MA Conducting Lake Trout Survey in Quabbin & Wachusett Reservoirs
December 7, 2017
Each year, with the help of the MA Division of Conservation and Recreation, MassWildlife collects lake trout from the Quabbin Reservoir to examine population characteristics. For the past few years, MassWildlife has also been sampling for Lake Trout in the Wachusett Reservoir.
To capture lake trout, field crews set nets on spawning areas starting at sunset and check them about every 20 minutes. Captured fish are removed from the nets and placed in a live well. Next, biologists record the fish’s length, weight, and sex, and implant a small Passive Integrated Tag (PIT). Prior to release, the adipose fin is clipped to provide an external mark indicating that the fish has been captured before.
Data collected provide biologists with an understanding of the current condition of lake trout populations. If fish are recaptured from previous tagging efforts, biologists can calculate individual growth rates. Lake trout are long-lived and slow-growing, and it is common for a tagged fish to be recaptured 10 years later. In fact, the longest recapture interval recorded was 24 years!
Lake ]trout typically spawn in late October and November when the surface water temperatures are around or below 50°F. The spawning grounds are typically shallow, rocky waters on windy shores; spawning occurs mostly after dusk.