencing was conducted to determine sequence type (ST), clonal complex (CC), capsular polysaccharide (Cps) genotype, virulence factors, and antibiotic resistance genes through comparative genome analysis. Results S. agalactiae colonization was detected in 51 (2.7%) of 1,924 pregnant women. The most common STs were ST8 (23.5%) and ST88 (15.7%). Cps genotyping showed high concordance between serological and molecular methods. Genes conferring resistance to tetracyclines ( tetM , 60.1%) and macrolides ( mreA , 100%) were identified. Key virulence factor genes, including cylE , bca , and scpB , were present in over 90% of the isolates. Conclusion Although GBS colonization prevalence was low, genomic analysis revealed the genetic diversity of S. agalactiae in Northeastern Mexico, emphasizing the importance of molecular techniques for epidemiological surveillance and infection control.

Platax teira (Forsskål, 1775) is distributed from the west coast of Africa and the Red Sea to the central Pacific Ocean. Here, we report the observation of an adult specimen at Cabo Pulmo National Park, Mexico, made during a recreational dive on 11 December 2023. This record represents an addition of a new genus to the reef-fish fauna of the Tropical Eastern Pacific. The possible means of arrival of the fish (natural dispersal with floating materials or a human-mediated introduction) is discussed.

Overexploitation of sea cucumbers wild populations has raised concerns, and aquaculture emerges as a sustainable solution. In response to increasing global demand due to the nutritional and medicinal value of sea cucumber, the aquaculture and feeding technologies of these species improve significantly during the last 10 years. The review highlights the advancements and challenges associated with species reproduction and survival. It focuses on optimal culture conditions, broodstock management, larval rearing, and disease outbreaks. Feeding technology is another important theme addressed in this document; the research essentially focused on replicating natural diets in aquaculture systems to ensure optimal growth. Biotics, including probiotics and prebiotics, are also explored as valuable supplements to improve the health and growth of sea cucumbers in aquaculture environments. Finally, future advancements, including genetic breeding and multitrophic aquaculture systems, are demonstrated as essential for ensuring sustainable production in the sea cucumber aquaculture industry. The document stresses the need for continuous research on nutrition, disease management, and environmental impacts to address ongoing challenges and improve the efficiency of sea cucumber farming. Graphical abstract

Understanding how human-mediated environmental change affects biodiversity is key for conserving evolvability. Because the most severe impacts are ongoing, such an understanding is proving exceptionally difficult to attain. Islands are natural, replicated experiments that serve as proxies for habitat fragmentation and, therefore, allow us to use historical changes in biodiversity under Island Biogeography Theory (IBT) to predict the consequences of immediate anthropogenic impacts on functional trait evolution. Rattlesnake venoms are molecular phenotypes that mediate interactions with prey, and diet and venom complexity are positively correlated. Consequently, rattlesnake venoms allow us to investigate how functional traits co-vary with changes in biodiversity according to IBT. We collected venom from 83 rattlesnakes across multiple species and 11 islands in the Gulf of California and estimated venom complexity using the Shannon Diversity Index. Using a mixed effects modeling approach, we found that the number of congenerics, island isolation, and island area best predicted venom complexity variability. All variables exhibited a negative relationship with venom complexity, contrary to predictions for island area under IBT. Larger islands with more congenerics exhibited reduced trait complexity, perhaps reflecting niche partitioning and venom specialization. Ultimately, we used a synthetic eco-evolutionary framework to predict functional trait evolution across fragmented landscapes.

As the impact of human activities continues to move beyond shallow coastal waters into deeper ocean layers, it is fundamental to describe how diverse and distinct the eukaryotic assemblages from the deep layers are compared to shallow ecosystems. Environmental DNA (eDNA) metabarcoding has emerged as a molecular tool that can overcome many logistical barriers in exploring remote deep ocean areas. We analyzed shallow water samples (<30 m) collected via SCUBA diving and adjacent deeper samples (mid-water 30–150 m, deep-water >200 m) obtained with Niskin samplers within 16 locations in a recognized hotspot of marine biodiversity (Gulf of California, Mexico). We sequenced an eDNA metabarcoding library targeting a fragment of the COI gene of eukaryotes. We demonstrated that the diversity of operational taxonomic units (OTUs) did not peak at shallow coastal regions and that the mid-water and deep-water benthic and pelagic samples had similar levels of biodiversity compared to shallow sites, but detected a significant vertical zonation between shallow and deeper habitats. Our results suggest that the deep refugia hypothesis, which posits that deep environments protect biodiversity during environmental changes, enabling species to survive and repopulate shallower regions, is not supported for most taxa and only applies to about a third (34.9%) of the 5,495 OTUs identified that were shared between the shallow and deeper layers. In comparison, the rest of the taxa were exclusive to either shallow (30.8%) or deeper zones (34.28%). The observation that mid-water and deep-water benthic and pelagic communities were as rich but quite distinct as shallow communities supports extending spatial management and conservation tools to deeper habitats to include a significant fraction of unique phylogenetic and functional diversity.

