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Bivalves' physiological functions (i.e. growth, reproduction) are influenced by environmental variability that can be concomitant with trophic resource variations in terms of quality and quantity. Among the essential molecules that bivalves need to acquire from their diet to maintain physiological functions, fatty acids (FAs) such as polyunsaturated fatty acids (e.g. 20:4n-6 (arachidonic acid), 20:5n-3 (eicosapentaenoic acid) and 22:6n-3 (docosahexaenoic acid)) have been described to play a critical role. The present study examined the FA composition of gill membrane lipids of two bivalve species, Nodipecten subnodosus and Spondylus crassisquama , sampled in a coastal lagoon of the Northeastern Pacific (Ojo de Liebre, Mexico), at two contrasting locations (inner versus outer part of the lagoon) and at two different periods (February and August 2016). Spatiotemporal variations showed that FA composition of gill membrane lipids was highly correlated to FA composition of reserve lipids from digestive gland. This highlights the marked impact of the diet on FA composition of gill membranes. Interestingly, both species presented differences in the seasonal accumulations of plasmalogens and of particular FA that are not found in their diet (e.g. non-methylene interrupted FA, 22:4n-9 trans , 20:1n-11), suggesting specific regulations of FA incorporation and lipid class composition in gill membranes to maintain optimal membrane function in their specific and changing environment. This study highlights the importance to characterize the spatial and temporal variability of food resources in order to apprehend the physiological consequences of environmental variability, as well as species differential regulation capacities in a changing world. [ABSTRACT FROM AUTHOR]

Highlights • Soil carbon density in these systems is higher than other arid and semi-arid regions. • Above and belowground biomass values are in the lower range of global estimates. • Monetary valuation of the ESs should consider distribution and species-dominance. Abstract Mangroves provide multiple ecosystem services (ESs), including fish and wildlife habitat, protection from coastal erosion and flooding impacts, food resources, water quality, carbon sequestration and storage. However, most of the mangrove wetlands structural and functional information useful to evaluate the quality, quantity and monetary value of its ESs has been obtained from studies at tropical latitudes usually dominated by large deltas and extensive coastal lagoon and estuaries. Thus, there is a major data gap for mangrove wetlands located in arid and semi-arid regions due to their limited land cover and location at the boundary of transitional climate gradients. Here we analyze the spatial distribution of mangrove wetlands carbon stocks and net primary productivity (i.e., litterfall and root productivity) in La Paz Bay, an arid coastal region in the Gulf of California, Mexico, where mangrove wetlands are spatially distributed in conspicuously extensive patches. We used this information to qualitatively rank ESs. Three peri-urban mangrove wetland sites (Balandra, Enfermeria, and Zacatecas) were characterized by different degrees of anthropogenic impact. Aboveground biomass (interval: 13.6 to 31.6 Mg C ha−1) was in the lower range when compared globally. The average C storage in mangrove soils (at 45 cm depth) in La Paz Bay is 175 Mg C ha−1, which is higher than the values reported for other arid zones (≥1 m soil depth: 43–156 Mg C ha−1). Belowground root biomass and productivity values (roots range: 0.22–0.31 Mg C ha−1; fine roots NPP: 0.06–0.09 Mg C ha−1 yr−1) were in the lower range. We found distinct differences in aboveground C storage values among sites where mangrove species formed monospecific stands across the landscape within each site. Areas dominated by the species Rhizophora mangle reflected the highest soil C density values (208.9 ± 144.6 Mg C ha−1), followed by Laguncularia racemosa (181.4 ± 118.2 Mg C ha−1) and Avicennia germinans (155.5 ± 72.1 Mg C ha−1). We identified ESs provided by each of the sites, including both cultural (i.e., ecotourism; especially in Balandra), and provisioning (fisheries) services. Our study is a first step in the quantitative assessment of functional and structural properties as ESs of arid mangrove wetlands in La Paz Bay that could be readily translated into robust economic estimates for this arid coastal region. [ABSTRACT FROM AUTHOR]

There are limited studies involving geomorphic factors and ecological patterns on a landscape scale of coastal features. This study examines the hypothesis that the structure of mangroves varies with habitat type. Using geomorphic criteria, we identified and classified 51 lagoons that contain mangroves on the Baja California Peninsula. Four lagoon types were analyzed: open drowned valley (I-A), barred drowned valley (I-C), Gilbert de Beaumont barrier lagoon (III-A), and cuspate lagoon (III-B). Structure patterns of mangrove forests growing at the edge of the lagoons were identified through photo interpretation and field observations, using landscape indices related to (1) area, density, and variability of the patches; (2) ecotone; and (3) form. Multivariate and univariate analyses were performed to determine the effects of habitat types on mangrove structure. Cluster analysis based on structural similarity showed two groups: (A) forests with limited structural development that grow mostly at the shore of lagoons I-A and I-C, and (B) larger forests with numerous patches, larger average size, average perimeters, and simpler forms than those in the first group, which grow mostly in lagoon type III-A. Similarity analysis showed no differences between the forests of lagoon types I-A and I-C, but there were differences between these two types and type III-A. Variance analysis showed differences in area, perimeter, and the shape of patches with respect to habitat type. Tukey's Honestly Significant Difference post hoc tests confirmed previously identified groups and showed that forest patches in lagoon type III-B are of intermediate structure. Lagoon type III-A appear to be more important in distribution and development of mangrove forests. Finally, we found that the spatial scale analyses and use of geomorphologically defined habitats were effective approaches for a first-order differentiation of mangrove forests. [ABSTRACT FROM AUTHOR]

