Thursday, April 19, 2012

Field Notes: Week 2 on the Conasauga River


After a week of some cooler weather, TNACI and CFI returned to the Conasauga River for two more days of field work.  We spent the first day catching more Conasauga Logperch and the second day  releasing juveniles at various locations in the Conasauga River. 

On April 12 we worked a 3 mile stretch upstream of the site sampled on April 5.  While the procedures for this week were the same as last week, the conditions were very different.  The water temperature was 50°F when we arrived in the morning; cold enough that some members of the team wore dry suits.  The rest of us wore 7 mm wet suits and everyone wore gloves and hoods to stay as warm as possible.
Dr. Anna George in a dry suit.
Despite the chilly conditions, it was another successful day on the river.  We were able to get nine more fin clips from Percina jenkinsi.  We also caught a few Mobile Logperch (P. kathae) who were also photographed and fin clipped.

Photographing and fin clipping Logperch
In the field it can sometimes be challenging to distinguish between Conasauga Logperch and Mobile Logperch initially.  However, upon closer observation there are some differences in the two species that make them distinguishable from one another.  One of the most distinguishing features is the red or orange color in the first dorsal fin of the Mobile Logperch.  The markings on the two species are different as well.  While both have bars, or “dorsal saddles,” down their body, the markings on the Mobile Logperch are a bit duller.  Conasauga Logperch have more defined stripes, a "teardrop" marking under the eye, and no color on the dorsal fin.  

Conasauga Logperch (Percina jenkinsi)
Mobile Logperch (Percina kathae)


While we were on the hunt for the very special Conasauga Logperch we were fortunate enough to see a few more aquatic animals that call the Conasauga home.

Coosa Darter
Crayfish
Hogsucker with a Lamprey attached



Speckled Darter
On April 13 we returned to release juvenile Conasauga logperch that had been hatched at CFI and reared either at their facilities or at TNACI.  We split up into two groups to cover almost 7 miles of river and release around 200 fish!

Releasing captive-bred fish into the wild is much more complicated than just dumping a bag full of fish into a river.  It takes scientific study and planning. During the previous two trips on the Conasauga, we took GPS coordinates of riffles so that we could designate release sites.  We also had four groups of juveniles (distinguished by the color and placement of their fluorescent elastomer tags).  Individuals from each group were designated to a release site.

Tagged juvenile Conasauga Logperch.
The water in which the fish were transported was a bit warmer than the river water, so the first step prior to release was to get the fish acclimated to the water temperature of their new home.  To begin the acclimation process, we placed the closed bags directly in the river.    

Pat from CFI acclimating fish.
After a little time getting used to the temperature, some water from the Conasauga River was placed directly into the bag to continue the acclimation process.  With our plans in hand and the fish acclimated, we loaded the bags into our boats and set off down the river to release these young fish into their new environment.
  
One of the release sites.

Evan getting ready to release Conasauga Logperch.
After being released, some individuals did not swim away immediately, giving us one more chance to photograph them before we left. 


We will be back on the Conasaua River soon to release the rest of this year's juveniles.  We will then continue monitoring the population of wild Conasauga Logperch, and we hope to recapture some of these individuals in the future. 


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