Driftnetting The Flint River In Alabama
Started by
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, Oct 06 2010 08:38 PM
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#1
Guest_fundulus_*
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Posted 06 October 2010 - 08:38 PM
Four of us got out the Flint River east of Huntsville, AL, this afternoon to collect driftnet samples in this riffle system. We set up two nets, rather than the single net we've used at Estill Fork of the Paint Rock River. Here's a picture of the others who went out today. Someone had to stand and hold this net in place for the hour that we ran it, since the substrate of this riffle system is patches of thin sand over larger boulders and it's hard to drive a stake securely into this substrate. This picture is from the new Pentax Optio W90 camera I have. I've found it won't give you the highest quality shots in all situations on "Auto", but I think it will survive being used for this kind of work which is important to me. I should add that you're looking at primo banded darter habitat, bandeds were 35 of 72 darters we caught along transects at this site.
#4
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Posted 07 October 2010 - 10:42 AM
No fish, we were purely setting nets to catch drifting macroinvertebrates which of course largely feed fishes like darters. In this stretch of river 12 days ago we caught, in descending order of abundance, banded, black snubnose, rainbow, greenside, fantail, redline and stripetail darters. Under current conditions we think it's too shallow for logperch which might change if it ever rains here again. And yesterday was borderline wader water temperature, at 15 deg. C. Next time it will be waders for sure.Any fish photos? Looks like a nice spot for darters
#6
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Posted 07 October 2010 - 02:38 PM
That's a good question. We never found any at Estill Fork, a much smaller stream although there are native unionids present. In the mainstem of the Flint we may encounter them. The net is made of organza silk, with a 30 micron mesh. In principle we should be able to catch them. I'm not sure if they're too fragile and might get shredded in our handling of the drift. What we do works great for arthropods and even worms. My really ambitious scheme is trying to figure out how we could catch the larval stage of various trematode Dactylogyrid gill parasites, which range in size from 30-50 micrometer diameter. Even better, we'd have to be able to differentiate one species from the other.Ever look for glochidia or mussel larvae in those drifts Bruce?
#7
Guest_FishheadDave_*
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Posted 08 October 2010 - 05:05 PM
My really ambitious scheme is trying to figure out how we could catch the larval stage of various trematode Dactylogyrid gill parasites, which range in size from 30-50 micrometer diameter. Even better, we'd have to be able to differentiate one species from the other.
Sounds like you need a graduate student and some undergraduate work study students...
#8
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Posted 08 October 2010 - 06:49 PM
Well, that's who is in the picture at the top of the thread. I hesitate to put anyone on a fool's errand of lookin through liters of water when we might not even trap the larvae anyway. Just examining what we find in the nets takes lots of time as it is. We have a year's worth of monthly net data from Estill Fork awaiting the final ordination with CCA, along with ammonia-nitrogen, pH, TDS, alkalinity, temperature, flow rate and phosphate data for what should be an impressive matrix (let's hear it for matrix math!).
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