Taxonomic gaps in community biodiversity assessments are now commonly addressed by combining traditional monitoring methods and environmental DNA (eDNA) metabarcoding, widely recognized for having the ability to uncover rare and cryptic diversity. However, only a few studies have assessed the efficacy of this novel technique for detecting cryptobenthic fishes and tested the limitations of incomplete genetic reference availability for a historically neglected component of fish communities. Our goals were (i) to compare cryptobenthic and conspicuous fish detections by 12S eDNA metabarcoding, visual surveys and anaesthetic fish collections, and (ii) to compare emerging regional diversity patterns against a long‐term historical record for the Gulf of California. Despite adding new local references for 36 cryptobenthic fishes, 12S eDNA metabarcoding detected only seven taxa. Visual surveys provided similar results, highlighting fish collections as the primary source, with 57 cryptobenthic fishes recovered. Conspicuous fishes had an equal and highly complementary contribution by 12S eDNA and visual surveys. When combining contemporary detections from all methods, we recovered 43% of cryptobenthic and 16% of conspicuous fishes, relative to the historical records. The spatial community structure for detected cryptobenthic fishes differed from historical expectations and conspicuous fishes, showing no differences in community richness nor composition between Northern and Central Gulf communities. Our study highlights the limitations of eDNA for monitoring cryptobenthic fishes, and that their patterns of community structuring are driven by distinct factors compared to conspicuous fishes.

This study examined if analytical procedures influence the relationship between lactate metabolism and fat oxidation during exercise in 54 young men (age: 27 ± 7; body fat: 23 ± 10%; VO2max: 46.9 ± 10.2 mL·kg-1·min-1). The first lactate threshold (LT1) was assessed using the log-log transformation of blood lactate and running speed (LT1log-log), an increase of 1 mM above baseline (LT1Bsln1.0), and a fixed blood lactate concentration of 2 mM (LT1OBLA2). The second lactate threshold (LT2) was determined using the maximal distance approach (LT2Dmax) and a fixed lactate concentration of 4 mM (LT2OBLA4). The highest (FATmax) and lowest (FATmin) fat oxidation rates were determined using a 3rd-degree polynomial regression (P3), visual inspection, and mathematical modeling (SIN). FATmax and FATmin showed the strongest correlation with LT1log-log (r: 0.65, p<0.01) and LT2OBLA4 (r: 0.81, p<0.01), regardless of fitness. FATmaxP3 and LTOBLA2 showed the best agreement in untrained individuals. Conversely, FATmaxP3 and LT1log-log showed the best agreement in obese men and trained subjects. LT2OBLA4 showed the best agreement with FATmin. When investigating the association between fat oxidation and lactate metabolism during exercise, LT1log-log and LT2OBLA4 should be computed, while mathematical modeling or visual analysis should be applied for FATmax, depending on fitness level.

Coastal wetlands, including seagrass meadows, emergent marshes, mangroves, and temperate tidal swamps, can efficiently sequester and store large quantities of sediment organic carbon (SOC). However, SOC stocks may vary by ecosystem type and along environmental or climate gradients at different scales. Quantifying such variability is needed to improve blue carbon accounting, conservation effectiveness, and restoration planning. We analyzed SOC stocks in 1,284 sediment cores along >6,500 km of the Pacific coast of North America that included large environmental gradients and multiple ecosystem types. Tidal wetlands with woody vegetation (mangroves and swamps) had the highest mean stocks to 1 m depth (357 and 355 Mg ha⁻¹, respectively), 45% higher than marshes (245 Mg ha⁻¹), and more than 500% higher than seagrass (68 Mg ha⁻¹). Unvegetated tideflats, though not often considered a blue carbon ecosystem, had noteworthy stocks (148 Mg ha⁻¹). Stocks increased with tidal elevation and with fine (<63 μm) sediment content in several ecosystems. Stocks also varied by dominant plant species within individual ecosystem types. At larger scales, marsh stocks were lowest in the Sonoran Desert region of Mexico, and swamp stocks differed among climate zones; otherwise stocks showed little correlation with ecoregion or latitude. More variability in SOC occurred among ecosystem types, and at smaller spatial scales (such as individual estuaries), than across regional climate gradients. These patterns can inform coastal conservation and restoration priorities across scales where preserving stored carbon and enhancing sequestration helps avert greenhouse gas emissions and maintains other vital ecosystem services.

