Asociaciones de larvas de peces en relación a cambios ambientales en las Bahías Chamela, Jalisco y Santiago-Manzanillo, Colima (2001-2002)

Spatial and temporal structure of fish larvae associations and their relationship to the environmental variability were studied at Bahía Chamela, Jalisco, and Santiago-Manzanillo complex, Colima, during 2001-2002. Two spatial aggregations were found, related to the coastal physiography and to the adult habitat. The first was observed at Bahía Chamela, which integrated a combination of species belonging to coastal, demersal and inshore habitats (Bregmaceros bathymaster, Bairdiella sp., Cynoscion sp., Engraulis mordax, and Labrisomidae type 1) and the other in Santiago-Manzanillo composed by species from lagoon and inshore areas (Eucinostomus sp., Abudefduf troschelii, Haemulidae type 2 and 3, and Enneanectes sexmaculatus). Temporal organization was influenced by the environmental shift between two periods (warm and temperate) defined by the regional environmental variability. The warm period was characterized by tropical species (Harengula thrissina, Eucinostomus sp., Auxis sp., and Haemulidae type 3), related to high temperature and rainfall, while temperate period was dominated by species with a tropical-subtropical affinity (B. bathymaster, Bairdiella sp., Cynoscion sp., and E. mordax) and related to lower temperature and elevated nutrients, chlorophyll a and plankton concentrations.Se analizó la influencia de los factores ambientales sobre las asociaciones espacio-temporales de larvas de peces frente a Bahía Chamela, Jalisco y el conjunto de bahías Santiago-Manzanillo, Colima, durante un ciclo anual (2001-2002). Se identificaron dos agrupaciones relacionadas con la fisiografía de la costa y el hábitat de los adultos, una frente a Bahía Chamela integrada por una mezcla de especies de hábitats costero, demersal e intermareal-submareal (Bregmaceros bathymaster, Bairdiella sp., Cynoscion sp., Engraulis mordax y Labrisomidae tipo 1) y otra en Santiago-Manzanillo compuesta por especies de origen lagunar e intermareal-submareal (Eucinostomus sp., Abudefduf troschelii, Haemulidae tipos 2 y 3, así como Enneanectes sexmaculatus). La organización temporal estuvo influenciada por la alternancia entre dos periodos (cálido y templado) definidos por la variabilidad ambiental regional. El periodo cálido estuvo caracterizado por especies principalmente tropicales (Harengula thrissina, Eucinostomus sp., Auxis sp. y Haemulidae tipo 3), relacionadas con una mayor temperatura y precipitación pluvial, en cambio durante el periodo templado dominaron las especies de afinidad tropical-subtropical (B. bathymaster, Bairdiella sp., Cynoscion sp. y E. mordax), relacionadas con una menor temperatura e incrementos en las concentraciones de nutrimentos, clorofila-a y zooplancton

Annual cycle of microphytoplankton from the coasts of the tropical Mexican Pacific

Despite the length of littorals, studies of annual cycles for phytoplankton in the Mexican Pacific are rare, especially in tropical areas. A study of the phytoplankton (basically microphytoplankton) was realized in six locations off the States of Jalisco and Colima, from June, 2001 to May, 2002. A total of 286 taxa belonging to the taxonomic groups diatoms, dinoflagellates, cyanophyceae and silicoflagellates were identified. The best represented groups were dinoflagellates (157 taxa) and diatoms (119 taxa). Moreover, the study included a small fraction (15-25 %) of the diatom planktonic flora and 43% of the dinoflagellate flora from the Mexican Pacific. The flora showed a strong tropical-subtropical affinity. Dinoflagellate species appeared to be more important in late spring and early summer, whereas relative abundance of diatoms was higher most of the year of study. Five new records of dinoflagellates for the Mexican Pacific are annotated: Amphisolenia palmata, Amphisolenia truncata, Gonyaulax jollifei, Kofoidinium splendens and Protoperidinium divaricatum, from which only one is a non-thecate form; these findings may be due to the lack of previous detailed floristic studies in the area. No clear relation existed between microplankton and other variables found in the literature, such as chlorophyll a and nutrients. However, several patterns of phytoplankton succession were detected during our study: three stages were recognized, although they did not correspond with the diversity index values calculated

