Abstract

The objective of our study was to determine the oxygen consumption rates of nauplii of two small calanoid species, Paracalanus quasimodo and Temora turbinata, and compare their rates with those of three other planktonic species. The comparisons reveal that motion results in higher oxygen consumption i.e. higher energy expenditure than little or no motion. In addition, the type of motion results in different oxygen consumption rates, and therefore different energy expenditures. Our findings also show that nauplii consume more energy per unit body weight than their copepodids. This implies that small calanoid nauplii, having few energy reserves, are at a disadvantage in relation to copepodid stages as they require continuous food supply and continuous feeding which here is accompanied by continuous motion. That leaves them vulnerable to predators. Thus, not only predation but also discontinuous/intermittent feeding activity could result in increased mortality of calanoid nauplii.

Keywords: Copepod nauplii; Oxygen consumption; Metabolism