The effects of zebra mussels on benthic macroinvertebrates in Otsego Lake

Transcription

1 The effects of zebra mussels on benthic macroinvertebrates in Otsego Lake Jennifer M. Vanassche 1, Wai Hing 1,2*, Willard N. Harman 2, and Matthew F. Albright 2 ABSTRACT The zebra mussel, Dreissena polymorpha (Pallas 1771), was first documented in North America in the 1980s. Zebra mussels were first documented in Otsego Lake in 2007 and were considered abundant of Surveys of macroinvertebrates were performed during and prior to 1997 and in In 2013, surveys of benthos in deep and shallow sites in the lake were repeated and taxonomic composition was described to assess the impacts of D. polymorpha on the benthic community. INTRODUCTION Dreissenid mussels including the zebra mussel (Dreissena polymorpha Pallas, 1771), originating from the Ponto-Caspian area (Black, Asov, and Caspian Sea), and the quagga mussel (Dreissena rostriformis bugensis Andrusov, 1897), originating from the mouths of the Rivers Southern Bug and Dnieper, are both species native to Eastern Europe (Van der Velde et al. 2010). Both zebra and quagga mussels were accidently introduced into the Laurentian Great Lakes in North America in the 1980s most likely in ballast water (Ludyanskiy et al. 1993; Carlton 2008; Van der Velde et al. 2010). It was first reported that the zebra mussel was found in North America in 1988 in Lake St. Clair (Hebert et al. 1989); however, a recent paper (Carlton 2008) provided convincing evidence that it was present as early as 1986 in Lake Erie. The first occurrence of the quagga mussel in North America was documented in 1989 in Lake Erie (Mills et al. 1993), but it was first identified as a separate species and given the common name quagga in a paper by May and Marsden (1992). This species was later identified from morphological and genetic material as Dreissena bugensis (Spidle et al. 1994, Rosenburg and Ludyanskiy 1994); however, a recent genetic comparison between D. bugensis and D. rostriformis indicated no distinct difference between the two taxa (Therriault et al. 2004). Otsego Lake in Otsego County, New York is a mesotrophic, dimictic lake formed by glacial over-deepening of the Susquehanna River Valley (Harman 1997). Zebra mussels were first documented in Otsego Lake in 2007 (Waterfield 2009) and were abundant by 2010 (Anonymous 2009; Anonymous 2010a, b). Dreissenid mussels initially have a minor impact on the ecosystem in which they were introduced (Wong et al. 2011); however, over time exponential increases in dreissenid populations drastically affect the ecosystem by changing microhabitats (Higgins and Zanden 2010). Zebra mussels have a positive impact on some macroinvertebrates while negatively impacting others; they affect the environment directly by altering the substrate they colonize or indirectly by increasing water clarity (Ward and Ricciardi 2010). The ability of zebra mussels to easily colonize hard substrates is especially detrimental to 1 Department of Biology, SUNY College at Oneonta 108 Ravine Pkwy Oneonta, NY. 2 Biological Field Station, SUNY College at Oneonta, 5838 State Highway 80, Cooperstown, NY. *Corresponding author

