Yucatan Coast Research Articles

Application of Artificial Neural Networks for Dengue Fever Outbreak Predictions in the Northwest Coast of Yucatan, Mexico and San Juan, Puerto Rico.

Modelling dengue fever in endemic areas is important to mitigate and improve vector-borne disease control to reduce outbreaks. This study applied artificial neural networks (ANNs) to predict dengue fever outbreak occurrences in San Juan, Puerto Rico (USA), and in several coastal municipalities of the state of Yucatan, Mexico, based on specific thresholds. The models were trained with 19 years of dengue fever data for Puerto Rico and six years for Mexico. Environmental and demographic data included in the predictive models were sea surface temperature (SST), precipitation, air temperature (i.e., minimum, maximum, and average), humidity, previous dengue cases, and population size. Two models were applied for each study area. One predicted dengue incidence rates based on population at risk (i.e., numbers of people younger than 24 years), and the other on the size of the vulnerable population (i.e., number of people younger than five years and older than 65 years). The predictive power was above 70% for all four model runs. The ANNs were able to successfully model dengue fever outbreak occurrences in both study areas. The variables with the most influence on predicting dengue fever outbreak occurrences for San Juan, Puerto Rico, included population size, previous dengue cases, maximum air temperature, and date. In Yucatan, Mexico, the most important variables were population size, previous dengue cases, minimum air temperature, and date. These models have predictive skills and should help dengue fever mitigation and management to aid specific population segments in the Caribbean region and around the Gulf of Mexico.

Taxocoenosis of epibenthic dinoflagellates in the coastal waters of the northern Yucatan Peninsula before and after the harmful algal bloom event in 2011–2012

Eutrophication causes the major impact in the coastal waters of the state of Yucatan. In general, loss of water quality and biological communities and massive development of toxic microorganisms are some of the consequences of this phenomenon. To reveal changes in species composition and cell abundance of the taxocoenosis of epibenthic dinoflagellates before and after a harmful algal bloom event in the water column that lasted about 150days (August–December 2011) in the Dzilam – San Crisanto area (northern Yucatan Peninsula, southeastern Gulf of Mexico) were the main objectives of the present study. In August 2011 and September 2012, sampling along 20 transects perpendicular to the coastline along the entire northern Yucatan coast, starting from 20 sampling sites from El Cuyo in the east to Celestún in the west, at a distance of 50, 150 and 250m from the coast, was carried out. Physicochemical characteristics measured before and after the bloom were within the ranges previously reported in the study area. Salinity was the most stable characteristic, with mean values of 36.25 and 36.42 in 2011 and 2012, respectively. Phosphates were the only parameter that showed a wide range with higher values before the bloom (0.03–0.54μM/l). A total of 168 macrophyte (seaweeds and seagrasses), sponge and sediment samples (105 in 2011 and 63 in 2012) that included associated microphytobenthos were taken by snorkeling from 0.7 to 5m depth. Six substrate types were distinguished: Chlorophyta, Phaeophyceae, Rhodophyta, Angiospermae (seagrasses), Demospongiae (sponges) and sediment. Chlorophytes dominated the collected samples: 38 samples in 2011 and 23 in 2012. Avrainvillea longicaulis f. laxa predominated before the bloom and Udotea flabellum after it. In total, 25 epibenthic dinoflagellate species from 11 genera were found. The genus Prorocentrum was the most representative in terms of the number of species. The highest total dinoflagellate cell abundances were observed in the sites with different types of macrophytes (up to 2441cells/g substrate wet weight in 2011 and up to 1068cells/g in 2012). The lowest cell densities were observed in the areas with scarce or no macrophytes on sandy seafloor. Before the bloom, Prorocentrum rhathymum (up to 4995cells/g) and P. cf. sipadanensis (up to 5275cells/g) were the most abundant, and after the bloom the latter was dominant (up to 3559cells/g); in 2012, both variety of substrates and dinoflagellate cell abundance diminished. A canonical correspondence analysis revealed significant relationships between the physicochemical variables and epiphytic/benthic dinoflagellate species either before or after the bloom. The pelagic bloom resulted in the loss of substrate for epiphytic dinoflagellates, which caused replacement of the dominant species and a decrease in cell abundance of the whole taxocoenosis.

