Pond Boss Forums STOCKING A NEW POND Types of fish to choose Gizzards invade Arizona

First they got to Lake Powell, now they're in our inland lakes. How exciting, can't believe I didn't see this last month. Big forage fish for our LMB. Any biologists hazard a guess on what will happen to fish populations in an old lake that gets Gizzard?

http://www.azgfd.net/fish/fishing-news/b...elt/2008/12/03/

Biologists discover gizzard shad population explosion at Roosevelt
December 3rd, 2008

PHOENIX – Arizona Game and Fish Department biologists conducting an autumn fish survey at Roosevelt Lake discovered that a relatively new invader, the American gizzard shad, has experienced a population explosion here at Arizona’s largest inland lake.

“This species looks like threadfin shad on steroids,” said Fisheries Chief Kirk Young. “These wide-bodied invaders from the eastern United States are shaped like footballs and can readily grow past the size where they are available to most sport-fish as forage.”

Young added that it is a wait-and-see proposition to determine if these invasive shad will have positive or negative impacts on Roosevelt or possibly the other popular fisheries along the Salt River.

During the recent fish survey at Roosevelt Lake, most gizzard shad sampled were in the 9- to 14-inch range and the largest two shad measured 17.7 inches long and weighed 2.3 pounds.

“We are still entering all the survey data, but based on what we saw during the sampling process, it appeared that gizzard shad were almost as numerous as the largemouth bass,” said Natalie Robb, the Mesa regional fisheries program manager.
At Roosevelt Lake, gizzard shad were first discovered during water quality sampling during January of 2007. Department biologists at the time recognized that gizzard shad are capable of rapid reproduction – a single female can produce up to 400,000 eggs. But the biologists were not expecting these newcomers to experience such a rapid population expansion. more

Fascinating, Aaron.

I grew up in Tucson, spent many days on Roosevelt and Apache, as well as Powell.

If I had to speculate, I'd expect an explosion of really huge stripers in Powell, where they spawn and have eaten themselves to a seriously stunted condition with only TS for forage. My guess is that they'll have positive effects on the LMB in Roosevelt for years to come, then ultimately form a large population of really huge shad [growing like crazy on all the agricultural runoff from the Salt River], at which time the lack of really large predators such as stripers will be problematic.

Hard to know about Apache, that's always been a wierd lake, getting so much of the cold, deep outflow from the generators at Roosevelt. With its smallies and the abundance of crayfish, it's more difficult to predict. Of course, everything may have changed in 15 years.

Of note - the size sampled were mostly large. Why no small GShad ? Check for any changes in tropic status of the lake. A hint GShad can be a huge problem especially for competing lepomis , yoy LMB and small fishes who feed on plankton. Any tilapia in those lakes ? TShad have been shown to suppress GShad reproduction.

No tilapia in these lakes.. it will be very interesting to see what happens. I noticed the 'average' size catch of the fish as well. Think the smaller ones are doing what they should do, and getting eaten?

Roosevelt has been a great largemouth lake, and decent smb. Tshad have been key forage for a long time. 18 inch shad aren't so helpful as forage themselves.. but it will be interesting to see if the larger forage available moves the LMB up in weight. Over 20,000 surface acres, so we're never going back in time...

Amazing at Lake Powell in just a few year this happened: "Biologists at Lake Powell first noted gizzard shad in 2000 near the San Juan inflow. In netting surveys at Powell in 2006, gizzard shad accounted for almost as much fish flesh as striped bass." Yikes.

That is what GShad do - take up lots of carrying capacity. MY very WAG is the TShad are suppressing the GShad spawn and survival.

I know the GShad population can explode initially, but isn't it fair to assume that large lakes such as these will have decent numbers of mature LMB? Especially in the south where LMB approach double digits much sooner than up north, isn't it a matter of time before the LMB (or other predators) bounce back and keep the GShad in check?

