Search

Search Results

• 1. [Article] Aquatic Invasive Species Surveys of Upper Klamath Lake, Fourmile Lake, and Lake of the Woods, OR During 2012

  Three lakes located within the Klamath River Basin in Oregon (Upper Klamath Lake, Fourmile Lake, and Lake of the Woods) were surveyed for aquatic invasive species during the summer of 2012. Specimens were ...

  Citation × Citation Citation Abstract Copy Title: Aquatic Invasive Species Surveys of Upper Klamath Lake, Fourmile Lake, and Lake of the Woods, OR During 2012 Author: Miller, Rich, Sytsma, Mark D. Year: 2013 Three lakes located within the Klamath River Basin in Oregon (Upper Klamath Lake, Fourmile Lake, and Lake of the Woods) were surveyed for aquatic invasive species during the summer of 2012. Specimens were collected using plant rakes, benthic dredges, plankton nets, and crayfish traps. No invasive aquatic plants, gastropods, snails, bivalves or crayfish were detected in the lakes. Title: Aquatic Invasive Species Surveys of Upper Klamath Lake, Fourmile Lake, and Lake of the Woods, OR During 2012 Author: Miller, Rich, Sytsma, Mark D. Year: 2013 Three lakes located within the Klamath River Basin in Oregon (Upper Klamath Lake, Fourmile Lake, and Lake of the Woods) were surveyed for aquatic invasive species during the summer of 2012. Specimens were collected using plant rakes, benthic dredges, plankton nets, and crayfish traps. No invasive aquatic plants, gastropods, snails, bivalves or crayfish were detected in the lakes. Close

• 2. [Article] OSMB Final Report, Task 4: Oregon Lake Watch

  The Oregon Lake Watch (OLW) volunteer monitoring program was resurrected after over a decade in hibernation. The new program was designed to educate the public about threats of aquatic invasive species ...

  Citation × Citation Citation Abstract Copy Title: OSMB Final Report, Task 4: Oregon Lake Watch Author: Strecker, Angela L., Miller, Rich, Morgan, Vanessa Year: 2014 The Oregon Lake Watch (OLW) volunteer monitoring program was resurrected after over a decade in hibernation. The new program was designed to educate the public about threats of aquatic invasive species (AIS), provide early detection of AIS invasions, and provide long term water quality data for the better management of Oregon’s lakes and reservoirs. Protocols were created for citizen scientists to survey for AIS, collect temperature and water clarity data, and record the data through an online data entry portal. An OLW website was developed to educate about AIS and provide survey protocols and identification materials to volunteers. AIS surveys were focused on Watch List Species which are selected AIS that have a negative impact on the beneficial uses of our waterbodies. Eighteen volunteers were trained during five sessions conducted in western and central Oregon. Fourteen of the trained volunteers collected data from sixteen waterbodies. Six Watch List species and one other AIS species were observed in four of the waterbodies. The three Watch List Species observed in Salish Pond and one in Olallie Lake were new observations. Temperature measurements indicated a wide range of thermal profiles and Secchi transparency measurement indicated a range of trophic status from oligotrophic to eutrophic. Title: OSMB Final Report, Task 4: Oregon Lake Watch Author: Strecker, Angela L., Miller, Rich, Morgan, Vanessa Year: 2014 The Oregon Lake Watch (OLW) volunteer monitoring program was resurrected after over a decade in hibernation. The new program was designed to educate the public about threats of aquatic invasive species (AIS), provide early detection of AIS invasions, and provide long term water quality data for the better management of Oregon’s lakes and reservoirs. Protocols were created for citizen scientists to survey for AIS, collect temperature and water clarity data, and record the data through an online data entry portal. An OLW website was developed to educate about AIS and provide survey protocols and identification materials to volunteers. AIS surveys were focused on Watch List Species which are selected AIS that have a negative impact on the beneficial uses of our waterbodies. Eighteen volunteers were trained during five sessions conducted in western and central Oregon. Fourteen of the trained volunteers collected data from sixteen waterbodies. Six Watch List species and one other AIS species were observed in four of the waterbodies. The three Watch List Species observed in Salish Pond and one in Olallie Lake were new observations. Temperature measurements indicated a wide range of thermal profiles and Secchi transparency measurement indicated a range of trophic status from oligotrophic to eutrophic. Close

• 3. [Article] Survey of Aquatic Invasive Species in Selected Umpqua National Forest Lakes and Ponds

  Eleven lakes and ponds within the Umpqua National Forest were surveyed for invasive aquatic macrophytes, snails, bivalves, and crayfish during the summer of 2011. Yellow floating heart (Nymphoides peltata), ...

