Differences in rotifer populations of the littoral and sub-littoral pools of a large marine lagoon

Abstract

The rotifer populations of littoral and sub-littoral pools of a large marine lagoon are described. Significant differences (P < 0.05) were found between the rotifer populations of the chlorophyte algae, the phaeophyte algae of the high littoral pools, and the algae of sub-littoral hollows. Large populations of Proales reinhardti (Erhenberg) were found in the phaeophyte alga (Pilayella sp.) during spring, but were mostly absent in the pools containing chlorophytes (Percursaria sp., Blidingia sp. and Enteromorpha sp.). Encentrum marinum (Dujardin) - the only other species to be found in appreciable numbers - and Lindia torulosa (Dujardin) were mainly found in the chlorophyte pools. Few rotifers were found in the sub-littoral algae, where sediment loading was found to be significantly higher (P < 0.05). Proales reinhardti populations disappeared from all pools at the beginning of May. Laboratory experiments showed that P. reinhardti had a high reproductive rate at 8 °C but did not survive at 18 °C, which suggests that rising temperatures in Spring are the main factor in controlling P. reinhardti populations.