Fisheries biologists Don Miller and John Viar have been out many nights sampling forage fish populations in the Lakes Region on the research vessel Forager. They are finding lots of smelt in Winnepesaukee this year, which is good news for anglers!
We have a few last slots left in the intermediate fly-fishing weekend for women coming up September 28 - 30 at Purity Spring Resort in Madison, N.H. Some fly-fishing experience is required. Applications at www.nhbow.com or call (603) 271-3212.
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THE KEY TO NEW HAMPSHIRE'S LARGE-LAKE FISHERIES by John A. Viar, Region 2 Fisheries Biologist
When you're fixed on hooking big fish, it's easy to forget about the small ones. The really small fish -- forage fish smaller than your pinky -- are surprisingly important. Without rainbow smelt, managing salmonids (landlocked salmon, lake and rainbow trout) in our large lakes would be difficult, if not impossible. Although lake and rainbow trout will prey on a variety of food items, salmon ultimately depend on a thriving population of smelt. The growth rate and body condition of our large-lake salmonids is highly proportionate to the abundance of smelt.
Successful anglers on New Hampshire's large lakes like Winnipesaukee have reported most activity from 30-50 feet. There's a good reason for that. Experienced anglers know this band of water represents the thermocline, a layer of quickly descending water temperatures sandwiched between warmer surface and colder bottom water -- a key to consistently finding mid- to late-summer salmonid action.
A Balancing Act
Smelt populations are extremely difficult to manage. A variety of natural factors such as spring precipitation and nutrient levels can affect year-class strength and overall abundance. Young-of-the-year/age-0 smelt (born this spring, about 1.5-2 inches long right now) account for the bulk of most New Hampshire smelt populations. Their availability is critical, since salmon, particularly age-1 fish stocked earlier in the year, need them for rapid growth. Another important pelagic (open water) forage fish in New Hampshire's large lakes is juvenile white perch, which are also readily gobbled up by salmonids.
Balancing this predator/prey relationship is imperative -- which is why we need an estimate of forage fish abundance in order to stock appropriate numbers of salmon. If too many salmon are stocked, forage is decimated and salmon growth and body condition suffers greatly. When smelt populations are healthy and stable, the typical stocking rate is about 0.5 salmon per acre of surface water. In Winnipesaukee, for example, this translates to about 22,000 yearling salmon stocked each spring - again, ultimately dependent upon forage fish resources.
Welcome Aboard
The tool for the job is called the Forager, a converted 22-foot Eastern lobster boat that has been set up to survey our large-lake forage-fish populations. The boat cruises along transect lines while a sophisticated hydroacoustic unit (sonar "fish-finder") counts the number and size of fish targets. This tells us how many forage fish there are. But to verify the species and condition, we use a large trawl net designed to catch small young-of-the-year fish. As you may expect, most fish caught are smelt, but we also catch young-of-the-year white and yellow perch. Although we trawl slowly, and bigger fish are able to avoid the net for the most part, occasionally we catch adult smelt and the odd lake trout or salmon.
All work is done at night, when smelt move into the thermocline to feed on zooplankton (tiny animals). Most smelt hold near bottom during the brightest daylight hours to try to avoid predation by salmonids (smelt are sitting ducks high in the water column). This explains why dusk and particularly dawn are usually the best fishing times. Salmonids are primarily sight feeders, so limited feeding occurs at night. By dawn, they're voracious and ready for a hearty breakfast. The first traces of daylight let them hunt effectively, slashing upward (most predatory fish prefer to feed upward, since their prey has a blind spot directly beneath them) into schools of smelt, which are just beginning to descend to the bottom, after their night of feeding.
To date, we have completed sampling on Newfound Lake and are about halfway done on Lake Winnipesaukee. At Winnipesaukee in particular, age-0 smelt appear to be in excellent abundance. In the next several weeks, we'll also survey Big Squam, Winnisquam and Sunapee.
For more information on New Hampshire's large-lake fisheries management, feel free to contact Fish and Game's Region 2 Fisheries Biologists John A. Viar at jviar@nhfgd.org or Donald R. Miller at dmiller@nhfgd.org.
ANGLERS - HELP STOP THE SPREAD OF "ROCK SNOT"
If you're fishing New Hampshire's rivers, keep a sharp eye out for the aquatic nuisance algae known as "Didymo" or "rock snot." This nasty invader has been discovered in the northern reaches of the Connecticut River and potentially is on the move in New Hampshire. Dydimo can infest new areas by even just one cell of the alga breaking off and drifting downstream. It is very easily spread by waders, fishing gear, paddles and any equipment that touches the bottoms of streams in infested areas, so it is critical to check and clean your fishing gear. Do your part to protect New Hampshire's waters.
If you observe Didymo in New Hampshire, contact Amy Smagula at the N.H. Department of Environmental Services: 603-271-2248 or asmagula@des.state.nh.us.
REMINDER FOR LAKE WINNIPESAUKEE BASS ANGLERS:
N.H. Fish and Game continues to count on help from anglers for an ongoing study of the movement of largemouth and smallmouth bass after bass tournament release. Angler captures of tagged bass are the major source of information for this study. Bass are being tagged upon release from tournament weigh-ins at Ames Farm Inn on Lake Winnipesaukee, identified with a numbered yellow tag at the base of the fish's dorsal fin. IF YOU CATCH A TAGGED BASS - PLEASE DO NOT REMOVE THE TAG!!
Bass Movement Study contact: Gabe Gries, Fish and Game Warmwater Fisheries Project Leader: NHFG Region 4, 15 Ash Brook Court, Keene, NH 03431; phone 603-352-9669; fax 603-352-8798; or email ggries@nhfgd.org.
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