Taxonomic composition and distribution of cephalochordates (Cephalochordata: Amphioxiformes) from Mexico

Based on the number of specimens examined, review of reference collections and literature, we determined the presence of four cephalochordates (two genera and one family) in the seas of Mexico; moreover, the registry of the locations is denoted also a taxonomic key for their identification comes attached. The presence of three of the four species for the Gulf of Mexico and the Mexican Caribbean is registered, of which Branchiostoma caribaeum has the largest distributional area, from Veracruz coasts to the Yucatan Peninsula; B. longirostrum has been registered only on the west part of the Gulf of Mexico and Asymmetron lucayanum in front of the northeastern coast of Yucatan. Branchiostoma californiense is the only one registered on the Pacific coast of Mexico but it counts with a wider distribution.

Calcareous green algae standing stock in a tropical sedimentary coast

Calcareous green algae (CGA) are important producers of carbonaceous sediments in coastal environments; they fix carbon producing CaCO3 and organic compounds through photosynthesis contributing to the carbon budget of these ecosystems. In this study, the CGA standing stock (as dry weight) and its organic matter (OM) and inorganic carbon (CaCO3) were estimated along the north coast of Yucatan at two sampling sites (Cerritos 1 and Cerritos 2), five times between summer 2014 and summer 2015. The standing stock annual average of three CGA species: Halimeda incrassata, Halimeda opuntia, and Penicillus dumetosus was 1214.8 g m−2, of which 89% corresponded to CaCO3 and 11% to OM. Significant seasonal differences were found (p < 0.05) with a maximum of 1335.5 g m−2, CaCO3·1178.1 g m−2, OM 156.4 g m−2 in summer time in Cerritos 2. From the three species present, the largest standing stock was from H. opuntia (annual average 1142.9 g m−2). Seasonal changes were significant correlated with changes in temperature (Kendall Tau_b correlation 0.161, p < 0.0001); which is consistent with several studies that demonstrate that calcification is regulated by temperature. The CGA annual average standing stock found in this study is above the values reported for the Caribbean side of the peninsula. In our study sites H. opuntia is dominant and its high values are consistent with the “weedy” behavior reported in reef sites, making this species an important contribution of OM and CaCO3 into the local system. This study provides the baseline for future estimation of carbonate production of CGA and the role of CGA in the carbon budget of Yucatan.

Presence of Infectious Hypodermal and Haematopoietic Necrosis Virus (IHHNV) in Native Shrimps from Southern Mexico

A survey for Infectious Hypodermal and Haematopoietic Necrosis Virus (IHHNV) and White Spot Syndrome Virus (WSSV) was performed during two catching seasons of native shrimps in the Yucatan Coast in the Gulf of Mexico. The mtDNA COI barcode identified two endemic species; the southern pink shrimp Penaeus notialis (Pérez Fantante, 1967) and the northern pink shrimp Penaeus brasiliensis (Latreille, 1987) (previously described as Farfantepenaeus brasiliensis). The prevalence of IHHNV was of 18.18% in 2016, and of 8.57% in 2017. All organisms tested negative for WSSV. This is the first identification of wild shrimps in the state of Yucatan Mexico by mtDNA COI barcode as well as the first identification of IHHNV in such species. The presence of IHHNV in wild shrimps populations has a potential of persisting in the coast of Yucatan with putative detrimental effect on local fisheries because once established in natural waters and hosts; such pathogens are almost impossible to eradicate.

Groins along the Northern Yucatán Coast

ABSTRACT Tereszkiewicz, P.; McKinney, N., and Meyer-Arendt, K.J., 2018. Groins along the northern Yucatan coast. Coastal erosion is a global issue, putting increasing physical and socioeconomic stresses on coastal communities. While shoreline protection structures are typically seen as potential solutions, negative environmental impacts often result. Groins, a shore-normal type of structure, can successfully impound sediment; however, improper design can lead to downdrift erosion and create hazardous rip currents. Widespread construction of groins on the northern coast of the Yucatan Peninsula is thought to have caused significant morphologic change to the shoreline, raising questions as to their effectiveness. The objective of this regional survey was to collect geodata on shoreline position and existing shoreline protection structures. Methods included (1) GPS mapping of the shoreline and groin structures along a 13-km stretch of coastline; (2) developing a classification for groin construction, conditi...

