ABSTRACT
The composition and structure of octocoral communities on coral reefs close to a submarine outfall were studied at Reparto Flores, west of Havana City, Cuba. Octocoral community changes after the deployment of the submarine outfall in 2000 were monitored from June 2002 to September 2005, taking as baseline the data existing before its construction. The area also receives the influence of the polluted river Quibú that passes through a great part of the west side of the City. Sampling was done by means of SCUBA diving, counting and identifying colonies in situ within a 1 m2 frame that was randomly placed as many times as to warrant stabilized values of Shannon and Weaver's heterogeneity index H'. In agreement with the available hydrochemical information, changes in the diversity indexes (Shannon and Weaver's heterogeneity index H', Pielou's equitability index J', and Margalef's species richness index R1), the Herrera-Moreno's comparative pollution index (ICC), and density of some octocoral species at a depth of 10 m suggest a decrease in the influence of polluters from 1989 to 2005. Nevertheless, these indicators were affected in 2004 by a sudden intense but brief colonization of Briareum asbestinum, a species that is not typical of polluted places. At a depth of 20 m, a co-dominance of Plexaura kuekenthali and Eunicea clavigera (resistant and non resistant to pollution, respectively) and an increase of the comparative pollution index (ICC) was observed. The increase of P. kuekenthali, a pollution indicator, suggests a rise in the pollution effect 20 m in depth, because of the recent impact caused by the greater closeness of the outfall mouth 50 m deep. Results corroborate the hypothesis about the pollution indicator character of P. kuekenthali. However, this could not be explored for Eunicea flexuosa (also considered a pollution-indicator) due to an intensive illegal selective extraction for lucrative handicraft purposes, which...
Para profundizar en las respuestas de las comunidades de octocorales a la influencia de residuales urbanos se estudió su composición y estructura en sitios de arrecife cercanos a un emisario submarino urbano en el Reparto Flores, La Habana, Cuba. Desde junio del 2002 hasta septiembre del 2005, se efectuó el monitoreo de los cambios ocurridos en las comunidades después de la puesta en operación del emisario en el año 2000, tomando como línea base datos existentes antes del inicio de su construcción. El muestreo se realizó mediante buceo SCUBA, contando e identificando las colonias in situ dentro de cuadricula de 1 m2 de lado. Diversos índices sugieren una disminución de la influencia de la contaminación en la última década.El incremento de P. kuekenthali (indicadora de contaminación, , sugiere un aumento del efecto de la contaminación a 20 m de profundidad debido al impacto reciente de la mayor cercanía del desagüe del emisario que se encuentra a 50 m de profundidad. B. asbestinum y E. clavigera se perfilaron como poco resistentes a la contaminación.