Search Results (4)

Overexploitation is the main anthropogenic threat to groupers (Epinephelidae) that aggregate to spawn. Fishing negatively affects their reproductive success and indirectly harms fishery economic yield. In the southern Gulf of Mexico, grouper catches, which include thirteen species, are in decline. A lack of biological information on each exploited species prevents optimising fishery management. Using histological examination of the gonads, the reproductive traits of red hind Epinephelus guttatus and yellowfin grouper Mycteroperca venenosa were studied from January 2008 to October 2009. Collections were made at two reef systems (Alacranes Reef and Bajos del Norte) on the continental shelf of the Yucatan Peninsula, Mexico, where these species form transient spawning aggregations. The results confirmed that previously identified spawning aggregation sites at both reefs constitute productive seasonal and perennial “hotspots” for both groupers; they spawn annually between January and April. Females of these protogynous hermaphroditic species exhibit a reproductive strategy characterised by asynchronous ovarian development organisation and ovulation. Sex ratios and maximum sizes at each reef suggest that populations of both groupers had a good conservation status as of the late 2000s. Both reefs are now marine protected areas, and a discussion is made of the consequent possible benefits to grouper population conservation and sustainability in the southern Gulf of Mexico. Full article

An oceanographic cruise with 34 stations was conducted in the central-southwestern region of the Gulf of Mexico from February 19 to 10 March 2013. This study included the measurement of hydrographic and phytoplankton bio-optical parameters, and pigment samples were collected at two depth levels (10 and 50 m). Our results showed a warm and nutrient-depleted water column associated with low chlorophyll a (<1 mg Chla m⁻³) and average values of a_ph440 (0.01 ± 0.008, m⁻¹) and a_d350 (0.04 ± 0.02, m⁻¹). In addition, nano-microphytoplankton abundance and pigments were analyzed using a light microscope and HPLC, respectively. Overall, the Gulf of Mexico exhibited oligotrophic characteristics, with Chla (0.17 ± 0.11 mg m⁻³) and NO₃⁻ (0.03 ± 0.001 µM), except at 50 m depth in some stations north of Yucatán and in Campeche Bay and at surface level off the Tamaulipas shelf. In these three regions, values of a_ph(440), a_d(350), (Chla) and phytoplankton abundance (>12 × 10³ cells L⁻¹) were observed near river mouths and under seasonal oceanographic forcings, which increased the growth and diversity of phytoplankton. The most relevant pigments found were DVchla (0.06 ± 0.13 mg m⁻³), Chlb (0.16 ± 0.21 mg m⁻³), Zea (0.06 ± 0.03 mg m⁻³), and Hex-fuco (0.02 ± 0.02 mg m⁻³); these are associated with the presence of Prochlorococcus, chlorophytes, Synechococcus, prymnesiophytes, and diatoms. Through the bio-optical variability, we determined the ecological geography of phytoplankton in four different spectral shapes, where M1 and M2 represent the group of cyanobacteria (Prochlorococcus and Synechococcus) and M3 and M4 represent a mixture of diatoms, dinoflagellates, and chlorophytes. In conclusion, we consider that oceanographic processes such as cyclonic and anticyclonic structures and permanent rivers determine the favorable changes in phytoplankton (>nutrients, Chla, a_ph440) and an increment in the number of phytoplankton spectral shapes). Full article

Cocos nucifera L. is one of the most cultivated palm trees in the world since it is used to obtain both raw materials and food. From a human point of view, the coconut fruit is a very valuable product, producing an aromatic and tasty liquid endosperm (coconut water) containing high levels of sugars, amino acids and other molecules of nutritional and nutraceutical value. Most of the chemical composition studies conducted on coconut to date have focused on the determination of fatty acid content in coconut oil and the extension of the shelf life of coconut water. Despite the economic importance of this species, the maturation of the coconut fruit is a complex biological process scarcely studied from the metabolic approach and biochemical changes occurring during fruit maturation are not well-known. The objective of this study is to investigate and elucidate the metabolic changes that occur during the maturation process of coconut (Cocos nucifera L.) fruits, specifically focusing on the liquid endosperm of the Yucatan green dwarf variety. In this study, the liquid endosperm of coconut fruits at the immature, intermediate and mature stages have been analyzed through an untargeted metabolomics approach by ultra performance liquid chromatography coupled to high resolution mass spectrometry (UPLC-HRMS). A total of 591 spectrometric features were detected and the corresponding identified compounds were classified into 24 chemical classes. The principal component analysis (PCA) showed segregation among the samples, according to their stage of maturation. Most of the metabolites detected were related to the metabolism of flavonoids, carbohydrates and organooxygen compounds. Pathway analysis showed that sphingolipid, starch and sucrose metabolisms were among the most over-accumulated during ripening, followed by the metabolism of glyoxylates and dicarboxylates and the metabolism of amino acids such as alanine, aspartate and glutamate, and others. This is the first study that focuses on elucidating the metabolic profiles of the liquid endosperm of coconut Yucatan green dwarf variety during three stages of maturation with an untargeted metabolomics approach through UPLC-MS. Full article

Marine renewables represent a promising and innovative alternative source for satisfying the energy demands of growing populations while reducing the consumption of fossil fuels. Most technological advancements and energy yield assessments have focused on promoting the use of kinetic energy from tidal streams with flow velocities higher than 2.0 m s⁻¹. However, slower-moving flows from ocean currents are recently explored due to their nearly continuous and unidirectional seasonal flows. In this study, the potential of the Yucatan Current was analysed at nearshore sites over the insular shelf of Cozumel Island in the Mexican Caribbean. Field measurements were undertaken using a vessel-mounted Acoustic Doppler Current Profiler (ADCP) to analyse the spatial distribution of flow velocities, along with Conductivity-temperature-depth (CTD) profiles as well as data gathering of bathymetry and water elevations. Northward directed flow velocities were identified, with increasing velocities just before the end of the strait of the Cozumel Channel, where average velocities in the region of 0.88–1.04 m s⁻¹ were recorded. An estimation of power delivery using horizontal axis turbines was undertaken with Blade Element Momentum theory. It was estimated that nearly 3.2 MW could be supplied to Cozumel Island, amounting to about 10% of its electricity consumption. Full article