Terminos Lagoon Research Articles

Spatial distribution of PAHs, nickel, and vanadium in sediments from a large coastal lagoon near a petroleum extraction area in the southern Gulf of Mexico

One of the world's crucial areas for crude oil exploration and extraction is the southern Gulf of Mexico, where Terminos Lagoon (TL) is located. Sediments from the TL region were used to assess the spatial patterns, origins, and ecotoxicological risks associated with 16 priority polycyclic aromatic hydrocarbons (PAHs; 3.1–248.9 ng⸳g−1 dry weight basis, dw) and trace metals (Ni = 11.0–104.0 mg⸳kg−1; V = 2.0–35.0 mg⸳kg−1 dw) linked to anthropogenic activities. Although origin indices based on PAHs and metals concentrations indicate no crude oil pollution in the region, sources of pyrogenic PAHs were identified. A chemometric approach demonstrated associations between organic matter and PAHs, and that metal accumulation depends mostly by the input of lithogenic materials. Ecotoxicological risk estimations showed a higher risk of possible adverse effects in sites near swamps and mangrove zones, highlighting the need of future monitoring. This study provides a reference for policymakers to conserve Mexico's largest coastal lagoon and other oil-impacted coastal areas worldwide.

Variability of Dissolved Inorganic Carbon in the Most Extensive Karst Estuarine-Lagoon System of the Southern Gulf of Mexico

Coastal ecosystems with karstic geology have a unique characteristic where the dissolution of carbonate rocks can increase total alkalinity (TA) and dissolved inorganic carbon (DIC). This results in higher inorganic carbon budgets in coastal areas. One such ecosystem is the Terminos Lagoon, the most extensive tropical estuarine lagoon system in Mexico, located in the karstic aquifer of the Yucatan Peninsula and connected to the southern Gulf of Mexico (sGoM). We measured TA and DIC to evaluate the variability in Terminos Lagoon’s of the carbonate system. We also estimated pH, partial CO2 pressure (pCO2), and aragonite saturation (ΩAr) along two transects from the main lagoon tributaries (Palizada and Candelaria rivers) to the coastal zone during the dry and rainy seasons. During the dry season, TA and DIC concentrations were significantly higher (3092 ± 452 µmol kg-1 TA, 2943 ± 522 µmol kg-1 DIC) than during the rainy season (2533 ± 228 µmol kg−1 TA, 2492 ± 259 DIC µmol kg−1). Our calculations indicate that the rainy season pCO2 (2532 ± 2371 µatm) seems higher than in the dry season (1534 ± 1192 µatm). This leads to a reduction in pH (7.9 ± 0.3 to 7.8 ± 0.3). These significant changes indicate that rain increases the flow of unsaturated river water into the lagoon. The results of this work contribute toward a dissolved inorganic carbon variability baseline in the sGoM and can be helpful to Terminos Lagoon decision-makers.

Impact of some environmental factors on the temporal variability of pink and white shrimps postlarvae in Terminos Lagoon, Southern Gulf of Mexico

Impact of some environmental factors on the temporal variability of pink and white shrimps postlarvae in Terminos Lagoon, Southern Gulf of Mexico

Potential Residence and Coexistence Strategy of Tursiops truncatus in a Coastal Lagoon in the Southern Gulf of Mexico: Ecological Inferences Using Stable Isotopes

The Terminos Lagoon Flora and Fauna Protection Area is the largest coastal lagoon in the southern Gulf of Mexico and has the largest population of bottlenose dolphins, Tursiops truncatus, reported in the region. Photo identification studies have reported permanent and seasonal residence of dolphins; however, how dolphins coexist ecologically is unknown. In the present study, from 17 dead specimens stranded on the coast of Isla del Carmen (barrier island) between 2014 and 2016, stable isotopes in the liver, heart, and muscle, which represent different time scales, were analyzed to determine residence through δ13C values and niche width and trophic coexistence through δ15N values. Differences between sexes (δ13C liver: p = 0.009; heart: p = 0.01) and age classes (δ15N muscle: p = 0.02) were found, which indicated trophic sexual segregation and changes in resource use during growth, respectively. The lack of significant differences in δ13C values indicated isotopic equilibrium between the tissues, indicating the possible permanent residence of 12 dolphins in Terminos Lagoon as a coastal ecotype (− 16‰) and a second group (five dolphins) as an oceanic ecotype (− 18‰). In conclusion, most dolphins stranded in the Terminos Lagoon are potential permanent residents of this habitat, with evidence of resource partitioning as a coexistence strategy.

