Pond Boss Forums INTRO Questions & Observations Using structure to protect from predation?

So basically that's the question.

I have seen Great Blue Heron, Mink, and now even Cormorants(those things can dive forever and are fantastic swimmers!) actively feeding in my pond. (1/4 acre, 10 feet deep, mostly trout , but added 20 female-only LMB)

So basically I've created an all-you-can-eat buffet for predators.

My options are to actively trap the mink, shoot the cormorants, scare off the GB Heron, etc. Or enclose the pond with fencing - not something I'll want to do. The pond is right next to a river here in New England, there is lots of habitat (forest regrowth from 100 years ago), and eradicating predators is going to be tough.

So my question to you piscatorial savants goes to putting structure in the pond. It's basically a square, flat clay bottom right now. Something like the BG Condos that I've seen discussed here in the PB forums. A series of stacked 6 inch PVC pipes, or submeged xmas trees, etc. Would the trout use them? Would there be protection against such aggressive predators as cormorants.

Any experience out there dealing with active predation on trout?

Bump.

I can't answer your question about structure and wild predators because I have never managed a pond. I'm designing and managing the construction of 2 ponds at this time and they will both get a high percentage of structure (around 20% of the bottom area). Even though I'm not one of the experts I think the logic behind balancing predation by providing cover for fish is sound. Naturally occurring ponds usually maintain fish populations and I imagine they have more structure than the average man made pond. Of course most people design their ponds to be easy to fish and have very dense fish populations. If they accomplish this wild predators naturally respond to the ample supple of easy prey.

NE Mason I don't mind addressing your question in several respects. I have no knowledge of how trout use or relate to cover/structure so I did not comment earlier.

I suggest you look at the threads in the archives on the subject for ideas and discussion.

Cover/structure has several effects depending on the situation and type of cover. Loose cover aids bigger fish ,tight cover smaller fish. There is no doubt it reduces predation but also concentrates fish. A line or string of cover gives the concentrated fish a place to move to escape predation. Most info on the subject does not address cover wrt mink and bird predation. As long as the bird can't perch on or near the cover (be sure the cover does not become a trap because it sticks up out of the water)it should help. There are several topics here on cormorants. The best advice is do what it takes to keep them out. There are several threads here on using line or string to impede herons. Mink and otter are like cormorants. I hope this helps. If you have any specific question please ask it.

If it were me I would be sinking cedar trees to give the fish some cover.

GW wrt otter and cormorants your premise is wrong. Most LMB/BG ponds with overcrowded fish populations have to many small fish (LMB under 10in and BG under 5in). Otter and cormorants target the bigger fish first. Thus you end up with even fewer large fish and more small fish subject to stunting. I don't know about mink. FWIW I have seen several times where an otter (or several - family group) over a summer cleaned out a 1 acre pond of most all the LMB over 10in and BG over 6in. I guess if that is what someone wants it is truly thinking outside the box.

Secondly I would rather be the one selecting which fish come out (via fishing , trap or seine) rather than letting a predator do so indiscriminately. FWIW we have big great blue heron , a green heron family and kingfisher family which have free use of the ponds but otter or cormorants are not welcome.

Further I think NE's questions were as to trout using cover. While there are a few trout experts here (not me thus my statement above) they may not know the answer to his question.

GW I sent you a PM. The sarcasm worked to make a point to all here. I put that in the text on purpose. Your reply "I don't appreciate the sarcasm" speaks volumes. It offended you as it would most people. That is why negative comments toward people here don't work. Whether they are sarcastic or accusatory or demeaning or negative or angry/frustrated they just don't achieve a positive result. I suggest that before anyone does that they think (a lot) about how the comment will be received and the results. Those things should be done outside the open forum by PM , email etc. This does not , of course , apply to the humor threads here.

GW, I don't think any meant to offend you or put words on your mouth. For what it's worth I've enjoyed your posts, from our banter during the GSF/Warmouth scandal to your post regarding Gams. Although I don't know you personally, I envision you as a guy that is gonna push the boundaries and walk against the flow of the crowd just to see what will happen. I like that attitude. I didn't post to your BSF thread (and to be completely honest tried to avoid opening it because I am well aware of your photo posting capabilities) because maggots give me the heebie jeebies. :o. Hang in there and keep posting - I'm reading (except maybe for the BSF thread (did I mention I don't like maggots?).

I read this thread and though it was a great question. For what it's worth I have the following non-educated, expert free observations.

Observation One:
Vision if you will a small (about 15 feet across) koi pond in Mom & Dads back yard. It has a fair number of koi of various sizes. They breed so much that Mom & Dad give away (yes for free, crazy I know) the young to a breeder. Anyhoo, a few smart Egrets discovered the pond and decided it was too good to be true. Koi began disappearing at an alarming rate. After consulting with a koi pond guy he suggested cutting a trash can in half down the side (in other words not going around the can but down the side of the can) and weighing it down in the pond. It would give the koi a place to swim into for shelter. Dad calls it his Koidominium (see where I get my humor now don't cha). Although it helped some the Egrets if nothing else are persistent and they still managed to eat a bunch. Finally Mom and Dad had to get one of those motion activated sprinkler things. So in this instance the hidy-hole had limited success but then again we are talking about an awful small pond here.

