248 Macrobenthic invertebrate survey of Waneta and Lamoka Lakes, Schuyler County, September 16, 1996 and May 12, 1997 M.F. Albrigh( W.N. Harman INTRODUCTION Schuyler County encompasses 331 square miles of the Appalachian Plateau in the Finger Lakes region (Curatolo, 1991). The County's economy is largely tourism-based, relying heavily upon its aquatic natural resources. The eutrophic nature of some of these water bodies, including Waneta and Lamoka Lakes (Figure 1), has had detrimental impacts on traditional lake uses. Macrophyte growth and algal blooms have negatively impacted swimming, fishing, boating, and the perceived aesthetic qualities of theses areas. These changes are believed to have lead to a decline in both tourism and in lakeside property values (Curatolo, 1991). In order to address these concerns, Schuyler County initiated an aquatic vegetation control program in 1986 (Curatolo, 1991). This program was to serve as an integrated approach to manage the county's aquatic resources through monitoring, research, macrophyte harvesting, upland treatment, and public education. In 1990, a comprehensive study was undertaken in order to provide baseline information upon which lake management plans would be based (Curatolo, 1991). This work included a characterization ofthe physical qualities ofthe local lakes, surveys oftheir macroinvertebrate benthic populations, a description of macrophyte harvesting activities, a determination of the feasibility of conducting dredging operations in selected areas. It also addressed means of reducing nutrient inputs to these lakes. This document describes a two part benthic survey of Waneta and Lamoka Lakes, conducted 16 September 1996 and May 12 1997. The timing of these collections was to ensure documentation of temporal diversity. This database, when compared to previous work cited, and future works, will document the impacts of macrophyte management on the benthic faunal communities. The background material for this report is derived largely from Curatolo, 1991. BACKGROUND Waneta Lake (Figure 2) is 781 acres in surface area, of which over 90% is located in Schuyler County. The lake, at 1099 feet in elevation, occupies a volume of approximately 10,860 acre-feet and has about 6.8 miles of shoreline. This lake has a maximum depth of <30 feet. Approximately 450 dwellings and a Boy Scout camp line the shore. The substrate varies from silty to organic clay. Eurasian milfoil (Myriophyllum spicatum) dominated most of the shallows, 'Staff assistant, SUNY Oneonta, BFS 249 LAMOKA LAKE Figure 1. The location of Waneta, Lamoka, and Seneca Lakes in Schuyler County, New York (modified from Curatolo, 1991). 250 '6'.. ::-..,'---­ . " .. ,:1 5 ~ • BoAT LAUNCH SITES of I ~ UNLOADING SITES \I .-....... EXTENT OF VEGETATION \1 ffi SAMPLING STATION ;I~ o PUBLIC ACCESS iI~ I I~ i ~ I~ i,~ ~ ~I ffi 'f.) • Point !~1 4 ! ~I J~ Shoreline .\ , .\ .~ o N :\\". ..... , '.). '/ I i Scout Camp ',3 II . , ~ 0' \ \ . I'\ \.,. 1000 'I 1\ i' 0' \'. I .. \. \' , .\ 2 1. :- I .•' 8 '-'-;J'. L::;J~ Figure 2. Waneta Lake, Schuyler County, New York, showing sampling stations (modified from Curatolo, 1991). 251 with plant diversity being considerably higher at the southernmost shores. On both sample dates, all substrates encountered in Waneta Lake were oxygenated. Lamoka Lake (Figure 3), contiguous with Mill Pond to the south and connected to Waneta Lake via a navigable channel to the north, is located in western Schuyler County. This shallow «47ft) eutrophic lake occupies 826 acres in surface area, 16,410 acre-feet in volume, and has approximately 11.3 miles of shoreline. In 1990, about 325 houses occupied the shoreline. Recreational activities include swimming, fishing, and boating (Curatolo, 1991). During benthic sampling, deeper substrates were dominated by anaerobic organic muds; a notable exception was observed at a drop-off at the northeastern shore (Site #L2), where compact sand was encountered. Here, shells ofUnionid clams were collected. The predominating macrophytes encountered were the nonindigenous Eurasian milfoil (Myriophyllum spicatum) and curly leafed pondweed (Potamogeton crispus). Toward the southern, shallower end of the lake diversity was considerably higher, with Nuphar, Ceratophyllum, Heteranthera, and Vallisineria being well represented. At the time of sampling milfoil was practically absent from the Mill Pond area. The channel connecting Waneta and Lamoka Lakes exhibited a flora similar to that encountered in Mill pond. Access is provided to both lakes by boat launch sites maintained by the New York State Department of Conservation (NYSDEC). Neither lake is used as a potable water supply. Both lakes have been rated as moderately impaired on the NYSDEC 1989 Priority Problem List (NYSDEC, 1989). Despite inclement weather encountered throughout both days of sampling (45°-50° F, steady rain), bird activity was considerable. On 16 September 1996 large numbers of tree swallows (Iridoprocne hicolor) were active on Waneta Lake, presumably feeding on emerging aquatic insects. Two