Los derrames de petróleo constituyen una fuente importante de perturbación de los macroinvertebrados bentónicos de aguas continentales. Sin embargo, los estudios referentes a estas perturbaciones en las regiones tropicales, y particularmente en el Neotrópico, son limitados. En el presente trabajo se evaluaron los efectos de un derrame de 11 700 barriles de petróleo en las comunidades de macroinvertebrados bentónicos de los ríos Santa Rosa, Quijos y Coca, amazonia ecuatoriana, mediante el uso de índices bióticos, variables de calidad de agua y sedimentos, tanto en sitios impactados como en sitios de referencia en los años 2011 y 2012. Las correlaciones de Spearman establecieron relaciones negativas significativas (p < 0.05) entre la variable “hidrocarburos totales de petróleo” y los taxa Ephemeroptera-Plecoptera-Trichoptera (índice EPT), Trichoptera, y la familia Elmidae. Se estableció una relación inversa entre el índice SIGNAL2 con los hidrocarburos totales de petróleo. El procedimiento de permutación de respuesta múltiple determinó una diferencia entre las comunidades de macroinvertebrados de estaciones de referencia e impactadas del año 2011, y entre las comunidades de macroinvertebrados de estaciones de referencia año 2011 y estaciones impactadas año 2012. El escalamiento multidimensional no-métrico implicó usar tres dimensiones, en el cual el eje dos estuvo mejor relacionado con los hidrocarburos totales de petróleo (r = 0.45). Estos resultados sugieren que factores distintos a hidrocarburos totales de petróleo son los responsables de la composición heterogénea de las comunidades de macroinvertebrados.

We analyzed the infestation of the attached copepod species Lepeophtheirus sp on a wild population of Sciades herzbergii. The infestation and occurrence of attached copepods were related to body size, maturity and sex of host and the presence of lesions on fish skin were described. In 61 fish specimens (37 males and 24 females), total of 218 ectoparasitic copepods, including 204 mature and 14 immature stages were found. Copepods were attached to different regions of fish body without any regular pattern. The prevalence of infestation was 80.3% and intensity between 1 and 15 copepods/fish. No significant differences were found between sex or maturity and the presence of attached Lepeophtheirus sp. However, a contingency table including both sex and maturity status, and the total number of attached copepod per combined category showed a significant association. A positive correlation was found between body length of fish and intensity of infestation. Similarly, when comparing the infested fish according to group size, we found more copepods on larger individual. Attached copepods were associated with the presence of lesions visible to the naked eye. Histological analyses showed changes in cell architecture when sections of copepod-free tissues and attached copepods were compared.

We present an updated checklist of the rotifer fauna from inland aquatic habitats in continental Ecuador and the Galápagos islands based on published rotifer records found in the literature. The checklist summarizes the status of the current taxonomic and faunistic knowledge on rotifers in Ecuador, updates the nomenclature, and reports the regions where each species has been found in the country. A total of 287 valid species (269 monogononts and 18 bdelloids was found. The Ecuadorian region with the highest number of records was Amazonia (228) followed by the Coastal region (139) and the Andes (121), whereas in the Galápagos Archipelago only 40 species have been recorded. Studies of the rotifer fauna of the areas are scarce and quite recent, pointing to important gaps in our knowledge on taxonomy and biogeography of Ecuadorian rotifers.

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