Pond Boss Forums INTRO Questions & Observations Can Otters do this much damage?

Hi,
First time poster here. We bought some land with a 17 acre lake/pond on it. Put in an aeration system, and dredged it, now 8 foot max depth. Central Wisconsin. In the last 1.5 years we have stocked over 20k fish, hybrid bluegils, perch, lmb, and some tiger muskies. There were tons of fish in it this summer. This winter ice fishing we have barely caught, or seen any fish w underwater cameras. Neighbor saw an otter a month ago. Can they clean out a lake this size of that many fish???? doesn't seem possible ? ! ! ?

I don't know much about otters but have a lot of experience with underwater cameras in my ponds. My ponds, which are shallow like yours with very clear water are loaded with fish.

I gave up using the camera thru the ice. When I use to drop a camera down it looked like the dead sea. I might see a couple of small BG, YP or BCP. But never saw large schools of fish. The first year I used them I was convinced my ponds had winter killed. I was so depressed that winter. A very nice surprise when spring rolled around and the ponds were full of fish.

I had thought that but last winter I used my camera and large schools (in the hundreds) of bluegills and perch would swim right thru...they didn't seem bothered by the camera down there last winter so I assume they wouldn't this winter. I'm going back Saturday in hopes I see more fish....

I've had my ponds now for 10 seasons and the fish stop biting around the first of the year. I don't know why, they just do. Its been like that since I built them.

Did you ice fish your pond last year at this time?

Yes, ice fished last year with decent success. Last winter we only had about 4,000 fish in it and I would see very large schools swimming around w the camera this time of year. We have since added a lot more fish so I was shocked when I saw about 5 fish ...total!
drilled all over...shallow and deeper...nada, zilch.

Otter can do a lot of damage. They can unbalance a fishery very quickly. Having said that , I don't think one or two will eat all the fish (lots of small fish will remain).

Any signs of otter still there ?

Why don't you tell us more about your stocking history? And your aeration system for an 17 acre lake?

We put in 2000 yellow perch about 5-7" in fall of 2011 and 2000 hybrid bluegills 4-7" at the same time.
In 2012 at various times we put in a hundred LMG, 5000 hybrid gills, 5000 yellow perch, some walleyes and saugeyes, as well as some smallmouth bass and a small number of crappies. Fish were all in the 3-9" range, tho this sept we did put in 300 very large 8"+ hybrid bluegills.
I have ice fished it 4 x now and have seen maybe 20 fish. I have seen a bass or 2, a few gils, and maybe 10 perch. No large schools, no walleyes or saugeyes spotted. I did ice fish it one day and then went out on the ice the following day and 2 hybrids were on the ice by my holes with just their eyeballs gone. I would think that is clear evidence of otters ? so far the only thing I can come up with is otters. any other thoughts?

8' deep sounds like almost not enough for WI to avoid potential winter kill.

we have 6 aerators that pump o2, 24/7/365, The water quality guy from Aquatic Biologists is out every few months and o2 levels are great, the pond never freezes over by the 6 oxygen diffusers....

Hi Msky - welcome to the forum! Your fishery sounds like a blast, and that's one nice sized BOW, too.

I have a high density population in my pond which is less than 20% your size and I too was surprised by my inability to mark very many fish with my vexilar or locate fish with the aqua-vu. I too checked multiple depths, and feared I had experienced winter kill. I built the pond in 08, and I've felt this way EVERY WINTER since, including this year. For some reason, although the fish are still there, the majority seem to elude my efforts during winter to mark them. However, as soon as there's open water and I start feeding, I see the population is as strong as ever. I've been ice fishing for 20 years, far from a novice, and still my fishery has me stumped under the ice.

I'm not saying this is the case for you, just relating that even in a much smaller BOW like mine I too was convinced the fish had all but disappeared. I still don't understand where the majority of these fish are holding under the ice, but since my pond is devoid of structure I know they are constantly on the move as there's nothing much to relate to except depth/contour changes.

I don't have any experience with otters, thankfully, and I've read conflicting information on the forum and in Pond Boss magazine on the extent of damage they can cause a fishery. Hard for me to believe a single otter would be the cause for such an apparent decline in population, but again I'm not speaking from experience. I suspect the fish are there, like mine have been, but numbers are simply eluding you - maybe they too are on the move constantly. Have you been setting tipups in multiple locations to help locate fish? Could it be they are holding close to open water near your diffusers which is inaccessible to you without a boat?

Sounds like your aeration system is great. Because you're using a consultant, probably no risk of super-cooling the water.

The smaller the water body the more impact that an otter will do. I'm not an expert but I think it would take at least 70-100 acres of water to support an otter without significant impact. Otter is a aquatic warmwater predator and has a similar niche to other terrestrial predators such as coyote, wolf, badger, mountain lion, etc., it takes a fairly large ecosystem or home range to naturally support the needs of these predators.

How about Cormorants? I just asked the neighbor if he saw them and he said there were 5-20 quite often this fall. Almost every day.
Maybe a combination of cormorants and an otter or 2??? anyone have experience with cormorants?

Those are 2 things (Cormorants and otter) we don't let hang around because of the damage they do. The third is beaver. Lots here on all 3.

Yah just reading some old threads now...I think I know where our fish went.

5-20 cormorants can eat a lot of fish smaller fish.........
Must have been good feeding to atract that many that ofen...
they should be discuraged from doing that...........

Otters won't eat just the eyeballs. Cormorants could eat a couple pounds of fish per bird per day.