RESUMEN
Tilapia is a model fish species used as a pollution biomonitor due to its tolerance and availability in many contaminated sites. Blue tilapia Oreochromis aureus specimens (n = 320) were collected in eleven dams influenced by mining in the SE Gulf of California region (dams 1, 2 and, 3 comprise 55 mining sites; dam 4 comprises 8; dams 6, 8, 10, and 11, ≤ 6; and dams 5, 7, and 9 include 19, 20, and 16 mining sites, respectively). Cadmium, Cu, Pb, and Zn concentrations were analyzed in the muscle, liver, gills, and guts to identify metal pollution and evaluate risks and seasonal changes. The distinct tissues exhibited different metal accumulation capacities, therefore allowed develop a diagnosis comparative between the eleven dams. In general, metal concentrations were higher in dams 1, 2, 5, and 9, which are associated with more mining sites in their sub-basins. The four metals exhibited the highest levels in the tilapia liver in dams 1 and 2, which can be related to the present and past mining activity in the lower watershed (55 sites) and the geothermal activity in these dams. In general, Zn exhibited the highest level in the tilapia livers from dams 1, 2, 3, 4, 5, and 10 compared to the maximum mean (220 µg/g) concentrations previously recorded. The non-carcinogenic risks indicated that the Pb risk was enhanced when the intake was ≥ 231.5 g week-1 of tilapia muscle, indicating a potential risk of adverse health effects for the entire population.
Asunto(s)
Metales Pesados , Minería , Tilapia , Contaminantes Químicos del Agua , Animales , Tilapia/metabolismo , Contaminantes Químicos del Agua/análisis , Medición de Riesgo , Metales Pesados/análisis , Hígado/metabolismo , Hígado/química , Monitoreo Biológico , Músculos/química , Músculos/metabolismo , Monitoreo del Ambiente/métodos , Branquias/metabolismo , Branquias/químicaRESUMEN
Abstract Release or escapes of aquaculture organisms may impact the genetic composition and variability of wild populations, leading to diverse issues that may compromise long-term wild stock fitness. Therefore, it is relevant to determine if farmed stocks are currently interacting with wild populations. Shrimp farming is an aquaculture activity taking place along the tropical Pacific coast of the Americas, and represents the most important culture business of Northwestern Mexico. In this study, wild and farmed whiteleg shrimp Litopenaeus vannamei from the State of Sinaloa were genetically evaluated to determine admixture levels. A newly developed set of 14 microsatellite markers (mean number of alleles per locus 11.8, and 0.836 expected heterozygosity) was obtained by Next Generation Sequencing to characterize samples. Sampling consisted of 32 wild shrimps collected during three years (2002, 2012, and 2013) and three different sites, and two hatchery stocks from 2007. No significant differences were observed among years in the wild samples, but cluster analyses showed that hatchery-produced individuals were different from wild specimens. Deviations from Hardy-Weinberg Equilibrium and genotype assignment tests indicated that a fraction from each sample could contain individuals from hatchery origin. Even though the estimated fraction of escaped farmed individuals in the most recent samples (2012-2013; mean = 7.1 %) is considered of low genetic risk, management recommendations for hatcheries and farms were provided. Besides, the reasons that explain the intended and unintended farmed shrimp release into the wild were discussed. Rev. Biol. Trop. 66(1): 381-393. Epub 2018 March 01.
Resumen La liberación o escape de lotes de cultivo pueden impactar la composición y variabilidad genética de las poblaciones silvestres, dando lugar a diversos problemas que pueden comprometer la eficacia biológica a largo plazo. Por lo tanto, es relevante determinar si las poblaciones de cultivo se encuentran actualmente interactuando con las poblaciones silvestres. El cultivo de camarón es una actividad de acuicultura que tiene lugar a lo largo de la costa del Pacífico tropical de América, y es la más importante en el noroeste de México. En este estudio, el camarón blanco Litopenaeus vannameisilvestre y de cultivo proveniente del Estado de Sinaloa, México, fueron evaluados genéticamente para determinar los niveles de mezcla. Se desarrolló un lote de 14 marcadores microsatélites nuevos (número de alelos promedio por locus de 11.8 y heterocigosidad esperada promedio de 0.836), mediante secuenciación de nueva generación, para la caracterización de las muestras. El muestreo consistió en camarón silvestre recolectado durante tres años (2002, 2012 y 2013) y dos lotes de unidades productoras de larva del 2007. No se observaron diferencias significativas entre años en las muestras silvestres, pero el análisis de agrupamiento indicó que los lotes de las unidades productoras de larva fueron distintos a los ejemplares silvestres. Desviaciones del equilibrio de Hardy-Weinberg y los análisis de asignación de genotipos indicaron que una fracción de cada una de las muestras silvestres podría contener individuos originados del larvicultivo. Se discuten las razones que explican la liberación de camarón de cultivo intencional y no intencional al medio silvestre. Aun cuando la fracción estimada de individuos de origen de cultivo en las muestras silvestres más recientes (2012-2013; promedio = 7.1 %) se considera de bajo riesgo, se dan recomendaciones de manejo para unidades de larvicultura y granjas de cultivo.