Smelt and Lake Trout Natural Reproduction
NY DEC has generally seen the presence of smelt as one of the primary reasons that lake trout are not able to reproduce successfully in waters containing good numbers of both species. Smelt prefer the same water temperature as lake trout and are reportedly very adept predators of lake trout eggs and fry. My observations (as someone interested in fisheries) corroborate this theory. Lesser numbers of smelt don’t seem to impact lake trout reproduction very much, but heavy smelt populations appear to be devastating to wild lake trout production.
I attended a Trout Unlimited meeting back in 1997 (or around that time frame) and Tom Chiotti, the DEC biologist responsible for Cayuga Lake mentioned that they had found young wild-produced lake trout for the first time in the 30 plus years since he’d been working on the lake. Since the late 1990s, wild produced lake trout have generally accounted for 10% to maybe 12% of the adult fish in the population.
Seneca Lake has had some wild fluctuations in the percentages of wild fish present. According to DEC documents, Seneca Lake’s natural recruitment of lake trout was estimated at about 70% in the 1950s. By 1977 it was down to 30% wild fish. By 1980 it was down to 5%! In 1990 it jumped back up to 70%. What changed? The smelt numbers on Seneca Lake exploded during the 1970s. The smelt population declined dramatically in the late 1980s over there. By the time Cayuga Lake finally started producing wild lake trout, the smelt population had begun to decline markedly over there too.
Lake Trout naturally reproduce in all the Great Lakes except for Lake Erie. Guess which lake has the highest smelt population? Yes – it’s Lake Erie, where they are the major forage fish.
In the Finger Lakes Owasco Lake might have the highest smelt population of any of the larger lakes. There is virtually no lake trout natural reproduction there. I’ve handled one wild lake trout over on Owasco in the past 17 or 18 years. Fin-Clips are occasionally missed, but the one fish I observed had all the signs of being wild – more vivid colors, large straight fins and obviously no fin-clip. Lakes with very few smelt, like Canandaigua and Keuka (which probably has none) experience wild production of lake trout.
Hemlock Lake has a good smelt population (maybe the best for its size) and 98% of the lake trout there during the most recent lake trout assessment were stocked fish. Canadice Lake’s lake trout has good numbers of wild lakers, though the lake is still stocked with some lake trout. I’m not sure what the smelt numbers are over there.
The big news now according to my friend Mike, who was recently at a DEC meeting is that lake trout wild production has not only been detected in Lake Champlain, but it at around 58%!!! Wild lake trout were wiped out here by about 1900 according to information I found online. Alewives (which contain an enzyme “thiaminase” that can interfere with natural reproduction of various fish species) showed up in the lake back in the 1990s if my memory serves me correctly. Since alewives have appeared, the smelt population has gone way down and the lake trout fry are finally surviving past their earliest stages.
I really miss the dip net smelt fishery in Cayuga Lake, but having some natural wild-produced lake trout is a worthy trade off.