Mexican Pacific Coast Research Articles

Lizard species on three islands off the Mexican Pacific Coast: effects of insularity

This study provides a descriptive panorama of the lizard communities on 3 islands and the mainland on the Pacific coast of Mexico, estimating the effect of insularity (ecological changes between lizards on the islands and on the mainland) on lizard populations. The panorama included the number of species, encounter frequency and age classes. The insularity effects were estimated by comparing these variables, as well as basking behavior, activity related to microclimate, and perch height among the islands and the mainland. Of 11 species recorded, 8 occurred on the islands; however, every insular community was composed of 3 to 5 species (4 are protected by Mexican law). The encounter frequency for all species ranged between 11 and 0.1 individuals per hour. Lizard communities were predominantly composed of adults. Only 2 lizard species, Aspidoscelis communis and A. lineattissima, were shared among all sites, showing no insularity effects on the encounter frequency nor basking behavior. There were signs of insularity, however, on age classes and a clear effect on perch height, suggesting niche expansion. The study contributes to the regional knowledge of lizard species, as well as to ecological theories such as niche expansion and density compensation.

Genomic DNA extraction and phenolic content of salty and tannic plant material of two mangrove tree species from the mexican pacific coast

Abstract Mangroves, unique tree and shrub species inhabiting coastal saline environments, exhibit distinctive ecological and morpho-physiological traits, including forming pure intertidal stands and possessing specialized mechanisms for salt excretion and aerial root respiration. These species produce valuable antioxidants, such as phenols and tannins, with significant pharmacological, ecological, and toxicological implications. This study aimed to develop a highly efficient DNA extraction protocol for mangrove leaves rich in salt and tannins. The commonly used CTAB extraction protocol and a commercial DNA extraction kit were modified to enhance DNA purity and yield. The antioxidant capacity of the samples was assessed using various protocols. The results demonstrated that the modified commercial kit outperformed other methods in extracting DNA from mangrove leaves, effectively overcoming challenges associated with high salt and phenolic compounds that could impede next-generation sequencing (NGS) analysis. Furthermore, the findings revealed an inverse relationship between tannin concentration and DNA extraction yield. This study offers a valuable resource for DNA extraction protocols from tannin-rich plant materials. In conclusion, the modified commercial kit represents the most efficient and effective approach for extracting DNA from tannin-rich mangrove leaves.

Inter ocean basin moisture fluxes and the onset of the summer rainy season over southern Mexico

The onset of the rainy season in monsoonal climates is a key element for the development of water related activities. In southern Mexico, it starts in late May or early June, while in western and northwestern part of the country in begins between early and mid-July. Previous studies indicate that it depends on the meridional position of the eastern Pacific Inter Tropical Convergence Zone (ITCZ). By mean of analyses of the Vertically Integrated Moisture Flux, the low level atmospheric dynamics in the tropical Americas is analyzed to establish the temporal evolution of inter ocean moisture fluxes that lead to the onset of the summer rainy season in southern Mexico. The onset of the rainy season depends on the longitudinal position of the center of maximum convective activity in the ITCZ, which induces a quasi-stationary low-level cyclonic circulation that results in moisture fluxes to the Mexican Pacific coast and rains. The Caribbean Low-Level Jet (CLLJ) is a mechanism that modulates inter ocean basin moisture fluxes into the eastern Pacific ITCZ and the location of the maximum convective activity in this system. We propose that the sequence of events that leads to the onset of the rainy season in southern Mexico is: (i) an episode of strong moisture flux from the Caribbean Sea into the eastern Pacific ITCZ, (ii) a region of intense convective activity in the ITCZ that triggers a quasi-stationary low-level cyclonic circulation which in turn, induces moisture flux into southern Mexico, and (iii) the development of convective activity in southern Mexico that determines the onset of the rainy season. The intensification of the CLLJ from June to July also results in a westward displacement of the region of maximum convection within the ITCZ that leads to changes in the atmospheric circulations and moisture fluxes that determine the onset of the rainy season at higher latitudes in the Mexican Pacific coast.

