Gonzalez-Baheza A.,Autonomous University of Baja California Sur |
Arizpe O.,Autonomous University of Baja California Sur
Climate and Development | Year: 2017
Coastal zones and adjacent land areas support 60% of the human population and eight of the top-10 largest cities in the world. These regions are exposed to natural hazards and climate-change-induced stresses, which requires continuous assessments of their vulnerability in many coastal regions around the world. Evaluations and monitoring of vulnerability models in coastal areas will assist in formulating environmental policies and guiding decision-makers to address the central tenets for the sustainable development of coastal cities. Baja California Sur (BCS) is the Mexican state with the longest coastline in the nation, and its capital city of La Paz is the most crowded city and without a vulnerability assessment. In this context, La Paz was regionalized based on biotic, natural landscape and socio-economic factors within geographic information systems, obtaining 74 environmental units (EnvUs). Assessment of each unit with a coastal vulnerability model involved physical, environmental and socio-economic indicators and composed indices which considered three main elements: (1) a fixed component defined by Coastal Vulnerability Index; (2) a Pressure Index and (3) a Fragility Index. Nearly 38% of EnvU and over 60% of total area showed high and very high fragility, including the capital city. Only 7% of EnvU and 14% of all the area of interest presented high and very high pressure. Nearly a third of EnvU had high and very high vulnerability, mainly in La Paz and southwest of the study area without actual human pressure, especially due to the presence of lower slopes and high-energy streams. Results allow focusing efforts on environmental policy instruments to implement adaptation measures for sustainable development in the BCS region. © 2017 Informa UK Limited, trading as Taylor & Francis Group
Angel Ojeda Ruiz de la Pena M.,Autonomous University of Baja California Sur |
Ramirez Rodriguez M.,National Polytechnic Institute of Mexico
Ocean and Coastal Management | Year: 2014
In order to provide information to strengthen the implementation of management measures as part of the ecosystem, we analyzed the fleet operation dynamics of "Catarina" clam and shrimp, as well as the overlap of fishing seasons and zones at Magdalena-Almejas Bay region. Maps were created delimiting fishing zones, considering the lagoon complex physiographic features, fishing gear in use, depth and the spatial and temporal distribution of catches. The validated results by a study of local knowledge help us to understand how fleets operate during periods of interaction between these fisheries, the perceptions, preferences and tactics of producers to these events. It was found that economic units have permits to exploit multiple resources and must decide in the medium term which fishing gear to invest and in the short term which fishery and area to participate. The impacts of direct interactions are reduced by the users trading strategies, who to choose among more than an open season, use the abundance of the resource as the main criterion (65%), followed by the beachfront price paid for the resource (15%). The spatial interactions analyzed in thematic map of frequency of use showed congestion and distribution problems that tend to worsen over time so it is recommended to move from the management scheme of one fishery to multi fisheries within a region or ecosystem. © 2013 Elsevier Ltd.
Ramirez-Rodriguez M.,National Polytechnic Institute of Mexico |
Ojeda-Ruiz M.T.,National Polytechnic Institute of Mexico |
Ojeda-Ruiz M.T.,Autonomous University of Baja California Sur
Marine Policy | Year: 2012
To understand small-scale fisheries in Mexico, the spatial and temporal distribution of the landed catch of several species was analyzed, including abalone, clams, snails, octopus, squids, lobsters, shrimps, blue crabs, sharks, rays and finfish along the 349. km of the Gulf of Ulloa coast. Data reported by fishers from 1998 to 2009 on catch volume and value per group of species and per fishing locality, together with the number of landing events, were used to define fishing zones and the relative importance of each fishery. Finfish turned out the primary fishery in the region, but the other fisheries showed relevant spatial changes that should be considered when establishing management goals and fishing regulations according to resource availability, fleet efficiency, processing capacity, commercialization of fishing products and profit distribution. © 2011 Elsevier Ltd.
Koch V.,Autonomous University of Baja California Sur |
Koch V.,Leibniz Center for Tropical Marine Ecology |
Peckham H.,Grupo Mexico |
Peckham H.,Stanford University |
And 2 more authors.
PLoS ONE | Year: 2013
Strandings of marine megafauna can provide valuable information on cause of death at sea. However, as stranding probabilities are usually very low and highly variable in space and time, interpreting the results can be challenging. We evaluated the magnitude and distribution of at-sea mortality of marine turtles along the Pacific coast of Baja California Sur, México during 2010-11, using a combination of counting stranded animals and drifter experiments. A total of 594 carcasses were found during the study period, with loggerhead (62%) and green turtles (31%) being the most common species. 87% of the strandings occurred in the southern Gulf of Ulloa, a known hotspot of loggerhead distribution in the Eastern Pacific. While only 1.8% of the deaths could be definitively attributed to bycatch (net marks, hooks), seasonal variation in stranding frequencies closely corresponded to the main fishing seasons. Estimated stranding probabilities from drifter experiments varied among sites and trials (0.05-0.8), implying that only a fraction of dead sea turtles can be observed at beaches. Total mortality estimates for 15-day periods around the floater trials were highest for PSL, a beach in the southern Gulf of Ulloa, ranging between 11 sea turtles in October 2011 to 107 in August 2010. Loggerhead turtles were the most numerous, followed by green and olive ridley turtles. Our study showed that drifter trials combined with beach monitoring can provide estimates for death at sea to measure the impact of small-scale fisheries that are notoriously difficult to monitor for by-catch. We also provided recommendations to improve the precision of the mortality estimates for future studies and highlight the importance of estimating impacts of small-scale fisheries on marine megafauna.
