Reports of poor fishing success and low fish populations on Seneca Lake prompted an inquiry to the NYS DEC in early June. Brad Hammers, the DEC fish biologist responsible for the Finger Lakes responded:
June 6, 2017
Thanks for your report from Seneca Lake. Sorry you have been having poor fishing experiences. We have been hearing similar issues from other anglers. Results from this years’ derby tended to correspond with angler reports of poor fishing as many anglers indicated it was tough fishing. During last years’ derby conditions were similar, however the fish that were brought in were some of the largest on record for the derby since it began. We were expecting to see similar results. Not many fish but large ones. We are not sure why that did not occur. We did hear from many anglers they were marking a lot of bait and fish around the bait, but had difficulty getting them to strike. Data from 2000 – 2012 indicated an overabundant lake trout population, low forage abundance and extremely high catch rates. However, based on angler comments and trends in the last few years of trout catches in the angler diary program, trout and/or forage abundance may have started to change.
Several possibilities exist to explain lower catch rates experienced by some anglers including, potential increase in forage (alewife) abundance (i.e. more natural baitfish less likely to strike a lure), changes in distribution as a result of the recent weather patterns, recently enacted regulations to reduce the lake trout population or shifts in habitat preferences/areas of the lake due to zebra and quagga mussel effects on the lake. Also, although we were able to perform a couple of lamprey treatments the past couple years, our timing was delayed due to high water events and we may have missed a large segment of the population. Hence possibly a high number escaped into the lake before we could get them. These adult lamprey will remain in the water for up to 1.5 years until they head up into the tributaries to spawn. They can have a very negative effect on primarily trout and salmon. Our next treatment is scheduled for Spring 2018. Also, fish populations fluctuate all of the time and the population may just be in a low cycle. In addition, there could potentially be a drop in natural recruitment if lake trout are eating more alewives which contain an enzyme thiaminase which can negatively impact trout survival. Or it is likely a combination of several factors. We may never know for sure, but we should be able to find out a little more during our next netting survey scheduled for this coming summer. We are also going to be conducting an experiment looking at a few types of gear to assess forage on the Finger Lakes and Seneca is the first one we anticipate working on. Hopefully by the end of the summer we will have a few more answers.
Water quality is constantly being monitored in Seneca Lake by a variety of organizations. We have not been able to identify any specific concern relating to runoff, pesticides/herbicides, etc. that would relate to the decrease in fishing quality. We do know that zebra and quagga mussels have significantly altered the food chain as well as water quality parameters. We have also heard of a few fish kills after the fact and have not been able to collect any fresh samples to send to Cornell for diagnosis. There may be some virus/disease issues that are having impacts, but to date, fish we have collected in routine sampling have tested negative for anything specific. If we can get fish in the midst of a die-off that would greatly increase our chances of determining if that may be a cause.
Seneca Lake is a large complex system with a lot variables that influence fish population characteristics. Just when we think we know what is going on, something changes that can effect everything. It could be something under our control such as stocking or regulations or usually something completely out of our control such as weather or invasive species.
If you have any other questions or concerns, please let me know. Again, we should have a few more answers, at least pertaining to trout and forage base at the end of the summer.
SLPWA and the NYS DEC rely on observations and reports from Seneca Lake community to help document the extent, frequency and location of water quality issues. If you observe a fish kill or have another other water quality concern, please document your observations by taking photographs and then visit the SLPWA website and submit a Water Quality Concern report.