Fisheries biologists, I've got a population sampling question

  • We are currently upgrading MFK. thanks! -neo
L

Longshot

Gambusia
MFK Member
May 28, 2012
308
0
16
Central Texas
I know there are a few of you lurking, so could I get some opinions?

I'm working on my Master's degree research project where I am taking about 30 years of detailed water quality data and pairing it with 30 years of good fisheries data. I'm coming from the water quality side of things and have some questions about sampling methods. The two main forms of collection are gill netting and electroshocking. I've just started entering data and am wondering if I can cut corners on entry by using only gill netting results.

Is there an advantage to including shock results? Also, if I do keep it, should I dump it in with the gill net to be doing my population calculations or should the calculations be separate since there is a significant difference in the quantity of fish sampled.

I'm still doing reading on it but just looking for some other points of view.

Thanks!
 
Well electroshocking has no bias on the fish size, fish species or habitats. Gillnetting may be a little biased since they can only set up in specific parts of the lake and that only fish that is big enough to be caught in the gill nets. Not mentioned that several species of fish avoid the gill nets where other species are vulnerable to the gillnets but that's my experience.
 
don't wanna sound too dumb, but can electroshocking JUST stun fish only w/o killing them, or does it only kill them?
 
I believe it only stuns the fish, but i'm sure there are always random fatalities in sampling? Don't quote me on that one.
 
Cod said:
don't wanna sound too dumb, but can electroshocking JUST stun fish only w/o killing them, or does it only kill them?
Click to expand...
Stun them most of times.
 
MN_Rebel said:
Well electroshocking has no bias on the fish size, fish species or habitats. Gillnetting may be a little biased since they can only set up in specific parts of the lake and that only fish that is big enough to be caught in the gill nets. Not mentioned that several species of fish avoid the gill nets where other species are vulnerable to the gillnets but that's my experience.
Click to expand...
True, I guess what is an extra 200 fish? I've already got 1200 entered after working on it this last week about 2 hours per day.

Empyreal said:
I believe it only stuns the fish, but i'm sure there are always random fatalities in sampling? Don't quote me on that one.
Click to expand...

Sometimes it just stuns them, other times it overrides the nervous system. The Scottish Fisheries Coordination center has a really interesting training manual that I stumbled across.
 
Personally I would think that you should do calculations separately each methods but that's just me. I take it that 200 fish came from electroshocking?
 
I would just dismiss the electroshocking data and focus on the gill net results.
 
You must log in or register to reply here.
MonsterFishKeepers.com
Top Bottom