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.

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.

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.

Arribazones de Sargassum en la costa norte occidental de Cuba

The pelagic macroalgae finches of the Sargassum genus in the Caribbean Sea currently represent a very natural problem due to their negative impact on the tourism industry, fishing industry, the environment and society in general. This work presents an above report of Sargassum that occurred on the north western coast of the Cuban archipelago in March 2019. The macroalgae species identified in the tidal zone were Sargassum fluitans and S. natans, and the specific geographic area where the impact of the upheaval occurred was from the west of Matan-zas bay to Mariel bay. The finches of these macroalgae were cataloged with a moderate magnitude compared to other reports in the Mexican Caribbean and in the Dominican Republic. This order of magnitude was cataloged based on its covered area of 169.3 km and its distribution along the coast in large patches, but very fragmented, despite the prevailing winds from the first quadrant (from north to east) during this period. Other events of this type reported in Cuba and the Caribbean region are taken up and discussed. Keywords: Caribbean Sea, Sargassum fluitans, Sargassum natans, Cuba.

Estructura de la Comunidad de Peces de la Laguna Mecoacán, Tabasco

The fish community of the Mecoacan lagoon plays a main ecological and economic role in the coastal zone of the Gulf of Mexico since they are key indicators of the health of aquatic ecosystems, maintain a flow and ex-change of energy with other systems and offer various ecosystem services. Because of the scarcity of studies on the structure of the fish community, the objective of this study was to describe and analyze the abundance and diversity of ichthyofauna to determine the ecological interactions of fish with environmental variability. Three sampling campaigns were conducted (January, May and September 2018), in 10 sampling sites. In each site, the environmental variables and ichthyological collections were carried out with a trawl net. The abundance was calculated as density (ind/m2), biomass (g/m2), and average weight (g/ind). The different components of diversity were determined by Shannon y Weaver (H’n), Margalef (DMg) and Pielou (J ‘) index. The dominant species were identified through the Relative Importance Index. A total of 853 fish were collected grouped into 12 orders, 17 families, and 27 species with a total combined weight of 10.9 kg. The range of variation of density was 0.12-0.26 ind/m2, of biomass 1.17-3.4 g/m2 and average weight 9.21-15.42 g/ind. The highest abundance stands out in January and sites 2, 3 and 4. On a temporal scale, greater diversity and equity were observed in the rainy season, and on a spatial scale, site 9 stood out for presenting greater diversity and species richness. 10 species with ecological dominance were identified being Cathorops aguadulce, Diapterus rhombeus, and Opsanus beta those with the highest values for the relative importance index. The cluster analysis associated two groups of species and through an analysis of canonical correspondence the abundance of two groups of fish was correlated with the temperature and dissolved oxygen. Keywords: abundance, diversity, ichthyofauna, dominant species.

Participación comunitaria en la transferencia tecnológica de un sistema acuícola de peces nativos

Low-scale aquaculture can be a successful model in rural settings because it can reduce demand for products and job creation, but one of the limiting factors to establish these aquaculture systems is the weakness of the manage-ment of technological processes in fish production by farmers. It is therefore necessary to promote training and technology transfer to the productive sector in order to promote conditions of self-employment, food security and to include beneficiaries throughout the process. Technological transfer is a mechanism that can increase aquaculture productivity and boost its profits. This scenario sought to design and build an aquaculture system for tropical gar (Atractosteus tropicus) and Mayan cichlid (Mayaheros urophthalmus) culture, with the participa-tion of local skilled people through the technological transfer of aquaculture. This system was developed in a locality in the Centla Swamps in southeastern México from 2017 to 2019 in five phases: diagnosis, presentation, design and construction, implementation and monitoring. The transfer of technology for the culture of species was made possible by the advice of the working teams and the support of the inhabitants. It was identified that the participants had a change in their perception of aquaculture and acquired skills in this activity. Community participation is an essential part of technology transfer. Keywords: Tropical gar, Mayan cichlid, fisheries, capacity, adaptation.

Distribución de plaguicidas organoclorados (OCPs) en sedimentos costeros de América Latina

Organochlorine pesticides (OCPs) are compounds that have been forbidden in most of the World countries for been highly toxic and persistent. Due to their intrinsic characteristics, even today, they can be found in almost any environment. In this work it was aimed to analyze their distribution in Latin American coastal sediments, at Atlantic and Pacific oceans, through the analysis of thirty three scientific publications that characterized a total of fifty five sites. It was observed that general concentrations depended of the own characteristics of each site, being larger closer to big cities or intensive agricultural fields, as well as semi-closed environments with larger rates of water permanence and consequently larger influence from the continent. Likewise it was observed that the composed addition of OCPs was similar among sites located in the same country or region. Keywords: Organochlorine pesticides, sediments, coasts, Latin America, composition.

Uso de biomarcadores en la evaluación ambiental de ecosistemas marinos en América

The use of biomarkers in the assessment of the marine environmental status offers an integrated approach to the effects caused by diverse pollutants. This article compiles and analyzes the original research on the study of possible biomarkers in wild coastal-marine organisms from America. One of the outcomes of this review research is the need for a continuous evaluation of organisms in conjunction with the assessment of environmental vari-ables and the levels of pollutants that may be found in any ecosystem. It is well stated that the use of biomarkers is a practical tool for the environmental management; however, some limitations apply and there are several questions in regards to specificity, sensibility, usability, replicability, and interpretation to be solved, yet. Along the American continent, multiple biomarkers have been used to evaluate specific pollutants or highly impacted zones at marine-coastal environments. The most commonly used organisms are fishes and bivalves and they have been also extensively used in marine turtles. In regards of the type of biomarkers, plenty of authors integrate biomarkers from different groups, sorted in this review as biometric biomarkers (morphologic and corporal in-dexes), histological biomarkers (for tissues), molecular biomarkers (genetic) and biochemical and physiological biomarkers (both at the cellular and molecular levels). Following this classification, the most used biomarkers were biochemical and physiological biomarkers, due to the great advantages and information that they provide. It is of utmost importance to set guidelines and referenced threshold values for each biomarker to allow the early environmental diagnosis and integrated evaluation of harmful pollutants effects. Keywords: Biomarkers, environmental assessment, America.

Hidrocarburos Aromáticos Policíclicos (HAPs) en ambientes marinos: Una revisión de América

The polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic compounds of global concern. They pres-ent mutagenic and carcinogenic characteristics, in addition to a wide variety of other adverse effects in the or-ganisms. They are widely distributed in marine environments, implying several health risks for both ecosystems and public health. Therefore, require constant monitoring and tailoring of preventive measures for their control. This review is based on the PAHs original research within coastal-marine environments published along the past ten years in America, considering the main environmental matrix such as sediment, water, organisms, and air. The review shows an outstanding PAHs monitoring activity led by USA and Mexico –at all matrix-, followed by Argentina, Brazil and Chile which demonstrate a rising environmental concern on these compounds, focused in highly anthropized areas. The present data for South America is still scarce, including many areas with null information. This review demonstrates that along all the continent and all matrixes, detectable concentrations of PAHs from multiple sources are reported, with levels ranging from minimum to extremely high. Keywords: Polycyclic aromatic hydrocarbons (PAHs), marine environments, America.