Coastal vulnerability assessment with a hierarchical coastal segments approach

Coastal vulnerability assessment is crucial for the effective planning and management of coastal zones, particularly in the face of climate change and increasing coastal hazards. Currently, there is no universal method to accurately assess coastal vulnerability. Therefore, many coastal vulnerability assessments are based on the combined use of physical and social data, simple models, and expert judgment. In this study, the coastal vulnerability index was evaluated using 13 variables related to the physical and social aspects of Campeche state coastline. In addition to an intervention index was identified based on the physical characteristics of the study area. Finally, using the information from the vulnerability index and the action index, areas were defined as hierarchical coastal segments and classified as low, medium, or high priority depending on the economic activities, population, and natural environments present in the area. The results show the distribution of vulnerability along the coast of Campeche: 24% have low vulnerability, 41% have moderate vulnerability, and 35% have high vulnerability. These highly vulnerable areas are in the south, near Laguna de Terminos, the most important coastal lagoon in Mexico, because of its socioeconomic and environmental relevance. The hierarchical coastal segments allow decisions to be made regarding actions that integrate natural and anthropic elements in a more regional and not only local way. The results are useful for medium and long-term planning and management of coastal zones since they allow the identification of vulnerable areas that require a comprehensive solution to the coastal risks to which they are subject. The applied method has the advantages of being replicable and generating a solid base of applicable knowledge owing to the participation of local and foreign experts.

Co-occurrence of biodiversity, carbon storage, coastal protection, and fish and invertebrate production to inform global mangrove conservation planning

Mangrove forests support unique biodiversity and provide a suite of ecosystem services (ES) that benefit people. Decades of continual mangrove loss and degradation have necessitated global efforts to protect and restore this important ecosystem. Generating and evaluating asset maps of biodiversity and ES is an important precursor to identifying locations that can deliver conservation outcomes across varying scales, such as maximising the co-occurrence of specific ES. We bring together global datasets on mangrove-affiliated biodiversity, carbon stocks, fish and invertebrate production, and coastal protection to provide insight into potential trade-offs, synergies and opportunities from mangrove conservation. We map opportunities where high ES provision co-occurs with these areas that could be leveraged in conservation planning, and identify potential high-value opportunities for single ES that might otherwise be missed with a biodiversity focus. Hotspots of single ES, co-occurrence of multiple ES, and opportunities to simultaneously leverage biodiversity and ES occurred throughout the world. For example, efforts that focus on conserving or restoring mangroves to store carbon can be targed to deliver multiple ES benefits. Some nations, such as Vietnam, Oman, Ecuador and China, showed consistent (although not necessarily strong) correlations between ES pairs. A lack of clear or consistent spatial trends elsewhere suggests that some nations will likely benefit more from complementarity-based approaches that focus on multiple sites with high provision of different services. Individual sites within these nations, however, such as Laguna de Terminos in Mexico still provide valuable opportunities to leverage co-benefits. Ensuring that an ES focused approach is complemented by strategic spatial planning is a priority, and our analyses provide a precursor towards decisions about where and how to invest.