Wurl J.,Autonomous University of Baja California Sur |
Mendez-Rodriguez L.,National Polytechnic Institute of Mexico |
Acosta-Vargas B.,National Polytechnic Institute of Mexico
Journal of Hydrology | Year: 2014
The San Antonio-El Triunfo mining district is located in a mountain region 60km southeast of La Paz, the capital of the Mexican state of Baja California Sur. Mining activities, focused on gold and silver extraction, which began in the second half of the 18th century; the main activity took place between 1878 and 1911. The minerals were treated through the cyanide method, burned, and smelted. In effect between 800,000 and 1milliontons of mine waste materials were scattered in an area of approximately 350-400km2. This area contains today several byproducts as a result from arsenopyrite oxidation, such as arsenolite (As2O3).The aim of this study was to analyze groundwater composition in order to define the actual concentrations of relevant parameters to detect ore mining contaminations, especially in respect to arsenic. In the autumn of 2010, 29 groundwater samples were obtained using flow-through bailer or down-hole pump methods, and a total of 37 variables were measured in each sample. Arsenic (dissolved) exceeded the values established by the World Health Organization (WHO, 2011) (0.01. mg/L) in 41% of the monitored sites. The maximum concentration of arsenic found in one observation well was 0.45. mg/L.Four water samples, which were characterized by elevated concentration of boron (max. conc. 9.5. mg/L), fluoride (max. conc. 3.25. mg/L) and alkaline pH values (>9), showed a composition typical for hydrothermal water. Because all four samples had arsenic concentration under 0.008. mg/L, we conclude that no significant impact of arsenic from hydrothermal fluids is found in the study area. © 2014 Elsevier B.V..
Henriques M.C.,Federal University of Rio de Janeiro |
Villas-Boas A.,Institute Pesquisas Jardim Botanico Do Rio Of Janeiro |
Rodriguez R.R.,Autonomous University of Baja California Sur |
Figueiredo M.A.O.,Institute Pesquisas Jardim Botanico Do Rio Of Janeiro
Helgoland Marine Research | Year: 2012
Little is known about the diversity of non-geniculate coralline red algae (Rhodophyta, Corallinophycidae) from deep waters in Brazil. Most surveys undertaken in this country have been carried out in shallow waters. In 1994, however, the REVIZEE program surveyed the sustainable living resources potential of the Brazilian exclusive economic zone to depths of 500 m. In the present study, the rhodolith-forming coralline algae from the continental shelf of Espírito Santo State were identified. Samples were taken from 54 to 60 m depth by dredging during ship cruises in 1997. Three rhodolith-forming species were found: Spongites yendoi (Foslie) Chamberlain, Lithothamnion muelleri Lenormand ex Rosanoff and Lithothamnion glaciale Kjellman. These records extend the distribution ranges of these species into Brazilian waters and extend the depth distribution of non-geniculate coralline red algae into Brazilian water to 58 m. © 2011 Springer-Verlag and AWI.
Bahia R.G.,Rio Of Janeiro Botanical Garden Research Institute |
Riosmena-Rodriguez R.,Autonomous University of Baja California Sur |
Maneveldt G.W.,University of the Western Cape |
Amado Filho G.M.,Rio Of Janeiro Botanical Garden Research Institute
Phycological Research | Year: 2011
Samples corresponding to Sporolithon ptychoides Heydrich were collected in the mesophotic zone (50 m depth) south of Espírito Santo State, Brazil. The collected material presented features characteristic of the species, namely: tetrasporangia of 75-105 × 40-55 μm grouped into sori that are raised above the surrounding vegetative thallus surface; presence of a basal layer of elongate cells in areas where the tetrasporangia develop; presence of buried tetrasporangial compartments deep in the thallus; and 3-5 cells in the tetrasporangial paraphyses. These same features said to collectively characterize S. ptychoides, were all observed in a representative specimen and the type specimen of Sporolithon dimotum (Foslie & Howe) Yamaguishi-Tomita ex M.J Wynne. This latter species is thus conspecific with S. ptychoides and is therefore considered a heterotypic synonym thereof, as S. ptychoides has nomenclatural priority. This study expands the known geographical distribution of the species and may give insight into the origin of the species into other geographical regions. © 2010 Japanese Society of Phycology.