  Citation × Citation Citation Abstract Copy Title: Survey of Aquatic Invasive Species in Selected Umpqua National Forest Lakes and Ponds Author: Sytsma, Mark D., Miller, Rich Year: 2012 Eleven lakes and ponds within the Umpqua National Forest were surveyed for invasive aquatic macrophytes, snails, bivalves, and crayfish during the summer of 2011. Yellow floating heart (Nymphoides peltata), an invasive floating leaf macrophyte species, was detected in Willow Sump within the Little River drainage. European ear snails (Radix auricularia), an invasive species present in several Umpqua National Forest waterbodies, were detected in Beaver Pond within the Steamboat Creek drainage. One native crayfish species, the signal crayfish (Pacifastacus leniusculus), was observed in Crayfish Lake within the Brice Creek drainage. Diverse assemblages of native plant species were observed in the lakes and ponds. The UNF and the Oregon Department of Agriculture are exploring ways to eradicate the yellow floating heart infestation in Willow Sump. Title: Survey of Aquatic Invasive Species in Selected Umpqua National Forest Lakes and Ponds Author: Sytsma, Mark D., Miller, Rich Year: 2012 Eleven lakes and ponds within the Umpqua National Forest were surveyed for invasive aquatic macrophytes, snails, bivalves, and crayfish during the summer of 2011. Yellow floating heart (Nymphoides peltata), an invasive floating leaf macrophyte species, was detected in Willow Sump within the Little River drainage. European ear snails (Radix auricularia), an invasive species present in several Umpqua National Forest waterbodies, were detected in Beaver Pond within the Steamboat Creek drainage. One native crayfish species, the signal crayfish (Pacifastacus leniusculus), was observed in Crayfish Lake within the Brice Creek drainage. Diverse assemblages of native plant species were observed in the lakes and ponds. The UNF and the Oregon Department of Agriculture are exploring ways to eradicate the yellow floating heart infestation in Willow Sump. Close

• 4. [Article] Aquatic Plant Surveys in the Bureau of Land Management, Medford District, 2010-2011

  The introduction of invasive aquatic plant species (IAPS) can cause significant ecological and economic harm. IAPS can displace native aquatic plant species, impair recreation, and degrade water quality. ...

  Citation × Citation Citation Abstract Copy Title: Aquatic Plant Surveys in the Bureau of Land Management, Medford District, 2010-2011 Author: Sytsma, Mark D., Miller, Rich, Morgan, Vanessa Year: 2011 The introduction of invasive aquatic plant species (IAPS) can cause significant ecological and economic harm. IAPS can displace native aquatic plant species, impair recreation, and degrade water quality. Early detection of new invasions can improve chances for successful eradication or containment to reduce the risk of IAPS spread. The Oregon Department of Agriculture (ODA) lists the most egregious offenders as “Noxious Weeds” which are defined as plants classified by the Oregon State Weed Board that are injurious to public health, agriculture, recreation, wildlife, or any public or private property (ODA 2011). Several IAPS classified as noxious have been detected within the Medford District of the Bureau of Land Management (BLM) in Southern Oregon including yellow floating heart (Nymphoides peltata) and yellow flag iris (Iris pseudacorus). During the summers of 2010 and 2011, IAPS surveys were conducted at selected reservoirs, lakes, and river boat launches within the Medford District to determine the extent of IAPS infestations as well as the distributions of native aquatic plant species. This report summarizes results of the surveys and provides recommendations for management of IAPS within the Medford District. Observations of any invasive aquatic animal species such as New Zealand mudsnails (Potamopyrgus antipodarum) are also reported. Title: Aquatic Plant Surveys in the Bureau of Land Management, Medford District, 2010-2011 Author: Sytsma, Mark D., Miller, Rich, Morgan, Vanessa Year: 2011 The introduction of invasive aquatic plant species (IAPS) can cause significant ecological and economic harm. IAPS can displace native aquatic plant species, impair recreation, and degrade water quality. Early detection of new invasions can improve chances for successful eradication or containment to reduce the risk of IAPS spread. The Oregon Department of Agriculture (ODA) lists the most egregious offenders as “Noxious Weeds” which are defined as plants classified by the Oregon State Weed Board that are injurious to public health, agriculture, recreation, wildlife, or any public or private property (ODA 2011). Several IAPS classified as noxious have been detected within the Medford District of the Bureau of Land Management (BLM) in Southern Oregon including yellow floating heart (Nymphoides peltata) and yellow flag iris (Iris pseudacorus). During the summers of 2010 and 2011, IAPS surveys were conducted at selected reservoirs, lakes, and river boat launches within the Medford District to determine the extent of IAPS infestations as well as the distributions of native aquatic plant species. This report summarizes results of the surveys and provides recommendations for management of IAPS within the Medford District. Observations of any invasive aquatic animal species such as New Zealand mudsnails (Potamopyrgus antipodarum) are also reported. Close

