04/07/2004 Council Packet - Laserfiche WebLink

Home Search

adults and young had left the colony. There would have been sufficient time for young • herons to have successfully fledged by this date. • • We conclude from all these observations that at least some of the 300 + pairs of Great Blue Herons and a few of the 12 Great Egret pairs successfully nested at the Peltier Island colony this year. Please recall that at its maximum size in 1996, however, that this colony was home to an estimated 1100 pairs of three nesting species including an estimated 250 pairs of Great Egrets and at least 12 pairs of Black- crowned Night Herons. The No -Wake Zone Human disturbance — boats and aircraft Wayne LeBlanc reported all ice was off the lake by April 12th and that the buoys were in the water demarcating the no -wake zone. This year, the no -wake line was set in place well before the Memorial Day influx of boaters to the lake. The information sign at the boat launch and the no trespass signs on the island were in place in a timely manner as well. A lakeshore resident reported people on the island on May 17t. For the most part, however, boaters seemed to respect the no -wake speed limits and the no trespassing restrictions on the island. Compliance with the no -wake zone was apparently good and no observations of speeding boats scaring herons were reported. Helicopters were twice noted over the lake by observers. Seaplanes seemed to be complying with the request not to use Peltier Lake and apparently have relocated their training activities to Big Marine Lake in Washington Co. The DNR received a report in early July of increased seaplane use of Big Marine Lake with the consequent death of loons which were reportedly being "runover" by the planes. This report of loon mortality is unconfirmed. In September, we had a request from DNR Forestry to use the lake for firefighting planes to scoop water if needed. Because the birds had finished nesting by this date, we concluded that such plane activity would not be a problem in late summer or fall. Water Quality and Aquatic Vegetation The water depth north, west and east of the island is shallow, being roughly 1 meter (3 feet) deep. Consequently, the submergant aquatic plants in this area are extremely vulnerable to disturbance from high speed boat traffic. This disturbance has been documented on aerial and other photos from previous years showing a roughly 2,000 foot by 200 foot area of reduced native aquatic vegetation north of the island where the slalom water -ski course was previously located. Observations in the summer of 2003 show native plants beginning to return to that area. We believe that the no -wake zone restricting boat speeds has been crucial to the recovery of these aquatic plants.