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So for the last week I've been out with a couple of grad. student sampling a series of 4 lakes we use a reference systems up in Eastern Ontario. The lakes are Sharbot Lake (the one with a provincial park on it), Eagle Lake, Buck Lake and Devil Lake. They are all your classic deep water lake trout lake also containing cisco (a herring species) and mysids (a large zooplankton eating invertebrate).
We are studying the lakes and tracing contaminant movement through their foodweb. The contaminant levels are very low and we are more interested in using the contaminant signatures as ecological tracers rather than assessing pollutants. Our days were pretty long. On Thursday for example, we started work at 6:00 am and ended up the night at 1:00 am (with a couple of meal breaks). It was pretty intensive sampling because different critters had to be captured at different times. Also we are sampling (legitimately through a OMNR scientific collector's permit) with gill nets for the fish and thus had to check them over short intervals to limit bycatch (fortunately this worked out well).
Our first lake - Sharbot Lake, which we've been studying for about 5 years now. This is right off the public ramp:
Some loons on Sharbot
Our two sampling vessels, one a 17' aluminum boat with 25 hp outboard and the 2nd is a rubber dingy - with a keel, solid floor and 8 HP merc. outboard. The dingy is quite nice for the more remote systems where ramp access is not available. With two people you can man handle the boat in place (although its still weights 100 + lbs).
During the day we were using a grab sampler to collect various invertebrates in the shallow (littoral) zones. This was an attempt to get a good handle on contaminants in the diet of one of our study species - the bluegill sunfish. We were collecting gram quantities of isopods, dragon fly nymphs (odonata), caddisflys, damselfly nymphs, small snails and oligochaetes.
One of the grad students was also snorkelling to collect freshwater clams - the water was a balmy 14oC !
At night, we used a course zooplankton net to collect mysids - these large zooplankton inhabit the deep waters (60 + feet) and stay near the bottom by day. At night, they rise up to the surface and follow their smaller zooplankton prey which also undergo diel vertical migrations to feed on plankton at night.
Here is a close up of the mysid
This a shot of Eagle lake - amazing cottages on some of the small islands out there!
We are studying the lakes and tracing contaminant movement through their foodweb. The contaminant levels are very low and we are more interested in using the contaminant signatures as ecological tracers rather than assessing pollutants. Our days were pretty long. On Thursday for example, we started work at 6:00 am and ended up the night at 1:00 am (with a couple of meal breaks). It was pretty intensive sampling because different critters had to be captured at different times. Also we are sampling (legitimately through a OMNR scientific collector's permit) with gill nets for the fish and thus had to check them over short intervals to limit bycatch (fortunately this worked out well).
Our first lake - Sharbot Lake, which we've been studying for about 5 years now. This is right off the public ramp:
Some loons on Sharbot
Our two sampling vessels, one a 17' aluminum boat with 25 hp outboard and the 2nd is a rubber dingy - with a keel, solid floor and 8 HP merc. outboard. The dingy is quite nice for the more remote systems where ramp access is not available. With two people you can man handle the boat in place (although its still weights 100 + lbs).
During the day we were using a grab sampler to collect various invertebrates in the shallow (littoral) zones. This was an attempt to get a good handle on contaminants in the diet of one of our study species - the bluegill sunfish. We were collecting gram quantities of isopods, dragon fly nymphs (odonata), caddisflys, damselfly nymphs, small snails and oligochaetes.
One of the grad students was also snorkelling to collect freshwater clams - the water was a balmy 14oC !
At night, we used a course zooplankton net to collect mysids - these large zooplankton inhabit the deep waters (60 + feet) and stay near the bottom by day. At night, they rise up to the surface and follow their smaller zooplankton prey which also undergo diel vertical migrations to feed on plankton at night.
Here is a close up of the mysid
This a shot of Eagle lake - amazing cottages on some of the small islands out there!
