Lake Surveys: Trap Net vs. Gill Net

[Vitreus]

Which is a more accurate standard to consider? Some will show fish numbers in the average range for one type of net but far above or below for the other. Does it depend on species?

[goblueM]

All sampling gears have some sort of bias/selectivity to them. Depending on mesh size of gill nets, funnel opening size and mesh size of trap nets, you might sample very differently-sized fish.

And it does depend on species somewhat, for example bass are notoriously net-shy, whereas walleye and perch are much more prone to getting caught by these gears.

I like to look at the breakdown of size structure for all gears and combine that with my knowledge of the lake, which might come from fishing it personally or from reading up about it on a forum. Sidenote, make sure you pay attention to the year the survey was done. A survey from 1994 might not be very useful, for example

[Vitreus]

Huh, so I wonder if they maintain a similar size mesh for all sampling in order to keep all of the surveys on an even playing field. I'm going to call the DNR tomorrow and get more details. Thanks for your response. If I find out anything useful, I'll be sure to add it here.

[goblueM]

The answer to your question is yes - they have standardized sampling procedures, setting the same amount of nets with the same mesh sizes year after year, usually at the same time every year. Without that, it'd be very difficult to make any inferences about these data.

[Stick in Mud]

Is there any way to control for water temps or "funny" weather, goblue? I'm thinking specifically of a place like Mille Lacs this spring, when the water was warmer than a normal year and the fish (the bigger ones, anyways) were out of their normal early-season spots earlier than normal.