Hybrid Renewable Energy System for Terminos Lagoon, Campeche, Mexico

The implementation of renewable energies represents a crucial step in meeting the sustainable development goal of the United Nations for affordable and clean energy. The Terminos Lagoon region in Campeche, the largest coastal lagoon in Mexico, offers potential for renewable energy sources such as wind, photovoltaic, and current energy. This study presents a renewable energy potential assessment for the main city at Terminos Lagoon, Ciudad del Carmen, which has the largest oil activity in Mexico and high electricity consumption. The outputs of high-resolution numerical models were analyzed to evaluate wind and photovoltaic resources and currents. A hybrid system consisting of 24 wind turbines, 5516 photovoltaic panels, and 32 hydrokinetic turbines could generate 521.33 GWh, which is 39.63% of the state’s energy demand and exceeds the energy consumption of Ciudad del Carmen by 10.24%. Wind and photovoltaic energy are the most significant contributors (517.15 GWh and 3.77 GWh, respectively), while hydrokinetic energy contribution is marginal (0.407 GWh) and requires further research and development. The results suggest that the region has the potential for clean and renewable energy technologies to reduce greenhouse gas emissions and contribute to the energy transition.

Environmental risk of microplastics in a Mexican coastal lagoon ecosystem: Anthropogenic inputs and its possible human food risk

Coastal lagoons are ecosystems that are considered providers of a variety species of commercial value to the humans. However, they are currently threatened by a variety of anthropogenic-derived impacts, including environmental pollution by microplastics (MPs). For these reasons, it is necessary to identify suitable biomonitors for monitoring MP activities in aquatic environments and for estimating human ingestion of MPs from the consumption of commercial shellfish species. Therefore, our aims were to identify the anthropogenic activities that supply MPs into a coastal lagoon in the southern Gulf of Mexico and their variety; to determine whether oysters (Crassostrea virginica) are suitable biomonitors to perform MPs monitoring activities and to conduct an estimation of how many MPs could a human consume by the ingestion of a commercial portion of oysters harvested in this coastal lagoon. Our results noted that MP concentrations from water and sediment collected in Laguna de Terminos were 210,000 and 11.3 times higher than values reported in other protected areas worldwide. MPs chemical composition revealed that fishing and urban activities supply mainly polyethylene (21.1 %), poly (butadiene) diol (12.6 %) and polyethylene terephthalate (9.5 %). It was also determined that oysters did not reflect the spatial distribution of MPs within the study area and that a human could consume up to 806.1 MPs per 237.1 g serving of an oyster cocktail. Finally, a coastal lagoon polluted with MPs increases the risk of affecting species used for human consumption.

First report of synophthalmia and leucism in a bull shark (Carcharhinus leucas) embryo from the southeastern Gulf of Mexico

An abnormal embryo (male of 465 mm total length) and 13 other embryos were removed from a pregnant female bull shark (Carcharhinus leucas) caught in coastal waters between the Grijalva River and Terminos Lagoon in the southwestern Gulf of Mexico. The first record of synophthalmia and leucism in the bull shark is presented. The shark cyclopia case is reviewed.

Source Identification, Toxicity, and Persistence of PAHs in Sediment Core from a Natural Protected Area in Mexico

Sediment cores maintain a historical record of the various sources of polycyclic aromatic hydrocarbons (PAHs). In 2020, one sediment core was collected within the oyster farming area of the Pom–Atasta lagoon system and the Terminos lagoon. A total of 16 PAH compounds were analyzed to identify the historical patterns of PAH inputs and the relationship with sediment materials. The core was classified into three strata at depths of 0.0–0.2 m, 0.2–0.6 m, and 0.6–1.1 m, in which the high content of silt–sand, organic matter, and carbonates indicates a system of high energy and productivity. The hydrology and characteristics of the sediment suggest a free access of adsorbed PAHs to the study area, mainly of pyrolytic origin. The concentration of ∑PAHs decreases from the surface (527.0 ng g−1 dw) to a greater depth (75.7 ng g−1 dw), which corresponds to 60% of the HMW (high molecular weight) of the total PAHs as combustion products at low temperatures, while LWM-PAH (low molecular weight) inputs are from discharges of petroleum products. The core sediments showed a low probability of toxicity quotient of 9%. The analysis of the carcinogenic toxic equivalent (TEQcarc) in each section of the core was variable, decreasing with the depth from 107.91 ng TEQ g−1 dw to 57.65 ng TEQ g−1 dw, with the compounds benzo(a)pyrene (53.55 ng TEQ g−1 dw) and dibenzo(a,h) anthracene (29.2 ng TEQcarc g−1 dw) having the highest TEQcarc. The anthropogenic activities around the study area may increase the carcinogenic and mutagenic risk to human health. However, in the present study, the low toxic carcinogenic equivalents (TEQBaP) and mutagenic equivalents (MEQBaP) indicate a low probability of sediment toxicity. The ecosystem could be under constant threat from increasing anthropogenic activity; therefore, monitoring programs for the conservation of these ecosystems and oyster farms should be considered.

