Pond Boss Forums INTRO Questions & Observations BG Die-Off, 140 and counting. Help!

My bride and I drive long-haul, so we are home every 2 months or so. Came home this time to 140 dead medium to large BG, slightly decayed to relativey fresh. Here are the pond and weather facts.
200' X 300', 18' deep at this time. 45* sides.
Auto-Feeder off since late October
Lots (and I mean LOTS) of BG
175 LMB introduced last Fall
150 Channel Cats, mostly 6" but up to 10".
No dead Bass or Cats
Saw 2 almost dead BG but no others as I cleaned up the dead this morning.
All dead BG are of medium to large size, no babies.
Pond water pretty clear, no smell, BUT...
We had severe winds on the 14th of Dec.
We are in Southern Oregon and the pond does not freeze over. Temps have been cold to freezing though, no ice on pond at all.

Question: Could this die-off be caused by turn-over, or would "over-crowding" cause just a BG die-off? Help! Thanks for any help.

Overcrowding allows stressors to affect fish, leading to bacterial infections, diseases and death of weaker fish. If a die-off is similar size, singular species, it is probably disease related. If multiple species, multiple sizes, it is probably water related.
If water temps are warmer than 55 degrees F, you can feed the fish medicated feed.

Thanks Bob. That sounds correct to me, common-sense-wise anyway. The 2 lethargic BG I saw this morn had darkened vertical stipes, unlike the normal pale and light-green sides the BG normally have. The water temp is well below feeding temps now. Will have to wait for early Spring here. Will aerating help in any way?

I'm studying medicated fish food. How do I know if it is 'parasites' or 'bacteria', or should I just treat for both?

Double-Camp:

See this link from the archives where Bill has some info and a good link on Fish Kills.


http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=22;t=000038

Read my blog for tilapia. It gives a good recipe for medicated feed. Try feeding, see if they will come at all. They may. If not, don't medicate the feed.

Excellent link! The only stressor that is new to the pond is a flock of 10 (or so) Merganzer diver-ducks. As we are gone most of the time, we don't know when they arrived, BUT, they are having a field day out there with the fish. I am wondering if they are a mixed blessing, along WITH the die-off. I introduced the bass to help kill off the too-many BG in the pond while growing fat in the process. (The original idea was to keep the pond stocked for the many kids that fish it, but the BG still over-populated. I guess I'll just ride this out and see if only the larger BG are the ones dying. I will keep ya'll posted. Thank you so very much for the help. I was despairing for sure. 4 years of babying this pond along looked to be turning into a disaster, but it appears pretty localized. I'll do another dead-count in the am and report it back here. Again, Thank You.

Bob, good recipe in your blog! I didn't realise that we can use human vitamins on our fish! Checked the die-off again before sundown and from the marks on a few of the 10 dead and dying BG, and too, watching the aggressive nature of the Hooded Merganzers, I am going with stress and actual wounds killing them at this time. (I watched a Merganzer catch and swallow a BG that was 3 times as big as it's own head!) It is like I have my own Cormerans (sp?)... As they just migrated in, I will help them fly on down south tomorrow...

Double-Camp

You may want to look at these 2 threads. The first takes a questioner through a winter BG dye off to assess what and why they were dying. The second is a list of diseases/stressors.

http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=7;t=000311


http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=7;t=000295

Good stuff! I am quite settled into one of the facts that the BG population is simply over crowded, since that is all I am losing right now. I mean, when the feeder goes off (Spring thru Fall), am + pm, it looks like a Hollywood African Pirahna feeding frenzy, seriously. An area 100' in diameter boils up. Along come the Merganzers in the dead of winter and from what I can observe by their success, the poor fish have GOT to be stressing, bad. A good point made was, if I don't fish it out, Mother Nature will ajust the numbers for me. I was warned here (PB) that an "all BG pond" was not a good idea, and they were right. I thought it would be fished more. The plans of mice and men... I introduced about 150 small, medium and large LMB last summer, and 150 small CC, but too little, too late no doubt. As long as I'm not losing Bass or CC, I guess I'm doing OK. I'd leave the Merganzers alone except for the fact that they might get into those small cats eventually, and persnally, that would be my biggest food loss. Words do not express my appreciation for all of you PB folks in here. PB has been, for me anyway, equivelant to an "Online College Course" in fish/pond biology. I am calling to re-new my sub early and also get another pond-owner friend a sub to PB magazine. (-:

Sunday Update: I harrassed the Merganzers a little the past few days, and a LOT this morning. My die-off has practically stopped all together. 10+ aggressive large diver-ducks on a highly BG populated 1.75acre pond is cause for major stress I would think. (My neighbor did say that he found 3 dead (small 6") LMB that he tried to disect, though didn't really know what to look for.) This has been a real eye-opener for me. Just another day in the classroom of Pond Knowledge. Now that I have the "cause" narrowed down, Do I protect the over-populated BG numbers, OR, let the diver ducks and Mum Nature thin and stress-kill the BG out, taking the chance on losing a few LMB and CC in the process?