Annual cycle of microphytoplankton from the coasts of the tropical Mexican Pacific

Despite the length of littorals, studies of annual cycles for phytoplankton in the Mexican Pacific are rare, especially in tropical areas. A study of the phytoplankton (basically microphytoplankton) was realized in six locations off the States of Jalisco and Colima, from June, 2001 to May, 2002. A total of 286 taxa belonging to the taxonomic groups diatoms, dinoflagellates, cyanophyceae and silicoflagellates were identified. The best represented groups were dinoflagellates (157 taxa) and diatoms (119 taxa). Moreover, the study included a small fraction (15-25 %) of the diatom planktonic flora and 43% of the dinoflagellate flora from the Mexican Pacific. The flora showed a strong tropical-subtropical affinity. Dinoflagellate species appeared to be more important in late spring and early summer, whereas relative abundance of diatoms was higher most of the year of study. Five new records of dinoflagellates for the Mexican Pacific are annotated: Amphisolenia palmata, Amphisolenia truncata, Gonyaulax jollifei, Kofoidinium splendens and Protoperidinium divaricatum, from which only one is a non-thecate form; these findings may be due to the lack of previous detailed floristic studies in the area. No clear relation existed between microplankton and other variables found in the literature, such as chlorophyll a and nutrients. However, several patterns of phytoplankton succession were detected during our study: three stages were recognized, although they did not correspond with the diversity index values calculated

Larval fish associations related to environmental changes in Bahía Chamela, Jalisco and Santiago-Manzanillo, Colima (2001-2002) [Asociaciones de larvas de peces en relación a cambios ambientales en las Bahías Chamela, Jalisco y Santiago-Manzanillo, Colima (2001-2002)]

Spatial and temporal structure of fish larvae associations and their relationship to the environmental variability were studied at Bahía Chamela, Jalisco, and Santiago-Manzanillo complex, Colima, during 2001-2002. Two spatial aggregations were found, related to the coastal physiography and to the adult habitat. The first was observed at Bahía Chamela, which integrated a combination of species belonging to coastal, demersal and inshore habitats (Bregmaceros bathymaster, Bairdiella sp., Cynoscion sp., Engraulis mordax, and Labrisomidae type 1) and the other in Santiago-Manzanillo composed by species from lagoon and inshore areas (Eucinostomus sp., Abudefduf troschelii, Haemulidae type 2 and 3, and Enneanectes sexmaculatus). Temporal organization was influenced by the environmental shift between two periods (warm and temperate) defined by the regional environmental variability. The warm period was characterized by tropical species (Harengula thrissina, Eucinostomus sp., Auxis sp., and Haemulidae type 3), related to high temperature and rainfall, while temperate period was dominated by species with a tropical-subtropical affinity (B. bathymaster, Bairdiella sp., Cynoscion sp., and E. mordax) and related to lower temperature and elevated nutrients, chlorophyll a and plankton concentrations

Additive partitioning of reef fish diversity variation: A promising marine biodiversity management tool

Additive partitioning was applied to variation in reef fish spatial diversity at Isla Isabel National Park, Nayarit state, Mexico, and to identify the environmental and spatial variables that best explains it. Analyses included expected and observed species curves, rare species analysis, additive partitioning of alpha- and beta-diversity, and canonical redundancy analysis. A total of 10,517 individuals were recorded from 75 species and 33 reef fish families, representing 85% of expected richness. Species richness beta-diversity was dependent on the site scale, while the alpha-diversity of the Shannon diversity was most significant at the transect scale. Canonical partitioning showed species richness and Shannon diversity was explained by spatially-structured environmental components. Variation in species composition and abundance was explained by a purely environmental component. Therefore, elements of habitat structure (especially corals), topographic complexity, and refuge availability determine fish species diversity. Our results suggest that greater emphasis is required to conserve sites that promote β-diversity, increasing fish spatial diversity. In Isla Isabel, these sites would be mostly those located at eastern and southern of protected sides, where coral reef patches are well represented. The results of this multi-scale analysis are valuable and useful as an addition and complement to the holistic management strategies implemented at Isla Isabel. © 2011 Springer Science+Business Media B.V