1. Initial Assessment of Habitat Use by Stocked Lake Sturgeon in the Genesee River D. E. DITTMAN 1 and E. C. ZOLLWEG 2 1 Tunison Laboratory of Aquatic Science, Great Lakes Science Center, U.S. Geological Survey, Cortland, NY 13045. 2 Lower Great Lakes Fishery Resources Office, U.S. Fish and Wildlife Service, 405 North French Road, Suite 120A, Amherst, NY 14228. ABSTRACT NEXT STEPS Benthic Invertebrate Community The benthic invertebrate community example for the successful recapture site 1. LITERATURE CITED INTRODUCTION Lake sturgeon (Acipenser fulvescens) is a threatened species in New York State (Carlson 1995). Historically one of the sturgeon waters of New York was the Genesee River, which flows through Rochester NY into Lake Ontario. River has had its water quality improve significantly in the past 20 years (Elliot 19970. Successful management of threatened species requires an extensive assessment and the evaluation of the availability and quality of physical and biotic habitats for all life stages of the species of concern over multiple years (Busch and Lary 1996, Threader et al. 1998). One often successful technique is the experimental evaluation of habitat use by hatchery reared fish. We present here the initial data from an experimental stocking in the Genesee River. Busch, W.D.N. and S.J. Lary. 1996. Assessment of habitat impairments impacting the aquatic resources of Lake Ontario. Can. J. Fish. Aquat. Sci. 53(Suppl.1):113-120. Carlson, D.M. 1995. Lake sturgeon waters and fisheries in New York State. J. Great Lakes Res. 21:35-41. Elliott, R.S. 1997. Monroe County Environmental Report Card.. Division of Environmental Health, Monroe County Department of Health. Rochester NY. Threader, R.W., R. J. Pope, and P.R.H. Schaap. 1998. Development of a habitat suitability index model for lake sturgeon (Acipenser fulvescens). Ontario Hydro Report No. H- 07015.01--0012 Thanks for invaluable assistance with field work and laboratory work and analysis go to D. Carlson, B. Darris, K. Douglas, M. Goehle, S. Hanna, A. McCarthy, D. McDonald, P. Randall, T. Wallbridge, M. Weimer, W. Pearsall, and NYSDEC field and hatchery personnel. OBJECTIVES: 1. Assessment of Genesee River habitat use by stocked Lake Sturgeon. 2.Assessment of physical and biotic habitat parameters in the areas of stocked sturgeon recapture. RESULTS: Recapture of Stocked Sturgeon METHODS Environmental Measures : Water flow, depth, temperature, and substrate characteristics were recorded at sturgeon capture sites. Data on the benthic macroinvertebrate community were collected using a Ponar grab and standard benthic invertebrate sorting and identification techniques. Sturgeon Stocking: Lake sturgeon were reared in the New York State Department of Environmental Conservation Oneida hatchery. 900 were stocked into the Genesee on September 23, 2004. The site was km 9.1. This is a sandy/silty site, < 1m deep, out of the main flow of the river, just downstream of Seth Green Island. 1. Complete netting assessment of the stocked lake sturgeon through the 2004 field season 2. Continued measurement and analysis of stocked sturgeon habitat use in the Genesee. Figure 4: Experimental sturgeon stocking section of the Genesee River. Area is from just upstream of the Lower Falls, at km 10, north to the harbor area and Lake Ontario The benthic invertebrate community example at the second successful recapture site. Lake sturgeon (Acipenser fulvescens) is a native fish species that is a species of concern across the Great Lakes Region. Federal, state, and native American fisheries managers have identified lake sturgeon as a key target species for recovery and restoration in the Lake Ontario - St. Lawrence River system. One management tool is the experimental stocking of hatchery-reared fish into areas where the original populations have been extirpated. The Genesee River is one of the major tributaries to Lake Ontario and part of the Rochester Embayment Area of Concern. In September 2003, 900 juvenile lake sturgeon were stocked into the Genesee River, NY at river kilometer 9.1. These sturgeon had an average length of 180 mm with a range of 85 to 220mm. An assessment using standardized gill netting from river km 3 to 9 was conducted with experimental gill nets, 125’ long with 5 panels of bar mesh sizes 1” to 3”. Nine juveniles were recaptured during the Fall 2003 assessment. All were tangled in the 1” mesh. Eight of these fish were captured at river km 8.2 and remaining one was captured at river km 6. Five were captured at site 1 during the last week of this assessment (11/04 to 11/06). The first successful recapture site is the first relatively deep area downstream of the release site. It averages over 6 m and has a gravelly substrate. The second successful capture site is the deepest area of the river at 9 to 10m also with a gravelly, rocky substrate. Assessment of the use of Genesee River habitats by the stocked juvenile lake sturgeon will continue through 2004. Results of this research in the Genesee River will provide information needed for future steps in the restoration and enhancement of lake sturgeon in Lake Ontario and its tributaries. Sturgeon Assessment: We conducted systematic gill netting from km 9 to km 3 using experimental nets with 25’ panels of 1” to 3” bar mesh. Fig. 2 Sturgeon Stocking Loading up! Figure 3. Stocking Site. River km 9.1. Just downstream of Seth Green Island. Successful capture site 1, river km 8.2. East side of the river just downstream of the Rt.104 Bridge Successful capture site 2, river km 6. West side of river. The deepest spot in the target assessment area. Other Catches: Zebra mussels Site 2 Figure 1. Size and weights of a 100 fish subsample, 4 days before stocking. Average length was 180 mm. !Nine sturgeon were recaptured Fall of 2003! Figure 5. Sizes of the 4 sturgeon recaptured in the first month of the assessment compared to stocked size distribution September 25 th capture Figure 6. Lengths of sturgeon captured the first week of November compared to the original length distribution 11/06/03 10/08/03 November 5 th at Site 1.