Observation Two:
Now change the channel to my pond. About 2.5 to 3 acres (depends upon the season and my exaggeration level that day). Chock full of Elodea (bane of my existence). Lots of places for fish to hide. At this pond we have two types of herons. Don't know the common or scientific name and it ain't really important. One kind is short the other tall. Both are quite good at stocking the shallows and picking off fish even with all of the Elodea. I've observed the larger herons take down two to three fish in just a few minutes. These guys are good. If I could only convince the herons to be Vegans I'd have it made. So even with a ton (actually probably several tons) of cover in dense Elodea the herons get their fill.

And none of these birds dive down. What's the moral to these stories - don't have a clue - just my un-scientific, non-expert observations.

i liken this forum more to a shipping crate than a box.

gee-dub, i miss yer old name, and i for one hope you dont go away for lack of enthusiasm, but if you decrease yer activity here, i respectfully request that you provide an annual report to the GSA entitled "the causes and affects of warmouth as a top pond predator". you sir are ripping the envelope and the GSA is watching.

speaking to the question of how trout relate to cover (assuming a still water body w/ no current). i'm not sure what conclusions you can draw comparing trout behavior in large lakes to small ponds, but from experiences on our local reserviors, overall trout distribution is mostly controlled by the temperature profiles and movement of baitschools. in the summer they go deep (i.e. up to 200 feet!) and i usually see them (on fish finder) congregate in the submerged stream channels. in late fall, winter, and early spring, they tend to school up and can be found anywhere in open water, plus they move up and down (surface to ~30 feet) depending on time of day or night and lunar cycle. exceptions are those i have found (usually in morning or late evening) feeding along relatively flat shallows and relating to large submerged boulders or tree stumps (just like bass). so i think if you put structure in (assuming good temps and DO levels at the depths of the structure), the structure will attract both forage and trout.

NE Mason,

Great question. It's something I've been struggling with for eight years now. My bluegill condos I think have a positive effect of keeping the bluegill slightly "offshore", so that GBH and other shore-oriented predators don't have such easy access. The steep slopes of my ponds make it so that the herons can't wade out very far, and consequently can't be a threat to the BG around the condos. Thank goodness no cormorants or mink in my aread lately. Whew! If there were, I'd bet that there would almost no hiding areas for the fish. I guess it's conceivable that the bird could be discouraged by a series of stainless wires suspended under the surface of the water, but I think the traditional method is to simply use audible and visual threats in the above water world. Meadowlark had purchased a propane cannon at one time that I thought was a very interesting idea, but if I remember correctly, his birds didn't come back the following year, so he didn't have to use it. Meadowlark is extremely creative and would love it if he sees a chance to jump into this thread.

I think that these predatory animals need to have good agility and intelligence in order to be successful, so my intuition tells me that no amount of bottom contouring or structure addition would be a complete deterrent. It would probably be cheaper and more practical to utilize your resources to add more fish later.

This is something I've given a lot of thought to, but the best structure addition I've made is the offshore condos. Encouraging fish to stay away from the edges is probably the most logical way to keep the herons at bay.

Cecil Baird has also been outside the box with his use of trip wires around the edge of the pond. Perhaps we can track down some of the old threads, that I thought were quite creative in regards to frustrating the herons with small physical barriers.

One general comment to add...with the new forum, you can see how many have viewed a post. I don't know how to go back and see how many had viewed it a few days back. But I know everyone was reading it.

I can tell you that I read his post, and frankly, I had no clue as to what to tell him. I did think about it, and more so, I thought about his story of the mink (or otters, or whatever they turned out to be); then I scratched my head and thought 'so his best LMB cover was also where these rodent-things lived or hung out, so what should he do?'

Regarding the Black Soldier Fly thread, I did read it for the first few postings, and then I stopped viewing it. But I had reasons.

I've bought an electric bug-lite feeder. I have never used it. I don't have electricity at my pond. I had intended to rig a solar set up with battery reserve. Haven't got to it yet, and it's been three or four years.

I bought a timer based, battery/solar, automated feeder. I knew it would have to be set up way out in the water so it wouldn't be stolen. Haven't got around to it yet, and it's been about three years.

Regarding rot baskets, I love the idea, but I'm man enough admit that I do not have the constitution to be handling dead animals. The thought of cleaning out or restocking a rot basket on a hot day almost makes me puke. I am a wus in that regard.

I now know that I don't have time to do all the things that I want to do, therefore, when something comes up, that may even be a great idea, I know whether or not I'm going to give it attention.

I also don't read all of the threads on the worm raising threads only because I know that it's not something I'm going to be doing anytime soon.

I would almost like to do a survey to see how many "commonly accepted practices" each of us on the forum really use.

For instance:

1) Do you feed?

2) If you feed, feeder or by hand?

3) Do you stock forage fish?

4) Do you use a rot basket?

5) Do you take temperature measurements?

6) Do you take DO measurements?

7) Do you take R/W measurements?

etc.

I think we would be surprised at the results. All great ideas and/or proven concepts, but everyone's case is different.

