Irondequoit Bay Fish Stock Assessments 2005-2015

Abstract

Warm water fisheries assessments using standard gangs of gill nets were conducted in Irondequoit Bay in September of 2005, 2010, and 2015. In addition, a nighttime electrofishing survey was conducted in June 2009. The surveys were conducted to 1) assess the fish community; 2) determine the contribution of stocked fingerlings to the walleye (Sander vitreus) population; 3) estimate population characteristics of walleye, northern pike (Esox lucius), yellow perch (Perca flavescens), and largemouth bass (Micropterus salmoides), 4) compare fish community structure to statewide surveys; and 5) guide the development of appropriate management recommendations. From 2005 to 2015 overall gill net catch per unit effort (CPUE) increased and species dominance shifted from yellow perch to white perch (Morone americana). Walleye CPUE doubled, but the portion of legal sized fish declined during this time period. The walleye population is mainly sustained by stocked fingerlings, despite migratory spawning runs in Irondequoit Creek that could be producing fry that potentially recruit to adults. Survival and recruitment of the stocked fingerlings is good, but may be declining. Mean total lengths (TL) are above New York State (NYS) averages at all ages, and growth rates show an increasing trend. Mean TL of all walleyes declined from 2005 to 2015 because younger, smaller individuals, absent from the 2005 sample, were sampled in 2015. Walleye condition is near established standards. Even with declining survival, the fishing quality for Irondequoit Bay walleyes should be very good for several years. Northern pike relative abundance declined from 2005 to 2015. Most northern pike sampled during the period were legal size. Adult pike, while fast growing, are in below average condition in Irondequoit Bay. Yellow perch relative abundance in Irondequoit Bay remained nearly constant from 2005 to 2015. Survival of the 2004 to 2009 yellow perch year classes is generally very good. Growth and condition of yellow perch is good to fair, but showing a stable to slightly increasing trend. Competition with other species, namely very abundant white perch, may be a factor that explains fair yellow perch growth and condition in Irondequoit Bay. Yellow perch fishing in Irondequoit Bay has been outstanding in recent years. Relative abundance of white perch increased fourfold, while mean total length and relative weight declined from 2005 to 2015. This suggests that intraspecific competition due to high white perch abundance and interspecific competition with abundant yellow perch may hamper growth of both species. Rock bass (Ambloplites rupestris) and bluegill (Lepomis macrochirus) relative abundance in Irondequoit Bay appears to have been consistent, but low, from 2005 to 2015. Irondequoit Bay rock bass and bluegill exhibit good growth and are in good condition, which might be expected given the low abundance of these species. Largemouth bass relative abundance in Irondequoit Bay is average when compared to other New York State waters. The size quality is good, while growth and condition of largemouth bass is excellent in Irondequoit Bay. It is recommended that all current management actions be continued, walleye pond fingerlings be stocked every other year, the success of stocked walleye fingerlings be evaluated, and a fisheries management plan be developed for Irondequoit Bay.