• 5. [Article] Aquatic Invasive Plant Surveys in the BLM Medford District During 2012

  Aquatic plant surveys were conducted at 22 waterbodies located within the Bureau of Land Management’s Medford District during the summer of 2012. Sites included eleven lakes, ponds or reservoirs and six ...

  Citation × Citation Citation Abstract Copy Title: Aquatic Invasive Plant Surveys in the BLM Medford District During 2012 Author: Miller, Rich, Morgan, Vanessa, Sytsma, Mark D. Year: 2013 Aquatic plant surveys were conducted at 22 waterbodies located within the Bureau of Land Management’s Medford District during the summer of 2012. Sites included eleven lakes, ponds or reservoirs and six reaches along the Rogue and Applegate Rivers. Five sampling areas surveyed during 2010 and 2011 were revisited to determine the extent of known non-native species infestations, positively identify rare species, or verify the absence of an expected non-native species. Plant specimens were collected at up to 50 sites at each waterbody using plant rakes or by observation. The non-native submersed species curly leaf pondweed (Potamogeton crispus) and Eurasian x northern watermilfoil (Myriophyllum sibiricum x spicatum) were widespread throughout the District. Eurasian watermilfoil (Myriophyllum spicatum) was present at two sites. Emergent non-native aquatic species included parrotsfeather (Myriophyllum aquaticum), yellow flag iris (Iris pseudacorus), purple loosestrife (Lythrum salicaria), reed canary grass (Phalaris arundinaceae), floating primrose-willow (Ludwigia peploides) and slender waternymph (Najas gracillima). Title: Aquatic Invasive Plant Surveys in the BLM Medford District During 2012 Author: Miller, Rich, Morgan, Vanessa, Sytsma, Mark D. Year: 2013 Aquatic plant surveys were conducted at 22 waterbodies located within the Bureau of Land Management’s Medford District during the summer of 2012. Sites included eleven lakes, ponds or reservoirs and six reaches along the Rogue and Applegate Rivers. Five sampling areas surveyed during 2010 and 2011 were revisited to determine the extent of known non-native species infestations, positively identify rare species, or verify the absence of an expected non-native species. Plant specimens were collected at up to 50 sites at each waterbody using plant rakes or by observation. The non-native submersed species curly leaf pondweed (Potamogeton crispus) and Eurasian x northern watermilfoil (Myriophyllum sibiricum x spicatum) were widespread throughout the District. Eurasian watermilfoil (Myriophyllum spicatum) was present at two sites. Emergent non-native aquatic species included parrotsfeather (Myriophyllum aquaticum), yellow flag iris (Iris pseudacorus), purple loosestrife (Lythrum salicaria), reed canary grass (Phalaris arundinaceae), floating primrose-willow (Ludwigia peploides) and slender waternymph (Najas gracillima). Close

• 6. [Article] Aquatic Invasive Species Surveys of Eastern Oregon Waterbodies in 2013 and 2014

  Early detection aquatic invasive species (AIS) surveys were conducted at 33 Eastern Oregon waterbodies during the summers of 2013 and 2014. Submerged aquatic plants, gastropods, bivalves, and crayfish ...