Solar powered dryers in agricultural produce processing for sustainable rural development worldwide: A case study from Nayarit-Mexico

• Essential parameters of Sustainable Development Goal – 12 are introduced • A specific case study for farm production in Nayarit State, Mexico is presented • Prospects for solar powered solar drying is illustrated for sustainable development • Large-scale solar drying integrates recent innovations, applicable worldwide. Nayarit state on the Mexican Pacific Coast has a land area of 27,850 km 2 and a coastline of 290 km. The state represents 1.4% of the national territory, of which 438,400 hectares are currently dedicated for agricultural use. Nayarit is home to 1.23 million people, and produces tropical fruits such as mango, 316,750 metric tons and soursop 15,400 tons (May-July); pineapple, 34,250 tons (March-April); bananas 27,800 and jackfruit, 23,250 tons. Presently these add up to a total of 500,000 tons of yearly tropical fruit harvest amidst an increasing public awareness that these hold essential nutritional ingredients to help the population maintain its health and well-being. However, the water content in the produce of typically above 80% w/w, leads to bacterial and fungal activity. Consequently, a notable fraction of the produce perishes in a short period of time before they reach the consumer. Globally, such loss is 1.3 billion tons every year, as defined by the food loss index (FLI) and the food waste index (FWI). According to Sustainable Development Goal (SDG)-12 of the Food and Agricultural Organization (FAO), both FLI and FWI should be reduced to one-half its current levels by the year 2030. To meet this goal, a significant fraction of the farm produce may be set apart for drying in solar powered dryers at the farm-site. With an aperture of 36 m 2 each, letting in UV filtered solar radiation and with an electric grid-integrated PV system, we estimate that 3500 of such dryers can produce nearly 480,000 kg of dried farm produce per day. This production represents 25% of the harvest, recovering also a significant amount of potable water released from the produce while drying. Thus, rural areas would produce dried farm products utilizing renewable energy; supply these worldwide, and benefit themselves from sustainable development.

Ground-Motion Similarities in the Valley of Mexico from Subduction Earthquakes

ABSTRACT Since the eighties, several subduction earthquakes on the Mexican Pacific coast have been recorded at accelerometric networks in the Valley of Mexico (VM). Such are the cases of the 19 September 1985 M 8.1 Michoacán earthquake and the recent 7 September 2021 M 7.1 Guerrero earthquake. These events have caused from minor damages to widespread structural collapses in the VM. The vertical ground motion recorded at several sites in the VM clearly show recurrent Rayleigh wavetrains, which present similar characteristics in period, amplitude, and duration among stations. These characteristics are very stable in space and time. On the other hand, the corresponding horizontal ground motion are strongly affected by the surface geology of the valley because of the shear wave-energy trapped at the uppermost soft layers. In addition, the horizontal response at several soft-ground sites displays significant azimuthal effects. Based on these observations, we analyze thrust-faulting subduction earthquakes that occurred along the Mexican Pacific coast from Michoacán to Chiapas states, all recorded at the VM accelerometric networks. We identified similarities in the vertical and horizontal ground motion not only among stations but also between seismic events recorded at the same station. The local generation of surface waves is studied using a kinematic analysis in the frequency–wavenumber domain (f-k), and sundry techniques in frequency and time domains. As a preliminary explanation, our analysis suggests that azimuthal effects related to thrust faulting subduction earthquakes strongly influence the local generation of surface waves affecting the 3D response of the valley. Moreover, for all earthquakes in all stations, our results show that while the vertical ground motion is similar and its amplifications are small and governed by earthquake size, the two horizontal components reveal strong site effects.

COVID-19 Impacts on Whale-Watching Collaboration Networks

Whale-watching tourism generates high-income seasonal livelihoods in coastal communities on the Mexican Pacific Coast; however, this sector is at risk from accelerated global changes. We evaluated the responses of a collaboration of tourism networks regarding the impacts COVID-19 using a longitudinal social network approach. We used a two-wave snowball method to identify potential interviewees and followed geographic and jurisdictional criteria using a face-to-face survey to map collaboration ties between 38 stakeholders involved in whale-watching tourism before and after the second wave of the pandemic. We also asked this group of stakeholders about their perceived impacts of COVID-19. We found slightly higher connectivity and centralization levels in the social networks after the pandemic. Loss of income and reservations, a decrease in both conservations and pollution, and an increase in the reduction in wildlife tourism were the main self-reported impacts. We also detected harmful pandemic legacies, such as whale-watching tours conducted using unregulated private boats. This research directly informs Mexico’s whale-watching tourism policy by showing the management and coordination challenges that stakeholders face in a post-pandemic context. While the social fabric of coastal communities has been resilient to the COVID-19 pandemic, we found indications that the governance of marine resources can easily unravel if rule of law is absent.

