Tecnociencia (Jun 2011)
SEASONAL DIATOM AND COPEPOD ABUNDANCES IN THE GULF OF MONTIJO, PANAMA
Abstract
Between November 1996 and December 1997 a study was conducted in the gulf of Montijo, Panamá to evaluate the spatial and seasonal diatom-copepod abundances. Water temperature averaged 29.1ºC and salinity fluctuated from a minimum of 21.6 psu in November 1996 to a maximum of 30.3 psu in March 1997. Secchi depths increased from inshore to offshore stations with higher values in March and October. A seasonal pattern of rainfall prevailed in the gulf with cumulative precipitation peaked in June, September and November whereas lower values were registered from January to April. Copepods and nauplii were numerically the major component of the zooplankton community comprised over 90% of the catches whereas phytoplankton was diatom dominated. Both groups showed a distinct seasonal pattern. Whereas copepods were dominant during the rainy season, diatoms were in the dry season. In addition, an inverse spatial diatom-copepod relation was observed. Copepod and nauplii abundances decreased from inshore to offshore stations whereas diatom increased. Field observations were consistent with an expected inhibitory effect of diatom on copepod population.