Long-term multiscale analysis of temporal variability in the fish community in Terminos Lagoon

The distribution of biological communities is structured at multiple spatiotemporal scales. The identification of trends and patterns in highly variable coastal ecosystems contributes to explaining the relative importance of the different scales. Herein, a temporally nested hierarchical analysis was applied to a fish community in order to determine the temporal variation in three time scales (month, season, and year) for four community attributes (species richness, abundance, biomass, and taxonomic distinctness) and two facets of species assemblages (species composition and abundance, and species composition and biomass). The analysis relied on data from four similar sets of samples belonging to a multidecadal series of Terminos Lagoon (1980, 1998, 2010, and 2016). In accordance with the hydrographic variability over time, the results revealed recurrent configurations of fish community characteristics, where the year (long term) and season (intermediate term) scales determined distribution trends and species composition patterns. In particular, trends emerged for the community attributes in the long term, whereas in the intermediate term, fluctuations were mostly recorded, which had higher values during the rainy and cold fronts seasons. Distribution patterns in both facets of species assemblages were consistent in the long and intermediate term, with the first one corresponding to an associated group of species for each year and the second one corresponding to a variable interaction with transparency and salinity according to the weather season. The present study highlights the fish adaptive response, which contributes to the ecological processes driving their temporal variability in Terminos Lagoon and is associated with hydrographic variability and estuarine condition shifts.

EVALUATION OF POTENTIALLY TOXIC METAL CONCENTRATIONS IN THE TERMINOS LAGOON, CAMPECHE, GULF OF MEXICO

The Terminos Lagoon is a region of great environmental and economic importance, due to its biodiversity, abundance of natural resources and proximity to the Campeche Sound. These characteristics encourage the development of numerous human activities in its surroundings, including oil, agricultural, industrial, urban and sanitary activities. We evaluated the concentration of Cr, Ni, Pb and V in surface sediment samples from Laguna de Terminos, Campeche, Mexico. The results obtained show that the concentrations of Cr and Pb remained below the ecological criteria of the minimum and maximum adverse ERL and ERM conditions for the biota, as well as within the ranges reported for other coastal lagoons in the Gulf of Mexico, with the exception of Pb, which decreased by almost 100%. Ni recorded values above the ERL and ERM, which have shown fluctuations in concentrations depending on the rainy and dry seasons. V maintained its concentrations below 27.73 mg/kg. High correlations were found between metals Cr – V, Cr – Ni and Ni – V, suggesting that these elements share the same source of origin. The statistics show that there are significant differences between the sampling sites PLZ and C, and PLZ and CDL. The reduction may be due to a decrease in urban, tourist, fishing and agricultural activities.

Accumulation and fluxes of potentially toxic elements in a large coastal lagoon (southern Gulf of Mexico) from 210Pb sediment chronologies

Three 210Pb-dated sediment cores were used to evaluate the contamination degree and flux ratios of potentially toxic elements (PTEs; As, Cd, Cr, Cu, Ni, Pb, V, and Zn) in seagrass meadows from the northern margin of Términos Lagoon (TL), southern Gulf of Mexico. The sediments displayed minor Cd, Ni, V, and Zn enrichments but moderate to strong enrichment by As. Results from a chemometric analysis revealed that: 1) salinization and grain size, along with 2) the terrigenous inputs are the major factors influencing the PTEs accumulation. The historical trends of PTEs flux ratios nearly follow the large-scale land-use changes around TL, linked to the growth of the Mexican oil industry in the area since the 1970s. Our findings showed the critical role of seagrass meadows as PTEs sinks. This information is useful for decision-makers to develop restoration projects for a vulnerable site within the largest coastal lagoon ecosystem in Mexico.

