Zooplankton and secondary production

Abstract

Relatively little is known about the Zooplankton of Lake McIlwaine. Munro (1966) compiled the first species list of the Zooplankton of the lake. He found Ceriodaphnia dubia Richard to be dominant for most of the year, particularly during late winter and spring (July to December) when populations of between 50 and 275 x 10³ m^-3 were observed (Fig. 5, Munro, 1966). More recently Magadza (1977a) has examined the Zooplankton of the lake and has noted the absence of many of the species described by Munro (1966), notably Ceriodaphnia dubia. Numerous other differences were observed (Table 6) but these were attributed mainly to sampling frequency and methodology (Magadza, 1977a). Unfortunately, Magadza (1977a) gives no indication of the relative abundance of the Zooplankton species which he recorded from the lake except to say that Thermodiaptomus syngenes Keifer was more numerous than Tropodiaptomus orientalis Brady; the former being the first record of Thermodiaptomus syngenes north of the Tropic of Capricorn. A complete list of the Zooplankton species recorded from Lake McIlwaine is given in the addendum.