  Citation × Citation Citation Abstract Copy Title: Aquatic Invasive Species Surveys of Eastern Oregon Waterbodies in 2013 and 2014 Author: Miller, Rich, Sytsma, Mark D. Year: 2014 Early detection aquatic invasive species (AIS) surveys were conducted at 33 Eastern Oregon waterbodies during the summers of 2013 and 2014. Submerged aquatic plants, gastropods, bivalves, and crayfish were collected using a thatch rake, benthic dredge, plankton net, and modified minnow traps. Shoreline aquatic noxious weeds were noted when present and water quality characteristics were measured. Two AIS snail species, one AIS crayfish species, and five AIS plant species were detected during the surveys. Big-ear radix snails (Radix auricularia) were newly detected at 14 waterbodies distributed across the survey area. Chinese mystery snails (Cipangopaludina chinensis) were detected in one waterbody. Rusty crayfish (Orconectes rusticus) were newly found at high densities at one lake. AIS plant species included Eurasian watermilfoil (Myriophyllum spicatum), a hybrid of Eurasian with the native northern watermilfoil (M. spicatum x sibiricum), curlyleaf pondweed (Potamogeton crispus), fragrant waterlily (Nymphaea odorata) and reed canarygrass (Phalaris arundinacea). Fifty-six native aquatic plant species were identified in the waterbodies. Water quality conditions ranged from clear, low ionic strength water to highly turbid, productive, high ionic strength water. Title: Aquatic Invasive Species Surveys of Eastern Oregon Waterbodies in 2013 and 2014 Author: Miller, Rich, Sytsma, Mark D. Year: 2014 Early detection aquatic invasive species (AIS) surveys were conducted at 33 Eastern Oregon waterbodies during the summers of 2013 and 2014. Submerged aquatic plants, gastropods, bivalves, and crayfish were collected using a thatch rake, benthic dredge, plankton net, and modified minnow traps. Shoreline aquatic noxious weeds were noted when present and water quality characteristics were measured. Two AIS snail species, one AIS crayfish species, and five AIS plant species were detected during the surveys. Big-ear radix snails (Radix auricularia) were newly detected at 14 waterbodies distributed across the survey area. Chinese mystery snails (Cipangopaludina chinensis) were detected in one waterbody. Rusty crayfish (Orconectes rusticus) were newly found at high densities at one lake. AIS plant species included Eurasian watermilfoil (Myriophyllum spicatum), a hybrid of Eurasian with the native northern watermilfoil (M. spicatum x sibiricum), curlyleaf pondweed (Potamogeton crispus), fragrant waterlily (Nymphaea odorata) and reed canarygrass (Phalaris arundinacea). Fifty-six native aquatic plant species were identified in the waterbodies. Water quality conditions ranged from clear, low ionic strength water to highly turbid, productive, high ionic strength water. Close

• 7. [Article] Physical, Chemical and Biological Assessment of Yoncalla Log Ponds

  The Yoncalla Log Ponds are a series of four ponds located in within the city limits of the town in Yoncalla in northern Douglas County, Oregon. The ponds were created in stages between the late 1930s and ...

  Citation × Citation Citation Abstract Copy Title: Physical, Chemical and Biological Assessment of Yoncalla Log Ponds Author: Miller, Rich, Sytsma, Mark D., Strecker, Angela L. Year: 2014 The Yoncalla Log Ponds are a series of four ponds located in within the city limits of the town in Yoncalla in northern Douglas County, Oregon. The ponds were created in stages between the late 1930s and the 1950s and used for log storage through the 1970s (North Douglas Betterment 2014). North Douglas Betterment purchased the land surrounding the ponds and contracted with the Center for Lakes and Reservoirs at Portland State University to assess the current morphometry, vegetation and water quality status of the ponds and provide recommendations for management of the aquatic vegetation. The scope of this document covers the current status assessment of the ponds using data collected from June 2013 through May 2014. Title: Physical, Chemical and Biological Assessment of Yoncalla Log Ponds Author: Miller, Rich, Sytsma, Mark D., Strecker, Angela L. Year: 2014 The Yoncalla Log Ponds are a series of four ponds located in within the city limits of the town in Yoncalla in northern Douglas County, Oregon. The ponds were created in stages between the late 1930s and the 1950s and used for log storage through the 1970s (North Douglas Betterment 2014). North Douglas Betterment purchased the land surrounding the ponds and contracted with the Center for Lakes and Reservoirs at Portland State University to assess the current morphometry, vegetation and water quality status of the ponds and provide recommendations for management of the aquatic vegetation. The scope of this document covers the current status assessment of the ponds using data collected from June 2013 through May 2014. Close

• 8. [Article] 2014 Aquatic Weed Surveys in Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake

  The Clackamas River Hydroelectric Project No. 2195 (Project) is located on the Oak Grove Fork of the Clackamas River and the mainstem of the Clackamas River in Clackamas County, Oregon. Reservoirs included ...

