Presented for Issue 93
Once regarded as a trophy fishery, the status of Lake Crescent slowly declined after the discovery of carp (Cyprinus carpio) in 1995, and repeated extreme drought and low water levels caused a significant decline in trout populations. The establishment of carp in Lake Crescent not only posed a risk to the trout through the destruction of suitable habitat and decreased water quality, but also had the potential to outcompete the threatened Golden galaxias (Galaxias auratus).
As a result, Lake Crescent was immediately closed from the public in 1995 and intensive fishing strategies were implemented in an attempt to control the spread of carp. By 2007, only one carp was caught, and all evidence suggests this pest has been completely eradicated from this lake. Continued monitoring is still occurring, but so far no carp have turned up and things are looking positive. Lake Crescent was officially re-opened in 2005, but the number of returning anglers was minimal.
A combination of low water quality, as well as the reduced trout population is likely to have discouraged people from returning back to this lake. However all is not lost and Lake Crescent is continuing to show increasing signs of improvement. Since the extreme low water levels in 2008, the average total turbidity of Lake Crescent has improved considerably. This is likely to be a direct result of the dilution by clear inflows and some flushing of suspended sediments down the Clyde River.
Currently, the water quality of Lake Crescent is the best it’s been for the past 10 years (See Figure 1). The expected high water levels this coming season combined with flushing flows this winter, should contribute further to improving water quality in the lake and help speed the rate of recovery of the fishery.
What is even more exciting for anglers were the results of the annual carp survey conducted in March 2011. It turned up a healthy number of outstandingly conditioned brown and rainbow trout, ranging from 2-4kg. This should entice a greater number of anglers back to Lake Crescent this season. There is also a lot of clear water in the back marshes of the wetlands, providing ideal areas for anglers this coming season. These marshes harbour a range of food items for trout, from frogs and galaxiids to a variety of aquatic invertebrates.
The service is currently working to re-establish Lake Crescent as a trophy fishery through a conservative stocking program. In the past few months, 5000 diploid brown and 5000 triploid rainbow trout have been released to this water.
Taking into account the highly productive waters of the lake, it should not be long before these fish become worthy adversaries on light line! This boost in recruitment in conjunction with increased water quality and overall productivity is bringing Lake Crescent a step closer to its former glory.