Efecto de factores abióticos en el desarrollo de raíces primarias, crecimiento y supervivencia de propágulos en Rhizophora mangle L.

Se realizó un experimento para conocer el efecto de los factores abióticos en el desarrollo de raíces primarias, crecimiento y supervivencia de propágulos de mangle rojo (Rhizophora mangle L.). Se colectaron 180 propágulos en la ciénaga de Santa Clara, en la costa norte de Yucatán, México, y se formaron 6 grupos de 30 individuos. Los propágulos se colocaron en orificios de una lámina de poliestireno expandido y se mantuvieron durante 48 días en recipientes de plástico, en posición vertical y con el hipocótilo inmerso en agua. Se establecieron tres salinidades: dulce (5-7 ups), marina (30-40 ups) e hipersalina (70-75 ups), bajo dos condiciones de iluminación (sombra y radiación solar directa) con un máximo albedo. Las plantas que permanecieron bajo condiciones de sombra (SD, SM y SH) presentaron una sobrevivencia de 100%, mientras que en los tratamientos expuestos directamente a la radiación solar directa (LD, LM y LH) presentaron una sobrevivencia inversa a la salinidad. El desarrollo de las raíces fue gradualmente menor al aumentar la salinidad, disminuyendo cuando los propágulos se encontraron expuestos a la insolación directa y a una mayor temperatura del agua. Los propágulos sometidos al tratamiento sombra-dulce (SD), presentaron una mayor ganancia de peso por el desarrollo de raíces y hojas (sólo en este tratamiento se produjeron hojas). La salinidad es el factor que controla la producción de raíces en los propágulos de R. mangle en la etapa de establecimiento. La insolación y la temperatura provocan un incremento del estrés fisiológico en los propágulos, disminuyendo la producción de raíces y aumentando la mortalidad.

Classification of Beach Erosion Vulnerability on the Yucatan Coast

ABSTRACTBeach erosion can have important socioeconomic and environmental consequences, particularly in tropical regions where tourism is a significant source of income. Although caused by natural processes, erosion is often aggravated by disorderly anthropogenic modification of the coast and extreme events. In Yucatan, Mexico, increasing urban development and deficient coastal management strategies as well as hurricanes have affected beach stability. This has highlighted the need for adequate coastal planning and policies that ensure the protection of key coastal ecosystems, such as beaches and sand dunes. To address this, a methodology to classify the coast according to its vulnerability is presented in this work. This methodology assumes that morphological features are indicators of beach evolution and the processes driving it and that these can be associated with different levels of vulnerability. The features considered are beach width, dune vegetation, anthropogenic pressure, and shoreline orientation, which were analyzed through aerial images and a multicriteria evaluation. It was observed that the most vulnerable areas are found near the most developed parts of the coast, where narrow beaches with little dune vegetation dominate. It is expected that this index will be of use to coastal planners and decision makers, particularly in the identification of critical zones.

Identifying Coastal Defence Schemes through Morphodynamic Numerical Simulations along the Northern Coast of Yucatan, Mexico

ABSTRACT Ruiz-Martinez, G.; Marino-Tapia, I.; Mendoza Baldwin, E.G.; Silva Casarin, R., and Enriquez Ortiz, C.E., 2016. Identifying coastal defence schemes through morphodynamic numerical simulations along the northern coast of Yucatan, Mexico. A beach segment on the northern coast of the Yucatan Peninsula, where sandy beaches have widespread erosion problems, was studied with morphodynamic numerical simulations to identify the most appropriate protection scheme for mitigating coastal erosion in the region. The numerical model Delft3D was used to model hydro-morphodynamic patterns. Three types of solution were simulated: (1) beach nourishment only, (2) beach nourishment and groynes (linear, Y- and T-shaped), and (3) beach nourishment and offshore breakwaters. Measured time series of wind, sea level, and shelf currents were fed into the numerical model. Morphodynamic simulations were validated by comparing the modelled volumetric changes with those observed from beach profiles. The morphodynamic evolution ...