  Citation × Citation Citation Abstract Copy Title: 2014 Aquatic Weed Surveys in Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake Author: Miller, Rich, Sytsma, Mark D., Brittain, Jeffrey Thomas Year: 2014 The Clackamas River Hydroelectric Project No. 2195 (Project) is located on the Oak Grove Fork of the Clackamas River and the mainstem of the Clackamas River in Clackamas County, Oregon. Reservoirs included in the Project include Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake. The operator of the Project, Portland General Electric (PGE), was issued a license on December 21, 2010 by the Federal Energy Regulatory Commission (FERC) for continued operations and maintenance. The Final Environmental Impact Statement (FEIS) for the license noted that regular surveys for invasive aquatic weed species would be conducted as part of the Project’s Vegetation Management Plan. The term “aquatic weed” is used here to refer to any non-native aquatic plant species. Information from repeated aquatic surveys will help determine native species distributions and the need for treatment of problematic aquatic weed species, particularly hydrilla (Hydrilla verticillata), Brazilian elodea (Egeria densa), and Eurasian watermilfoil (Myriophyllum spicatum). Surveys conducted for PGE by Portland State University (PSU) in Timothy Lake, Lake Harriet, and North Fork Reservoir in 2011 did not locate any problematic submerged or floating leaved aquatic weed species. Earlier surveys of Timothy Lake, and Timothy Lake and Lake Harriet, also indicated the reservoirs were free of aquatic weeds. Heaton et al. (1996) noted that the native species Bidens beckii was present and had the potential to become weedy, however, this species was not found during the 2004 or 2011 surveys. This report covers the results of follow up aquatic vegetation surveys conducted in Lake Harriet, Timothy Lake, and North Fork Reservoir between August 14 and August 21, 2014, as well as new surveys of Faraday Lake and Estacada Lake. Shoreline surveys for emergent invasive species such as yellow flag iris (Iris pseudacorus) and purple loosestrife (Lythrum salicaria) were included in surveys for the first time. Title: 2014 Aquatic Weed Surveys in Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake Author: Miller, Rich, Sytsma, Mark D., Brittain, Jeffrey Thomas Year: 2014 The Clackamas River Hydroelectric Project No. 2195 (Project) is located on the Oak Grove Fork of the Clackamas River and the mainstem of the Clackamas River in Clackamas County, Oregon. Reservoirs included in the Project include Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake. The operator of the Project, Portland General Electric (PGE), was issued a license on December 21, 2010 by the Federal Energy Regulatory Commission (FERC) for continued operations and maintenance. The Final Environmental Impact Statement (FEIS) for the license noted that regular surveys for invasive aquatic weed species would be conducted as part of the Project’s Vegetation Management Plan. The term “aquatic weed” is used here to refer to any non-native aquatic plant species. Information from repeated aquatic surveys will help determine native species distributions and the need for treatment of problematic aquatic weed species, particularly hydrilla (Hydrilla verticillata), Brazilian elodea (Egeria densa), and Eurasian watermilfoil (Myriophyllum spicatum). Surveys conducted for PGE by Portland State University (PSU) in Timothy Lake, Lake Harriet, and North Fork Reservoir in 2011 did not locate any problematic submerged or floating leaved aquatic weed species. Earlier surveys of Timothy Lake, and Timothy Lake and Lake Harriet, also indicated the reservoirs were free of aquatic weeds. Heaton et al. (1996) noted that the native species Bidens beckii was present and had the potential to become weedy, however, this species was not found during the 2004 or 2011 surveys. This report covers the results of follow up aquatic vegetation surveys conducted in Lake Harriet, Timothy Lake, and North Fork Reservoir between August 14 and August 21, 2014, as well as new surveys of Faraday Lake and Estacada Lake. Shoreline surveys for emergent invasive species such as yellow flag iris (Iris pseudacorus) and purple loosestrife (Lythrum salicaria) were included in surveys for the first time. Close

• 9. [Article] Hydroacoustic Survey and Point Sampling of Macrophytes In Diamond Lake 2009

  MaxDepth Aquatics, Inc. was contracted to conduct a hydroacoustic survey of macrophyte distribution in Diamond Lake in 2009. The survey essentially repeated surveys conducted in 2002 and 2007, allowing ...

