tmag

While it may be true that environments will continue to change, when the changes are brought about through human activities which includes invasive species the problem is that the changes happen so quickly that the environment can't respond fast enough. With zebra & quagga mussels, they cleared the water. This led to a much deeper weed line. This favored some warm water species. Interestingly, walleyes, which tend to lay their eggs along rocky shoals, have apparently benefited from zebra mussels in that some of the eggs get down in between the mussels. Go figure. Similarly, more weeds & clearer water was advantageous for pike which whose eggs have a natural adhesive that cling to the weeds. The mussels out-competed smelt which have disappeared. But the smelt were introduced anyway albeit delicious and a great prey source for the trout fishery. I believe that alewife were introduced as well. Rainbow trout, brown trout, and salmon are all introduced species. Personally, I think alligator gar, Argentine golden dorado, goliath tiger fish, wels catfish, and payara would all be fabulous introductions

I will respond separately to the muskies of the St. Lawrence also mentioned above: https://www.newyorkupstate.com/outdoors/2021/09/alarming-muskie-decline-in-the-st-lawrence-river-invasive-fish-species-could-be-contributing.html https://www.outdoorlife.com/fishing/st-lawrence-muskies-in-trouble/ https://ottawacitizen.com/news/local-news/st-lawrence-musky-population-threatened-by-invasive-gobies some good news: https://www.nny360.com/news/jeffersoncounty/battling-muskie-decline-researchers-release-tens-of-thousands-of-young-fish-into-st-lawrence-river/article_f7becb63-3419-5c86-8646-6ba890ec1de7.html https://www.savetheriver.org/latest-news/a-win-for-st-lawrence-river-muskie-spawning-habitat/ Nonetheless, invasive species have put tremendous pressure on NY / Great Lakes fisheries.

Some years back, I know there was a fungus affecting the smallmouth in the Susquehanna. Further upstream on the Chemung and Tioga, the DEC told me that there were a lot of fish but few of any size. They weren't sure why. Meanwhile, in the late 80s / early 90s, PA stock millions of walleye fry in the reservoir(s) near the PA border. They did not take. So, PA stopped stocking. Some local fishermen began to blame the muskies: "They're eatin' everything!" The reality is, many of these guys, fishing small rivers, would repeatedly limit out; even bragging how they had bagged over a hundred walleye in a season. Nonetheless, PA told me that after PA stocked stocking fry and fingerlings, fishermen downstream would probably notice this. Back/earlier issues affecting the Susqy and note the reference to climate change, too: https://pfbc.pa.gov/images/reports/2013bio/gsSusqR_smb_2010.pdf https://www.pennlive.com/opinion/2013/06/the_susquehanna_river_-_too_big_to_ail_editorial.html https://www.usgs.gov/programs/environmental-health-program/science/new-virus-identified-melanistic-skin-lesions https://www.ydr.com/in-depth/news/2021/02/03/3-iconic-susquehanna-river-aquatic-species-struggle-survive/5853999002/ https://apnews.com/general-news-b58ca60d6e1f41c49cbbb7a1a4172dd9 https://afspubs.onlinelibrary.wiley.com/doi/10.1002/fsh.10491