First record of albinism in three-rowed sea cucumber, &lt;I&gt;Isostichopus badionotus&lt;/I&gt;

The first case of albinism in the three-rowed sea cucumber, Isostichopus badionotus (Selenka, 1867), is reported here through the study of two specimens caught by commercial divers fishing off the Yucatan coast of Mexico. The dorsal lengths of the albino sea cucumber specimens were 24.5 and 25.5 cm, with gutted weights of 350 and 400 g, respectively. The entire sea cucumber bodies were completely white in color and devoid of pigmentation. Additional sampling and monitoring is necessary to evaluate the causes and incidence of albinism in I. baniodotus off the Yucatan coast.

Presence of giant tiger shrimp Penaeus monodon (Fabricius, 1798) in eastern Peninsula of Yucatan coast, Mexico

Giant tiger shrimp Penaeus monodon has been indicated as an invader on the western coast of Atlantic Ocean. We report the first record of P. monodon in the eastern Peninsula of Yucatan, Mexico. On October 14 and November 25, 2014, three giant tiger shrimps were caught in Rio Lagartos lagoon. The total lengths of the shrimp were between 210 and 290 mm and weighed between 111.6 and 200 gr. Further sampling and monitoring is required in other coastal lagoons in Yucatan state to assess the invasion area and the origin as well as the probable invasion route of this species.

Landscape Analysis for PaV1 Infection in Lobsters Panulirus argus from the Artisanal Fishery of the Eastern Coast of Yucatan, Mexico

Panulirus argus virus 1 (PaV1) is considered a major threat to spiny lobsters Panulirus argus. In this study Geospatial analysis was used to analyze PaV1 distribution in an artisanal fishery of spiny lobster Panulirus argus population from the north coast of the Yucatan Peninsula. Adult and sub-adult P. argus and seabed coverage data were collected from thirty artisanal fishing sites. Five seabed coverage types were identified: seagrass; sand/seagrass mixture; sand only; coral/sand mixture; and seaweed. No juveniles were examined. Of the 358 collected lobsters, PaV1 was identified in four organisms (three sub-adults and one adult) from two fishing sites (termed A ＆ B), both found in a seagrass coverage area. Overall prevalence was of 1.12%. Prevalence was of 20% (2/10) at one site and of 12.6% (2/16) at the other.

Possible Tsunami Deposits on the Caribbean Coast of the Yucatán Peninsula

ABSTRACT Shaw, C.E. and Benson, L., 2015. Possible tsunami deposits on the Caribbean coast of the Yucatan peninsula. The western Caribbean Basin is notable for its tectonic stability. It has experienced no historical earthquakes or the tsunami that sometimes accompany them. This paper describes a single, wedge-shaped, boulder-covered, coastal berm on the Yucatan coast of Mexico that stretches unbroken for 50 km across a coastal segment characterized by rocky headlands that alternate with crescent beaches. The remainder of the 350 km of Yucatan coast consists mostly of mangrove that extends 1 to 30 km inland, often behind long, sandy beaches. On the headlands, the surface of the berm is densely paved with boulders—large boulders on its seaward face and smaller boulders and cobbles on its gently sloping inland surface. The top of the berm reaches an elevation >4 m, above the reach of all but the largest modern storm waves. Berm sediments on the headlands consist of two distinct layers of unbedded coarse san...

Spatial Analysis of the Abundance and Catchability of the Red OctopusOctopus maya(Voss and Solís-Ramírez, 1966) on the Continental Shelf of the Yucatan Peninsula, Mexico

The red octopus Octopus maya is an endemic species of the continental shelf of the Yucatan Peninsula, Mexico and supports the largest octopus fishery in the American continent. Little is, however, known about its spatial dynamics. The study of the space-time variation of catchability is a key element in the stock assessment, because it allows behavioral aspects of the resource and qualities of the various exploitation strategies to be clarified, which are essential for the fishery management. The objective was to analyze the spatio-temporal variations of the abundance and catchability of the octopus O. maya on the continental shelf of the Yucatan Peninsula, Mexico. During the fishing season of 2012 (August–December), fishery landings from the small-scale fleet in 13 ports of the Yucatan Peninsula, were analyzed to obtain data on catch, effort and fishing zone for O. maya. During the closed season of 2013 (January–July) fishing hauls were performed across a network of stations along the coast of the Yucatan Peninsula. Spatio-temporal variations in mean catch per unit effort (CPUE) in terms of number of organisms per hour of effective fishing were analyzed. Catchability and its variation with size, time, and zone were estimated through a model based on the Leslie transition matrix and frequency distributions of mantle length. The results showed significant changes in the distribution of O. maya. During the fishing season, the greatest abundances were found along the coast of Campeche (western zone), whereas, during the closed season the highest abundances were recorded along the coast of Yucatan (eastern zone). Trends of decreasing and increasing catchability were observed with respect to size according to the different zones. A high catchability was presented for small sizes along the coast of Campeche during the fishing season. The results indicate the need to investigate possible management measures differentiated by region (west-east) to ensure the fishery sustainability.

