7 April 2013
I had an opportunity today to photograph a shrimp bloom in Kathleen Lake and measure the lake level drop in the past by use of a laser level from waterline to permanent vegetation at the forest edge. The history of Kathleen Lake is covered in this overview by Friends of Knox Mountain. http://www3.telus.net/fkmp/society.htm
Location
http://wikimapia.org/21731033/Kathleen-Lake
For the shrimp [Class Branchiopoda], I used a fine mesh dip net for live sampling, photography and then returned the subjects to the lake. Here are my results.
Limnologist at work.
Lake overview. Kathleen lake may be an old vent of Tertiary vulcanism 50 mybp volcano that is Knox Mtn. Note the forest edge which was the high water wetted perimeter at some time in the past century.
In this picture, it is obvious that after all the snow has melted in the draw dowwn area and drainage slopes, there isn't enough water to inundate the cat tails. The foreground is growing into thistles, other species, sedges and grasses through riparian succession.
Standing at lake level my laser held at eye level, the beam struck the middle of the dead wood clump just below the left hand grass clump. To the grass edge would add another few cms. Estimated water level drop below normal high water wetted perimeter is 1.83 m +/-.06 m.
Long ski pole for scale.
The shrimp bloom members appear to belong to a single species, either fairy shrimp or brine shrimp. I will attempt to key them out from the photos.
Secchi disk reading at about 1 ft to illustrate shrimp density at a normal sample site.
Not sure which species it is but some pics and an Anostraca key can be found at this site for those interested.
http://museumvictoria.com.au/pages/36868/timms_scireport_16_final_14june2012.pdf
More key information.
https://www.google.ca/search?q=Anostraca+keys&hl=en&client=safari&rls=en&tbm=isch&tbo=u&source=univ&sa=X&ei=YtlhUf7kOYOdiQKH5IDQCw&ved=0CHQQsAQ&biw=1066&bih=668
The shrimp hatch is being used by waterfowl for filter feeding and is also no doubt a boon to dragonfly and damselfly larvae in the pond as well as visiting shorebirds. I am not aware of any fish that are in this lake but there should be considerable salamander activity emanating from the hatch.
For more information and the future of Kathleen Lake, see the Knox Mtn Management Plan. http://www.kelowna.ca/CM/page2063.aspx
Copyright 2013 Jorma Jyrkkanen. All rights reserved.
- Current Mood:
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