2 native mussels in the family Unionidae. Unionids, which have been in decline since the mid- 1800s, compete with zebra mussels for food and space (Cope et al. 2003). Zebra mussels often colonize the shells of the latter, preventing them from eliminating wastes and feeding; this contributes to the decline of native mussels (Cope et al. 2003). Several other species are negatively impacted by zebra mussels, including the molluscan family Pisidiidae and the amphipod genus Diporeia (Nalepa et al. 2009; Ward and Ricciardi 2010). Declines in populations of macroinvertebrates may contribute to declines in populations of fish that do not have flexible diets (Owens and Dittman 2003). Because zebra mussels are a low-energy alternative to the animals they displace, fish species that become dependent on zebra mussels for food are smaller and weigh less than fish of the same species that eat other macroinvertebrates (Owens and Dittman 2003). Dreissena polymorpha can have a positive effect on other macroinvertebrates; zebra mussel colonization increases the complexity of the substrate, providing more cover from predators (Ozersky et al. 2011; Nalepa et al. 2009; Ward and Ricciardi 2010). Feces and pseudofeces released by zebra mussels may also provide a food source for some macroinvertebrates (Hecky et al. 2004). Furthermore, dreissenids have indirect effects on macroinvertebrates by changing water clarity and phytoplankton production and by changing nutrient contents of lakes, including the removal of phosphorus in lakes (Higgins and Zanden 2010). As a result, the invasion of the zebra mussel to Otsego Lake is expected to have resulted in changes in the benthic community. Benthic macroinvertebrate surveys were performed in 2013 to evaluate that hypothesis. METHODS In 1968, Harman collected benthos at 53 shore stations and deep water benthos at sites along 6 transects at various depths from the surface of Otsego Lake (Harman 1994). The eulittoral and transect (littoral and profundal) studies were repeated in 1993 by Wheat (1994) and Hayes (1994), respectively. Harman (1994) calculated species richness at the eulittoral sites from records of taxa present between 1968 and 1988 and compared the data to collections made between 1989 and Benthic samples were collected on Otsego Lake from the research vessel Anadontiodes in July An Ekman dredge was used to collect samples along three transects (Figure 1) at depths of 0m to 50m. Transects were sampled between 10 July 2008 and 21 July Samples were preserved in jars in 70% ethanol. In June and July 2013, rose bengal was added to each jar and macroinvertebrates were removed from the samples and sorted. If less than 50% of a single organism was present, the organism was discarded. Macroinvertebrates were identified to subclass, order, family, or genus. Nematodes were not identified further than phylum. Annelids were identified to subclass and Platyhelminthes were identified to class. All other taxa were identified to family or genus excluding two unknown arthropods. Morphological differences within these broader taxonomic groups were used to estimate more specific taxonomic richness, which was then calculated for each site (Peckarsky et al.1990; Merritt and Cummins 1996; Harman 1997).

3 Figure 1. Transects and sites that were sampled in Otsego Lake, New York during July 2008 (Iannuzzi 1990). Contours are given in feet (1 m = 3.28 ft). Collections were made within the shaded areas. Benthic samples were collected with an Ekman dredge on Otsego Lake along 7 transects from the research vessel Anadontiodes in June, July, and August Samples were preserved, sorted, and identified as in In August through November 2013, benthic macroinvertebrates were collected at 47 sampling stations along the shoreline of Otsego Lake. Most of the sampling stations are the same sites used by Harman (1994) except sites 610, , , 652, and 653 sampled in 2013 which were not sampled in 1997, and 613 and 646 sampled in 1997, which were not sampled in Sites at which samples were collected from in 2008 were sampled in nearby areas in Samples were preserved in 70% ethanol and identified in the same way as the deep samples.

