| | Water & Atmosphere Vol. 9 No. 2, June 2001 - NIWA (Site not responding. Last check: 2007-10-20) |
 | | For example, some lakes such as Hawea, Pukaki and Tekapo may undergo big reductions in water level – usually during the winter when power demand is higher – and it has been unclear what effects such changes in lake level have on fish populations and their food supplies. |
 | | Brown trout were relatively more abundant in a stable turbid lake (Ruataniwha) than in a fluctuating turbid lake (Pukaki), apparently because the light-limited shallow weed beds in the former are eliminated when water levels are lowered in a fluctuating lake. |
 | | On the other hand, rainbow trout appeared to show variable depth preferences in different lakes, and their size and condition were not closely related to water clarity or lake-level fluctuations, suggesting that spawning success and food supplies in the open water zone were more important for this species. |
| www.niwa.cri.nz /pubs/wa/09-2/clarity.htm (1011 words) |