28 August 2011

Lake Champlain's zebras

We left Montreal Friday morning and a couple of hours later left Canada near Rouses Point, New York. After exiting the U.S. border station, we took Route 2 that crosses Lake Champlain into Vermont. While still on the bridge, we stopped for lunch at a convenient parking lot facing north.

After I finished my sandwich, I had my customary quick walk along the shore of the lake to check out the local mollusk fauna. These small mussels were abundant on the rocks at the edge of the water.

If I am not mistaken, they are the infamous zebra mussels (Dreissena polymorpha) that have been present in Lake Champlain at least since 1993.

These mussels are native to southeast Europe. They were 1st seen in North America in 1988. Despite its small size, the zebra mussel is a nuisance species, because it is invasive and often present abundantly (more info from the USDA).


thepowmill said...

From the Seaway into rivers and lakes...There has been one 'good' thing about them...they have cleaned the waters of a great deal of pollution. I wonder what effect it has on the mussels themselves?

Fred Schueler said...

Things have certainly changed since...

29 July 1996 - USA: New York: Clinton County: Champlain: Rouses Point, US 11 turn. (50m waypoint), 31A/14, 44.98296N 73.36268W TIME: 1652. AIR TEMP: 26 ca, light overcast. HABITAT: lakeside town. OBSERVER: Frederick W. Schueler, Aleta Karstad Schueler. WAYPT/016, reference (cartigraphic reference) (event). drive. WAYPT/016.

moved 2.5 km NE.
USA: Vermont: Grand Isle County: Alburg: US 2/Kelly Bay Access Area, Lake. Champlain. 44.99800N 73.33900W TIME: 1656-1707. AIR TEMP: 27, light overcast. HABITAT: clear lake Scirpus-bay, highway causeway, Soft Maple woods. 96/163/aa, Viviparus georgianus (Banded Mystery Snail) (Mollusca). scattered shell, dead, seen, pr?. WAYPT/017, the only conspicuous mollusc. I waded around, to 1 m depth, through swamp islands, and along the causeway, and saw no sign of unionids.

(same location) 96/163/ab, Rana pipiens (Leopard Frog) (herp). many juvenile, seen. in grass & at waters edge.

(same location) 96/163/ac, Spartina pectinata (Prairie Cord Grass) (Plant). dominant herb, in bloom, seen. along boulder/gravel highway causeway.

moved 13.4 km SSE.
US 2/S. Alburg causeway, Lake. Champlain. (50m waypoint(assumed)), 44.88596N 73.27784W TIME: 1729-1744. AIR TEMP: 26, light overcast. HABITAT: murky water shale-flake mud bay L. Champlain. EOBM(MOLL)00872, 96/163/ba, Elliptio complanata (Eastern Elliptio) (Mollusca). 21 shell, specimen. WAYPT/018, on shale beach, in 1 m water, no concentrations. This is right at the W end of the causeway. Three pairs, 18 valves, largest 70 mm, some with hinge morphology very like that of Elliptio ditatata.

(same location) EOBM(MOLL)00873, 96/163/bb, Lampsilis radiata (Eastern Lamp-Mussel) (Mollusca). 29 shell, specimen. scattered on shale beach, in 1 m water, no concentrations. This is right at the W end of the causeway. Five pairs, 24 valves, largest 70 mm,

(same location) EOBM(MOLL)00874, 96/163/bc, Viviparus georgianus (Banded Mystery Snail) (Mollusca). 5 shell, specimen. scattered on shale beach, in 1 m water, 5 taken, largest 32.5 mm. Sample includes a Helisoma trivolvus (Larger Eastern Ramshorn).

(same location) 96/163/bd, Cyprinus carpio (Carp) (fish). 3 adult, seen. huge & grey, in 1.4 m depth.

moved 7.8 km S.
Hero: North Hero, Highway 2. (50m waypoint), 44.81662N 73.29030W TIME: 1754. AIR TEMP: 26 ca, light overcast. WAYPT/019, reference (cartigraphic reference) (event). drive. WAYPT/019, nice clear beach N of here along turn in Highway 2.

moved 5.2 km S.
US 2/just S Knight Pt Park, Lake. Champlain. (50m waypoint(assumed)), 44.76965N 73.29301W TIME: 1759-1816. AIR TEMP: 25.5, light overcast, Beaufort light breeze. HABITAT: shale-flake lake beach & bottom, clear water. EOBM(MOLL)00554, 96/163/ca, Lampsilis radiata (Eastern Lamp-Mussel) (Mollusca). 11 shell, specimen. WAYPT/020, 2 pairs, 9 valves, all old, largest 89 mm, chunky & heavy. The water here was clear but easily roiled with green plankton-like algae. There were lots of good skipping stones, and a 3 m rocky scarp above the beach with exotic Juniperus (Juniper) and Thuja entwined. There were also Pyrus malus (Apple) trees along the road as if this was an old house site.

(same location) EOBM(MOLL)00555, 96/163/cb, Elliptio complanata (Eastern Elliptio) (Mollusca). 4 shell, specimen. old heavy rounded valves, largest 80 mm.

(same location) EOBM(MOLL)00556, 96/163/cc, Pyganodon cf grandis (Common floater) (Mollusca). 1 shell, specimen. old 57 mm pair, ripply beak sculpture.

(same location) EOBM(MOLL)00557, 96/163/cd, Neohelix () (Mollusca). 1 shell, drift, specimen. old 29.3 mm shell, narrow lip.