4 RESULTS In the three transects sampled in 2008, 30 taxa were found compared to 19 in 2013 (Table 1). A similar reduction was found between 1997 and 2013; along all 7 transects sampled, 85 taxa were found in 1997 and 51 were found in 2013 (Table 2). The phyla Cnidaria, Ectoprocta, and Entoprocta and the family Unionidae were not found in 2008 or Plecopterans, which had not been found in Harman s 1997 study or in 2008, were present in The reduction in richness in 2013 compared to 2008 along transects 2, 4, and 6 primarily includes Ephemeroptera, Odonata, and Trichoptera. Between 2008 and 2013, 4 genera of ephemeropterans disappeared while one new genus was identified. No families of Odonata and Trichoptera were identified in 2013 compared to 2 families each in 2008 along the three transects. A reduction in richness of ephemeropterans also occurred between 1997 and Hemipterans in Otsego Lake experienced decline; in families of hemipterans were found, whereas only one was found in 2013 along all 7 transects. Diversity of Odonata declined between 1997 and During taxa of odonates were found and 3 were found in 2013; however, the two years had no genera in common. The mollusk families Unionidae, Viviparidae, Pleuroceridae, and Succineidae were not found after Table 1. Comparison of lake macrobenthic taxa of Otsego Lake between 2013 and Presence of a taxon is marked with an x. Taxon Taxon Presence Phylum Class Order Family Genus Annelida Hirudinea x x Annelida Oligochaeta x x Arthropoda Branchiopoda Diplostraca (Suborder Cladocera) x Arthropoda Insecta Coleoptera Elmidae x Arthropoda Insecta Diptera Ceratopogonidae x x Arthropoda Insecta Diptera Chironomidae x x Arthropoda Insecta Diptera Tipulidae x Arthropoda Insecta Ephemeroptera Caenidae Brachycercus x Arthropoda Insecta Ephemeroptera Caenidae Caenis x Arthropoda Insecta Ephemeroptera Ephemeridae Hexagenia x x Arthropoda Insecta Ephemeroptera Heptageniidae Stenacron x Arthropoda Insecta Ephemeroptera Heptageniidae Stenonema x Arthropoda Insecta Ephemeroptera Leptophlebiidae Leptophlebia x Arthropoda Insecta Megaloptera Sialidae Sialis x Arthropoda Insecta Odonata Coenagrionidae Coenagrion x Arthropoda Insecta Odonata Corduliidae x Arthropoda Insecta Trichoptera Leptoceridae x Arthropoda Insecta Trichoptera Polycentropodidae x Arthropoda Arachnida Trombidiformes x x Arthropoda Entognatha Collembola x Arthropoda Malacostraca Amphipoda Gammaridae Gammarus x x Arthropoda Malacostraca Amphipoda Hyalellidae Hyalella x

5 Arthropoda Malacostraca Isopoda Asellidae x x Mollusca Bivalvia Veneroida Dreissenidae Dreissena x x Mollusca Bivalvia Veneroida Sphaeriidae/Pisidiidae x x Mollusca Gastropoda Basommatophora Lymnaeidae x Mollusca Gastropoda Basommatophora Physidae x x Mollusca Gastropoda Basommatophora Planorbidae x x Mollusca Gastropoda Heterostropha Valvatidae x x Mollusca Gastropoda Neotaenioglossa Hydrobiidae x x Nematoda x x Platyhelminthes Turbellaria x x Porifera Demospongiae Haplosclerida Spongillidae Spongilla x Table 2. Comparison of lake macrobenthic taxa of Otsego Lake between 2013 and Presence of a taxon is marked with an x. Taxon Taxon Presence Phylum Class Order Family Genus Annelida Hirudinea x x Annelida Oligochaeta x x Arthropoda Branchiopoda Diplostraca (Suborder Cladocera) x x Arthropoda Insecta Coleoptera Chrysomelidae x Arthropoda Insecta Coleoptera Curculionidae x Arthropoda Insecta Coleoptera Dryopidae x Arthropoda Insecta Coleoptera Dytiscidae x x Arthropoda Insecta Coleoptera Elmidae x x Arthropoda Insecta Coleoptera Gyrinidae x Arthropoda Insecta Coleoptera Haliplidae x x Arthropoda Insecta Coleoptera Hydrophilidae x Arthropoda Insecta Coleoptera Psephenidae Ectropria x Arthropoda Insecta Coleoptera Psephenidae Psephenus x x Arthropoda Insecta Diptera Ceratopogonidae x x Arthropoda Insecta Diptera Chironomidae x x Arthropoda Insecta Diptera Culicidae x Arthropoda Insecta Diptera Sciomyzidae x Arthropoda Insecta Diptera Stratiomyidae x Arthropoda Insecta Diptera Tabanidae x x Arthropoda Insecta Diptera Tipulidae x Arthropoda Insecta Ephemeroptera Baetidae Baetis x x Arthropoda Insecta Ephemeroptera Baetidae Callibaetis x Arthropoda Insecta Ephemeroptera Baetidae Centroptilum x Arthropoda Insecta Ephemeroptera Baetidae Cloeon x Arthropoda Insecta Ephemeroptera Caenidae Brachycercus x Arthropoda Insecta Ephemeroptera Caenidae Caenis x x