Comparison of Phenolic and Flavonoid Content and Antioxidant and Chelating Activities of Rhizophora mangle in Different Anthropogenically-Polluted Coastal Lagoons

The production of total phenolic content (TPC) and total flavonoid content (TFC), antioxidant (AA), and copper chelating (CACu+) activities of Rhizophora mangle from three coastal lagoons under different grades of anthropogenic pollution and pollutant presence were analyzed. R. mangle is a mangrove plant that inhabits tropical coastal lagoons and shows the ability to accumulate pollutants in their tissues and respond to environmental stressors via the production of secondary metabolites AA and CACu+ activities. In total, 108 samples (June 2010 to August 2011) of leaves, barks, and the roots of R. mangle from Magdalena Bay (MBAY), Navachiste Lagoon (NLAG), and Terminos Lagoon (TLAG) (Mexico) were collected. Folin-Ciocalteu colorimetric, aluminum chloride colorimetric, ABTS∙+ discoloration, and pyrocatechol-violet methods calculated TPC, TFC, AA, and, CACu+, respectively. Atomic absorption spectrometry, gas chromatography, and Walkley–Black methods were used to calculate the metal content, organochlorine pesticides (OCPs), and organic matter (OM) in sediments. One-way ANOVA and post hoc Tukey’s, Scheffé’s, and Bonferroni and Holm multiple comparisons were used to determine significance, and Pearson’s test was applied to determine the coefficient of correlations. Significant differences among the lagoons of TPC, TFC, AA, and Cu+CA activities of Rhizophora mangle are explained by their different grades and type of anthropogenic pollution. A significant increase in the TPC and TFC in bark implies a response to the metal and OCPs pollution in surrounding sediments. Significant AA and Cu+CA activities responded to combat environmental stress conditions caused by the OCP and trace metal concentrations in surrounding sediments. Strong and positive correlations among OCP and trace metal were found and related to the constant pesticide residues input. However, OCP concentrations in the surrounding sediments of R. mangle trees did not influence the phenolic production of AA or the Cu+ CA. R. mangle is affected by the type of anthropogenic pollutants and was reflected in the bio-compounds production, antioxidant, and chelating activities related to the concentration of the metals in sediments.

Physicochemical gradients in a coastal lagoon from the southern Gulf of Mexico; a multivariate approach

The high environmental variability that characterizes estuarine ecosystems can be approached through multivariate methods which would allow us to achieve an integrated view of the change ratios and direction of the environmental variables. The aim of this study was to make a spatio-temporal characterization of Términos Lagoon (TL) using a multivariate approach enabling us to better understand the high variability of the system and to recognize underlying gradients. Five samplings were carried out at TL in a period of two years during which physicochemical variables were measured along 25 stations. A principal component analysis was made to analyze changes and interactions between variables in the lagoon, using the scores values at each station to represent the spatial variation for each component. The mapped scores allowed us to detect multivariate gradients generated by the variable interactions in the new components. Each sampling displayed multivariate gradients composed by the interaction of different variables correlated to the principal components. Our results allow us to recognize the processes occurring in TL that are responsible for these gradients. One of the main processes was freshwater discharge, whose influence was irregular. The multivariate gradients proposed evidenced the high variability that characterizes TL and, likely, coastal systems in general. We thus consider that the present methodological approach is adequate for modeling both spatial and time variations in a coastal system.

