Why Dead Fish at Lost Creek?

[Trent_S]

I took my toon out on Lost Creek today. After launching I noticed many dead fish all along the bottom in about 10 feet of water. There were at least 100 that I could see. I am pretty sure they were trout and all the same size (about 12" long). The water temp was 67F today. The visibility was about 10'. I am guessing these were planters that had some sort of acclimation problem (perhaps with oxygen)? On my sonar I saw other masses of fish along the bottom in that area that might also have been dead (they were more like bumps on the bottom than arcs). These fish were already grey colored and starting to rot. They probably did not die today but several days ago.

Are there any experts on this site that know what the cause is for this? 

Thx.

[Anglinarcher]

Without more data, I am not sure that anyone could be an expert on this one.  If the fish were 12", they were not recent plants, the state has this habit of planting 9.25" fish this time of year.

The heat spell we are in could indeed be causing an oxygen problem.  We went to high heat very fast and if it created a shallow thermocline, that might explain it.  I sure hope not.  The first good wind should and may already have busted up a shallow thermocline and a new one will develop deeper.

Lost creek is suppose to be 67% full, so with the depth we should still have more than enough cold water.

This is concerning, but I fear it is the first of many such reports this year to come out.

[GpaRon]

I happened to be at Lost Creek on Wednesday fishing.  While pulling my boat out sometime after lunch I saw that a few pelicans were congregated around the ramp and there were several 8-9" (certainly not 12") rainbow planters lining the bottom of the ramp and surrounding area. I had noticed sometime mid morning what appeared to be the fish tanker truck pulled up on the ramp and unleashed the unlucky guys into their new environment, apparently several didn't even survive the trip to the water. The pelicans and sea gulls ate well that day! I guess there were still some left over when you arrived.  Because all the dead fish were / are around the ramp it wasn't an issue with die off or another strange happening.

BTW- fishing was a little slow in the windy conditions Wednesday. Between my grandson and self we managed to land 6 (5 slot cuts and one decent rainbow).  The water is way down and there are a few spots showing shallow out in the center of the lake that I never worried about before, had to be paying attention with the downriggers.

[wiperhunter2]

Thanks much for the rest of the story about what happened to those fish and welcome to the site.

[Anglinarcher]

GpaRon, that does indeed answer the question. THANKS.

[Joe_Dizzy]

Guess its a real problem for the slime rocket factories this year... low/warm water and crap loads of hatchery-raised 9" rainbows that need to be dumped into the drink.

Freshly stocked trout into 67* F surface temps is not a good formula for success. At those temps fish are getting into their stress zones with respect to dissolved oxygen. These fish are typically disoriented to begin with after their truck ride and swim along the shoreline in loose schools - sometimes for days before normalizing to their new home.

Thermal shock is not uncommon by the way. All trout anglers should carry a thermometer, especially if you are C&R angler. Even fish that seem to swim away normally in risky water temps will be very challenged to extract the needed oxygen from warm water. Many fish nose dive to their grave after being fought/released under these conditions.