Changes in species composition and abundance of fish larvae from the Gulf of Tehuantepec, Mexico

Se determino la composicion floristica de microalgas epifitas sobre Ulva spp. en la Bahia de Santiago de Cuba. Para ello, se hicieron muestreos en cinco localidades (Alameda, Punta Sal, Belmare, Caracoles, Cayo Granma) ubicadas segun el gradiente de contaminacion del ecosistema, de febrero a mayo de 2007. Se identificaron 27 especies de microalgas pertenecientes a 24 generos y 3 divisiones sobre Ulva lactuca, U. fasciata, U. flexuosa y U. rigida . La taxocenosis de microalgas epifitas estuvo dominada por cinco especies de diatomeas ( Cocconeis pinnata, Eunotia sp., Licmophora lyngbyei, Pinnularia sp., Navicula sp.) y dos de cianoficeas ( Anabaena lemmermannii y Oscillatoria limosa ). La mayor riqueza de especies epifitas se observo en febrero y marzo; su distribucion parece condicionada por la abundancia y distribucion del sustrato, la forma del talo, y el nivel de contaminacion. En la bahia, la menor riqueza de microalgas epifitas se presento en el lobulo interior (Alameda y Punta Sal), y la mayor hacia el lobulo exterior (Belmare, Caracoles y Cayo Granma). Spatial variation of epiphytic microalgae composition in Ulva spp. (Chlorophyta: Ulvaceae) in the Santiago de Cuba bay The floristic composition of epiphytic microalgae on Ulva spp. in the bay of Santiago de Cuba was determined. Sampling was carried out in five locations (Alameda, Punta Sal, Belmare, Cayo Caracoles and Granma) located according to a pollution gradient, from February to May 2007. We identified 27 species belonging to 24 genera and 3 divisions, on Ulva lactuca, U. fasciata, U. flexuosa and U. rigida . The taxocoenosis of epiphytic microalgae was dominated by five species of diatoms ( Cocconeis pinnata, Eunotia sp. Licmophora lyngbyei, Pinnularia sp., Navicula sp.) and two of the blue-green algae ( Anabaena lemmermannii and Oscillatoria limosa ). The greatest richness of epiphytic species was recorded on February and March. Their distribution seems to be conditioned by abundance and distribution of the substrate, thallus shape and contamination level. The lowest richness of epiphytic microalgae was observed in Alameda and Punta Sal (the interior lobe of the bay), which are more contaminated, and a higher richness was observed in healthier localities: Belmare, Cayo Caracoles and Granma, from the outer lobe.