In the case of Seneca Lake, the Department of Environmental Conservation has some 40 years of history and biological data garnered from the National Lake Trout Derby, held each year over the Memorial Day Weekend.
Biologists and technicians are present at the three weigh stations (Geneva, Sampson State Park and Watkins Glen), inspecting each fish and recording length, weight, fin clips, lamprey scar numbers and in some cases, scale samples for later analysis.
"We couldn't afford to gain this much data on our own," said DEC Senior Biologist David Kosowski.
The event provides a significant overview of the health of the fishery in just three days and allows the examination of more than 1,500 trout and salmon, taken by more than 2,000 anglers in search of their portion of the $29,325 in cash prizes.
Lake trout make up the largest number of entries and the bulk of the data, but in recent years, with the expansion of the contest to include brown trout, rainbow trout and landlocked salmon, the biologists gain a full spectrum of knowledge of the coldwater fisheries in Seneca Lake.
DEC encourages anglers to bring to scale any legal fish caught during the derby rather than practice catch and release. In fact, the management plan for Seneca calls for a reduction in stocking of game fish in order to protect the forage base.
With the arrival of the zebra mussel, the ecology of the lake has been changed. Smelt, for example, which only a few years ago were a major part of the forage base and a significant spring sport fishery for anglers who dip netted the tasty critters in the local streams, are all but extinct.
The competition for plankton was too great from the exotic mussel for the smelt to survive.
There has been a steady decline in the average size of the trout and salmon as the forage base was stressed.
There has also been an increase in the natural reproduction of lake trout in Seneca Lake.
The deep-water colonies of zebra mussels have made ideal spawning grounds for lake trout.
Many of the traditional spawning gravel beds had been covered with silt, and Seneca's wealth of lake trout previously depended on help from hatcheries using eggs and sperm collected in fall netting operations.
Stocking has been reduced to a rate of 20,000 yearlings and 40,000 fingerlings annually.
All stocked lake trout are now fin-clipped to better evaluate the natural reproduction.
Increased wounding rates by sea lamprey are also contributing to the depressed growth rates of lake trout.
The improved water clarity helps these sight-feeding lamprey find their prey.
'Still one of the best'
If all this sounds like a warning to steer you away from Seneca Lake, think again. It is still one of the best coldwater fisheries in the state.
Day in and day out, the folks who fish Seneca have reported in their fishing diaries for the 2004 season they caught lake trout which averaged 3.2 pounds and that it took only 1.4 hours of angling effort to catch a legal salmonid.
Every year lake trout are caught that weigh in the double figures.
The largest lake trout to win the Lake Trout Derby was 17 pounds, 13 ounces. But consistently, a winning fish must be more than 10 pounds.
Since the rules have been expanded to allow any of the four species to be a winner, three brown trout have taken the top money, including a brown of 17.36 pounds that was taken in 1998.
Trolling for trout and salmon is perhaps the most popular of the fishing methods and has been responsible for the majority of the derby's winning fish.
The secret to success for lake trout is to find 44-degree water where it meets the bottom of the lake and put your lures in this zone. Or, if a thermocline layer has formed as the water warms, fish at or just below this separation of the cold bottom layers of water from the upper layers of warm water.
The thermocline is an abrupt change in water temperature of at least 4 degrees in a span of 3 feet of water column. You can also see this on a graph depth recorder if you turn up the gain.
A dirt or scum line will show on the screen, which is the trapped plankton, which in turn attracts baitfish that attract game fish.
For browns, rainbows and salmon the winning temperature is 55-degree water. Work the shallows in the early morning hours before the light is too intense.
Unlike lake trout trolling speed, which is normally 1.5 to 2 mph, the other species are more likely to take a lure or bait trolled at a faster speed, say 2.5 to even 3 mph.
Still-fishing with live alewives, or sawbellies as they are called locally, is also productive. Your rig includes a slip or barrel sinker and an English bait hook.
The trout or salmon will run with the bait when it first picks it up and before it swallows it. Thus, you need a friction-free system to include an open bail on your spinning reel.
Set the hook on the second run. Productive depths for still-fishing at this time of year will range from 20 feet to 90 feet of water.
Previous winners of the derby have come from all sections of the lake and by anglers using every fishing method possible.
If you are totally confused, fish the default level of 90 feet of water, trolling just above the bottom or using live bait or white jigs while still-fishing.
Public access to the 40-mile-long lake is superior. Starting at Geneva you have a free double launch and docking. Just off the Seneca River/Barge Canal from Seneca is Seneca Lake State Park with both a launch, temporary and seasonal docking.
Head south 14 miles along the east side of the lake on Route 96A and you will come to Sampson State Park, which includes a 128-slip marina, four-lane launch, 245 electric service campsites, beach, comfort stations and more.
This is also centered on some of the best deep-water fishing in the lake.
Continue south about 13 more miles and you have Lodi Point Marine Park followed by Smith Park at Hector.
Smith has a steep entry road, however, and is suitable only for small boats.
At Watkins Glen, Clute Park has a double hard ramp on the canal portion of Catharine Creek.
The west side has more limited access. Severne Point, about 12 miles north of Watkins Glen, is the only public facility on that side of the lake.
There are several private marinas, however, on the west side that will service your needs.
Material from Fishing & Hunting News
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