I'm gonna go out on a limb here (taken from "Stripes), that less than 15 of us use rot baskets.

Just out of curiosity how many ponds do you all know of that have the maximum recommended amount of structure? For that matter, what is the maximum percentage of structure recommended? Somewhere I got the impression that 20% is the number. I also get the impression that most ponds have far less than that.

I would be interested in hearing about a small pond with maximum structure and what the effect of predation was for it.

BTW, NE Mason does have trout but his original thread was about otters preying on his LMB.

Sunil, you know that my BSF don't occupy a basket over a pond right? It's more like raising worms really. You use household food scraps and there isn't a bad odor...

Thanks JHAP and DIED, I appreciate the kind words, even though you guys are tards.

I purposely keep my ponds to absolute minimal structure, mostly because it helps me with some management objectives, such as seining.

I have a good friend with a pond that has structure that's probably about 40% of his pond, and that's probably too much. The fishing is extremely difficult because the overall biomass of the pond is so spread out that it actually makes it harder to locate concentrations of fish. He certainly doesn't have any problems with predators of any kind. Also fishing is a pain in the rear, because you lose so much gear.

As frustrating as predators are, imagine how a fish farmer feels who has his livlihood going down the drain when an otter shows up. It would be the equivalent of a hail storm for a row crop farmer. Lots of money going down the drain fast. Honestly, the fish farmer is at an especially high risk becaue of his need to have as little structure as possible.

If you were a fish farmer it would almost HAVE to cross your mind to use any and all means neccessary to get rid of the critters. Fortunately I don't make my living with my fish, so it's not such a monumental deal for me.

I'll defer to those smarter than me, but I'd bet that the 20% is a reasonable number, depending of course on the needs of the particular species of fish you are managing for. Lots of cover for LMB, very little for HSB, etc.

GW the % recommended varies depending on who you ask. Usually between 10 and 20%. Sometimes it is given in number per acre. Usually 1 to 3 per acre depending on the size and configuration of the pond and type of fish and goals. As I said earlier most of the data I have seen addresses fish on fish predation and not birds and mammals. Keep in mind that cover both protects fish that can use it but also helps hide the predator. Surface plants are a good example. Fish can hide in it but they also can't see the predators as well. The shoreline is often the biggest structure/cover in ponds so the smaller the pond the bigger % of cover it represents. One point often made is that thick cover such as a pond full of xmas trees greatly reduces fish on fish predation and adversely effects predator fish due to lack of catchable food.

Most people use cover to concentrate fish to catch and not for fish protection. I do use xmas trees for small fish protection adjacent to BG beds. They help protect small BG from LMB and the herons and kingfisher. I remove some of the branches depending on the size of the fish I want to protect and the location. I do agree with your idea that lots of cover will help protect fish from some predators but it will also make it much harder for predator fish to get enough to eat. I have seen underwater films of both otter and cormorants feeding. I think cover would help the fish but both of those predators are very agile underwater and I think would still do to much damage for my liking.

I hope this helps a little and maybe starts a discussion.

GW, I realize the BSF thing is not like the rot basket. What I was saying in my longwinded post was that I just don't have time for all the projects.

The 3-ish year periods of time delays in my projects coincide with the birth of my first kid.

Simply put, if I had more time at my pond, I would be doing a lot more of the ideas given here on PB.

Sometimes I think that 10-20% of structure is too low. This is mostly because whenever I sink a bunch of X-mas trees, and I think I've done good, I seem to feel that I need to quadruple the effort.

THEN he had another one.

I highly resemble that remark.

That is pretty much the situation in my pond. Islands of Elodea. The Elodea dies back in the winter and grows like mad spring through summer. By the end of summer I have it all along the shore and even islands in the middle. I have been able to treat it yet except for manual removal - which is a very short term solution. Anyway it doesn't slow down herons much they will wade into it and pick off fish.

I think that it would depend upon the type of vegetation cover.

I like the idea of the propane canon and it just occurs to me that a propane canon might also be useful in scarring trespassers (different thread).

Scaring, or scarring?

Both.

Wait a minute.....


I have an idea for a deterrent....


I admit that I might have somewhat stolen or modified someone else's idea.....


but I think this could work as an in-the-water deterrent...

LMAO.

No doubt these are as exotic and appealing as the far flung Isles of Langerhans.

Cindy's 6+ acre pond site is heavily wooded and many of the trees are 2 ft diameter at the base. I'm considering using most or all of the stumps as structure. I'm aware that this would make fishing more difficult but the truth is I'm not trying to create easy fishing. I'm trying to create a thriving and diverse, low(er) maintenance habitat.

I grew up fishing in natural creeks, rivers, and ponds. Part of that experience involved chasing less than trophy sized fish around snag promoting structure and uncontrolled aquatic weed growth. Often we wouldn't catch anything at all. Fishing was tough back then AND WE LIKED IT!

I agree with you GW. At my place it's easy to snag a lure. Between the Elodea, some reeds, a few submerged trees and in several places trees from the shore that hang into the pond you have a lot of obstacles to fish around. It makes fishing more challenging and I think probably has some effect to reduce the hook shy situation.