We (unintentionally) have GShad in our LMB pond. The pond is only about 3.5 years old, which means we don't have an established fishery with lots of mature LMB. But so far the predators (largest bass) have kept them under control. The electrofishing survey produced good numbers of GShad, but nothing alarming. The largest bass also had the highest Wrs. I would predict the same thing in a larger lake with a moderate to high population of GShad.

I snagged a Gshad last spring fishing for hickory shad that was 20.5" long. That thing was a horse! Took me almost 10 minutes to get it in and foul hooking didn't help the matter. They are so thick in spots you snag one every 3rd or 4th cast when they are in their spawning runs. Any lake with big predators like striped bass should not see them take over, but lakes without big mouths may have some issues. A few musky or stripers will put a hurting on them though...

Three very basic rules of Gizzard Shad. (These rules are subject to change due to the million or so variables you can have in a body of water)

1. Your largemouth bass will do a little better.

2. You bluegill, redears and other lepomids will do a lot worse.

3. Gizzard Shad smell funny, and if you touch them you'll want to go wash your hands.

I want to wash my hands after touching any fish. How are Gizzards worse? Never touched one.. but I want to go fish Roosevelt to see what's going on. Really, they smell that much different?

Go ahead......try it.

Gshad just wreak of fishiness! I mean stink! But I guess that is why they make such great catfish bait. Castnet a few fresh gshad and let them sit in a likely catfish hole in the Potomac River and you're arms will be hurting by the end of your fishing trip from having caught so many 20 plus pound blue cats.

A good link:

http://www.dnr.state.md.us/fisheries/fishfacts/americangizzardshad.asp

He speaks the truth.

If you guys think Shad stink, try skipjacks...they are in the herring/anchovie family. Us catfish guys love a good stinky fish!!!

Salmonid

Gizzard Shad and teenage boys.

That's what I tell my daughter.

Shad scales tend to fall off really easy too. And then stick to anything you touch. Cork handled fishing rods are especially good at attracting shad scales.

Yeah, and your aerator intake so they clog up your livewell... They just make such darn good bait it is all worth it!

It will take a 40+ inch LMB to eat a 18 inch 2 lb GShad - have you seen any LMB that size - it would be worth at least a million $.

So they stink and they get too big... will be interesting to update this thread in 5 years and see where the lake is at!

40+ inch would be nice... how about 32.5 inch?

Well, this is my most perplexing problem at the moment, those darn gizzard shad. Went to the aquaculture conference yesterday, saw a very interesting presentation on how the alwives (sp?) messed up Lake Michigan for a long time, they are in the same family as these g. shad. We have applied for a permit to do a fish kill, but still hoping that this winter may have killed some g. shad with ice/snow cover since November. Do these g.shad eat the largest zooplankton first so the zooplankton can't eat the algae like they usually do?

GShad can survive colder waters with no problem. The local lake (Koontz Lake {365 ac}) has them and they make up the majority of fish in the lake. The DNR completely killed the lake with Rotenone in 1969 due to an over population of carp and gar, and started re-stocking in 1970. They put in BG, RES, YP, Black Crappie, Walleye and Blue Cats in the Spring, LMB and Northern Pike in the Fall. The bass fishery was great for the first 5 or so years, few Blues were caught in the same time frame, along with a few Walleye. Then the carp showed back up, followed by Gizzard Shad. The Pike fishery never recovered to what it was back then, and now with the Eurasian Water Milroil, it's a constant battle to keep the weeds down enough so boating is possible. I feel that the DNR screwed up by taking out the dam that drained water from the bottom and installed a spillway. After that happened, the lake seemed to silt in at a more rapid pace.

Now you can catch Pumpkinseeds, Yellow Bullheads, White Bass, BG, RES, LMB, Dogfish, YP, Golden Shiners, and Black Crappie. The carp fishery is great if you like catching them - there are 30#+ fish in there. I'm waiting for the Zebra mussles to show up. It seems that the Panfish population took a dive after the larger GS started showing up.