6 Arthropoda Insecta Ephemeroptera Ephemerellidae Ephemerella x Arthropoda Insecta Ephemeroptera Ephemerellidae Timpanoga x Arthropoda Insecta Ephemeroptera Ephemeridae Ephemera x x Arthropoda Insecta Ephemeroptera Ephemeridae Hexagenia x x Arthropoda Insecta Ephemeroptera Heptageniidae Epeorus x Arthropoda Insecta Ephemeroptera Heptageniidae Heptagenia x Arthropoda Insecta Ephemeroptera Heptageniidae Stenacron* x x Arthropoda Insecta Ephemeroptera Heptageniidae Stenonema x Habrophleboi Arthropoda Insecta Ephemeroptera Leptophlebiidae des Arthropoda Insecta Ephemeroptera Leptophlebiidae Leptophlebia x x Paraleptophle Arthropoda Insecta Ephemeroptera Leptophlebiidae bia x Arthropoda Insecta Ephemeroptera Siphlonuridae x Arthropoda Insecta Hemiptera Aphididae Rhoalosiphum x Arthropoda Insecta Hemiptera Corixidae x Arthropoda Insecta Hemiptera Gerridae x Arthropoda Insecta Hemiptera Notonectidae x Arthropoda Insecta Hemiptera Pleidae Neoplea x x Arthropoda Insecta Hemiptera Sialidiae Saluda x Arthropoda Insecta Lepidoptera Pyralidae Acentria x Arthropoda Insecta Lepidoptera Pyralidae Nymphula x Arthropoda Insecta Lepidoptera Pyralidae Petrophila x Arthropoda Insecta Megaloptera Corydalidae Chauloides x Arthropoda Insecta Megaloptera Corydalidae Nigronia x x Arthropoda Insecta Megaloptera Sialidae Sialis x x Arthropoda Insecta Neuroptera Sisyridae Sisyra x Arthropoda Insecta Odonata Aeshnidae x Arthropoda Insecta Odonata Coenagrionidae Argia x Arthropoda Insecta Odonata Coenagrionidae Coenagrion x Arthropoda Insecta Odonata Coenagrionidae Enallagma x Arthropoda Insecta Odonata Coenagrionidae Ishnura x Arthropoda Insecta Odonata Corduliidae x Arthropoda Insecta Odonata Gomphidae Arigomphus x Arthropoda Insecta Odonata Gomphidae Gomphus x Arthropoda Insecta Odonata Lestidae Lestes x Arthropoda Insecta Odonata Libellulidae x Arthropoda Insecta Odonata Macromiidae Macromia x Arthropoda Insecta Plecoptera Nemouridae x Arthropoda Insecta Plecoptera Perlidae x Arthropoda Insecta Trichoptera Helicopsychidae x Arthropoda Insecta Trichoptera Hydropsychidae x Arthropoda Insecta Trichoptera Hydroptilidae x x x

7 Arthropoda Insecta Trichoptera Leptoceridae x x Arthropoda Insecta Trichoptera Limnephilidae x x Arthropoda Insecta Trichoptera Philopotamidae x Arthropoda Insecta Trichoptera Phryganeidae x Arthropoda Insecta Trichoptera Polycentropodidae x x Arthropoda Arachnida Trombidiformes x x Arthropoda Entognatha Collembola x x Arthropoda Malacostraca Amphipoda Crangonyctidae Crangony nx x Arthropoda Malacostraca Amphipoda Gammaridae Gammaru s x x Arthropoda Malacostraca Amphipoda Hyalellidae Hyalella x x Orconect Arthropoda Malacostraca Decapoda Cambaridae es x x Arthropoda Malacostraca Isopoda Asellidae x x Cnidaria Hydrozoa Anthoathecatae Hydridae x Ectoprocta Phylactolaemata Plumatellida Lophopodidae Pectinella x Fredrecel Ectoprocta Phylactolaemata Plumatellida Plumatellidae la x Entoprocta Phylactolaemata Plumatellida Lophopodidae Urnatella x Mollusca Bivalvia Unionoida Unionidae x Mollusca Bivalvia Veneroida Dreissenidae Dreissena x x Mollusca Bivalvia Veneroida Sphaeriidae/Pisidiidae x x Mollusca Gastropoda Architaenioglossa Viviparidae x Mollusca Gastropoda Basommatophora Ancylidae x Mollusca Gastropoda Basommatophora Lymnaeidae x x Mollusca Gastropoda Basommatophora Physidae x x Mollusca Gastropoda Basommatophora Planorbidae x x Mollusca Gastropoda Heterostropha Valvatidae x x Mollusca Gastropoda Neotaenioglossa Hydrobiidae x x Mollusca Gastropoda Neotaenioglossa Pleuroceridae x Mollusca Gastropoda Stylommatophora Succineidae x Nematoda x x Platyhelminthes Turbellaria x x Porifera Demospongiae Haplosclerida Spongillidae Spongilla x *Includes MacCaffertium

