Vertical structure of larval fish assemblages during diel cycles in summer and winter in the southern part of Bahía de La Paz, México

• Published in: Estuarine, coastal and shelf science Vol. 76; no. 4; pp. 889 - 901
• Main Authors: Aceves-Medina, Gerardo, Saldierna-Martínez, Ricardo, Hinojosa-Medina, Alejandro, Jiménez-Rosenberg, Sylvia P.A., Hernández-Rivas, Martín E., Morales-Ávila, Raúl
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.03.2008; Elsevier
• Subjects: Abudefduf troschelii; Achirus mazatlanus; Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Bahía de La Paz; Biological and medical sciences; Brackish water ecosystems; circadian rhythms; Etropus; fish larvae; Fundamental and applied biological sciences. Psychology; Gulf of California; México; seasonal variations; Stegastes rectifraenum; Synecology; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; vertical distribution; Central America; Mexico; America; ISE, Mexico, Baja California Sur, La Paz; Gulf of California; fish larvae; vertical distribution; México; Bahía de La Paz; circadian rhythms; seasonal variations; Vertical; Brackish water environment; Vertical distribution; Biological rhythm; Circadian rhythm; Marine environment; Vertebrata; Larva; Animal community; Seasonal variation; Pisces
• ISSN: 0272-7714; 1096-0015
• DOI: 10.1016/j.ecss.2007.08.016

The effect of environmental variables on the vertical structure of larval fish assemblages in a tropical coastal lagoon was analyzed. Ichthyoplankton samples were collected from the near-bottom and surface strata near the mouth of a subtropical lagoon during contrasting seasonal conditions of temperature, photoperiod, light intensity, and tidal heights. During summer, larval fish assemblages had high species richness ( R) and were dominated by tropical species. During winter, assemblages had lower R values and were dominated by subtropical and temperate species. Vertical distribution patterns of the taxa were determined by the interaction of environmental variables and behavior of each species to maintain their position in a stratum in the water column, or to achieve vertical migrations induced by environmental stimuli that, in this case, were thermal gradient, column water stratification, and intensity of light. Depth position and vertical migration of fish larvae, coupled with the flood and ebb tide conditions, played an important role in their retention and displacement toward the lagoon. Fish larvae with distribution restricted to the inner part of the inlet, such as Achirus mazatlanus, Etropus sp., and several gobies, were more abundant in the near-bottom stratum during the ebb tide, allowing them to avoid exportation, whereas those that could spawn outside, but depended on the inlet as a nursery area, were more abundant near the surface during flood tide, such as Abudefduf troschelii and Stegastes rectifraenum.