Abstract: We conducted a four year interdisciplinary collaborative project focused in the Gulf of California, the most important fishing region for Mexico. We reviewed published reports, collected and analyzed physical, chemical and ecological data sets, and developed models for the physical (atmosphere and ocean) and ecological components of this large marine ecosystem, to examine prevalent scientific questions regarding climate variability and change in the region, covering three time scales (ENSO, decadal-to-interdecadal, and long-term trend). We were able to describe how the Gulf of California influences the northward propagation of coastal trapped Kelvin waves associated with El Niño (ENSO) events, and how this signal, together with changes in the atmospheric forcing, results in a ENSO signature inside the Gulf. For the decadal-to-multidecadal scales, we found coherent trends among series, and with the Pacific Decadal Oscillation (PDO). The long-term temperature signal for the Gulf of California shows a warming that occurred in the mid 20th century, approximately a decade before that in the California Current. This signal is coherent with fluctuations in the industrial fisheries catch records (sardine and shrimps). For the recent decades we found no significant sustained long-term trend in any of the time series of physical and ecological variables that we considered. Instead, variability seems to be fully dominated by the interaction of PDO and ENSO. We stress the urgent need for more modeling efforts and the establishment of interdisciplinary (physical and biological) observation platforms for the marine environment in the Gulf of California. [ABSTRACT FROM AUTHOR]

The Gulf of California system presents major challenges to the still developing frameworks for ecosystem-based management (EBM). It is very much an open system and is intermittently subject to important influxes of migratory visitors, including large pelagic predatory fishes and small pelagic forage fishes. These migrants include the more tropical species from the coastal ecosystems to the south and perhaps subtropical sardines and anchovies from the California Current upwelling system. In addition to the multi-annual ENSO-scale and what may seem to be rather erratic episodes of major population incursions, the Gulf presents nonstationary, transient aspects on a variety of longer time scales. Moreover, the removal of top predators by commercial and sport fisheries has introduced trends that must be affecting the entire ecosystem, and certainly the forage fishes that are their major prey base. In addition to size limits, fishing seasons, area closures and license limitations, the fishery is managed by an ad hoc adaptive management system, in which the fishing season can be shortened or additional areas closed to fishing if pre-season exploratory fishing surveys indicate a shortage of small pelagic fishes on the fishing grounds. Whether this system is likely to be sustainable in the long term is difficult to determine, given the potential for rapid changes in the system because of environmental changes and/or feedbacks within the food web. Thus it appears that innovative management frameworks, among other things utilizing the comparative method, may be required in order to determine defensible tradeoffs between precaution and resource utilization. [ABSTRACT FROM AUTHOR]

This study analysed growth and recruitment of Pacific yellowleg shrimp, Farfantepenaeus californiensis (Holmes, 1900) populations inhabiting semi-arid coastal lagoons and the continental shelf in a semi-arid, subtropical region in the Gulf of California, Mexico. Sampling of the yellowleg shrimp population was conducted in the coastal lagoon and offshore on a monthly basis from December 2001 to November 2003. The length of females ranged from 90 to 150 mm, greater lengths were more common offshore during April and July. In the lagoon, smaller specimens prevailed all year. There were no significant differences between lagoon and offshore in mean length to within 1% of probability. The dynamics of penaeid shrimp in semi-arid climate lagoons differ from the pattern found in more semi-tropical parts of the Mexican Pacific, where lagoons do not have permanent communication with the Gulf of California. Evidence suggests that this species can complete its life cycle in the lagoon system or on the continental shelf. [ABSTRACT FROM AUTHOR]

Sustainable development, as a multi-dimensional concept, is difficult to measure. Some efforts using indicators and indices have appeared in recent years, but most were developed on a national scale. Use of sustainability indicators has proven valuable for attaining better management of the environment by minimizing information gaps and maximizing community capabilities in terms of economic, social, environmental, and institutional sustainability dimensions. However, at least in the case of developing countries, the potential exists that national sustainability measures, based on national-level indicators, may mask problems in sub-national zones with highly unsustainable conditions. This paper proposes a methodology to evaluate sustainable development at a local level, the use of which could be helpful in comparing different regions within a country or even among different countries. National sustainability indicators should result from a combination (whether additive or proportional) of regional sustainability indicators, as developed in this paper. [ABSTRACT FROM AUTHOR]

Presents a study that investigated sea temperature in the abalone banks at Bahia Asuncion in Baja California Sur, Mexico. Description of the study area; Materials and methods; Results of the study.

