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Se realizó un análisis de la producción de crías de tilapia Oreochromis niloticus en instalaciones acuícolas en México de 2014 a 2021, a partir de la producción pesquera y acuícola registrada a nivel nacional. Para ello se analizaron los registros de producción de crías de tilapia en laboratorios, los volúmenes de cosechas anuales registrados en las instalaciones acuícolas que operan en las diferentes entidades federativas y las capturas de tilapia registradas de 2009 a 2018. En 2018 se produjeron en México 168.359 t de tilapia y se importaron 127.981 t, con un consumo nacional aparente de tilapia registrado de 298.644 t. Ese año se produjeron 169,2 millones de crías de tilapia (Conapesca 2018). Para cubrir el déficit de tilapia por la importación de 127.981 t, se requiere teóricamente una producción adicional estimada en 511,9 y 383,9 millones de crías de tilapia, considerando los escenarios de siembra de 4 y 3 organismos para cosechar un kilogramo (2 organismos de 500 g de peso promedio), con supervivencias durante su cultivo del 50 y 66,6 % y producciones de 7,5 - 10 t por ha, respectivamente. Se analizaron los sistemas de producción de tilapia a nivel extensivo y semi-intensivo por su sustentabilidad y se emiten conclusiones técnicas para mejorar el aprovechamiento de este recurso biológico-pesquero, que impacta favorablemente en la socioeconomía de las diferentes regiones donde se cultiva.

The effect of temperature was studied on the synthesis of fatty acid alkyl esters by means of transesterification of waste beef tallow using ethanol and, iso-butanol and 1-butanol at supercritical conditions. These alcohols are proposed for the synthesis of biodiesel in order to improve the cold flow properties of alkyl esters. Alcohol–beef tallow mixtures were fed to a high-pressure high-temperature autoclave at a constant molar ratio of 45:1. Reactions were carried out in the ranges of 310–390 °C and 310–420 °C for ethanol and iso-butanol, respectively; meanwhile, synthesis using 1-butanol was assessed only at 360 °C. After separation of fatty acid alkyl esters, these samples were characterized by nuclear magnetic resonance (NMR) and gas chromatography coupled to mass spectrometry (GC-MS) to quantify yields, chemical composition, and molecular weight. Results indicated that yields enhanced as temperature increased; the maximum yields for fatty acid ethyl esters (FAEEs) were attained at 360 °C, and for fatty acid butyl esters (FABEs) were achieved at 375 °C; beyond these conditions, the alkyl ester yields reached equilibrium. Concerning the physicochemical properties of biodiesel, the predicted cetane number and cloud point were enhanced compared to those of fatty acid methyl esters.

Oysters are one of the most important groups in terms of production by fisheries and aquaculture in developed countries of temperate areas. In subtropical and tropical regions, oyster species are economic important resources but many are exploited in an artisanal way and without a legal framework, what can result in overexploitation. One alternative is aquaculture but biological information and development of techniques for local species are required. Therefore, this review organizes information on subtropical and tropical oysters from the American Pacific addressing on their fisheries, cultivation, management, and conservation. The study focuses on two native species Striostrea prismatica and Crassostrea corteziensis and two introduced species Crassostrea gigas and Crassostrea sikamea having more information and technological development. Fisheries and their problems are analyzed and some alternatives are proposed to improve their organization and preservation. The most important aquaculture technological aspects are described including the processes for the production of spat in hatcheries and the techniques used for field cultivation. Biological, physiological, and ecological studies as well as the implementation of legal measures are required to administrate, restore, and recover fisheries. The aquaculture of C. corteziensis and S. prismatica presents great advances but the other native species require the development of technologies to progress in many aspects. The production of C. sikamea is concentrated in one region without expecting further expansion, and the cultivation of C. gigas can be recreated on various sites and expanded to estuaries in tropical areas.