Spatial configuration of seagrass community attributes in a stressed coastal lagoon, southeastern Gulf of Mexico

Terminos Lagoon is the largest coastal lagoon in the southern Gulf of Mexico and is a highly biodiverse and productive system that supports important seagrasses. These key habitats are under significant stress due to anthropic activities around and inside the lagoon. Considering the lack of updated information about their distribution, cover, and ecological condition, the objectives of this study were to assess the current morphological and seascape conditions of seagrass meadows in Terminos Lagoon and to evaluate their morphological changes in almost one decade (2010–2018). We combined remote sensing and fieldwork to assess environmental parameters (sea surface temperature and a light attenuation index), quantify seascape metrics, evaluate morphometric variables of seagrasses, and quantify organic carbon budgets. Three species of seagrasses (Thalassia testudinum, Syringodium filiforme and Halodule wrightii) were distributed in the lagoon and showed the highest densities and cover in sheltered zones, where shallow and more transparent water conditions occurred. In general, the seascape-cover diversity was regularly distributed in the study area, with the highest meadow connectivity mainly along the inner littoral region of the island. While the values we recorded for T. testudinum leaf length (X̄ = 18.6 cm), shoot densities (X̄ = 249.5 m−2) and total biomass (X̄ = 195.2 g DW m−2) were consistent with other recent studies, they were lower compared with other coastal systems in southeastern Gulf of Mexico and different between 2010 and 2018 in the lagoon, presumably associated with strong anthropic influences in the region. Finally, we provide a spatially explicit baseline information on morphology, seascape configuration and the first sensitivity map for one of the most important coastal lagoons in Mexico.

Environmental variation vs co-occurrence of two fish families (Gerreidae and Ariidae) in Terminos Lagoon, Campeche, Mexico

Terminos Lagoon is recognized as an ecosystem of great diversity and productivity in the southern Gulf of Mexico. It is also the site of various anthropogenic activities in the lagoon as well as in its surroundings. In addition, in recent years this lagoon has showed variations in temperature and salinity as a result of global warming and/or watershed management. This has generated variations in the structure and function of fish communities, among other taxonomic groups. IIn this work, we analyze the changes in abundance and distribution associated with modifications in the salinity of fish species from two key families (Ariidae y Gerreidae) during the years 1980, 1998, and 2011. Salinity is analyzed in the three periods (ANOVA, Tukey (HSD); the abundance of species, environmental breadth according to salinity (Levins Index), environmental overlap (Pianka Index), and co-occurrence (C-score) are also analyzed. Statistical differences were tested using the null model. The results showed high variability in salinity, with a tendency to increase during the studied period with 24.7, 27.9, and 28.4 UPS for each year, respectively (p < 0.0001). The abundance of both families increased from 1980 to 1998 and decreased in 2011 (82% for Ariidae and 62% for Gerreidae). The C-score ranged from 1.07 in 1980 to 0.78 in 1998 and 2.71 in 2011. The observed averages were significantly lower than the simulated average (P <0.0001). In conclusion, the increase in salinity is probably one of the causes of a variation in the abundance of fish species. According to a possible more limited competition for space, fish abundance and C-score fluctuated inversely, indicating a trend towards a more generalist fish community. Keywords: Environmental breadth, environmental overlapping, co-ocurrence, and salinity gradient.

Record of changes in the regionalization of Terminos Lagoon, Campeche

The Terminos Lagoon is an estuarine-lagoon ecosystem, recognized as one of the largest coastal lagoons in the Gulf of Mexico, has great ecological, social and economic relevance, being a place from which various activities of commercial importance are carried out, in addition to being an area that presents high diversity. However, in the last 20 years it has been influenced by anthropic and natural impacts, which modifies the physicochemical characteristics of the water (temperature, salinity and pH) and changes in diversity species, being decisive in changes in regionalization. Therefore, in the present study, the spatio-temporal relationship of the physicochemical characteristics was analyzed, using geostatistics to characterize and predict possible new hydrological zones for Terminos lagoon. Samples were carried out monthly at 17 points, by zones and seasons (dry, rainy and wind/winter), in which significant differences were sought. To detect possible changes in regionalization, the GS+ software was used, where the values ​​of R2 were considered, defining the interpolation of Minimum Curvature (R2 <0.5). For the spatial distribution, the TNTmips program was used and to restructure the current zoning, a Cluster Analysis was applied. The results indicate for rainy season higher temperature values ​​(30.59 °C), higher salinity in dry (31.78 UPS), and higher pH in the wind/winter season (7.88). In the spatial distribution, the warmest areas were shown in the Candelaria River, the most saline areas by Isla de Carmen and the highest pH ranges near Pom-Atasta. According to the previous regionalization, 4 new zones are represented, which are influenced by fresh water discharges and the intrusion of salt water that is carried within the site. Keywords: Gulf of Mexico, ecosystem, refuge area, alterations, geostatistics.

