The Cayuga Fisher

Jigging for Lake Trout:  Behavior:  Life History

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Life History:  (A short summary)

Lake Trout eggs are laid on rocky or cobble bottoms, and depending on local conditions, in water 10 to 120 feet deep or more.  The wide range of spawning depths is generally due to climate and available habitat- in some marginal lake trout fisheries, deep water is covered with weeds and mud, leaving lake trout to crowd the shoreline in search of wave-swept gravel to spawn upon.  Water temperature plays a role as well, in Northern lakes lake trout can be found in relatively shallow water year-round.  In the Finger Lakes, lakers spawn at a variety of depths, depending on lake structure, and at slightly different times of the year.  Spawning grounds on Cayuga Lake are in the 90 fow range, while closer to 30 feet on some of the smaller lakes.

These eggs are laid from September through November on the preffered cobblestone lake bed, and filter down through cracks out of harms way.  The importance of a clean, mud free bottom is evident here- eggs laid on mud are susceptible to coverage and predation.  The large gravel or cobble bottom allows safety and water circulation for the spawn. After hatching the following spring, lake trout fry disappear!  Seriously, I don't know what they do... but in the Finger Lakes there is a problem with EMS, or Early Mortality Syndrome (aka the Cayuga Syndrome).  90-100% of lake trout and other salmonid fry die soon after hatching.  The problem has been linked to a thiamine deficiency caused by the Alewive, Alosa pseudoharengus- the primary food source of lake trout.

The Lake Trout young spend the next several years surviving.  Small lake trout feed on benthic zooplankton and crustaceans, with Mysis freshwater shrimp being a large portion of their diet.  Lake trout smaller than 10" are not often caught by fishermen in the Finger Lakes.  The smallest I've seen was around 13 inches. Updated: 9-10"!  Once the lakers reach 3-5 years old they become interested in baitfish and attract our interest as catchable fish.

In the majority of the Finger Lakes, the Alewife, or Sawbelly, is the main forage for all salmonids, including lake trout.  These fish, a relatively recent (past 70-100 years and a matter of debate) introduction to the ecosystem, form massive schools that nomadically travel the lakes.  It has been estimated that the alewife accounts for 90% of the biomass in Cayuga Lake!  This species only grows to about 7-9" in these waters, so that's millions of baitfish just waiting to be eaten by hungry lake trout... which follow the bait around the lake in droves.  Understand the movements of the alewifes, and you will be able to find lake trout at any time of the year.

The alewives themselves follow their own food supply- Mysis shrimp and other small organisms.  The shrimp follow a daily cycle- at night, they rise through the water column (sometimes as much as several hundred feet or more) to feed on the phytoplankton that grows in the sunlit layer of water.  As dawn approaches and day begins, the Mysis descend back into the depths for safety.  The alewives follow this food source, and exhibit the same pattern of behavior.  At night they school at the surface, feeding or spawning, and head for deeper water as the sun rises.  While lake trout rarely come to the surface in the Finger Lakes, as the alewive do, at dawn they can be found in relatively shallow water, depending on the time of year.  The best time to find lake trout near the surface is in late Spring (as the lake begins to stratify), and again in late Fall or early Winter as the lake turns over.  However, by late fall the alewive has moved offshore into the depths. In winter the alewife is found from 150-240 feet or so, deeper than the summertime, where they inhabit 60-150 feet of water, shallower during spawning activity.

Lake Trout can grow to great sizes, but rarely reach 20 pounds in the Finger Lakes area.  Even in the Great Lakes, fish over 30 pounds are rare these days, and a 20 pound laker is a nice fish.  With large size comes old age- many trophy lake trout are 20 years old or more, and some behemoths have been an estimated forty years old!  One interesting fact to note is that lake trout size is partially dependent on baitfish size.  The relatively small alewife effectively caps growth and size rates for lakers, as the fish's ratio of energy-expended to food-gained reaches a balance point.  Lake trout in the finger lakes historically fed on whitefish and cisco, now exterminated or nearly so in most New York waters.  Lakers grew fat and happy with these food sources, growing to 40 pounds and more in Cayuga Lake.

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