IFS Stocking Report June 2010

June has been a particularly busy month for IFS staff both in the hatchery and ‘in the field’ reports Brett Mawbey, IFS Hatchery Manager.

Young brown trout are hatching (entering the alevin stage) in the troughs, triploid brown trout eggs are incubating in the ‘up-wellers’ and there is continual grading of rainbow trout fingerlings from the growing tanks in preparation for stocking out.

Field work has focused on the transport and stocking of 10-20 g rainbow trout fingerling from the hatchery and the transfer of wild adult brown trout spawners from Liawenee Canal (Great Lake), Hydro Creek (Arthurs Lake), Mountain Creek (Lake Sorell), as well as rainbow trout grown at the Salmon Ponds and domestic Atlantic salmon from SALTAS (Wayatinah).

Also in June, Springfield Hatchery personnel assisted the IFS in its genetic modification of brown trout eggs to create triploid fish. Springfield lent its triploid vessel to the Service and delivered it to Liawenee for the day’s processing. Approximately 200,000 eggs were harvested from the bottom trap at Liawneee Canal and processed in the triploiding vessel under precise methodology (manipulating the pressure exerted for a set time on the newly fertilised eggs). The pressure-treated fertilised eggs, which were then transferred back to the New Norfolk hatchery and placed in the incubator up-wellers, are expected to hatch around mid July.

Rainbow trout fingerling, grown from wild stock at the hatchery, were stocked into a number of waters being developed as rainbow trout fisheries. Great Lake received its final rainbow fingerling stocking with 10,000 released at the start of the month, adding to the total of 100,000 for the year, and Lake Echo received a total of 40,000 fingerling over four stockings during June with another 60,000 still to come. Tooms Lake and Four Springs Lake each received 10,000 fingerling at 10 g. Improved weather and lower flows allowed the remaining 5,000 fin clipped browns to be transferred to the Break O’ Day River.

Adult browns from the Liawenee trap were sexed, weighed and measured to gain information on the annual average condition of fish in the spawning run. Of these fish, 1000 were transferred into Four Springs Lake, 300 went to Tooms Lake, and 50 went into Camerons Lagoon.

Other adult transfers included an additional 320 Arthurs Lake brown trout which were released into Tooms Lake and 370 browns from Lake Sorell which were transferred into Lake Dulverton. In addition, 550 Atlantic salmon from Saltas, weighing around 2 kg were released into Lake Barrington on the last day of the month. Craigbourne Dam also received 6,100 domestic diploid rainbows grown to about 100 g at the Salmon Ponds in two separate stockings during the month.

For a summary of the latest stockings, click here to download a Stocking Table for the month of June (pdf).