This is just a personal observation about the spread of zebra mussels. Up until 1999 in Sand Lake on the Rideau there were very few reported sightings. Dive teams near Jones Fall reported seeing a handful of zebra mussels in 1999. There were no reported zebra mussel sightings by cottage owners. In 2000, the zebra mussel population in the lake exploded. Entire shorelines which had never seen a single zebra mussel are now infested with thousands.
I'm not a mollusc expert - I have no idea why this type of spread occurs. I would have thought that the population would have grown in some sort of steady progression. Instead they went from 6 to 600,000 in a single season. Pretty impressive - pretty scary. If someone knows why this type of spread happened I'd be pleased to hear from you.
THEY'RE HERE TO STAY
My reporting of Zebra mussel sightings on the Rideau ends at 1997 because most aren't being reported anymore, and they have now been sighted throughout the entire Rideau Waterway. In 1999, they were occurring in very low densities in all of the lakes and there were high populations in the Rideau River downstream of Kars.
The future impact is uncertain. Water clarity, which has been improving throughout the last 15 years due to improved agricultural and municipal practices in the area and a greater awareness of man's impact on the watershed, will continue to improve as Zebra mussel populations grow and filter the water. Cottagers will get annoyed as water intake pipes get clogged. The locks, which use technology invented in the early 1800s, should be minimally impacted. Some local species of clams are going to have a tough go of it. Nutrient levels in the water will drop, and the impact on local fish populations as a result of this is uncertain. Aquatic weed distribution will change as sunlight penetrates deeper into the water of Rideau lakes and rivers.
The ecology of the Rideau, like all ecologies, changes over time. Nature is never static. Zebra mussels are going to accelerate that change. So all we can do now is to sit back, monitor, and learn from those changes.
The following are zebra mussel and veliger (zebra mussel larvae) sightings on the Rideau waterway reported to the Invading Species Hotline.
1997
increases in populations in the Manotick area
adult mussels in Dow Lake in Ottawa.
Note: With the closure of the Ministry of Natural Resources' Rideau Lakes
Assessment Unit in the fall of 1996, active monitoring for zebra mussels
ceased. Since the public has been aware of the presence of zebra mussels in
the Rideau for a number of years now, they are less apt to report findings to the Invading Species Hotline. It is still important to report sightings. If you see any sign of Zebra mussels in the Rideau Waterway, please call the Invading Species Hotline (toll free at: 1-800-563-7711) to report your findings.
1996
Big Rideau - in Hudson's Bay, approximately fifty, 2.5 cm size mussels were reported by the Rideau Lakes Fisheries Assessment Unit (R.L.F.A.U.) staff. The sighting was about 4 km west of Portland. In 1995 there was a report that the barge had zebra mussels on it and it is believed that this is the area that the barge was working.
Rideau River - about 7 km south of Manotick, more than fifty, 0.5 - 1 cm size mussels were reported. It was indicated that the mussel densities were higher than last season and that virtually every native clam had mussels attached.
Upper Rideau Lake - two adult mussels, 2.4 - 3 cm in size, floated in attached to a plastic bag at Newboro Lock Station.
Rideau Canal - an estimated 7,000+ adult mussels (1.5 cm in size) were reported growing on a dock and swim ladder at Manotick
Rideau River- more than 1000 mussels in the 0.4-1cm. range were reported 8
km. north of Kemptville at Lot 31, Conc. 4 Rideau Twp. A sample was received
and confirmed to be zebra mussels by Hotline staff.
Rideau River- approximately twenty four 0.3-1.3 cm mussels were found
attached to an aluminum boat about 4 km. north of Kemptville. The reporter
had not noticed any mussels last year.
1995
Big Rideau Lake , Hudson's Bay - hundreds of mussels attached to a barge that has been docked in the area since 1994.
Opinicon Lake, approximately 1.5 km southeast of Chaffey's Locks - eight veligers (four live, four open shelled) collected in a plankton haul, May 31.
Upper Rideau Lake, south side of lake just west of Narrows Locks - unknown number of veligers collected in a plankton haul, June 9
Upper Rideau Lake at Westport - unknown number of veligers collected in a water sample, reported June 22.
Opinicon Lake, near Newboro - reported by Gary Smith, Rideau Lake Fisheries Assessment Unit on June 22
Cataraqui River, approximately 1 km south of Kingston Mills - enough mussels to fill six one-gallon pails found by Rideau Canal staff on marker buoy 41, which was beginning to sink from the weight.
Rideau Canal, Lower Brewers Lock Station - one adult mussel found on debris retrieved from the bottom.
Rideau Canal, at Rideau Ferry - numerous mussels found on a boat that had been pulled out of the canal.
Big Rideau Lake, near Narrows Lock - adult mussels found on rocks where the barge (see 1st item) was docked last summer.
Rideau Canal, approximately 7 km north of Manotick - thousands of mussels found on a fiberglass boat October 16. The boat had been on this section of the river (between locks) since July.
1994
Rideau Canal, between Kingston Mills and Lasalle Causeway, south of the first lock on the Rideau, 4.8 km north of Kingston, hundreds (500+) of mussels attached to a steel floating channel marker. The markers hadn't been removed the year before.
Rideau River at Kars, at a marina, mussels on a boat which had come from Port Dover.
Upper Rideau Lake at McNally's Bay at a water quality collection site, 2 km north of Newboro - one 400um veliger found in a water sample collected May 24.
Opinicon Lake at Barrel Point, 1.5 km southwest of Chaffeys Lock - 3 veligers, 1 half shell found in a plankton haul collected June 20.
Big Rideau Lake in main basin, 4km northeast of Portland - one 250um veliger found in a plankton haul June 20. First time reported here.
Devil Lake (feeds into Newboro Lake but boaters cannot access it from the Rideau) approximately 13km south of Westport, one dead 250um veliger found in plankton haul July 11. First time reported here.
Lower Rideau Lake at Rideau Ferry - zebra mussels found on two boats which had been in the St. Lawrence River
Rideau River, throughout the lower section from Hogsback to Hartwell Locks, adult zebra mussels found on buoys and spars in this section of the canal, with the abundance decreasing going upstream. No zebra mussels noted upon reaching Long Island by Manotick.
Big Rideau Lake, 1km down from Narrows Lock end, 2km west of Freeland, reported October 31, 1994 - approximately 700 mussels found on a barge beached there most of the summer. It had apparently been at Hudson's Bay on Big Rideau Lake working on a boat launch in late July/early August.
1993
Lower Rideau Lake - 1 veliger collected by the M.N.R.
Hogs Back Lock - a number of adult mussels collected.
Indian Lake - adults reported on a boat docked near Chaffeys Lock - the boat had travelled to Kingston in the summer.
Opinicon Lake - adult mussels discovered in samples collected by the biological station located there.
Big Rideau Lake - adult mussels reported on a boat removed for storage. The boat had travelled to the Thousand Islands during the summer.
To report zebra mussels in the Rideau, call the Invading Species Hotline toll free at: 1-800-563-7711 or email: invading_species@ofah.org.
The Invading Species Hotline is a service run by the Ontario Federation of Anglers and Hunters. Visit their website at: www.invadingspecies.com
