|
The health of stocked rainbow trout is yet another testament to the amazing recovery of Diamond Lake. The growth rate of trout was phenomenal for 2007 and 2008 – fingerlings stocked in mid-June reached 11 inches by October.
Leading up to the Sept. 2006 rotenone treatment, both the growth rate of legal-sized trout and survival rate of stocked fingerlings was nearly zero. The estimated 95 million tui chub in Diamond Lake effectively out-competed trout for zooplankton and benthic invertebrate food sources. With a lake now free of tui chub, stocked fingerling trout grew an average of nearly two inches per month during the summers of 2007 and 2008.
To create a fish health index, biologists weigh and measure fish from snout to the fork in their tail fin. The Condition Factor (k) is a relationship between the fork length in centimeters and weight in grams of the fish where K=(100(W)) / (L^3)
See a graph of historic fish health (pdf) at Diamond Lake.
 |
 |
| ODFW employees pull a trap net on Oct. 31, 2007. Trout stocked earlier in the summer as fingerlings were measured and weighed to calculate fish condition. Trout over 14 inches were released. |
ODFW employee releases a healthy 16-inch rainbow trout during the trap netting operation. |
 |
| 100,000 fingerlings were stocked in Diamond Lake on June 12, 2007 |
|