Geostatistical analysis and spatial modeling of population density for the sea cucumbers Isostichopus badionotus and Holothuria floridana on the Yucatan Peninsula, Mexico

Spatial distribution of Holothuria floridana and Isostichopus badionotus was examined at two sites off the coast of Yucatan: Isla Arena, Campeche, and Dzilam de Bravo, Yucatan, at different times using geostatistics. By means of ordinary kriging, inverse distance weighted and spatial simulation; seven models representing spatial distribution were produced and compared: three for H. floridana and four for I. badionotus. Spatial continuity of population density was calculated using an experimental variogram. Five types of models were tested (spherical, exponential, linear, linear to sill and Gaussian). Three statistics were obtained to aid in model output interpretation: the proportion of spatial structure, the regression coefficient, and the residual sums of squares for each variogram. Ordinary kriging produced the models with highest goodness-of-fit, indicating that population density was a regionalized variable, especially when populations are at unfished levels. H. floridana and I. badionotus displayed spatial patterns including patchiness, with some patches covering more than 60km2. Fishing changed the spatial structure or patchiness degree of population density. Spatial structure of virgin stocks was better explained using exponential models; whereas spherical models better represented spatial structure after fishing impacts.

Artificial Weathering Analysis and Mechanical Behavior of Geotextiles Used for Coast Erosion Control and Beach Restoration

Nowadays geotextiles play a significant part in coastal protection and erosion prevention design and maintenance techniques. The growth in their use worldwide as geotubes for recovering damaged coastal due to its easiness of manipulation and excellent mechanical properties has been extraordinary. Considering that applications of geosynthetics are usually outdoors, the degradation of polymers must be taken in account when selecting polymeric textiles. There are many environmental factors, which influence aging mechanisms of geotextiles such as UV radiation, temperature, humidity, etc. However, a multiple exposures, such as a combination of moisture and heat or oxygen and light, can result in accelerated deterioration. This paper is related to mechanical behavior and durability consideration that geotextiles must withstand in order to be applied as geotubes for coast erosion and beach regaining. The paper provides an overview of the current erosion in the Yucatan coast and the solutions for shoreline protection as well as the effect of geotextile architecture on mechanical properties.

Metazoan parasite infracommunities of Mycteroperca bonaci (Poey, 1960) (Pisces: Epinephelidae) in reef and coastal environments off the coast of Yucatán, México.

The black grouper Mycteroperca bonaci is a commercially important fish off the coast of Yucatan, Mexico. To investigate possible differences between parasite communities in two different environments, 60 fish were collected from two areas during 2010 and 2011 and examined for parasites. The fish were classified into two age groups, in each of which the parameters of parasitic infection - prevalence, abundance and intensity - were determined. Parasite faunas were further described at the infracommunity level. Using both univariate (PERMANOVA) and multivariate statistical methods, the values of richness, abundance, diversity and Brillouin evenness as well as the Index values of Bray-Curtis and Jaccard for similarity were calculated and compared. The results of these tests and of CAP discriminant analyses at the two sites showed the existence of two distinct parasite communities. The parasite taxa mainly responsible for the differences were the digeneans Dollfustrema sp., Prosorhynchus spp., Lepidapedoides epinepheli and Hamacreadium mutabile, and the nematode Philometra salgadoi. The potential for some of these parasites to be used as biological tags for stock identification of M. bonaci is discussed.