Diele K.,Leibniz Center for Tropical Marine Ecology |
Koch V.,Autonomous University of Baja California Sur
Journal of Experimental Marine Biology and Ecology | Year: 2010
Reliable estimates of growth and mortality parameters are crucial for understanding how populations of exploited species may respond to shifts in fishing pressure. Results of previous studies on growth of the ecologically and economically important mangrove crab Ucides cordatus in Brazil differ strongly and age estimates for minimum legal capture size (60. mm carapace width) range between less than 1 and 6-10. years. These discrepancies are probably due to inherent problems of the applied methods, namely laboratory based observations and cohort-analyses. The present paper takes a new approach by measuring individual growth increments of U. cordatus in situ. Crabs were measured, tagged, released into 100. m2 field enclosures and periodically recaptured. There was no indication of an enclosure effect and 209 growth increments were obtained from specimens measuring 20.5 to 89.5. mm in carapace width (CW). For improving the size coverage of the von Bertalanffy growth curve, first instar juveniles were reared in the laboratory up to an age of six months. Their average percent size increase (PI) was 22.57 ± 6.75% during biweekly measurements, resulting in a CW of 7.8 to 11.5. mm after six months. Average PI of the enclosure crabs ranged between 10.87 ± 1.17% (indiv< 40. mm CW) and 1.43 ± 0.87% (indiv> 80. mm CW) per moult and two large females had moulted without growing. Growth analysis revealed a larger asymptotic size in males than in females (89. mm versus 72. mm) while the growth parameter K of the von Bertalanffy growth function (VBGF) was lower in males (0.17 versus 0.25), resulting in similar growth performance of the two sexes (males: 1.16; females: 1.10). Age at legal minimum capture size estimated by the inversed VBGF was 6.13. years in males and 7.38. years in females, corroborating the mid to upper range of earlier growth estimates. Mortality parameters (Z, M and F) were calculated using length converted catch curves. Z in males was higher than in females (0.69 versus 0.49), as expected from the male-biased fishery. M, F and the exploitation rate E were estimated for three different scenarios taking into account the uncertainty of the age/size of functional maturity. Our study provides key information for the sustainable management of the U. cordatus fishery and confirms that the species is relatively slow growing and long-lived (> 10. years), suggesting a high vulnerability to overfishing. © 2010 Elsevier B.V.
Romero O.E.,Instituto Andaluz Of Ciencias Of La Tierra Csic Ugr |
Lopez-Fuerte F.O.,Autonomous University of Baja California Sur
Diatom Research | Year: 2013
Based on light and scanning electron microscopy observations, a detailed description of a new marine alveolate Cocconeis Ehrenberg, C. thalassiana sp. nov., is presented. This large Cocconeis was found in samples collected from a shallow marine coastal lagoon of the Mexican Caribbean, as an epiphyte on the marine seagrass Thalassia testudinum Banks ex König. Among alveolate Cocconeis, the presence of long alveoli for every stria opening into the frustule interior by two long internal apertures of the sternum valve (SV) is a unique character. Other typical frustule features are: bilayered, convex SV thicker than the concave raphe-sternum valve (RSV), the inner face of the SV with hyaline areas between the two apical rows of apertures, the monolayered RSV with a narrow submarginal hyaline area following the valve outline, and the girdle consisting of only two valvocopulae (one for each valve). © 2013 The International Society for Diatom Research.
Alonso-Hernando A.,University of León |
Guevara-Franco J.A.,Autonomous University of Baja California Sur |
Alonso-Calleja C.,University of León |
Capita R.,University of León
Journal of Food Protection | Year: 2013
The influence of the temperature of the dipping solution on the antimicrobial effectiveness of several chemical poultry decontaminants was assessed. A total of 765 poultry legs were inoculated with gram-positive bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, or Brochothrix thermosphacta) or gram-negative bacteria (Salmonella enterica serotype Enteritidis, Escherichia coli, Yersinia enterocolitica, or Pseudomonas fluorescens). Samples were dipped for 15 min in solutions (wt/vol) of trisodium phosphate (12%), acidified sodium chlorite (1,200 ppm), citric acid (2%), peroxyacids (220 ppm), chlorine dioxide (50 ppm), or tap water or were left untreated (control). The temperatures of the dipping solutions were 4, 20, or 50°C. Microbiological analyses and pH determinations were carried out after 0, 1, 3, and 5 days of storage at 4°C. In comparison with the control samples, all chemical solutions were effective for reducing microbial loads. The temperature of treatment affected the microbial reductions caused by all chemicals (P < 0.001). The lowest average bacterial reductions caused by trisodium phosphate, acidified sodium chlorite, citric acid, and peroxyacids were observed at 4°C, all sampling days and microbial groups being considered simultaneously. The highest and the lowest effectiveness for chlorine dioxide were observed at 4 and 50°C, respectively. These results may be of use to meat processors for selecting the best conditions for decontamination treatments and may help the European Regulatory Authorities make their decisions for authorization of poultry decontamination treatments. Copyright ©, International Association for Food Protection.