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Volume 44 - Number 1 - 2009
Article

 


Seasonal variations of the community structure of fishes in two reefs: rocks-stone corals and octocorals, in Bajo Las Caracas, Venezuela

Ángel Rafael Fariña Pestano1 y Elizabeth Méndez De Elgueazabal1

 

1Departamento de Biología, Escuela de Ciencias, Universidad de Oriente, Núcleo de Sucre. Cumaná 6101, Estado Sucre, Venezuela

 

E-mail: afarina46@yahoo.com

 

We studied the seasonal variation of ichtyofauna on two reefs: a stony coral reef and an octocoral (soft coral) reef. Monthly visual censuses were implemented based on transects of 40 x 2 m (80 m2) placed in each ecosystem. The results indicate correlation patterns between annual changes in the fish community and the physical seasonal parameters. Such patterns occur principally within the soft coral reef, where the species richness and relative abundance are greatest during the months of upwelling. The observed groups of the pelagic species Sardinella aurita and Decapterus punctatus are responsible for the decreased diversity during the upwelling peaks. In the stony coral reef, species richness was positively correlated with visibility and abundance, coinciding with records of similar reefs in nearby areas. Comparing the monthly abundance of ichtyofauna, the dispersion in the data from the octocorals was greater compared to the stony coral reef. Coupled with the low number of constant species, this demonstrates that the ichthyofauna associated with the gorgonian make less frequent use of this ecosystem. Though the two reefs are adjacent to one another, nine species regularly present in the stony coral reef were not observed in the soft coral reef. This pattern conforms to the deterministic assumptions regarding the use of space and biodiversity in reef areas. In conclusion, the results reinforce that the octocoral reef is a particularly distinct habitat within the diversity of ecosystems in the Venezuelan submarine environment

 

Key words: Upwelling, Caribbean, ichthyofauna, Sardinella aurita, Aulostomus maculatus


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