Water Chemistry Results

Division of Wildlife - Getting intimate with Summerhawk's denizens of the deep!

Division of Wildlife conducted a electrofishing survey in the creek on Thursday, and not only did I meet a lot of really neat biologist folk - who always have a special place in my heart, but I learned a ton about our native species, got acquainted with some neat fish folk and learned how such a study is conducted.
 

Just downstream of the beaver hooch, a Division Of Wildlife team sweeps West Divide Creek with nets and electrodes used to deliver a mild shock to the fish and other critters living in the creek. Momentarily stunned, the fish are quickly collected to be identified, measured, and weighted. Once recorded, the fish go to a temporary holding pen until they are released back into the creek. This procedure is performed twice. This method produces a strong survival rate - despite the disruption to the aquatic life. In fact, even among the very tiny minnows, all injuries I observed (two) out of the many many fish recovered were caused from either netting or tromping mishaps - an unavoidable consequence of recovery of the specimen. I was very impressed with the professional care and thoughtful manner these folks exhibited in the conduct of their work.
 

Team members drag buoyed cable necessary to produce the electrical current used to stun the fishes. The team member on the far right is approaching the seep pools. Two live crawdads were collected from that location. I saw several dead crawdads here last week. A portable generator provides electricity for the operation. Each sweep, along 445' of the creek, lasted about an hour and a half.

The survey generates a species list, species’ population estimates, and age class information for different species.  DOW measures the area (total stream length and average of five stream widths) to determine density estimates of different species.

Divide Creek was up ten inches or so from last week (the irrigation ditch is low flow and the waters have been returned into the creek as ranchers cut hay for harvest). The higher waters have flushed the western and eastern pools where the orange gunk was previously quite prevalent. It is still prevalent in certain areas, but what looked, last week, like a large orange algae bloom has washed away. Just below the orange seep (above left) a dead crawdad lay between some rocks. It was the only one visible (above middle). A DOW team member recorded the dead crustacean in a photograph (above right). We also discussed the color of the creek. I and a family member had taken note of the discoloration, but when DOW mentioned it - that got my attention. The waters are clear yet appears tea-stained. This is an strange occurrence, as usually, by this time of year the waters look like any other creek - clear and reflective of the bottom colors and sky. I look at the orange gunk on the bank near the seep and I wonder about the orange-red-brown tint. I wonder if it's related? I wonder how much of West Divide Creek looks like this? Maybe I'll take a drive and look around upstream next week.

Meanwhile, team members conduct an invertebrate count. One member holds a net equipped with a collection canister (not visible) and another member scuffs up the creek bed. The natural flow of the creek causes dislodged snails, larvae, crawdads and other invertebrates to funnel into the net and canister for later transfer into a jar (above right) where they will be recorded.

After recording, fishes await the holding pen in these shared and (when big fishes drop in, too) cramped quarters! Fish only hang out in here for about 10 minutes max.... [07-10-08]

Fishes await release into Divide Creek after a short bivouac here creek-side. [07-10-08]
 

Upper row of specimen photos: 1)  Speckled Dace   2) Roundtail Chub   3) Bluehead Sucker   4) Roundtail Chub 

Lower row of specimen photos  5)  Bluehead Sucker   6) Crawdad (specific subspecies to to be identified)

Interestingly, the creek count yielded no trout. Folks have caught trout out of the creek before, and Mr. Langegger, also seemed surprised at their absence. But the lead biologist noted that trout are sensitive to both sediment and warmer temperatures, so those things could be factors.

The crawdad on the bottom right is probably five inches long or more - a biggie! Most are the size of a thumb and light greenish brown. This doozie was nearly completely black and well equipped to put the pinch on anyone not handling it correctly. The best way to grasp a crawdad is on the thorax - right behind the head. They will wave their claws about, but cannot easily grab hold. 

Only one frog - a leopard frog was collected, but it hopped away. We used to have tons of frogs in the creek - now, not so many.

At the end of the day, after sweeping 445' of West Divide Creek over riffles, pools and braided stream, an estimated 500 fishes were cataloged and released. Of the fishes, all four native species were accounted for in different stages of maturity indicating on-going breeding. Only a small number of one non-native species was present! 

I appreciate the DOW's effort to inventory the fish in Divide Creek.  It was a very special treat to be able to participate in this study and get up close and personal with our amazing denizens of the deep!

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