Year Two of Lake Hopatcong Trout Study

Alan Tuorinski holding an 18" brown trout caught from his dock in Mt. Arlington on October 9, 2022. The fish was quickly released back into Lake Hopatcong.
Alan Tuorinski holding an 18" brown trout caught from his dock in Mt. Arlington on October 9, 2022. The fish was quickly released back into Lake Hopatcong. Photo By: Linda Tuorinski

By: Tim Clancy

LAKE HOPATCONG, N.J. (3/6/2022)

The planned three-year trout study being conducted by The Lake Hopatcong Commission in conjunction with The Lake Hopatcong Foundation and The Knee Deep Club that began at Lake Hopatcong last spring has entered its second year. The goal of the study is to track and document holdover trout habitat through tag returns and more rigorous water quality studies than have ever been conducted at New Jersey’s largest lake. Instead of the typical monthly water quality sampling that has been done for nearly 40 years, during the summer months of the trout study, water quality monitoring will be conducted on a weekly basis. Also, the water conditions of the many streams entering the lake will be studied. Funding for the initial studies, conducted by lake environmental consultants Princeton Hydro, is largely funded through a grant from the New Jersey Highlands Council in partnership with Jefferson Township. The trout study group is hopeful it will be able to secure additional funding for these more frequent water quality studies, especially in light of the harsh temperatures and limited rainfall that occurred in both July and August of last year.


According to Fred Lubnow Ph.D., Senior Technical Director at Princeton Hydro, “some interesting results were already obtained during the first year of this high-frequency water quality monitoring over the summer season. First, it was assumed that carry-over trout habitat temporarily disappears and then reappears during particularly dry and hot conditions. However, the more frequent monitoring in 2022 revealed that this carry-over habitat can fluctuate over a period of weeks or even days.” Dr. Lubnow said, “In other words, it doesn’t just disappear in the late summer and reappear as conditions cool down in the fall. Second, very little near-shore refuge from elevated water temperatures was identified for the trout. The 2022 late summer season was particularly dry and hot, so it is unknown if these observations are typical and a result of climate change or if these conditions are more of an outlier. Thus, additional monitoring is needed to address this question.”


In addition to the water quality monitoring, one thousand tagged brown trout between 12” and 14” will be stocked each of the three years. Brown trout are being studied because they are the most tolerant of warmer water conditions than all other trout species. The larger-sized trout were chosen because scientific studies have shown they are more resilient in the warmer temperatures that can occur during the summer months at Lake Hopatcong. Last year’s fish bore blue tags, and 2023 stocked fish will have silver/metallic colored tags affixed to their jaws. The cost of the tagged trout is shared equally among the three partner organizations. Anglers are encouraged to report any tagged trout at and to try to include a photo of the fish if possible. Written forms can also be filled out at both Dows Boat Rental, 145 Nolans Point Rd. Lake Hopatcong and Lake’s End Marina, 91 Mt. Arlington Blvd. Landing. Also, a QR code that will take you directly to the reporting website can be found on dozens of signs placed at prominent locations around the lake.


Last year’s tag returns were much fewer than the trout group had anticipated. Between April and July, only 15 tagged trout were reported. One issue may have been that this is the first time tags have been used at Lake Hopatcong in almost 20 years, and anglers may not have been aware. When asked about the tag returns, KDC President John Moran stated, “in the early season, trout fishing was off from previous years, largely because of the very cool water.” John, who has fished at Lake Hopatcong for decades, went on “that many fishermen were simply unaware of the ongoing study; hopefully, over the past year, this information has fully circulated amongst the lake’s fishermen.”


While none of the tagged trout have yet been reported after the unusually warm summer, Alan Tuorinski of Mt. Arlington reported a nice 18” brown trout he caught right off his dock in Mt. Arlington on October 9. That is a sign that even with the extreme summer conditions, some trout absolutely survived.


Lake Hopatcong Commissioner Dan McCarthy, who also serves as the Trout Committee Chairman, stated, “while these first-year returns were less than expected, it’s if those 2022 blue tags get reported in 2023 and beyond that would be very important. Last year’s water quality data was not ideal for the trout, so we’ll be looking to see how well they did, but this project, which represents a joint effort by three prominent lake groups, is something we may want to strive for in future lake projects.”


It is hoped that anglers will release all tagged trout to continue as part of the study. There are an additional 10,000 trout stocked each spring in the lake by New Jersey Fish and Wildlife and the Knee Deep Club that can be kept without impacting the study results. All anglers who report their tagged trout will be eligible for one of five $100 Visa Gift cards generously donated by for each of the three years of the trout study. At the February meeting of the Lake Hopatcong Commission, the five winners from 2022 tag returns were drawn, and they include Les Barbire of Rutherford, Kevin Cool of Flanders, Lou Marcucci of Mt. Arlington, Jim Salerno of Hopatcong, and Bob Smith of Oxford.


This year’s stocking is scheduled for 9:30 AM on March 26 out of Dows Boat Rental. The public is invited to attend and help load the fish onto boats that will float stock them around the lake. Check the site for any schedule changes.