Protect the fish, send the mergansers on their way. As your bass grow, they will consume more (and larger) bluegill. Even though your pond may be out of balance now, a correction has already started.

Bob, once again, thank you. I was torn on this one, but leaned on the side of protecting the fish, so I went ahead and "stressed" the merganzers with barely 'out-of-range' peppering with the 12ga. No dead fish this evening. Merganzers are as smart as they are hungry, and getting shot at is NOT their cup of tea... I am encouraged to think how big and fast the Bass will grow with all that feed (BG's) in there! I'll keep you posted.

Temps have been cold to freezing though, no ice on pond at all

We had severe winds on the 14th of Dec.

I don't disagree with Bob whatsoever as you obviously have some clinical signs of disease and your fish density sounds very high for such a small pond, but too me the obvious stressor was the severe high winds and cold temps that probably mixed and changed water temps drastically. Too quick a change in water temps is very stressful on fish. Disease problems are trigged by a stresser and to me it's obvious what it was, considering you folks had winds up to and past hurricane force with that freak storm. I believe some areas out there had 90 mile an hour winds?

I have seen my fish stressed out by rapid water temperature changes. Additonally since there were so many they many have gone into winter in a weakened state due to less then optimum feed for all of them.

Yepp. The winds here in S Origun were such that my floating fish-feeder, with 2 8"X16" cement blocks for anchor, was dragged across the pond to the opposite side! But, that was 11 days ago, and until I dealt with the merganzers, the die-off was still appearing to be 10~20 BG a day. Exit the merganzers and the die-off stopped. The merganzers came back this morn, and in an hour of daylight that I wasn't watching, I had a bunch (uncounted yet) dead and dying BG along the shore already; a direct result of the merganzers. However, I agree that the added stressors of wind and temps exasperated the situation. And too, this is a 'normal' Origun winter, but this is the first year that the killer-ducks have found this food source. As far as disease, after the migrating merganzers leave, at what daily count, if I still have BG dying, should I be concerned?

It should run it's course. Personally if you are out in the middle of nowhere where no one can see what's going on... I would shoot, shovel, and shutup. It sounds like the birds are stressing the weakedend fish further by running them around under water. However in all fairness to the birds, they are doing what they are intended to do -- remove sick and dying fish.

Cecil B, I agree. The birds are just doing their "bird thing", so I elected to 'pepper' them at a distance, BUT,,, As I have said, Merganzers are really smart, and by this morn, I raked them pretty good and at first they just sort of flinched,,,,, Flinched at a blast from a 12ga!!! and then flew away at their leisure. The thing is, if i don't hassle/thin the merganzers, that many on my small pond will eventually wipe me out of BG, and most probably more. They are relentless hunters and I am seeing that they really do a number on the BG in very little time. Many of what they don't eat or wound, seem to have little heart attacks and die anyway. But too, a scare-crow after a season of peppering them might be the key. I have another week home to experiment, and then it's back on the road and the pond is back in the Lord's hands...

Killem all. Leave the expired Merganzers in Gods capable hands.

Good, effective advice. hehe* I'm just glad that we don't have cormorants... At least the merganzers aren't protected. As of this morn, I have no more dead BG!!! It coincides directly with the amount of 12ga rounds expended. Seems the closer I get to the fish-killers, the more the 12ga 'stresses' them right back. (-:
I will keep the posts coming when Spring and warmer feeding temps arrive. The CC will be the summer's interest for me! Thanks again for all the help, direction and plain-ol'-encouragement!

Uh, I expect they are protected.

Protected? They only wish... Nope. They have a season on them just like any other duck. I 'hear' that one can eat them, but they are a fish-eating-duck, so I guess ya soak them for 2 weeks in cheap wine, throw the duck away and drink the wine. Anyway, the score is Ducks m-10, BG zero dead today... Sure glad that it didn't turn out to be disease. The weird thing is, merganzers are river ducks. Can't figure out how they found me way out here in the country?

Could be our the freaky weather you had. Maybe they were blown off course?

WHich merganser? Common limit is duck limit 6 if hooded it is 1. They might be called river ducks but frequent most every pond we manage for high numbers of fish. BTW I never kill anything that I at least do not "try" to eat. Man oh man the merganser ranked right up there with the crow I tried. Just say this the house smelled like rotten fish for a week and do not feel bad shooting them and getting pic made and then feeding them to the opposum. They do decoy quite well however and hoddy drekes make great mounts.

Yepp. These are the 'hooded' variety. And yes, they wreak havoc on my BG here. I mean, I cleaned up all the dead and dying, took my eyes off the pond for 1 hour, and went back out to 15 dead fish, NOT counting the BG they simply ate! That's when I introduced them to my 12ga. And SMART??? I consider these 'hoods' to be the coyote of the bird world. I suppose that comes from their preditory nature. Any suggestions on how to "scare-crow" them away while I am out on the road? I'm too close to others for a carbide cannon, though truthfully, I doubt just noise would work anyway.