This study was undertaken to examine the present condition of the lakes and to assess the likely consequences of increased use for recreation. Some physical and chemical aspects of the lakes and their waters were measured and the macrophytes, phytoplankton and larger invertebrates were surveyed in June and July 1973. The type of recreation enjoyed at each lake was also recorded. The lakes were all oligotrophic but the three larger ones had higher levels of nitrogen and in one case, zinc in their waters; these lakes were also the most intensively used for recreation. The variations between the biota of the different lakes, as summarized by means of ordination and classification techniques, were found to be related to the sizes of the lakes and in some cases to the lake chemistry. The relationships between the groups of living organisms, and between them and their environment, were examined more closely by means of a series of regression analyses, the results of which also suggested that lake size, as well as chemistry, had an important effect on the biota. We concluded that man had affected the lake chemistry and we predicted that if recreation activity was allowed to increase the biota of the smaller lakes would be degraded by pollution and by mechanical damage to the macrophytes.