304-306Coexistence of unusual congregations of the chaetognath Sagitta enflata and the ostracod Cypridina dentata was observed in the zooplankton off the Maharashtra coast between 17 ° 20' to 19 ° 14'N and 72 ° 21' to 72 ° 56'E during the 12th cruise of RV Gaveshani in the west coast of India. They contributed 54 to 80% of the total biomass. Oceanic associations of plankton species usually exhibited high diversity and the coincident occurrence of 2 swarms of the distinct species was rare. Such dense concentrations of a few species may be considered as population explosions resulting in a situation referable to a 'monotone' plankton