Towards the definition of the humpback whale population units along the Mexican and Central American coasts in the Pacific Ocean

AbstractThe SPLASH project (2004–2006) revealed complex population structure and migratory connections, but no regional effort was made along the southern Mexican Pacific coast until dedicated research was initiated in 2010. It is unclear whether humpback whales documented in this region belong to the Mexican or Central American population units. This study aimed to establish the relationship between humpback whales of southern Mexico and those of the surrounding population units. Humpback whale photo‐identification images were compared from multiple locations in north, central, and southern Mexico and Central America. Whales' movements among regions were estimated using the Interchange Index (InI) and the Movement Index (MI). The results showed higher movements among the southern sampling areas, suggesting that whales from southern Mexico belong to the “Central American population unit.” This population unit migrates north to the feeding areas of the US West Coast using a migratory corridor along mainland Mexico to the mouth of the Gulf of California along the Baja California Peninsula. The degree of interaction with humpback whales from other population units is unknown. More studies are needed to understand population structure and disentangle photographic capture of whales on migration from whales where this is their main wintering area.

Modelling the functional connectivity of the grayish mouse opossum (Tlacuatzin canescens) in a highly threatened tropical dry forest of the Mexican Pacific coast

Landscape connectivity between protected natural areas and their surroundings is essential to maintain wildlife movement and to promote gene flow and genetic diversity. The grayish opossum mouse (Tlacuatzin canescens) was used for modeling functional landscape connectivity between the Chamela-Cuixmala Biosphere Reserve, an important biological reserve with large extensions of tropical dry forest in the Mexican Pacific coast, and surrounding vegetation patches. The model was estimated through graph and circuit theory, using a resistance matrix and the calculation of the minimum area of suitable habitat patches. Thirty-eight patches of suitable habitat for T. canescens and 60 potential corridors were identified. Three patches adjacent to the CCBR played the most important role in maintaining the connectivity of the tropical dry forest in the region. In contrast, suitable habitat patches with the lowest connectivity were embedded in a landscape matrix composed of areas for cattle raising and agriculture, increasing the loss and isolation of forest patches. Our results highlight not only the importance of maintaining large patches of suitable habitat, but also smaller patches which might play a significant role as stepping stones, promoting habitat connectivity for T. canescens and similar species.

Potential distribution of hybrids between [i]Crocodylus acutus[/i] and [i]Crocodylus moreletii[/i] on the Mexican Pacific coast outside the natural hybridisation zone

In Mexico, Crocodylus acutus is widely distributed along the Pacific coast, while C. moreletii occurs on the Gulf of Mexico. Both species converge in the Yucatán peninsula where natural hybridisation is reported, and later it was also reported in the Gulf of Mexico. Unfortunately, due to translocations and stochastic events, currently there are hybrids of both species on the coast of Oaxaca and Guerrero. In this study, we evaluated the potential colonisation areas of the hybrids on the Pacific coast through ecological niche analyses. The results indicate that the hybrid crocodiles and the parent species share preferences in at least three climatic variables: average temperature range, isothermality, and minimum temperature of the coldest month. Furthermore, it was found that the climatic niche of the hybrids is more similar to that of the C. moreletii leaving reminiscent areas for C. moreletii in Nuevo León, San Luis Potosí and small areas far from the coast in Veracruz, coinciding with what was previously reported by molecular analysis. On the other hand, the climatic niche of the hybrid crocodiles is also sufficiently similar to that of C. acutus, having the possibility to colonise the Pacific coast extensively, leaving reminiscent small areas for C. acutus on the northern coast of Sinaloa, southern of Sonora, central coast of Oaxaca and small inland areas of the Pacific coast. Keywords: Crocodilians, ecological niche, hybrids, species model distributions, conservation, Mexico

Storm surge forecast calculus on the Mexican Pacific coast using SWASH numerical model

Storm surge is a phenomenon that occurs on coasts with a higher incidence in the rainy season. The factors that promote its appearance are the wind and the tide whose force has been sometimes catastrophic. The objective of the study is to provide a storm surge forecast using the SWASH numerical model for some points on the Mexican Pacific coast. The approach of the experiment refers to previous works that use the infrastructure and data available from NOAA and SEMAR; the use of unstructured meshes used in a wave model to conclude in a beach wave model. In the validation of the results, the tide gauges of the study locations will be used; with the feedback obtained, the necessary adjustments are expected until the model has at least 60% correct measurements. Some authors agree that global warming affects the power with which the phenomenon has been manifesting itself, so that the development of technology could help minimize the consequences.