8 DISCUSSION The introduction of Dreissena polymorpha to Otsego Lake drastically impacts the ecosystem and microenvironments within lakes. Sampling that took place prior to 2007 indicates the state of the benthic community had not yet been affected by zebra mussels. At the time of sampling in 2008, lake-wide zebra mussel abundance was low and their influence on the benthic community was assumed to be minimal. Changes in benthic macroinvertebrates in Otsego Lake have been seen as a result of other invasive species, such as Eurasian milfoil, Myriophyllum spicatum L. (Harman 1997). Unfortunately, the 2008 sampling sites were originally designed for water quality monitoring (Iannuzzi 1990) which makes it difficult to compare with earlier surveys of the benthos (Harman 1997, Vanassche et al. 2014); however, profundal communities in Otsego Lake historically have been homogenous throughout the lake on similar substrates (WN Harman, personal communications). Based on anecdotal observation, zebra mussels have become dominant in the benthic community of Otsego Lake (Anonymous 2009; Anonymous 2010a, b). A systematic survey on zebra mussel abundance and benthic community structure is needed to help determine how D. polymorpha has influenced the benthos. With the introduction of zebra mussels, the benthic community may have drastically changed since Changes in the environment of the lake may benefit species that feed from the feces and pseudofeces deposited by the mussels (Atalah et al. 2010; Hecky et al. 2004). Increases in surface area, complexity, and heterogeneity of the substrate provide more refuges for macroinvertebrates to hide from predators and more habitat to live in (Horvath et al. 1999; Ozersky et al. 2011). The removal of phytoplankton and the subsequent increase in water clarity provides additional resources that may benefit some benthic organisms (Higgins and Zanden 2010). Of the taxa identified in 2013, 13 are new compared to 1997 and earlier while 3 are new compared to Despite reductions in overall taxonomic richness, 3 new genera of ephemeropterans were found and 3 new genera of odonates were found in 2013 compared to In addition, 2 new genera of pyralids were identified. Zebra mussels, while beneficial to some macroinvertebrate populations, are detrimental to others. For example, declines in unionid mussel and other filter feeding populations (Cope et al. 2003, Higgins and Zanden 2010) may occur more rapidly from the colonization of zebra mussels. Similarly, declines in other macroinvertebrates such as Pisidiid clams in the Hudson River (Strayer et al. 1998) and some amphipods, such as those in the amphipod genus Diporeia in the Great Lakes, may experience population declines (Nalepa et al. 2009; Ward and Ricciardi 2010). The overall taxonomic richness of benthic macroinvertebrates has decreased since zebra mussels colonized the lake. Many families and genera that were present in 1997 and 2008 were absent in the 2013 survey. Notable families that experienced reductions in diversity included Ephemeroptera, Diptera, Hemiptera, Odonata, and Trichoptera. Lake ecosystems are also affected overall as a result of major changes inflicted by zebra mussels; changes in chlorophyll a and phytoplankton production may result as zebra mussels remove phosphorus from the lake (Wong et al. 2010, Higgins and Zanden 2010). The removal of phosphorus and phytoplankton may affect macrobenthos by altering the amounts of food available to benthos in the lake (Higgins and Zanden 2010). The reductions in diversity in Otsego Lake are likely a result of the introduction of zebra mussels. Further surveys of the lake including statistical analyses of

