José A. Félix-Ortiz, Manuel E. Siu-Quevedo, Nicolás Castañeda-Lomas, Guillermo Rodríguez-Domínguez, Gustavo Rodríguez-Montes de Oca and E. Alberto Aragón-Noriega
The species composition and variation in density (postlarvae m−3) of penaeid shrimp postlarvae were surveyed every 14 days in two zones of the Mexican Pacific coast; in the north (Mazatlán, 23°N 106°W) and south (Gulf of Tehuantepec, 15°N 95°W). Sampling coincided with full moon and new moon, and they were carried out with plankton net (0.3 m mouth diameter and 450 μm mesh size). Average sea surface temperature (SST) for 1985-1995 increased from Mazatlán (26.2 ± 0.2°C) to Tehuantepec (28.3 ± 0.5°C). The difference in SST between the coldest and warmest month was 7.8°C in Mazatlán and 3.3°C in Tehuantepec. Four species of penaeid shrimp postlarvae were identified: Litopenaeus vannamei (Boone, 1931), L. stylirostris (Stimpson, 1874), Farfantepenaeus californiensis (Holmes, 1900) and F. brevirostris (Kingsley, 1878). There was a regional variation in the species composition. L. vannamei was abundant at both coasts with 40% and F. californiensis varied from south to north from 45 to 36%; the less representative species were L. stylirostris and F. brevirostris, which varied from south to north from 15 to 24%. The occurrence period near Mazatlán is seven months, and it is year-round in Tehuantepec. This study suggests that warm water and low seasonal SST variability facilitate the presence of the shrimp larvae over a longer period.
José A. Félix-Ortiz, E. Alberto Aragón-Noriega, Nicolás Castañeda-Lomas, Guillermo Rodríguez-Domínguez, Wenceslao Valenzuela-Quiñónez and Manuel E. Siu-Quevedo
In the present study we explored the effect of the tidal hour on the postlarvae abundance of the penaeid white-leg shrimp (Litopenaeus vannamei (Boone, 1931)) in three Mexican Pacific coastal lagoons. Correlation analysis of tidal hour against the hourly variation of the abundance of postlarvae was conducted in three regions of the Mexican Pacific; the system lagoon Huizache-Caimanero LHC, the region of the “Grandes Lagunas” SGL and the “Mar Muerto” Lagoon LMM. Two peaks were found in L. vannamei abundance in the three locations, at 04:00 and 16:00 of tidal hour in LHC and SGL, and 06:00 and 12:00 of tidal hour in LMM. Significant correlations between postlarvae and the tidal hour for the three regions were found. The tidal hour standardizes the time of ebb and flow. It is concluded that tidal hour can be used as cue for shrimp postlarvae immigration to nurseries.