Susceptibility to Flooding of Urban Areas Puerto Vallarta - Mexico

The Mexican Pacific coast is frequently affected by meteorological systems that cause rain. These events are beneficial when they precipitate in the internal valleys of the basins and water is captured from the highlands by filtration, recharging the aquifers, and allowing surface runoff through rivers and runoffs that are the natural sources of freshwater. On the other hand, these systems are adverse when they precipitate in excess, and additionally, they are associated with bad decisions and urban planning errors that put at risk the life and patrimony of some social sectors, this aspect has become a national security issue for the authorities. The region of Bahia de Banderas has a rainwater drainage network through open-pit channels that partially cover the urban area, a situation that puts the population and its assets at risk since rain considered common causes significant puddles, a situation that is progressively worsening, but the great danger of an extraordinary amount of rain, as has occurred in the past, is represented by the hydrological basins that cross or are adjacent to it, an aspect that will be discussed in greater detail in this article.

Parasite communities of the spotted rose snapper Lutjanus guttatus (Perciformes: Lutjanidae) off the Mexican Pacific coasts: Spatial and long-term inter-annual variations.

A total of 802 individuals of Lutjanus guttatus (Steindachner, 1869) specimens were collected over a 10-year period (August 2012 to February 2021) from four locations on the south-central Pacific coast of Mexico. Their parasite communities were quantified and analyzed to determine if they experience significant spatial and inter-annual variations. Thirty-two taxa of metazoan parasite were recovered and identified: four species of Digenea, four Monogenea, one Cestoda, two Acanthocephala, seven Nematoda, one Hirudinea, and nine of Crustacea (six Copepoda, and three Isopoda). Species richness was greatest among the digenean group, which represented 25% of the total species recovered, followed by the nematodes (22% of total species). Species richness at the component community level (10 to 20 species) was similar to reported richness in other Lutjanus spp. The component communities and infracommunities exhibited a similar pattern: low species richness and diversity, and dominance by a single species, mainly the monogenean Haliotrematoides guttati. Parasite community structure and species composition varied through the years, as well as between sampling locations. Variations were possibly caused by a combination of biotic and abiotic factors which generated notable changes in the infection levels of several component species. However, the similarity in the parasite species composition was high locally for short-term periods (one or two years). This result, therefore, suggests that parasite communities of L. guttatus may be more predictable locally, but only for short-term periods.

Potential Flood Risk in the City of Guasave, Sinaloa, the Effects of Population Growth, and Modifications to the Topographic Relief

The coastal city of Guasave, Sinaloa, located on the Mexican Pacific coast, is subject to extreme precipitation events, which have caused flooding with damage to the city’s infrastructure. The factors that influence flooding are vegetation, geology, degree of soil saturation, drainage characteristics of the watershed, and the shape of the topographic relief. Of the above factors, the topographic relief, which is the subject of the study, has been partially modified in some areas by infrastructure works (from 20.2 m to 17.6 m), and the population of the urban area has grown by 51.8% in 17 years (2004–2021); therefore, the objective is to evaluate the potential flood risk due to changes in this factor and the growth of the urban area. When using this method, the potential flood risk was determined considering four extreme events, 1982, 1990, 1998, and 2019. It was found that the potential risk increases for the whole city, being more intense in sector III, which, before the modification of the topographic relief, was the area with the lowest risk of flooding. In an extreme event such as Hurricane Paul in 1982, practically the entire city would be flooded.

Beta-diversity of macroinvertebrates associated to Pocillopora corals along the Mexican Pacific coast

