Jill VanWalleghem, a local MNR biologist, spoke to Rotary on the growing presence of “invasive species” within the lakes around Dryden.
What are the characteristics of an invasive spices? It has few predators, is adaptable to local conditions, reproduces quickly, thrives in disturbed systems, and out competes the local species for food and habitat.

5 Invasive Species in the Dryden Area

​VanWalleghem focused on five species which have entered our eco-system in the past decade :
  1. Rusty crayfish
  2. Spiny waterflea
  3. Black Crappie
  4. European frogbit
  5. Purple loosestrife

Rusty Crayfish 

Tears up weeds in the lake destroying fish habitat; 
Eats invertebrates (food for fish), fish eggs, at twice as much as native crayfish;
Reproduces quickly 
And is found in Eagle Lake

Spiny Waterflea 

Eats lots of zooplankton (food for fish)- can decrease numbers by 40%!
Fish with a stomach full of spines can’t eat or grow as much.
Small fish spit them out but large fish can't digest the spine.
Multiplies very quickly; eggs stick to boats, fishing equipment, and birds. 
Reports in Eagle Lake.

Black Crappie 

Yes, this is an invasive fish. It was introduced to our lakes about 2004.
It reproduces quickly and compete with walleye for food. They are voracious eaters. 
Can reduce numbers of walleye, pike. 
Not nearly as desired by anglers as walleye. 
Found in Wabigoon and Rugby lakes.
Has the potential to do economic damage to tourist fishing industry and The Walleye Master Tournament.

European Frogbit 

Grows quickly, makes dense mats;
Block out sun for other plants;
Nuisance for swimmers and boaters;
When it becomes large mats, it dies, decomposes and this impacts water quality.
Currently in Wabigoon/Dinorwic Lake in the quiet bays and the Laura Howe Marsh.
New plants can develop from stem fragments; and it can harm wild rice and be spread by wild rice boats.

Removal Efforts

It is possible to knock mats like this back, but very difficult to completely remove.

 Need to reassess next year to see if the spread is reduced in the marsh


Purple Loosestrife 

Loosestrife makes thick mats of roots crowding out native plants;
Impacts wetlands, roadsides, farmland, disturbed areas;
A few stands have appeared in the Dryden Area.

So what can you do?

Stop the Spread by
  • never moving species from one place in nautre to another
  • learning to identify invasive species
Spread the Word by
  • helping to raise awareness
  • spreading the word about what invasive species are in the area
Cleaning your boat between lakes
  • using hot water, or a pressure washer or leaving it in the sun for five days.
Don't dump your bait bucket into the water.