Pelagic fish assemblages at the Espíritu Santo seamount in the Gulf of California during El Niño 1997-1998 and non-El Niño conditions
Plankton samples and visual census from December 1995 to December 1998 were obtained to study adult and larvaeassemblages of fish at El Bajo Espíritu Santo (EBES) seamount. Tagging experiments of yellow fin tuna were carried out fromApril to September 1998. Records of tagged fish at EBES were regist...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2003 |
| País: | México |
| Institución: | Instituto Politécnico Nacional |
| Repositorio: | Redalyc-IPN |
| OAI Identifier: | oai:redalyc.org:56842319 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=56842319 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias de la Tierra Seamount tuna fish diversity pelagic fishes ultrasonic tagging |
| Sumario: | Plankton samples and visual census from December 1995 to December 1998 were obtained to study adult and larvaeassemblages of fish at El Bajo Espíritu Santo (EBES) seamount. Tagging experiments of yellow fin tuna were carried out fromApril to September 1998. Records of tagged fish at EBES were registered until February 2000. Five oceanographic cruises werealso carried out. Visual census of adult fish suggest that El Niño conditions favor migration of tropical species to EBES. Diversityindex showed higher values of 4.5 compared to non-El Niño years of 3.5 in 1996. An increased number of species, 85, in 1998 wasobserved in comparison to 53 of 1996. Larval fish assemblages indicate a decreased diversity index values during El Niño conditions.However, more than 50% of larval fishes during El Niño conditions belong to mesopelagic species of tropical affinity.Rarefaction curves of larval fish showed higher than expected number of species during non-El Niño years. Conversely, rarefactioncurves of El Niño years showed lower than expected number of species. Two groups of samples were obtained from clusteranalysis, corresponding to non-El Niño and El Niño conditions. Results of tagged yellow fin tuna showed residence on a dailybasis, and homing with absence of 15 days. During El Niño the mixed layer deepened to 70 m in the area of EBES. Sea surfacetemperature was about 2 °C higher in comparison to non-El Niño conditions. |
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