Although invertebrates are the most diverse organisms associated with corals, they have been poorly studied in the Eastern Tropical Pacific. Thus, this study analyzed macroinvertebrate assemblages associated with Pocillopora corals along the Mexican Pacific coast and assessed whether a latitudinal diversity gradient can be identified. Forty-two sites grouped in 12 localities were sampled by visual censuses from the southern Gulf of California (26° N) to the coast of Oaxaca (15° N). Ecological indices (species richness, abundance, and taxonomic distinctiveness) were compared among localities. A Bray–Curtis resemblance matrix was also created, and a non-metric multidimensional scaling (nMDS) was performed to identify locality groups based on macroinvertebrate abundance and occurrence. Beta-diversity as a measure of the proportional species turnover was determined in each locality group. A total of 129 species grouped in six phyla were recorded. All the ecological indices differed significantly among localities. Five groups that moderately followed a geographic pattern were formed by nMDS. Nevertheless, no evidence of a beta-diversity latitudinal gradient was found. Beta-diversity calculated in each group indicated that the central region of the Mexican Pacific and the Gulf of California have the highest species proportion in the studied area. Furthermore, the composition of macroinvertebrate assemblages had a “turnover and nestedness” beta-diversity pattern. These results are very useful for conserving species richness associated to coral communities along the Mexican Pacific coast. Establishment of marine protected areas in locality groups with a high macroinvertebrate beta-diversity should be considered, especially when harmful human activities can affect it negatively.

Interannual shifts in sea surface temperature and chlorophyl drive the relative abundance and group size of common bottlenose dolphins Tursiops truncatus on the Southeast Gulf of California

Despite being one of the most common odontocetes off Sinaloa (Mexican Pacific coast), basic studies on the ecology of common bottlenose dolphins (Tursiops truncatus) are scarce in the region. This study aimed to describe changes in the relative abundance, group size, and behavior of this species during 2007 – 2012. We used boat-based surveys and satellite images of sea surface temperature (SST) and chlorophyll-a (Chl-a) to model changes in dolphin relative abundance (RA) over time, using correlations in time series analyses. Overall, mean RA was 3.6 dolphins h-1 (SD = 8.0), and significantly higher RA (6.4 –16.7 dolphins h-1) occurred in 2008, 2011, 2012, which was concurrent with hydrographic effects of La Niña oceanographic conditions, as well as during the upwelling season (February – April) (SST: 17.3 – 25.0 °C; Chl-a: 3.7 – 21.4 mg m-3). Conversely, significantly lower RA values (0.5 – 3.8 dolphins h-1) occurred in 2007 and 2010 that were likely associated with El Niño effects on the biological productivity of the area (Chl-a: 0.3 – 7.6 mg m-3). We found significant correlations between monthly Chl-a and SST average values with mean bottlenose dolphins RA, and lags (22 – 29 days) in the trophic response to variations of the hydrographic parameters. Significantly larger dolphin groups were recorded during La Niña years possibly because of the higher availability of their prey. This hypothesis is supported by higher feeding frequencies (35 – 73%) observed during the upwelling seasons, especially during La Niña conditions, whereas the most frequent behavior throughout all other years was traveling (28 – 69%). Our results show that RA and group size of bottlenose dolphins inhabiting the waters off Sinaloa, Mexico, are likely influenced by the changes in hydrographic parameters, especially during extreme climatic events.

Holothuria (Lessonothuria) coronata sp. nov. (Echinodermata, Holothuroidea), a new species of sea cucumber from Socorro Island, México

?Holothuria (Lessonothuria) coronatasp. nov. occurs in depths of 5–10 m off the Mexican Pacific coast at the Revillagigedo Archipelago. It is clearly distinguished from other species of the subgenus by the presence of tables with a circular disc and big peripheral holes, sometimes with a second series of peripheral ones, a disc with a spiny or smooth rim and a spire crossed by a single cross-beam, dorsal papillae, and ventral tube feet with curved supporting rods with a spiny edge.

Microtextures on quartz grains from the Gulf of Mexico and the Mexican Pacific coastal sediments: Implications for sedimentary processes and depositional environment

Microtexture analyes on quartz from coastal sediments of the Gulf of Mexico and the Mexican Pacific Coast reveal 35 and 30 types of microtextures, respectively, which were grouped into mechanical, mechanical/chemical and chemical categories based on their mode of origin. Microtextures of chemical origin are rarer in the El Carrizal than in the Manzanillo beach sediments of the Mexican Pacific Coast. Microtextures of mechanical origin like straight and curved scratches, pits, broken edges, and V-shaped marks indicate high energy, fluvial to marine depositional environments. The scarcity to absence of chemical features suggest that the energy level was higher at the Mexican Pacific coast than on the Gulf of Mexico coast. V-shaped marks are common in the Gulf of Mexico sediments, whereas they are abundant in the quartz grains from the Mexican Pacific coast. Increased frequency and density of V-shaped marks are produced by exceedingly high wave velocity during storm events or tsunamis. Abundance of V-shaped marks with fresh surfaces of quartz grains from the Mexican Pacific coast indicate an extremely high-energy impact event. Many quartz grains from the El Carrizal beach of the Mexican Pacific coast have abundant closely spaced V-shaped marks with fewer fresh surfaces. Such high frequency of V-shaped marks is mainly linked to grain-to-grain collision, typically associated with high-energy sub-aqueous conditions with a large volume of sedimentary particles in the water column that are produced during a tsunami or storm events. In contrast, many quartz grains from the Gulf of Mexico have large fresh surfaces with moderate percentages of V-shaped marks that might have been produced by high-energy waves with low sediment concentrations during storm events.