This study compared survival, growth, feed conversion rate (FCR) and harvested biomass of two commercial strains of tilapia ( Oreochromis niloticus ) cultivated in Mexico: Spring Genetic-Benchmark Holding® originated from the Genetically Improved Farmed Tilapia GIFT (Genebank: GIFT GU477624.1) and strain B from different line-breeding (Genebank: Philippines GU477626.1, Guangdong GU477627.1, and America GU477628.1). The study was performed in six geomembrane ponds (2,520 m 3 ; 30×40×1.5 m) with supplementary aeration, in Los Pozos farm, El Rosario, Sinaloa, Mexico. In July 2016, 26,762 ± 170 fries of each strain (2.9 ± 0.1 g and 5.4 ± 0.2 cm) were cultivated in the nursery under similar conditions in triplicate at 11 ind m -3 for 34 days; then, they were transferred to the grow-out ponds and fed with 30% crude protein balanced feed (Purina®) at a rate of 12% live weight day -1 in three rations (07:00, 12:00 and 17:00 h) for 123 days. The results showed that Spring had a lower variation coefficient (VC) and higher survival, growth rate in weight, initial and final size, and harvested biomass. Survival was 30.7% greater in Spring and doubled harvested biomass (Spring 10 ± 0.8 t ha -1 vs. B strain 5 ± 4.7 t ha -1 ). Sixty percent of the Spring population reached a commercial weight of 500 g in day 123th of cultivation compared with 20% of B population in the same period. Except for FCR, VC was lower in the Spring strain. Differences in productive parameters were probably due to the genetic selection programs at which both strains were subjected.

Solubilities of two binary mixtures (α-tocopherol + capsaicin and α-tocopherol + palmitic acid) in supercritical carbon dioxide (CO2) are reported in this work. Measurements were done in a semiflow...

Biomass waste, as raw material for renewable energy, is an attractive alternative since it does not compete with human food supply. An emerging alternative for its treatment is supercritical water gasification (SCWG), due to the high moisture content of some types of biomass. On this regards, guava fruit (Psidium guajava L.) is one of the most wasted agro-food products in Mexico. This motivated us to evaluate gasification of guava waste on dry biomass base under supercritical water conditions for the first time, with the aim of analyzing the impact of moderate temperatures and feed ratios as reaction parameters on gas products. Temperature was varied in the range of 673.15–773.15 K and using a batch reactor loaded with biomass:water (B:W) mass ratios of 1:1, 1:4, and 1:6. Furthermore, the obtained solid, liquid, and gas phase products were characterized. Hydrogen (H2), carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10) were identified in gas phase and quantified by means of a gas chromatograph equipped with a TCD detector. Liquid and solid phase products were subjected to Fourier Transform Infrared spectroscopy analyses. This preliminary research indicated that high temperature operation and high biomass:water mass ratio enhanced gas yields (mol/kg) of about 4.137 for CH4, 6.705 for CO2, and 7.743 for H2; whereas the selectivity and gas efficiency for hydrogen was 65.26% and 58.94%, respectively.

The aim of this work is to perform synthesis of fatty acid methyl esters by means of one-step supercritical methanol transesterification from waste beef tallow without pre-treatment. Animal waste samples were collected from local markets and the experiments were carried out in a 170 cm3 batch reactor made of Inconel 625 alloy. On the first set of experiments, the fatty acid methyl esters were obtained by varying methanol:waste beef tallow (M:WBT) molar ratios from 25:1 to 47:1, at 613 K, 60 min of synthesis and pressures up to 27 MPa. Due to the high yield, a second set of transesterification reactions was carried out in order to assess the temperature effect in the interval of (578–693) K while keeping the molar ratio of 45:1. The fatty acid methyl esters were characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), gas chromatography coupled to mass spectrometry (GC-MS), high performance liquid chromatography coupled to mass spectrometry (HPLC-MS), cryoscopy, Gardner color, water content, free fatty acids and cloud point; calculations of the global yield from NMR and predicted cetane number were also performed.

