Lake Trout Sampling

Posted by Wayne G. Barber

This fall, our fisheries staff are sampling Quabbin and Wachusett Reservoirs in an ongoing effort to monitor Lake Trout populations. This 13 lb. female LakeTrout was captured, tagged, and released last night at Quabbin.

This fall, MassWildlife will be sampling the waters of the Quabbin and Wachusett Reservoirs in an ongoing effort to monitor Lake Trout populations. Each year, with the help of DCR, MassWildlife collects Lake Trout from the Quabbin Reservoir to examine population characteristics. This year, MassWildlife will be conducting a similar effort on the Wachusett Reservoir. To capture Lake Trout, field crews set nets on the spawning grounds starting around sunset and check them about every 20 minutes. Captured fish are removed from the nets, placed in livewells, and length, weight, and sex are recorded. In addition, a small tag is inserted into the fish that can be used to identify the individual if caught at a later date. If that same fish is collected next year, biologists will know exactly how much growth occurred in a one-year time period. Lake trout are very slow-growing fish and traditional methods of determining age, (i.e. reading the rings on scales) do not work well.
Lake Trout typically spawn in late October and November when the surface water temperatures drop to or below 50˚ F. The spawning grounds are typically shallow, rocky waters on windy shores of the Reservoirs; spawning occurs mostly after dusk. Night sampling on big waters can be cold and icy in November, but the information it provides biologists is well worth the effort. Sampling efforts like this are just one way that MassWildlife monitors the health of the fish resources of the Commonwealth.