Tsunami Effects on the Coast of Mexico by the Hunga Tonga-Hunga Ha'apai Volcano Eruption, Tonga.

The massive explosion by the January 15, 2022 Hunga Tonga-Hunga Ha’apai volcano in Tonga triggered a trans-oceanic tsunami generated by coupled ocean and atmospheric shock waves during the explosion. The tsunami reached first the coast of Tonga, and later many coasts around the world. The shock wave went around the globe, causing sea perturbations as far as the Caribbean and the Mediterranean seas. We present the effects of the January 15, 2022 Tonga tsunami on the Mexican Pacific Coast, Gulf of Mexico, and Mexican Caribbean coast, and discuss the underrated hazard caused by great volcanic explosions, and the role of early tsunami warning systems, in particular in Mexico. The shock wave took about 7.5 h to reach the coast of Mexico, located about 9000 km away from the volcano, and the signal lasted several hours, about 133 h (5.13 days). The shock wave was the only cause for sea alterations on the Gulf of Mexico and Caribbean Sea, while at the Mexican Pacific coast both shock wave and the triggered tsunami by the volcano eruption and collapse affected this coast. The first tsunami waves recorded on the Mexican Pacific coast arrived around 12:35 on January 15, at the Lázaro Cárdenas, Michoacán tide gauge station. The maximum tsunami height exceeded 2 m at the Ensenada, Baja California, and Manzanillo, Colima, tide gauge stations. Most tsunami warning advisories, with two exceptions, reached communities via social media (Twitter and Facebook), but did not clearly state that people must stay away from the shore. We suggest that, although no casualties were reported in Mexico, tsunami warning advisories of far-field tsunamis and those triggered non-seismic sources, such as landslides and volcanic eruptions, should be included and improved to reach coastal communities timely, explaining the associated hazards on the coast.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00024-022-03017-9.

Nature’s Contributions to People in Vulnerability Studies When Assessing the Impact of Climate Change on Coastal Landscapes

The geographic landscape is a recurrent unit of analysis in vulnerability studies. Single descriptions are often used to show the elements exposed in these landscapes. However, the concept requires specifying the components of the landscape and its functioning as a unit. Thus, the purpose of this research was to use the analysis of Nature’s Contributions to People (NCP) to describe the global contribution of landscape elements to human activities, prioritizing the units in which the effects of climate change may imply greater impacts on the human population. For this, we analyzed six categories of nature’s contributions applied to the landscape units in a fragment of the Mexican Pacific coast. The units with mangrove cover had the highest nature contributions. It is expected that the application of this approach in the exposure component of vulnerability studies will allow a better understanding of the non-return relationship and the search for adaptive nature-based solutions.

Mercury, selenium and cadmium in juvenile blue (Prionace glauca) and smooth hammerhead (Sphyrna zygaena) sharks from the Northwest Mexican Pacific coast

Cadmium, selenium, and mercury concentrations were measured in muscle and liver of juvenile blue (Prionace glauca) and smooth hammerhead (Sphyrna zygaena) sharks caught on the west coast of Baja California Sur, Mexico, to evaluate the human health risk associated with its consumption. Cd and Hg were lower than the maximum allowable limit for human consumption established by the Mexican government (Hg = 1.0 μg g-1 and Cd = 0.50 μg g-1). Interspecific differences in trace elements accumulation denoted diet variations and physiological requirements of each shark species. Calculated biomagnification factor (BMF) values confirmed a prey-predator trophic transfer of elements. Not significant results of Selenium health benefit Index value (P. glauca = −0.46; S. zygaena = −0.02) signify no potential risks for human health. However, calculated Hazard Index values displayed possible health hazards to the children who consume blue shark meat regularly. The local population is advised regarding the ingestion rates of shark.