ospreys (Pandion haliaetus) and parasitic jaeger (Stercorarius parasiticus) were seen over Lamoka Lake; the latter seabird is extremely rare in this region and was likely displaced by recent tropical storms (Butts, 1996). On 12 May 1997 several species of early migrating songbirds were observed, with diversity being the greatest along the channel between the two Lakes. Two hen mallards (Anas platyrhynchos) were seen sitting on nests, and a pair of Canada geese (Branta canadensis) were seen on Lamoka Lake with newly hatched goslings. WATER QUALITY MONITORING Temperature, dissolved oxygen, pH, and conductivity were measured using a Hydrolab Scout II multiparameter water quality monitoring instrument which had been calibrated the days of data collection following manufacturer's operating manual (Hydrolab Corp., 1993). Readings were taken at 1 meter (m) intervals from the surface to the bottom. The maximum depth encountered at Waneta Lake was 8.2 meters (26.9 feet); that for Lamoka Lake was 13.4 meters (44.0 feet). On 16 September 1996, Waneta was undergoing fall overturn, although slight, presumably temporary stratification was observed below 8 m. Temperature in that area was approximately 0.3 0 C less than the rest of the water column and dissolved oxygen was over 2 mg/lless than overlaying waters. Conductivity was between 198-202 mmho/cm throughout. On 252 FLEET .:.-~- COVE 1000 ft N I I BOAT LAUNCH SITES o • PUBLIC ACCESS ~ UNLOADING SITES -._.- EXTENT OF VEGETATION E9 SAMPLING STATION POND Figure 3. Lamoka Lake, Schuyler County, New York, showing sampling stations (modified from Curatolo, 1991). 253 12 May 1997, the earliest signs of stratification were observed, with sight decreases in temperature and dissolved oxygen observed at the greatest depths. Temperature, dissolved oxygen, and pH profiles are graphically presented in Figures 4A and 4B. Lamoka Lake was stratified on 16 September, with the thermocline located between 6 and 7 m. Hypolimnetic waters were essentially anoxic «0.3 mg/l), a situation similar to that reported by Curatolo (1991) for corresponding dates in 1988, 1989 and 1990. Conductivity was approximately 190 mmho/cm through the epilimnion and increased below the thermocline to 213 mmho/cm at the bottom. Spring turnover was underway on 12 May, 1996.Temperature, dissolved oxygen, and pH profiles are graphically presented in Figures SA and 5B. These data, while limited, do not indicate any further shift toward eutrophy in either Waneta or Lamoka Lakes since 1988. Water samples collected on 12 May were analyzed for calcium content using the EDTA titrimetric method (APHA, 1989). Surface concentrations were 18.9 and 17.4 mg/l in Waneta and Lamoka Lakes, respectively. Water transparency was measured using a standard 20 em Secchi disk. Transparency was 2.0 m (6.6 ft) in Waneta and 1.9 m (6.2 ft) in Lamoka on 16 September 1996 and 1.2 m (3.9 ft) in both Lakes on 12 May 1997. Values reported by Curatolo (1991) indicate that Lamoka was somewhat more transparent and Waneta twice as transparent in 1996 compared to similar dates in 1988-90. THE BENTHIC INVERTEBRATE COMMUNITY METHODS Macroinvertebrates were collected from nine sites on Waneta Lake and nine sites on Lamoka. These sites included eulittoral, littoral muds, littoral vegetation, and profundal benthos. The objective was to obtain faunal diversity and density data for comparison with previous (e.g. Curatolo, 1991) and future surveys to ascertain any effects of macrophyte and algae control programs, as well as other changes in water quality or the colonization of non-native species, on these populations. Benthic samples were collected in triplicate using either a 23 X 23 cm2 or a 15 X 15 cm2 Ekman dredge. The larger dredges, using a conventional cable and messenger, were used in deeper locations; in shallower areas, the smaller dredges were employed using extension handles. Eulittoral samples, where the substrate tended to be stony, were acquired by manually gathering all material within a 23 X 23 cm 2 quadrangle. Vegetative samples were collected by sweeping the macrophytes with a triangle net five times and rinsing the contents from the net. Effort was made to include the entire depth distribution of the macrophyte bed. Each vegetative sample was collected in quadruplicate. While it is recognized that these vegetative samples cannot be interpreted as truly quantitative, the attempt was made to standardize the method as much as possible so that future comparisons may be made. 254 2 4 6 8 10 12 14 16 18 20 2 4 6 8 10 12 14 16 18 20 A B I 2 2 3 3 4 4 5 5 6 6 ~ ~ 6 7 67 o:S ..J:: 0... ...... (1) 0... (1) Q 8 11 Q 8 9 9 10 10 11 11 12 12 13 13 14 14 SD= 2.0 M SD= 1.2 M ___ Temperature -- pH -.- Dissolved Oxygen Figure 4. Profiles of temperature (Qq, pH, and dissolved oxygen (mg/1) for Waneta Lake, 16 September, 1996 (A) and 12 May, 1997 (B). 255 2 4 6 8 10 12 14 16 18 20 2 4 6 8 10 12 14 16 18 20 A B 1 2 2 3 3 4 4 5 5 6 9 9 10 10 11 11 12 12 13 13 i 14 14 SD= 1.9 M SD= 1.2 M --- Temperature -- pH -..- Dissolved Oxygen Figure 5.