The article presents information on the biannual meeting held by the Mexican Chapter of American Fisheries Society (AFS) and the Mexican Fisheries Society from May 2 to 4, 2007 in La Paz, Baja California Sur in Mexico. The topics discussed at the meeting include the strategic plans for fisheries sciences in Mexico, the importance of achieving sustainability and the potential use of aquaculture to recover coastal species. The speakers included Mary Fabrizio from the AFS and Daniel Lluch-Belda of the Mexican Chapter.

Abstract: This paper presents original results on the Sb and heavy metals contents in sediments and waste tailings, plants and water from the giant Wadley antimony mine district (San Luis Potosí State, Mexico). The dominant antimony phases in mining wastes are stibiconite, montroydite and minor hermimorphite. The waste tailings contain high concentrations of metals and metalloids (antimony, iron, zinc, arsenic, copper, and mercury). Manganese, copper, zinc, and antimony contents exceed the quality guidelines values for groundwater, plants and for waste tailings. Results indicate that peak accumulation is seasonal due to the concentration by high metabolism plants as Solanaceae Nicotiana. The metal phytoavailability in waste tailings is highly dependant on the metal speciation, its capability to be transported in water and, more particularly, the plant metabolism efficiency. [Copyright &y& Elsevier]

In the Gulf of California; mineral deposits have contributed to high metal contents in coastal environments. This study examined cadmium; lead; copper; zinc; and iron contents in three fish species; Kyphosus vaigiensis (herbivore), Stegastes rectifraenum (omnivore), and Balistes polylepis (carnivore) at two mining sites. Metal concentrations were analyzed by atomic absorption spectrophotometry and stable nitrogen and carbon isotopes were estimated using mass spectrophotometry. Also, we assessed the risk to human health from the consumption of these three species based on permissible limits; although only two of them ( Kyphosus and Balistes ) are consumed as food. Metal concentrations differed among fish species; except for iron. The highest concentrations of metals were not always recorded in the species at the highest trophic level; i.e., Balistes . The highest concentrations (dry weight) recorded were cadmium (0.21 ± 0.03 µg g -1 ) and lead (1.67 ± 0.26 µg g -1 ), in S. rectifraenum ; copper (1.60 ± 0.49 µg g -1 ) and zinc (67.30 ± 8.79 µg g -1 ), in B. polylepis ; and iron (27.06 ± 2.58 µg g -1 ), in K. vaigiensis . Our findings show that each element accumulates differently in particular marine organisms; depending on the physiology of the species and the biogeochemistry of its habitat; which in turn is affected by the anthropogenic activities in adjacent areas. No risk of heavy metals toxicity is expected from the human consumption of the species and sites studied.

To determine the treatment needs and the care index for dental caries in the primary dentition and permanent dentition of schoolchildren and to quantify the cost of care that would represent the treatment of dental caries in Mexico.A secondary analysis of data from the First National Caries Survey was conducted, which was a cross-sectional study conducted in the 32 states of Mexico. Based on dmft (average number of decayed, extracted, and filled teeth in the primary dentition) and DMFT (average number of decayed, extracted, and filled teeth in permanent dentition) information, a treatment needs index (TNI) and a caries care index (CI) were calculated.At age 6, the TNI for the primary dentition ranged from 81.7% to 99.5% and the CI ranged from 0.5% to 17.6%. In the permanent dentition, the TNI ranged from 58.8% to 100%, and the CI ranged from 0.0% to 41.2%. At age 12, the TNI ranged from 55.4% to 93.4%, and the CI ranged from 6.5% to 43.4%. At age 15, the TNI ranged from 50.4% to 98.4%, and the CI ranged from 1.4% to 48.3%. The total cost of treatment at 6 years of age was estimated to range from a purchasing power parity (PPP) of USD $49.1 to 287.7 million in the primary dentition, and from a PPP of USD $3.7 to 24 million in the permanent dentition. For the treatment of the permanent dentition of 12-year-olds, the PPP ranged from USD $13.3 to 85.4 million. The estimated cost of treatment of the permanent dentition of the 15-year-olds ranged from a PPP of USD $10.9 to 70.3 million. The total estimated cost of caries treatment ranged from a PPP of USD $77.1 to 499.6 million, depending on the type of treatment and provider (public or private).High percentages of TNI for dental caries and low CI values were observed. The estimated costs associated with the treatment for caries have an impact because they represent a considerable percentage of the total health expenditure in Mexico.

Understanding the nature and origins of food sources supporting coastal lagoon-inhabiting organisms is necessary to evaluate the ecological status of such ecosystems. The trophic ecology of a bivalve species Spondylus crassisquama was studied in the Ojo de Liebre lagoon (Baja California, Mexico), combining stable isotope (SI), fatty acid (FA) and sterol analyses along a transect under oceanic influences. The second objective of the study was to investigate if sterol compositions give complementary information to those obtained from FA and SI. Temporal and spatial patterns of the three biomarkers in bivalve tissues suggest oceanic inputs at the mouth of the lagoon, while the inner station was characterized by a contribution of local sources including an important role of micro heterotrophs. This study revealed that the association of lipid biomarkers provide higher taxonomic resolution of the spatiotemporal heterogeneity in nutrient sources influencing the trophic functioning of a large coastal lagoon., (Copyright © 2019 Elsevier Ltd. All rights reserved.)