|dc.description.abstract||Freshwater surveys in New Zealand have not been numerous.
This is understandable when we consider that it has been settled for little more than a century, and is still sparsely populated. The only comparative study of a group of lakes published to date is the work of Cunningham et al. (1953) which is a contribution on the dune lakes of the western coast of the
North Island. In a country so richly endowed with a wide variety of lakes there is therefore a welcome opening for limnological surveys.
This thesis is a comparative study of the physical and chemical conditions and the phytoplankton and zooplankton of a number of lakes. It is based mainly on monthly records made over a twelve-monthly period on seven lakes in the Rotorua-Taupo thermal area namely, Okataina, Rotoehu, Rotoiti, Rotorua,
Tarawera, Taupo and Tikitapu. Data from Ngapouri, Okareka, Okaro, Rerewhakaitu, Rotokakahi, Rotomahana, Rotongaio, Waikaremoana and Waikareiti which were studied less consistently is also included. Lakes Waikaremoana and Waikareiti are the only North Island lakes outside the thermal area to have been observed. Waikaremoana could not be neglected since it is the deepest and most elevated lake of size in that island.
Comparable information derived during an earlier survey of some South Island lakes is offered to provide comparison between two genetically and geographically isolated groups. Lakes Hayes, Te Anau, Wakatipu and Wanaka were sampled seasonally, that is four times over a twelve-monthly period while Kilpatrick, Moke and Manapouri received less study.
The aim of this investigation was to achieve a means of assessing biological productivity. It is doubtful if this goal has been reached. However, the data collected on these seventeen North Island and seven South Island lakes which includes the largest and deepest of both Islands makes it possible to draw some comparisons and reach some conclusions, and it is hoped that the information here collected may provide a basis for further observations. [Preface]||en_NZ