This Fall, Potato Creek State Park (Worster Lake) was treated with a low dose of Rotenone to knock down the GS population. It's too early to tell if it worked. I believe their population was 60% or 70% by weight of the GS when the DNR sampled the lake via netting.

Not familiar with dogfish in freshwater? Any other common names for it?

Esshup:
Thanks for that informative info. I want the low dose here in our 10 acre lake that has no inlet from another lake, seems the others are set on a total fish kill, which I was told probably won't kill all the fish anyway.
My best fishing story ever has to do with a DOGFISH: Circa 1974, Rondeau Bay, Lake Erie, Canada. Broke teenage kids in love, me and my now hubby - borrowed a small boat from someone, put it on top of his Corvair, drove up there - there is a Provincial Park where he spent summers growing up, one side the big lake, the other side this bay just teaming with all kinds of fish and wildlife-it was like fishing in a barrel. I never put the bait on - I had a little panfish on my line, he was busy with a bass, all of a sudden a huge swirl, something grabbed my little fish, something really big, so big we pulled up the anchor and this fish pulled our boat, got it up close to the boat and it got off. Threw the 1/2 eaten fish on my line back in, it hit again! We did battle, got it up, and it was a DOGFISH- kind of like a catfish without wiskers, really ugly. Bopped it in the head, got it off the line and threw him back.
That was the nicest place, growing up in a family of 10, they would camp 1/2 summer there, then go to Lake Huron for the 2nd 1/2 of summer. There was a wildlife museum there, the six boys in his family caught the stuff for the museum, and they would catch fish and sell them, not on the lake side, on the bay side. Anyhow, something really bad happened, some chemicals were put in to kill off weeds and all the fish, frogs everything, killed. It was on TV, nothing living there. We rented a place there on our honeymoon, in 1990, walked into the store to ask how the fishing was: the lady says to somebody in the back "When was the last time anybody caught anything in the Bay?" Nobody knew. Very sad story.
The biggest fox snake was caught there, record size, they brought it down and registered it at the Detroit Zoo. I just looked up Rondeau and it looks like things may be cooking again up there, lots of conservation groups involved now.

Bowfin is another name for dogfish.
Bowfin
Article about Rotenone treatment of Gizzard shad in Lake Worster, IN

Here's some info on Rotenone, but I couldn't find where they speicfied the dosage for gizzard shad. Page 93-103 has info on it, but the rest of it was interesting as well.
info.

When I saw the title of this thread, y'all had me really excited.

My first thought was expansion of Area 51.



I was dreaming of aliens dropping gizzards out of the sky, ready for roasting.




Then I came to my senses.

CSJB -- when do they expect the shad to start coming up the Rappahannock?

The hickory shad start running first... In most years, you can start catching a scattering of hicks around mid March. By early April they are usually there in full force. About that time the first American shad make a showing. Not many in the Rapp but there are a few. I live 15 minutes from the fall line on the Rapp so it is a short drive, but I don't think the Rapp has the best shad fishing...

I have been fishing the Potomac a lot more. I really worked it hard last year. I had several days where I caught over 100 hickory and American shad. I caught one American last year that was 6 lbs 3 oz. I wish I had my camera to get a shot of her! Here are a couple hickory shad I caught last year. Hicks are mini tarpon!





The area near Fletcher's Boathouse is great. http://www.fletcherscove.com/fishing_report.htm Check the link, it will give you somewhat up to date fishing reports and you can check past years... That area of the Potomac is awesome! In one cast you could hook into a smallie, largemouth, striper, walleye, channel cat, blue cat, tiger musky, several species of sunfish, yellow perch, white perch and even a very lost hatchery rainbow trout! Last year I saw a snakehead get caught in that area for the fist time...

It is probably my favorite spot to warmwater freshwater fish because of the amazing variety of fish... If you want to make the trip, I'd be glad to take you out and show in the area.