9 changes in the benthic community should be performed to monitor the effects D. polymorpha has had in the lake. ACKNOWLEDGEMENTS We thank the sponsored undergraduate and high school interns at the Biological Field Station, and Emily Davidson from the Environmental Science Program, State University of New York at Oneonta who helped collecting benthic samples. REFERENCES Anonymous Otsego Lake Zebra mussel update. SUNY Oneonta Biological Field Station Reporter, summer 2009, p.3. SUNY Oneonta Biological Field Station, Oneonta, NY. Anonymous. 2010a. Otsego Lake Zebra mussel update. SUNY Oneonta Biological Field Station Reporter, winter 2010, p.2. SUNY Oneonta Biological Field Station, Oneonta, NY. Anonymous. 2010b. Otsego Lake Zebra mussel update. SUNY Oneonta Biological Field Station Reporter, summer/fall 2010, p.3. SUNY Oneonta Biological Field Station, Oneonta, NY. Atalah, J., M. Kelly-Quinn, K. Irvine and T.P. Crowe Impacts of invasion by Dreissena polymorpha (Pallas, 1771) on the performance of macroinvertebrate assessment tools for eutrophication pressure in lakes. Hydrobiologia 654: Carlton, J.T The zebra mussel Dreissena polymorpha found in North America in 1986 and Journal of Great Lakes Research 34(4): Cope, W.G., T.J. Newton and C.M. Gatenby Review of techniques to prevent introduction of zebra mussels (Dreissena polymorpha) during native mussel (Unionoidea) conservation activities. Journal of Shellfish Research 22(1): González, M.J. and A. Downing Mechanisms underlying amphipod responses to zebra mussel (Dreissena polymorpha) invasion and implications for fish-amphipod interactions. Canadian Journal of Fisheries and Aquatic Sciences 56(4): Harman, W.N A comparison of the Otsego Lake macrobenthos communities between 1935 and SUNY Oneonta Biological Field Station (BFS). Annual Report No 26, Hayes, B Analysis of littoral and profundal benthos from Otsego Lake, summer SUNY Oneonta Biological Field Station (BFS). Annual Report No 26, Haynes, J.M., N.A. Tisch, C.M. Mayer and R.S. Rhyne Benthic macroinvertebrate communities in southwestern Lake Ontario following invasion of Dreissena and

10 Echinogammarus: 1983 to Journal of the North American Benthological Society 24(1): Hebert, P.D.N., B.W. Muncaster and G.L. Mackie Ecological and genetic studies on Dreissena polymorpha (Pallas) - a new mollusk in the Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences 46: Hecky, R.E., R.E.H. Smith, D.R. Barton, S.J. Guildford, W.D. Taylor, M.N. Charlton and T. Howell The nearshore phosphorus shunt: a consequence of ecosystem engineering by dreissenids in the Laurentian Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences 61: Higgins, S.N. and M.J. Vander Zanden What a difference a species makes: a meta analysis of dreissenid mussel impacts on freshwater ecosystems. Ecological Monographs 80(2): Horvath, T.G., K.M. Martin and G.A. Lamberti Effect of zebra mussels, Dreissena polymorpha, on macroinvertebrates in a lake-outlet stream. The American Midland Naturalist Journal 142: Iannuzzi, T.J A model plan for the Otsego Lake watershed. Phase II: the chemical limnology and water quality of Otsego Lake. SUNY Oneonta Biological Field Station (BFS). Occasional Paper #23, Rept. No. 2a. Ludyanskiy, M.L., D. McDonald and D. Macneill Impact of the zebra mussel, a bivalve invader: Dreissena polymorpha is rapidly colonizing hard surfaces throughout waterways of the United States and Canada. Bioscience 43: May, B. and J.E. Marsden Genetic identification and implications of another invasive species of dreissenid mussel in the Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences 49: Mayer, C.M., R.A. Keats, L.G. Rudstam and E.L. Mills Scale-dependent effects of zebra mussels on benthic invertebrates in a large eutrophic lake. Journal of the North American Benthological Society 21(4): Merritt, R.W. and K.W. Cummins (eds) An Introduction to the Aquatic Insects of North America, 3rd edition. Kendall/Hunt Publishing Company, Dubuque, Iowa, 862 pp. Mills, E.L., R.M. Dermott, E.F. Roseman, D. Dustin, E. Mellina, D.B. Conn and A.P. Spidle Colonization, ecology, and population structure of the quagga mussel (Bivalvia, Dreissenidae) in the lower Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences 50:

