Shallow Lake Management Strategies. Steve McComas Blue Water Science Shallow Lakes Forum April 2014

Transcription

1 Shallow Lake Management Strategies Steve McComas Blue Water Science Shallow Lakes Forum April 2014

2 Shallow Lakes and Ponds Are Similar Shallow Lake Goal: Clear water and macrophytes. Clear Turbid

3 Aquatic Plants Are Key (Use the 40% Rule)

4 Web of Interactions in a Shallow Lake or Pond

5 Watershed Projects Are Essential Phosphorus fertilizer restrictions Rain gardens Stormwater ponds

6 Biomanipulation Is One Strategy Biological manipulation within a lake can occur at several levels.

7 Watershed Projects: Metro Area: Land of 10,000 Ponds Stormwater Ponds Act Like Shallow Lakes TP in Pond TP out Can they be a neighborhood resource and still remove TP?

8 Could Fish Be a Factor In Stormwater Ponds? (top-down effects)

9 Stormwater Ponds 2 to 4 feet Deep. Do They Support Fish? Stormwater ponds sampled with mini-fyke nets.

10 Some Stormwater Ponds: No Fish

11 Some Ponds: Fathead Minnows 40 pounds per net.

12 Shallow Urban Lake: Powderhorn, Minneapolis, MN 11 acres Both Bottom-Up and Top-Down Approaches

13 Bottom-Up and Top-Down Projects

14 Microbes and fish were manipulated. Powderhorn Lake

15 Bacteria Algae Manipulations Add organic carbon to enhance microbial growth and outcompete algae for phosphorus.

16 Powderhorn Lake Barley Straw Was Installed (350 lbs/ac).

17 Powderhorn Lake

18 Fish Manipulations Benthivores (carp) get the attention, but omnivores (black bullheads, fathead minnows and bluegills) can be factors as well.

19 Powderhorn Lake Channel Catfish Were Stocked by MnDNR (10 fish/acre for several years) 2 year gape 3year gape

20 Powderhorn Lake Secchi Disc

21 Lake Projects: Lee Lake, Lakeville, MN 25 acre lake Barley straw (350 lbs/ac) Fish removal 100 lbs/ac Alum treatment

22 Lee Lake

23 Lee Lake Alum Application

24 Alum Effect

25 Lee Lake Secchi Disc

26 Managing Lake Monsters Famous Lake Monsters Around the World Nessie: Loch Ness, Scotland Ogopogo: Canada Champ: Lake Champlain

27 Any Monsters in Your Lake?

28 Flying Carp

29 Source: wikipedia Chinese Mystery Snail

30 Carp

31 Curlyleaf Pondweed

32 Eurasian Watermilfoil

33 Zebra Mussels Photo courtesy of USGS

34 What Can We Do? Non-natives don t take over every lake.

35 Carp Population Dynamics And Control

36 Riley Lake Susan Lake Carp Habitat

37

38 Foreign fish dumped into ponds, lakes are removed by traditional 'kaibori' method War on invasive species continues The Japan Times (4/8/14)

39 Curlyleaf Pondweed

40 Early Season Scouting Challenge: (Curlyleaf Pondweed Increases in Density) Early (single stem) Late (runners) (Curlyleaf pondweed puts out runners from April to May)

41 Curlyleaf Pondweed in Mooney Lake April 11, 2012 (14 acres)

42 Mechanical Harvesting

43 Herbicides Contact herbicide

44 Coontail: Can be a native invasive species

45

46 Zebra Mussel Growth Characteristics Light Growth Heavy Growth

47 Growth Factors Shell Formation: calcium Food: algae Substrate: rock, wood, sand

48 Substrate Sand/Silt (Moderate Growth)

49 Substrate Clumps Found on Sand/Silt Bottoms

50 Round Lake Zebra Mussel Habitat Suitability Map Green = limited growth (low calcium) Blue = no growth (low oxygen)

51 Lake Riley Zebra Mussel Habitat Suitability Map Yellow = moderate growth (Blue-green algae) Blue = no growth (low oxygen)

52 Red Rock Lake Zebra Mussel Habitat Suitability Map Yellow = moderate growth (Blue-green algae) Green = light growth Blue = no growth (low oxygen)

53 Mitchell Lake Zebra Mussel Habitat Suitability Map Yellow = moderate growth (Blue-green algae) Green = light growth Blue = no growth (low oxygen)

54 Can Zebra Mussels Be Controlled? (large scale: Zequanox)

55 Zebra Mussel Control (large-scale: Drawdown)

56 Zebra Mussel Control (small scale) Small-Scale Control Techniques Are in progress Zebra mussel harvester is an option.

57 Zebra Mussel Harvester

58 Zebra Mussel Harvester

59 Summary Many lakes have monsters. Some monsters will have a worse impact in lakes compared to other lakes.