  Citation × Citation Citation Abstract Copy Title: Hydroacoustic Survey and Point Sampling of Macrophytes In Diamond Lake 2009 Author: Eilers, Joseph, Eilers, Benn, Sytsma, Mark D., Miller, Rich Year: 2010 MaxDepth Aquatics, Inc. was contracted to conduct a hydroacoustic survey of macrophyte distribution in Diamond Lake in 2009. The survey essentially repeated surveys conducted in 2002 and 2007, allowing for a detailed assessment of conditions in 2009 and comparisons among previous years. In addition, Portland State University was contracted to conduct a depth stratified random point sample survey of macrophyte species presence and absence. The point sample survey was similar to surveys conducted in 2005 and 2007. The results of the 2009 hydroacoustic survey showed that macrophytes were widely distributed throughout the lake at depths less than 8 meters, although some shorter aggregations of macrophytes were found at depths down to 14 meters. Average canopy height corresponded closely to macrophyte density in 2009. The recent survey showed that macrophytes had extended deeper throughout the lake compared to 2002 and 2007 and that canopy height had increased substantially in some locations. The 2009 distribution showed that recolonization of the near shore areas was proceeding, albeit at a relatively slow pace since the lake drawdown completed in 2006. The maximum density of macrophytes in 2009 was found between 4 to 6 meters. Five macrophyte species, one macroalgal species, and filamentous algae were present in the 2009 random point survey. The occurrence rates of the macrophytes Elodea canadensis, Ceratophyllum demersum, and Potamogeton praelongus in 2009 were similar to 2005 and 2007 while Potamogeton pusillus occurrence increased and Myriophyllum verticillatum decreased. Macrophytes were present in a few samples greater than 9 meters; however, biomass, as measured by the fullness of a sampling rake, was highest between 2 and 6 meters. The comparison of the grab sampling conducted in August with the hydroacoustic survey in early September showed poor correspondence in macrophyte density obtained by the two methods. This is likely due to differences in spatial scales of collected samples (10 m2 grid for hydroacoustics compared to < 1 m2 grab samples), comparison of a continuous analytic tool (hydroacoustic) versus an ordinal ranking of density (rake), and possibly some changes in the macrophytes community between the two sampling dates. Title: Hydroacoustic Survey and Point Sampling of Macrophytes In Diamond Lake 2009 Author: Eilers, Joseph, Eilers, Benn, Sytsma, Mark D., Miller, Rich Year: 2010 MaxDepth Aquatics, Inc. was contracted to conduct a hydroacoustic survey of macrophyte distribution in Diamond Lake in 2009. The survey essentially repeated surveys conducted in 2002 and 2007, allowing for a detailed assessment of conditions in 2009 and comparisons among previous years. In addition, Portland State University was contracted to conduct a depth stratified random point sample survey of macrophyte species presence and absence. The point sample survey was similar to surveys conducted in 2005 and 2007. The results of the 2009 hydroacoustic survey showed that macrophytes were widely distributed throughout the lake at depths less than 8 meters, although some shorter aggregations of macrophytes were found at depths down to 14 meters. Average canopy height corresponded closely to macrophyte density in 2009. The recent survey showed that macrophytes had extended deeper throughout the lake compared to 2002 and 2007 and that canopy height had increased substantially in some locations. The 2009 distribution showed that recolonization of the near shore areas was proceeding, albeit at a relatively slow pace since the lake drawdown completed in 2006. The maximum density of macrophytes in 2009 was found between 4 to 6 meters. Five macrophyte species, one macroalgal species, and filamentous algae were present in the 2009 random point survey. The occurrence rates of the macrophytes Elodea canadensis, Ceratophyllum demersum, and Potamogeton praelongus in 2009 were similar to 2005 and 2007 while Potamogeton pusillus occurrence increased and Myriophyllum verticillatum decreased. Macrophytes were present in a few samples greater than 9 meters; however, biomass, as measured by the fullness of a sampling rake, was highest between 2 and 6 meters. The comparison of the grab sampling conducted in August with the hydroacoustic survey in early September showed poor correspondence in macrophyte density obtained by the two methods. This is likely due to differences in spatial scales of collected samples (10 m2 grid for hydroacoustics compared to < 1 m2 grab samples), comparison of a continuous analytic tool (hydroacoustic) versus an ordinal ranking of density (rake), and possibly some changes in the macrophytes community between the two sampling dates. Close