Brake trout at FES

Brake trout are a cross between a brown trout female and a lake trout male. The brown trout come from the Egan Hatchery and are spawned with lake trout from Fish Lake. These hybrids are being used for various studies by the research section at FES to determine their resistance to whirling disease. In an earlier study, we found that the brake trout do get whirling disease, but they are more resistant than rainbow trout.

One of the problems with the brake trout is the difficulty of culturing them. We have had poor eye-ups and hatch rates. There also appears to be some cannibalism going on when the fry are about 700 fish/pound to about 200 fish/pound. Keeping fish at very low densities does not seem to solve this problem.

The first group of brake trout were spawned October 26, 1993 and eggs were eyed at the Fish Lake hatchery building. Eggs were then transferred to FES to be hatched and raised for future stocking into whirling disease infected waters. Eggs were heat shocked for triploidy. Hybrid eggs that were heat shocked tend to have higher hatch rates and survive better after stocking. Adult males and females were checked for viable gametes and they are sterile. In November of 1994, brake trout and reciprocal brake trout were spawned. These were not heat shocked. Hatch rates were much worse in these groups compared to the eggs that were heat shocked in 1993. In November of 1995 eggs were taken again, but this time all eggs were heat shocked. Fish were stocked at approximately 3 inches into Mill Meadow Res and Porcupine Res.

Lot	Eggs received	Percent hatch	Percent on feed	Percent stocked
Brake 1993	56,052	30.03	7.40	4.14
Brake 1994	96,938	3.56	0.87	0.07
Reciprocals 1994	74,561	17.39	0.20	0.08
Brake 1995	233,204	27.31	9.39	3.17
Brake 1996	256,242	39.12	24.92	6.49

Notes: The brake trout program in Utah will not continue. We determined that the returns are not worth the effort to raise these fish. The few brake trout that have been stocked can be found in Porcupine and Mill Meadow Reservoirs. All brake trout at the FES were stocked out during the summer of 1997.