Coastal zones are important areas for the development of diverse ecosystems. The analysis of chlorophyll a (Chl a), as an indicator of primary production in these regions, is crucial for the quantification of phytoplankton biomass, which is considered the main food chain base in the oceans and an indicator of the trophic state index. This variable is greatly important for the analysis of the oceanographic variability, and it is crucial for determining the tendencies of change in these areas with the objective of determining the effects on the ecosystem and the population dynamics of marine resources. In this study, we analysed the Chl a concentration distribution on the mainland coast of the Gulf of California based on the monthly data from July 2002 to July 2019, obtained from remote sensing (Moderate-Resolution Imaging Spectroradiometer Aqua (MODIS-Aqua) with a 9 km resolution). The results showed a clear distribution pattern of Chl a observed along this area with the maximum levels in March and minimum levels in August. A four-region characterisation on this area was used to make a comparison of the Chl a concentrations during warm and cold periods. The majority of the results were statistically significant. The spectral analysis in each of the four regions analysed in this study determined the following variation frequencies: annual, semi-annual, seasonal, and inter-annual; the last was related to the macroscale climatological phenomena El Niño-La Niña affecting the variability of the Chl a concentration in the study region.

The aim of this study was to evaluate Macrocystis pyrifera and Zea mays meals as nucleation sites in biofloc formation. Bioflocs were studied for a period of 12 weeks, by measuring volume, dry weight, organic matter, and ash weight. These were induced by the addition of bacterial inoculum, molasses and both types of meals to fresh water. After 4 weeks, a total of 100 tilapia fingerlings (1.60 ± 0.02 g weight and 4.76 ± 0.03 cm length) were transferred to 100 L tanks by triplicate for each treatment. Mean ± SD values of temperature (26.3 ± 0.2 °C), dissolved oxygen (3.42 ± .0.07 mg L−1), pH (7.95 ± 0.04), salinity (0.47 ± 0.01) and ammonia (0.245 ± 0.012 mg NH3 L−1) were similar in both treatments. However, floc volume of M. pyrifera was significantly higher (116.1 ± 20 ml L−1) than Z. mays flocs (58.4 ± 7.7 ml L−1), but had lower dry weight (55 ± 0.5 mg g−1 in M. pyrifera vs. 61 ± 2.0 mg g−1 in Z. mays). Fish weight and length gain and survival were significantly higher (p

We report isothermal volumetric properties for two binary systems constituted by 2,5-dimethylfuran ( x ) + a linear alkane (1 − x ); octane and dodecane are the representative alkanes. Compressed liquid densities were obtained via oscillating period measurements in two commercial vibrating U-shaped tube densimeters. The experiments were performed within the pressure and temperature intervals from 0.1 MPa to 70 MPa and from 293 K to 393 K, respectively. Properties for these binary systems were measured at x = (0.1154, 0.2999, 0.4967, 0.6962, 0.8924) for 2,5-dimethylfuran + octane mixtures; whereas, compositions measured for 2,5-dimethylfuran + dodecane mixtures were x = (0.1995, 0.4067, 0.4972, 0.6053, 0.8045). Experimental density data were correlated by using the Tammann-Tait equation. Thermodynamic derived properties were calculated from the same equation, and their dependence on pressure, temperature and composition was discussed. These properties were isobaric thermal expansivity, isothermal compressibility, thermal pressure coefficient, internal pressure and mixing molar volume.

The aim of this study was to determine the presence of the white spot syndrome virus (WSSV) in zooplankton organisms collected from an important shrimp-culture area of the Gulf of California. Environmental water parameters (temperature, salinity, dissolved oxygen, and pH) were monitored, and zooplankton was collected. Samples were sectioned according to taxonomic groups (from Phylum to Family) for the detection of WSSV via PCR. A total of 52 zooplankton taxa were identified, of which crustaceans were the most abundant (82%). From the 228 WSSV diagnoses performed, 35% were positive. Moreover, from 32 taxa recorded at least one positive result was observed during the study, and only 13 were negative in all tests. The highest prevalence was observed in three taxa of copepods, brachyurous and bivalves. However, considering prevalence and frequency of occurrence, it was determined that up to 12 taxa could be considered as high-risk vectors. Finally, a significant correlation was found between the number of diagnoses per station with biovolume (rs = 0.817) and taxa richness (rs = 0.995). The results suggest that zooplankton diversity and abundance are associated with virus dispersion; moreover, these results demonstrated that the dispersion capacity of the virus through different taxa has been probably underestimated in recent years.

