Efecto de la variabilidad ambiental en el reclutamiento y modelación bioeconómica en la pesquería de sardina del Pacífico (Sardinopssagax caerulea) de Bahía Magdalena, Baja California Sur, México

Ricker's stock-recruitment equation, including the multivariate ENSO index (MEI) as an environmental variable, was fitted to data of the Pacific sardine (Sardinops sagax caerulea) fishery from Magdalena Bay, Baja California Sur, Mexico. The equation was then incorporated into an age-structured, bioeconomic model. Uncertainty was incorporated by using environmental fluctuations; seven-year projections, equivalent to one sardine generation, were computed. Five management options were considered in the projections: open access, effort at maximum sustainable economic yield (fMSE), catch at maximum sustainable yield (CMSY), equivalent effort level applied in the year 2004 (f2004), and an arbitrary catch quota of 40000 tons (CQ40000). Projection results were summarised by the indicator Net Present Value (NPV) of the fishery for the modelled period. The strategies that involved some regulation in the effort level (fMSE and f2004) yielded the largest NPV. On the other hand, the strategies that involved regulation of the catch predicted—in addition to a lower NPV—a substantial increase in the effort to achieve the desired catch level. This study is the first bioeconomic approach for a sardine fishery management plan in this region.La ecuación stock-reclutamiento de Ricker incorporándole el índice multivariado del ENSO(IME) como variable ambiental fue ajustada a datos de la pesquería de sardina (Sardinops sagax caerulea) de Bahía Magdalena, Baja California Sur, México. Esta ecuación fue incorporada a un modelo bioeconómico estructurado por edad. La incertidumbre fue considerada al incorporar la variabilidad ambiental, y se realizaron proyecciones de siete años de duración, que equivalen a una generación de sardina. En las proyecciones se consideraron cinco estrategias de gestión: acceso abierto, esfuerzo en máximo rendimiento económico (fMRE), captura en el máximo rendimiento sostenible (CMRS), esfuerzo igual al aplicado en el año 2004 (f2004), y una cuota de captura de 40000 toneladas métricas (CC40000). Las proyecciones fueron expresadas como el valor presente neto (VPN) de la pesquería para el período modelado. Las estrategias que involucraron alguna regulación en el nivel de esfuerzo pesquero (fMRE y f2004) presentaron el mayor VPN. No así las estrategias que involucraron regulación en la captura, debido a que éstas predijeron un fuerte incremento en el esfuerzo para lograr el nivel de captura deseado. Este estudio es la primera aproximación bioeconómica para la ordenación de la pesquería de sardina en esta área

SCREENING FOR ANTIBACTERIAL AND ANTIPROTOZOAL ACTIVITIES OF CRUDE EXTRACTS DERIVED FROM MEXICAN MEDICINAL PLANTS

Background: Crataegus mexicana, Hyptis albida, Larrea tridentata, Ocimum baislicum, Prunus serotina, and Smilax spp. are used in Mexican traditional medicine to treat respiratory and gastrointestinal diseases such as flu, cough, diarrhea, dysentery, and other parasitic or microbial infections. Therefore this study was aimed at the pharmacological prospection of these plants against eleven bacterial species and three amitochondrial protist pathogens. Material and methods: The fruits or aerial parts of C. mexicana, H. albida, L. tridentata, O. baislicum, P. serotina, and Smilax spp. were extracted with different solvents. The antibacterial properties of organic and aqueous extracts of these plants were determined by the microdilution method and the microplate alamar blue assay against Stenotrophomonas maltophilia, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterobacter cloacae, Staphylococcus aureus, methicillin-resistant S. aureus, Listeria monocytogenes, Enterococcus faecalis, and Mycobacterium tuberculosis, whereas anti-protozoal activities of extracts were evaluated by a vial micro-assay against strains of Entamoeba histolytica, Trichomonas vaginalis, and Giardia lamblia. Results: H. albida, Smilax spp, and C. mexicana showed good activity against the Gram-positive strains, S. aureus, methicillin-resistant S. aureus, and E. faecalis. Four extracts (C. mexicana, H. albida, O. basilicum, and L. tridentata) showed good activity against E. histolytica, T. vaginalis, and G. lamblia. Conclusion: The extracts of these six medicinal plants could be a source for new antibacterial and antiprotozoal drugs. For this reason they are currently under investigation to isolate and characterize their active compounds