Spatial-temporal behavior of benthic communities in the Terminos Lagoon, Mexico: Possible areas of protection and conservation

Terminos Lagoon is classified as a Flora and Fauna Protection Area due to the high biodiversity it registers, however, given its size, it makes total protection difficult. The objective of this study was to detect possible specific areas of conservation within the lagoon, for which an analysis of the spatiotemporal behavior of biodiversity was carried out (based on geostatistics) and thereby establish key regions of laguna de Terminos for their protection and recovery. Monthly samplings (2016-2017) were carried out by trawling with a shrimp net in 17 stations classified in 4 regions during dry (February-May), rain (June-September) and wind/winter (October-January). The organisms were identified up to the species level and the indices of abundance, richness and diversity were applied to carry out the interpolation and generation of maps. 17,950 organisms (382.9 kg) were collected and 103 species were identified. According to the interpolation of minimum curvature, at the temporal level, the rainy season was the one that presented the highest values in terms of diversity and richness, while at the spatial level, region 1 (adjacent area of Boca Atasta and Palizada river) it was the most representative during the three climatic seasons for both indices. In terms of abundance, region 2 was the one characterized by presenting the highest values. In conclusion, regions 1 and 2 represent areas of great ecological importance for the balance of biodiversity, which is why they are key areas that should be protected in Terminos Lagoon. This information would contribute significantly to knowing the state of the habitat, since it provides us with knowledge of the biological conditions of the ecosystem. Keywords: Coastal lagoons, onterpolation, Protected Natural Area, Gulf of Mexico, diversity, richness.

Morphological aspects and its influence in the ecological role of two simpatric species (Lagodon rhomboides and Archosargus rhomboidalis) in Terminos lagoon, Mexico

In Terminos Lagoon the Sparidae family is represented mainly by Lagodon rhomboides (Lr) and Archosargus rhomboidalis (Ar), both reported with herbivorous habits, however, the record of carnivorous or omnivorous habits in other regions raises questions about the correct classification of the ecological role they play and the influences that morphological aspects may have (e.g. oral difference and intestine length). The objective was to analyze the trophic role (amplitude, overlap and trophic level) through the stomach content and its possible relationship with the morphological aspects of L. rhomboides. and A. rhomboidalis during three climatic seasons (30 individuals per species per season). As results, 180 individuals were analyzed with an average total length of 14.0 ± 2.5 (cm) for both species. According to the Index Importance Geometric (IGI), Thalassia testudinum was the main item of L. rhomboides (IGI= 86.3) and A. rhomboidalis (IGI= 63.3), however, the secondary items for A. rhombiodalis (Brachidontes (Hormomya) exustus= 5.70) and L. rhomboides (Parvilucina (Parvilucina) multilineata= 16.80) were different. The trophic breadth (“Bi”) indicated that L. rhomboides. and A. rhomboidalis are specialists (BiLr= 0.02 and BiAr= 0.01). At the intraspecific level, there is high similarity (ANOSIM) in the diet of both Sparids between seasons (RLr= 0.03 and RAr= 0.05), however, at the interspecific level, low similarity was observed (Rg= 0.15), which was reflected in the NT of both Sparids (NTLr= 2.22 and NTAr= 3.71). The average buccal area was smaller in L. rhomboides (12.90 mm) compared to A. rhomboidalis (13.07 mm). Based on the intestinal index, L. rhomboides is classified. (Ii= 2.20) as herbivore, and A. rhomboidalis (Ii= 0.71) as carnivore. In conclusion, both species presented differences in trophic roles, probably related to specific morphological aspects. This information is relevant to know the vulnerability of a species from simulation studies to different phenomena such as climate change. Keywords: Herbivore, Gulf of Mexico. Protected Natural Area, ANOSIM and Coastal Lagoons.