Oceanic mesoscale events such as eddies, coastal upwelling, filaments and fronts created by water mass intrusion present properties allowing them to concentrate, transport and disperse salt, nutrients and plankton, among other important constituents in the ocean. The use of satellite images enables the continuous monitoring of the ocean dynamics at different temporal and spatial scales, aiding the study of its variability. This study focuses on the identification of these mesoscale events in the Gulf of California (GC) by means of sea surface temperature (SST) and chlorophyll a (Chl a) fronts (edge) detection by processing 5-day satellite images from the 1998–2019 period. The annual occurrence or frequency and duration of each event was identified; the interannual variability was evaluated and underlying correlations with the Multivariate El Niño Index (MEI) and the Pacific Decadal Index (PDOI) were assessed via Principal Component Analysis. Most events showed a seasonal variability due to the seasonal behavior of forcing agents (i.e., Pacific Ocean and winds) that stimulate their formation or presence in the GC; seasonality was more evident in the northern region than in the southern region. The interannual variability of their frequency or duration was associated with strong and intense El Niño and La Niña conditions (positive or negative MEI values) together with positive or negative phases of the PDOI. The use of SST and Chl a satellite images with a 5-day temporal resolution allowed to better identify and quantify the annual frequency and duration of each mesoscale event. It allowed to detect a seasonal behavior of these events in the northern region, followed by the central region. The southern region, due to the interaction of different water masses with unique characteristics, exhibited a less evident seasonality in the frequency of eddies, and no apparent association between their interannual frequency and duration with the MEI and PDOI. Constantly monitoring these oceanic events and their variability will help in the understanding of how the different regions of this large marine ecosystem respond to these variations in the long term.

The anti-depressive and anxiolytic effect of galphimine B (isolated from Galphimia glauca) has been demonstrated by researchers. Therefore, it is necessary to explore extraction techniques that produce materials with adequate quality for pharmaceutical applications. In this work, supercritical extractions of galphimines from Galphimia glauca were performed in the presence of carbon dioxide. Pressure, temperature, particle diameter, and flow rate effects were examined to explore the conditions with the highest yield and the concentration profile of galphimines in the studied interval. The identification of the nor-seco triterpenoids and galphimine B and E was carried out by HPLC analyses. The mathematical modeling of the extraction curves was attained by the approaches proposed by Sovov&aacute, and Papamichail et al. According to results, the highest yield 2.22% was obtained at 323.15 K, 326 &mu, m, 3 L/min, and 33.75 MPa. Meanwhile, the content of galphimine B in the extract was, on average, 19.5 mg&middot, g&minus, 1.

The coastal zones are areas with a high flow of energy and materials where diverse ecosystems are developed. The study of coastal oceanography is important to understand the variability of these ecosystems and determine their role in biogeochemical cycles and climate change. Sea surface temperature (SST) analysis is indispensable for the characterization of physical and biological processes, and it is affected by processes at diverse timescales. The purpose of this work is to analyze the oceanographic variability of the Eastern Coastal Zone of the Gulf of California through the study of the SST from time series analysis of monthly data obtained from remote sensors (AVHRR-Pathfinder Version 5.1 and Version 5 resolution of 4 km, MODIS-Aqua, resolution of 4 km) for the period 1981 to 2016. The descriptive analysis of SST series showed that the values decrease from south to north, as well as the amplitude of the warm period decrease from south to north (cold period increase from south to north). The minimum values occurred during January and February, and ranged between 18 and 20 °C; and maximum values, of about 32 °C, arose in August and September. Cluster analysis allowed to group the data in four regions (south, center, midriff islands and north), the spectral analysis in each region showed frequencies of variation in scales: Annual (the main), seasonal, semiannual, and interannual. The latter is associated with the El Niño and La Niña climatological phenomena.