11 Nalepa, T.F., S.A. Pothoven and D.L. Fanslow Recent changes in benthic macroinvertebrate populations in Lake Huron and impact on the diet of lake whitefish (Coregonus clupeaformis). Aquatic Ecosystem Health & Management 12(1): Owens, R.W. and D.E. Dittman Shifts in the diets of slimy sculpin (Cottus cognatus) and lake whitefish (Coregonus clupeaformis) in Lake Ontario following the collapse of the burrowing amphipod Diporeia. Aquatic Ecosystem Health & Management 6(3): Ozersky, T., D.R. Barton and D.O. Evans Fourteen years of dreissenid presence in the rocky littoral zone of a large lake: effects on macroinvertebrate abundance and diversity. Journal of the North American Benthological Society 30(4): Peckarsky, B.L., P.R. Fraissinet, M.A. Penton and D.J. Conklin Freshwater Macroinvertebrates of Northeastern North America. Cornell University Press, Ithaca, NY. 442 pp. Rosenberg, G. and M.L. Ludyanskiy A nomenclatural review of Dreissena (Bivalve, Dreissenidae), with identification of the quagga mussel as Dreissena bugensis. Canadian Journal of Fisheries and Aquatic Sciences 51: Spidle, A.P., J.E. Marsden and B. May Identification of the Great Lakes quagga mussel as Dreissena bugensis from the Dnieper River, Ukraine, on the basis of allozyme variation. Canadian Journal of Fisheries and Aquatic Sciences 51: Strayer, D.L., L.C. Smith and D.C. Hunter Effects of the zebra mussel (Dreissena polymorpha) invasion on the macrobenthos of the freshwater tidal Hudson River. Canadian Journal of Zoology 76(3): Therriault, T.W., M.F. Docker, M.I. Orlova, D.D. Heath and H.J. MacIsaaca Molecular resolution of the family Dreissenidae (Mollusca: Bivalvia) with emphasis on Ponto- Caspian species, including first report of Mytilopsis leucophaeata in the Black Sea basin. Molecular Phylogenetics and Evolution 30: Vanassche, J.M., W.H. Wong, W.N. Harman and M.F. Albright Zebra mussels and other benthic organisms in Otsego Lake, New York in SUNY Oneonta Biological Field Station (BFS). Van der Velde, G., S. Rajagopal and A. Bij de Vaate The Zebra Mussel in Europe. Backhuys Publishers, Leiden, The Netherlands, 490 pp. Ward, J.M. and A. Ricciardi Community-level effects of co-occurring native and exotic ecosystem engineers. Freshwater Biology 55: Waterfield, H.A Update on zebra mussel (Dreissena polymorpha) invasion and establishment in Otsego Lake SUNY Oneonta Biological Field Station (BFS). Annual Report No 41.

12 Wheat, E A study of the macrobenthos of the eulittoral zone of Otsego Lake. SUNY Oneonta Biological Field Station (BFS). Annual Report No 26, Wong, W.H., T. Tietjen, S. Gerstenberger, G.C. Holdren, S. Mueting, E. Loomis, P. Roefer, B. Moore, K. Turner and I. Hannoun Potential ecological consequences of invasion of the quagga mussel (Dreissena bugensis) into Lake Mead, Nevada-Arizona. Lake and Reservoir Management 26: