Detailed Morphology, with Reference to Abundance, of Acartia Species in Malala Lagoon in Bundala National Park

Abstract

Freshwater Calanoid copepods are a group of free-living fresh water crustaceans. They are planktonic and limnetic and they occur in habitats varying from freshwater to seawater. We investigated detailed morphology of Acaftia specr'es and some abundance details, possibly the first recording in Malala lagoon, Bundala National Park. Attention was focused on population dynamics of Acartia specles with water quality variations. When several other Caianiod copepods were abundant Acartia specles was reduced to undetectable levels. Basic body measurements (mm) of Acaftia specles were observed as total body length 1.36 t 0.07, width 0.19 t 0.07, prosome length 0.7310.1 and antennae length'1.16 r 0.11. The species has a characteristics male 5th leg butwe could not finalize the species name due to some variations in narrow and longer furcal ramus. There was a slight change in body measurernents (mm) [total length up to caudal setae changed from 1.36t0.07 to 1.47t0.081 with changes in water quality, specially with a slight increase in salinity (from 0.78 t 0.15 to 6.59 t 0.92 g/l)and slight decrease in Nitrate (from247 t 6.54 to 167 x 5.47 mg/l). However, no correlation was found with respect to body measurements of Acartia specles and water quality parameters in Malala lagoon during our visits. Body measurements of Acartia species and relationships to habitat-ecosystem functions have been emphasized elsewhere. Therefore, further investigations of morphological variations of this species along with habitat quality changes are being studied. We believe these ecological relationships are important in habitat management practices of the Malala ecosystem.