Individual recognition mechanisms have played a key role in odontocete ecology, maintaining social cohesion and therefore ensuring the maintenance of long-term social ties. The current study was the first to identify and describe stereotyped whistle contour types by both a visual similarity value judgment task and acoustic and temporal parameters in free-ranging Risso's dolphins (Grampus griseus) in Mexican Pacific waters of the Gulf of the California. In total, 64.1% (118) of all analyzed whistles (184) were classified as stereotyped whistles (STW); 82.2% of them (97) met the SIGnature IDentification bout criteria and were, subsequently, ascribed into one of the five possible signature whistle (PSW) types. These signature call types accounted for 52.7% (97/184) of the acoustic repertoire. All PSW types were classified as sine (wavering sinusoidal whistles) and showed mean acoustic and temporal variable values similar to other studies of Risso's dolphins that did not differentiate signature whistles (SWs). External naive independent observers who lacked expertise in bioacoustics have confirmed the adopted classification created at high agreement level and near perfect match. Accordingly, the present study provided additional acoustic evidence of individually distinct vocalization in this species, reinforcing the need for further studies to help deepen and broaden the knowledge about the function, production and incidence of individual and "group signatures" and cognitive and recognition processes in the herein investigated species, among others.

Numerous evaluations of the economic value of fisheries, tourism, coastal protection, and carbon sequestration have been conducted for shallow reefs. However, no quantitative evaluations of the ecosystem services provided by mesophotic reefs as a whole or that only consider provisioning, regulating, supporting, or cultural services have been conducted. We used a remotely operated vehicle to describe the composition, community structure, and ecosystem services provided by reef fishes of Isla Espiritu Santo in three depth strata (“shallow” [13–22 m], “intermediate” [23–40 m], and “deep” [41–70 m]) defined by temperature, salinity, dissolved oxygen, percentage of incident light, and primary productivity. From 5-min videos (n = 189), we computed Hill numbers to describe fish community structure. We classified 12 ecosystem services (provisioning, regulating, supporting, or cultural services) offered by fish. Species richness and abundance were higher in shallow reefs than deep reefs. Diversity, evenness, and average trophic level did not change, even when qualitative differences in species composition were present between zones (a higher number of herbivores [Pomacentridae and Acanthuridae] and planktivores in shallow and mesophotic reefs, respectively). Regulating and provisioning services were significantly lower in deep reefs, while cultural services were significantly higher in shallow reefs. Finally, similarities in species composition and the lack of differences in most ecological indices support the hypothesis that the deep reefs of Isla Espiritu Santo may function as refugia. However, species richness and the scores of ecosystem services were significantly different among depth strata. We propose that the mesophotic reefs in the study area serve, at least partially, as refugia for fish species.

Background: The metabolome of COVID-19 patients has been studied sparsely, with most research focusing on a limited number of plasma metabolites or small cohorts. This is the first study to test saliva metabolites in COVID-19 patients in a comprehensive way, revealing patterns significantly linked to disease and severity, highlighting saliva’s potential as a non-invasive tool for pathogenesis or diagnostic studies. Methods: We included 30 asymptomatic subjects with no prior COVID-19 infection or vaccination, 102 patients with mild SARS-CoV-2 infection, and 61 hospitalized patients with confirmed SARS-CoV-2 status. Saliva samples were analyzed using hydrophilic interaction liquid chromatography–mass spectrometry (HILIC-MS/MS) in positive and negative ionization modes. Results: Significant differences in metabolites were identified in COVID-19 patients, with distinct patterns associated with disease severity. Dipeptides such as Val-Glu and Met-Gln were highly elevated in moderate cases, suggesting specific protease activity related to SARS-CoV-2. Acetylated amino acids like N-acetylserine and N-acetylhistidine increased in severe cases. Bacterial metabolites, including muramic acid and indole-3-carboxaldehyde, were higher in mild–moderate cases, indicating that oral microbiota differs according to disease severity. In severe cases, polyamines and organ-damage-related metabolites, such as N-acetylspermine and 3-methylcytidine, were significantly increased. Interestingly, most metabolites that were reduced in moderate cases were elevated in severe cases. Conclusions: Saliva metabolomics offers insightful information that is potentially useful in studying COVID-19 severity and for diagnosis.