EXPERIMENTAL STUDY ON GEOTEXTILE TUBE APPLICATIONS AS SUBMERGED BREAKWATERS FOR BEACH PROTECTION IN YUCATAN, MEXICO

The Yucatan coast, with a wide continental shelf and low sediment sources, is subject to a microtidal regime and low energy, short waves (Hs < 1 m, T=4-6s) with two main incident wave directions (from the E and NE) that generate a dominant westward longshore sediment transport. Approximately 60 of the 245 km extent of the Yucatan coastline have seen significant urban, industrial and touristic developments that have led to coastal erosion of 1 m/year over the last 10 years. In order to mitigate this trend, many structures (most of them emerged groins) have been constructed, but the majority of these efforts have been unsuccessful. From 2005 to 2007 geotextile tubes were empirically used as submerged breakwaters (GT-SBW) at several sites on the Yucatan coast, many of them placed between 10 and 30 m seaward from the shoreline. It was found that, in some cases, the beach was stabilized after placing the structure; but in other places the results were far from those expected. (Fig. 1). Considering the lack of knowledge in the design criteria and in the hydrodynamic performance of GT-SBW, this study analyses the results obtained through experimental tests using different model scales and geometries. The motivation for this study is to better understand the wave-structure interaction in terms of the effectiveness of the structure in minimizing the wave transmission coefficient (Kt). The main goal of this paper is to define optimal design criteria for the GT-SBW. The experimental tests were conducted in a wave flume (37x0.8x1.20 m) at the Coastal Engineering Laboratory of the Engineering Institute at UNAM, using two scales (1:5 and 1:10). The wave generation system is of a piston-type vertical paddle from HR Wallingford. Throughout statistical analysis of hindcast data, the mean wave regime was obtained in order to use representative data of the Yucatan coast. A total of 12 capacitance wave gauges were placed along the flume (before and after the structure) to record water surface elevations and to compute the transmission (Kt) and reflection (Kr) coefficients; Mansard and Funke’s (1980) separation method was used. During the experimental tests it was observed that the hydrodynamic behaviour of these structures is quite similar to that of low-crested breakwaters with very low permeability and that when the elevation of the breakwater crown is slightly below the mean water level, the waves break violently, thus dissipating wave energy. On the contrary, if the waves fail to break they are only steepened and the transmission coefficient can be even greater than one. From the data analysis it was found that the optimal freeboard should not exceed twice the design wave height. The experimental results and an empirical formula are shown in (Fig. 2).

Elasmopus yucalpeten sp. n. (Crustacea, Amphipoda, Maeridae) from the northern Yucatan coast, with a key for the genus in the Gulf of Mexico and biogeographic comments

A new amphipod species of the genus Elasmopus Costa, 1853 is described and illustrated based on material collected in a harbor on the northern Yucatan coast, southern Gulf of Mexico. Elasmopus yucalpeten sp. n. is recognized from its congeners by a two-articulate accessory flagellum, a group of long robust setae on the anterodistal margin of the gnathopod 2 basis, a distomedial concave portion on palm of gnathopod 2 propodus, long setae on basis posterior margin of pereopods 5–7, and an entire telson. The differences among closely related species are pointed out and they are compared with the new species. An identification key to species of the genus Elasmopus in the Gulf of Mexico and biogeographic comments at the regional and global scales are also provided.

A Coastal Yucatan Sinkhole Records Intense Hurricane Events

ABSTRACT Brown, A.L.; Reinhardt, E.G.; van Hengstum, P.J., and Pilarczyk, J.E., 2014. A coastal Yucatan sinkhole records intense hurricane events. The potential of tropical sinkholes as archives for historical hurricane events has yet to be fully explored. This study uses high-resolution (1-cm interval) particle-size analysis to examine two sediment push cores from Laguna Chumkopo, located on the Yucatan Peninsula, Mexico. Core CKC1 (62 cm) was collected from the base of a deep sinkhole located in Laguna Chumkopo at −79.9 m (msl), while the second core, CKC2 (93 cm), was collected from the shallow peripheral margin at −6.4 m (msl). Two coarse fining upward sequences (12 to 35 cm, 46 to 62 cm) in CKC1 had mean particle sizes of approximately 1.5 ϕ (medium sand) with intervening intervals of lime mud (<4 ϕ). Measured 137Cs activity in the bulk sediment (n = 15) and radiocarbon dating (n = 3) using bomb-carbon calibration determined that the lower coarse unit was deposited in the 1960s (after September 1957 ...