I had an invasion of Cormorants on my 2 acre lake this winter. I think I've finally sort them out. However my problem now is to determine what damage they did to my young fish. This lake was completely restocked two years ago with LMB, HBG, CNBG, and BHM. What size fish would the Cormorants take out? I've read anything from 2 inches to 12 inches in length.

So if 4 to 12 cormorants eat daily (unless disturbed by me) for 30 days, how much damage can they do?

I'm considering adding GS early in spring to let the other forage fish rebuild their stocks. Does this make sense?

I wouldn't personally as IMHO they are inferior to bluegills due to their smaller average size and propensity for interbreeding with bluegills. (Maybe that will get Jeff to show up?)

Here are some pics to show you what an appetite a cormorant can have and how large of fish they can consume. I think they were originally posted on this site. Keep in mind this was probably in one day.

Thanks for that...I think. Sad to see how many fish these things can take out in a day.

Cecil....those pictures are crazy.

I had no idea they ate that many fish in one day.

Thanks for posting.

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92442#Post92442

Golden shiners? Gizzard Shad? Green Sunfish?

I'm thinking you meant Golden Shiners. Depending on the LMB population, you might have to add a bunch if the cormorants wiped out a big portion of the forage fish population. To tell you the truth, there's no way to know without having a fish survey done. As you can see from the pictures that Cecil posted, they can eat fish of all sizes.

I did a quick literature review on cormorants a couple years ago as they began wintering in our area in large numbers. On average they consume a pound of fish per day. A flock of 25 birds can significantly reduce prey biomass in a lake. Do the math for a 3 month drop in.

So they could actually reduce numbers of bluegills in a stunted pond?

Yeah I think you're right Scott. For some reason I thought he meant green sunfish.

Big or little their choice - damage either way - cormorants are trouble.

Thanks guys. Yes I meant Golden Shiners. They descended on my lake and found abundant forage. I applied for a Cormorant Predation Permit and have been steadily eliminating the problem with every 12 gauge, 3 inch, #4 shot. Based upon your comments those things were taking out 5 to 10 lbs of fish a day for at least 30 days. For a 2 acre lake that's a lot of fish. I love it when they can't get airborne right away and have to circle the lake a couple of times to get above the treeline.

So I'll do a survey and see from there what I need to do. Probably need to closely monitor the weight of my LMB as well.

I researched cormorants when I first started duck hunting. I saw someone accidently ehhm ehhm shoot one. Anyways keep in mind there is a hefty fine associated with shooting cormorants. They do consume a heck of a lot of fish. I wonder if you could attract some falcons or other predators that might keep the flying rats away from your pond.

No fine if you get a permit.

No fine if you don't get caught

Not an option in my neighborhood with a well traveled highway in the front and neighbors all around me.

With something like this and when using subsonic ammo I doubt that the neighbors would even know. (you gotta file the correct paperwork of course.)



While I don't own one, they are legal for hunting in Indiana, and it IS tempting. Don't know if I want to be a larger blip on the radar though.........

It's not the sound as I'm worried about as much as visibility. I have used CB rounds in my 22 for herons when I got the permits, which don't sound like much more than a mild firecracker.

Haven't seen a cormorant yet and hope I never do.

Lay on your porch and you'll be pretty invisible. A pond in Illinois that is about the size of your front pond had 5 of them visiting daily. Not good for that pond!

I have set up a blind in the spare bedroom for when I had issues with herons on the trout pond and I had a permit to take them out. Officially that is not legal even with a permit. Trouble was I had to leave the window open a crack without a screen as opening it when the bird was around would make them fly off. The wife wondered why there was an increase in flies in the house.

Shooting toward the highway is a pretty scary proposition and something I won't do. As soon as you think you have a shot a semi suddenly appears. Can you imagine what trouble I would be in if i even looked like I was aiming at a vehicle on the highway, let alone a bullet hitting one?

Hoo Boy, would you be in trouble!

I used to be able to get away with pointing a shotgun at F-14's and such as they took off from Mirimar Naval Air Station, but that was only because we were trap/skeet shooting on the base at the time and the planes were beyond the shotfall zone. As far as I know, that range has been closed down.

That sure was a weird feeling tho. Call for the bird, start swinging the shotgun and have a jet fly past the clay bird as you were getting ready to pull the trigger!

Gamo and others make pellet guns that are very effective short range, shooting at about 1600 fps. However 1600 is not subsonic. Something in the 1200 range should do the job and be fairly quiet.

My depredation permit for the Phalacrocorax auritus is on it's way. I used to just scare em off. Now I can actually do something.

Bing, 1200 fps will still have a pretty good crack to it. Pellet rifles that shoot 900 fps are quiet and more accurate than the faster ones due to the pellet not having to transition from supersonic to subsonic, which sets up a pressure wave. Good pellet rifles shooting in the 900 fps range should be capable (taking the nut behind the trigger out of the equasion) of shooting a 1" dot at 50 yds repeatedly. So, head shots are doable, and very deadly at that distance and slightly beyond, depending on the skill of the trigger squeezer.

Also with pellet rifles, a moderator (silencer) is readily available and does not fall under the ATF rules and guidelines that silencers for firearms do. So, there is no added paperwork, no $200 tax, no waiting period. I've seen some Pre-Charged Pneumatic air rifles that were far quieter than a person sneezing.

Update on operation Cormorant......
I've eliminated 16 Cormorant under my predation permit...very satisfying! There's still one that makes an appearance once a week but he's a wise bugger. As soon as he spys my truck he starts flapping his wings and buggers off. Tactics will change to eliminate the poacher.

With temps in the 70's and my feeder running again, I'm saddened by the lack of mature BG coming to feed. I can only assume the Cormorants nearly wiped them out.

So now my problem is this: I added 200 LMB July of 2012 and now they are 15 inches and about 1.8 pounds each. Should I reduce the LMB numbers now? Or, will my BG numbers rebound without corrective stocking?

Drop them they are not native and they are very destructive.

seantOH

Are you sure they aren't native?