At COP16 in Cali, Colombia, significant progress was made in biodiversity conservation efforts. In this regard, financing has been considered a key issue for achieving the objectives. The overview of Mexico’s experience with biodiversity finance in this study presents the experience of an emerging economy, which must finance pressing development priorities and biodiversity and climate action at the same time. Therefore, it is very important to find synergies in the available finance and look for new innovative options. The large overlap between the climate and biodiversity agendas and the international commitments derived from these also presents an opportunity to accelerate biodiversity funding. The methodology applied is the Systematic Literature Review (SLR). The study presents the national strategy on biodiversity in Mexico (ENBioMex), the financial needs of the country, and the existing biodiversity financing, stressing the Global Environmental Facility (GEF), the Biodiversity Finance Initiative (BIOFIN), and the Adaptation Fund in Mexico. The discussion section centers on analyzing the existing results and outlining some proposals to enhance the existing instruments, looking for innovation and synergies. In the authors’ opinion, the financing of Ecosystem-based Adaptation (EbA) is the main instrument that can link biodiversity conservation and adaptation to climate change impacts, at the same time providing a sustainable way of life and guaranteeing the well-being of communities, but it is not adequately used. Finally, we present some concluding remarks and future research topics.

For the Cuban littorals in the Caribbean Sea, information on benthic diatoms is scarce, and hitherto non-existent for natural protected areas. Thus, to describe the structure of benthic diatom associations (BDAs) from a marine protected area in Cuba, sediment samples were collected in Playa Las Gaviotas (Refugio de Vida Silvestre Cayo Santa María) during dry (November) and rainy (July) seasons. Diatoms were separated, mounted in synthetic resin and identified under light microscopy. Species diversity of the BDA was estimated using Shannon (H′), Simpson (1 − λ) and Pielou evenness (J′) indices. We identified 354 taxa including 200 new records for Cuba; the nomenclature of 45 previously recorded taxa was updated. The currently recorded species richness of marine benthic diatoms for Cuba is 595. The most abundant taxa were Amphora cf. copulata, A. proteus, Diploneis smith var. pumila, Halamphora turgida, H. coffeiformis, Navicula zostereti, Nitzschia marginulata var. didyma and Psammodictyon panduriforme. The best-represented genus was Mastogloia with 70 taxa. Similarity values indicated homogeneous distribution of epipelic diatom taxa along the sandy bottom, suggesting a single diatom association. Mean values of H′ ranged from 4.91 bit/taxon in November to 4.95 bit/taxon in July. Structure analysis suggests a stable BDA with high species diversity characteristic of productive, pristine environments.

In Baja California Sur (BCS), Mexico, the municipality of La Paz has reported higher cancer rates compared to nearby areas, linked to arsenic contamination from abandoned gold mines and naturally high uranium (U) and arsenic (As) levels in sediments. This study evaluates the impact of human activities on natural U and As anomalies in watercourse sediments of the Los Planes watershed and adjacent areas. The geochemical database included 229 analyses from the Mexican Geological Service (SGM 2017) and nine samples analyzed via Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Multivariate statistical and geostatistical methods were used to interpret the data. Using the kriging method for U and the nearest neighbor algorithm for As, spatial models were developed to define the anomalies’ positions and extents. Hierarchical cluster analysis on 85 analyses and 28 parameters identified six clusters representing different influence areas. The study found As concentrations exceeding the Mexican limit of 22 mg/kg for soils in 13 cases, with a maximum of 1520 mg/kg, primarily due to historic gold mine contamination. U concentrations ranged from 0.53 mg/kg to 7.35 mg/kg, within international protection limits, originating from Sierra la Gata’s granites and granodiorites, with potential secondary enrichment in topsoil. The possibility of anthropogenic U impact from phosphatic fertilizers is noted, warranting further investigation.

Context Sharks have been captured globally for decades. Shark exploitation lacks appropriate regulation, hindering an assessment of captured and traded individuals. This necessitates the development of a method to quickly and easily identify shark species. Aims We aim to standardise and validate a rapid, effective method of shark species identification from Mexican markets. Methods Loop-Mediated Isothermal Amplification (LAMP) assays were developed for the identification of five commercially important shark species in the north-west region of Mexico: Carcharhinus falciformis, Prionace glauca, Isurus oxyrinchus, Sphyrna zygaena and Sphyrna lewini. A total of 350 samples was collected from markets and samples were labelled as ‘cazón’ (small shark), ‘marlín’ (marlin) and ‘tiburón’ (shark). Key results Through LAMP assay standardisation, individuals of five species were able to be identified: 17 individuals of S. zygaena, 17 of S. lewini, 24 of C. falciformis, 26 of P. glauca and 85 of I. oxyrinchus. To validate species identification by LAMP, sequences of COI and ITS2 were obtained and analysed by BLASTn. A 100% match identity for LAMP assays and associated sequences was obtained. Additionally, the DNA limit of detection was determined down to 0.1 ng/μL of shark DNA. Conclusions These results highlight an urgent need to effectively identify commercially traded species, some of which may be endangered and to establish species-level labelling in national policies. Implications Application of correct species labels to national seafood products could encourage consumers to make responsible food choices.