This study analyzed monthly and inter-annual variability of mesoscale phenomena, including the El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) climate indexes and wind intensity considering their influence on sea surface temperature (SST) and chlorophyll a (Chl-a). These analyses were performed to determine the effects, if any, of climate indexes and oceanographic and environmental variability on the central and southern coastal ecosystem of Sonora in the Gulf of California (GC). Monthly satellite images of SST (°C) and Chl-a concentration were used with a 1-km resolution for oceanographic and environmental description, as well as monthly data of the climate indexes and wind intensity from 2002–2015. Significant differences (p > 0.05) were observed while analyzing the monthly variability results of mesoscale phenomena, SST and Chl-a, where the greatest percentage of anti-cyclonic gyres and filaments was correlated with a greater Chl-a concentration in the area of study, low temperatures and, thus, greater productivity. Moreover, the greatest percentage of intrusion was correlated with the increase in temperature and cyclonic gyres and a strong decrease of Chl-a concentration values, causing oligotrophic conditions in the ecosystem and a decrease in upwelling and filament occurrence. As for the analysis of the interannual variability of mesoscales phenomena, SST, Chl-a and winds, the variability between years was not significant (p > 0.05), so no correlation was observed between variabilities or phenomena. The results of the monthly analyses of climate indexes, environmental variables and wind intensity did not show significant differences for the ENSO and PDO indexes (p > 0.05). Nonetheless, an important correlation could be observed between the months of negative anomalies of the ENSO with high Chl-a concentration values and intense winds, as well as with low SST values. The months with positive ENSO anomalies were correlated with high SST values, low Chl-a concentration and moderate winds. Significant inter-annual differences were observed for climate indexes where the years with high SST values were related to the greatest positive anomaly of ENSO, of which 2002 and 2009 stood out, characterized as moderate Niño years, and 2015 as a strong El Niño year. The years with the negative ENSO anomaly were related to the years of lower SST values, of which 2007–2008 and 2010–2011 stood out, characterized as moderate Niñas. Thus, variability associated with mesoscale oceanographic phenomena and seasonal and inter-annual variations of climate indexes had a great influence on the environmental conditions of the coastal ecosystem of Sonora in the Gulf of California.

Se evaluó la capacidad adsortiva de diez secuestrantes mexicanos de ocratoxina A por la identifi cación de la toxina libre (no secuestrada) por cromatografía de líquidos de alta resolución (HPLC). Se ensayaron tres modifi caciones del método de extracción de la ocratoxina A. Se midió el pH para conocer alguna relación con la capacidad de secuestro in vitro. En los aluminosilicatos previamente digeridos con ácido fl uorhídrico se midió el calcio, sodio, potasio, aluminio y silicio por espectroscopia de absorción atómica. Los resultados mostraron que la mayor parte de los productos evaluados secuestran OA in vitro entre 0% y 84%, y que no parece haber relación con el pH. Los aluminosilicatos tienen un bajo contenido de calcio, sodio, y potasio. Los valores de aluminio varían entre 3.1% y 6.1% y los del silicio entre 20% y 37%. La relación del contenido de aluminio con el silicio es de 1:3.5 al 1:7.4. Se observó una correlación negativa (r = –0.27) entre la capacidad de secuestro con la relación del aluminio y silicio.

Para el desarrollo del presente estudio se analizó el contenido de selenio en la dieta y la yema de huevo en gallinas domésticas de postura (Gallus domesticus), este ensayo duró 58 semanas y el análisis de selenio se practicó en 11 ocasiones distribuidas de acuerdo con el programa de muestreo. Se encontró que el contenido de selenio en el alimento fue el adecuado sólo en las semanas 40 y 52 (233.6 y 246.9 ppb, respectivamente) y se correlacionó con concentraciones altas en la yema del huevo (341 y 319 ppb, respectivamente) en este mismo muestreo al compararse con el resto de las concentraciones del estudio. El índice de correlación entre el contenido de Se en la dieta con el contenido de Se en la yema durante este estudio fue de r = 0.41, lo que significa que sólo en 41% de las muestras de yema de huevo se refleja el contenido de Se a partir del alimento. Esta mala correlación puede estar condicionada porque el contenido de Se en la dieta que ni siquiera llena las demandas corporales del ave y el contenido en la yema, puede aparecer sólo cuando el ave haya llenado sus demandas vitales. Si las aves se alimentan adecuadamente con Se, el contenido en la yema puede ser una excelente fuente para los consumidores del huevo de gallina.