Monday, August 6, 2018

Maine: Maranacook's Healthy but Vulnerable Trout/Salmon Fishery

Maranacook Lake is an 1800-acre water in Kennebec County, and is one of the jewels in the Winthrop lakes region.  Maranacook is almost like two lakes, with its northern basin that is relatively shallow and approximately 700 acres, and the 1,000 acre south basin that reaches depths of 118 feet and boasts a robust cold water fishery for salmon and brown trout.

Last fall, Region B fisheries biologists spent a number of weeks trap-netting Maranacook Lake. A trap-net, for those unfamiliar, is a stationary net intended to collect fish that are moving through shallow areas. The fall is an opportune time to use trap-nets, as most trout and salmon are in spawning mode and cruising the shoreline in search of suitable habitat and potential mates. Due to spawning habitat limitations, trout (brook & brown) and landlocked salmon stocked into Maranacook Lake are unable to spawn successfully, but that certainly doesn’t stop them from trying.

Three trap nets were deployed in early October near the outlet stream intown Winthrop, at Roseanne Brook on the western shore, and off a rocky peninsula along the eastern shore. The nets soaked for over a month and collected a whole mess of different fishes including brown trout, largemouth bass, golden shiners, white perch, white suckers, landlocked salmon, brown bullhead, and many more. While hundreds of fishes were measured, it was the salmon and brown trout that were most impressive.

In total, 94 salmon and 5 brown trout were trapped, measured, and released. The salmon were comprised of many age classes and averaged nearly 19” and 2.3-lbs. The 20 older salmon (age III+ and IV+) averaged over 21” and 3.3-lbs, with the largest individual tipping the scale at 24” and 5-lbs. The brown trout collection wasn’t as numerous, but it was equally notable. The five browns averaged nearly 20” and 2.5-lbs, with the largest measuring 26.5” and maxing out the 5.5-lb scale!

Maranacook is monitored closely since not only does it have an outstanding coldwater fishery, but it also is bordered by waters where invasive species such as pike and crappie are present. While these species are documented in Maranacook, both populations appear limited at present. For now, their scarcity means good things for the trout and salmon programs.

If you’re looking to catch trout and salmon in central Maine, Maranacook Lake is one you’ll want to put on your bucket list. The salmon are numerous and the brown trout grow large.  But, based on its close proximity to a handful of connected northern pike and black crappie waters, its trout and salmon programs are always in jeopardy. Both invasive species pose a constant threat to native salmonids in the lake. It’s a threat we take very seriously. We’ll continue to actively monitor the fishery through future nettings, frequent creel surveys, and regular correspondence with Maranacook Lake anglers.

Learn more about aquatic invasive species.