Snakeheads

[Broad Bill]

Originally Posted by AndyS

I guess if the invasive fish are displacing the introduced fish it's kind of a wash.
To be brutally honest my biggest fear is the Snakeheads and Flatheads find a taste for American Shad in the Delaware river and that whole eco systems collapses. You can't hatchery raise shad unfortunately.

Question. Has anyone ever caught a snakehead or flathead that's coughed up a mature shad or found one in its stomach if they retained either species. I'd guess the answer is no and I can assure you flatheads aren't chasing juvenile shad when they're returning to the sea in the fall and I'd doubt snakeheads are putting a dent in the juvenile population either if at all. Flatheads like big baits, not two inch long juveniles they'd have to chase to catch. I guarantee you more juvenile shad are killed every year in their down river migration by walleye and smallmouth than will ever be by flatheads. At the same time, flatheads don't typically get active in the spring before shad have already ascended the river. Don't know enough about snakehead feeding habits or habitat but I truthfully don't see either species being a threat to the American Shad fishery in the Delaware purely from a predator perspective even remotely close to the non invasive stocked predators that have existed in there for decades.

I've read articles concerning snakeheads and instances where they've been found to have and release diseases or viruses into a water system. If that's true, I'd be more concerned about snakeheads for that reason alone than I ever would be about flatheads. I don't know if anybody remembers the columnaris virus and the substantial impact it had on smallmouths in the Susquehanna and Delaware River in the late 90s. It was a naturally caused virus that killed off about 90% of the smallmouth population. If snakeheads in any way shape or form have the ability to cause that kind of damage to an ecosystem, I would certainly consider them a threat that needs to be addressed.

[AndyS]

What does a 40 pound Flathead Catfish eat in the Delaware river, nymphs ?
Fish are opportunistic feeders, can't see a Snakehead or Flathead turning up it's nose to some of the American Shad in the Delaware river.

Although NJ does stock over 1 million walleye fry in the Delaware river annually.

[Broad Bill]

Originally Posted by AndyS

What does a 40 pound Flathead Catfish eat in the Delaware river, nymphs ?
Fish are opportunistic feeders, can't see a Snakehead or Flathead turning up it's nose to some of the American Shad in the Delaware river.

Although NJ does stock over 1 million walleye fry in the Delaware river annually.

Probably same fish that a 40 lb. musky eats. Should we kill muskies too? How many shad succumb to the resident striper population in the Delaware. Should stripers be killed as well?

My point was flatheads don't become active until water temperatures reach into the low 60s in the spring and by that time the majority of the shad have already ascended the river. The biggest concentration of flatheads is in the middle to lower sections of the Delaware and I don't think the shad run is impacted for that reason. Do flatheads eat bluegills, sunnies, rock bass, suckers, perch, channels, bullheads, carp, walleye, eels, smallmouths etc.? Absolutely they do but I don't think because of the timing of the shad run and the timing of flatheads becoming active in the spring they're having any impact on the shad population. As I asked, have you or anyone else ever seen a flathead spit up a shad. I've fished for them for years and have seen them spit up a lot of other fish but not once have I ever seen one spit up a shad or a nymph for that matter.

I'd bet larger flatheads feed on smaller snakeheads and larger snakeheads feed on smaller flatheads so maybe nature will counter balance the two stocks on its own.

Check out haul seine statistics from Lambertville. Whatever's happening with lower numbers of fish coming back to the river is most likely happening in the ocean and not at all a result of flatheads and snakeheads eating American shad unless of course you believe they're eating them before they get to Lambertville. Fish and game should consider inserting microchips or tags into shad fry to collect data on what's happening to these fish when they return to the ocean for the 3 to 5 years they live out their life cycle. How many fish are succumbing to commercial fishing operations, natural predation or pollution before returning to the Delaware to continue the life cycle of the stock. In my opinion, if catches are down in Lambertville the problem is somewhere in the ocean before they reach maturity and return to their place of birth to spawn as opposed to snakehead and flathead predation once they return.

[thmyorke1]

Originally Posted by Broad Bill

flatheads don't typically get active in the spring before shad have already ascended the river.

My time on the raritan this spring where shad all stack up say otherwise, caught a 33 inch flathead the same time stripes and shad were up river, as well as ~8 other flatheads that day between 3 other anglers.

Those smaller flatheads were eating 3-5 inch swimbaits.

If you think a flathead isnt going to appetize an American shad, be it a YOY one or a big juicy one from the ocean, I have to disagree.

Although I agree they should study the contents of the stomachs and get real evidence

[Broad Bill]

Originally Posted by thmyorke1

My time on the raritan this spring where shad all stack up say otherwise, caught a 33 inch flathead the same time stripes and shad were up river, as well as ~8 other flatheads that day between 3 other anglers.

Those smaller flatheads were eating 3-5 inch swimbaits.

If you think a flathead isn't going to appetize an American shad, be it a YOY one or a big juicy one from the ocean, I have to disagree.

Although I agree they should study the contents of the stomachs and get real evidence

I thought we were talking about the impact of flatheads and snakeheads in the Delaware River, not the Raritan. What I said is in my opinion flatheads are having little to no impact on that fishery and I've never caught, seen caught or heard another angler say they saw an American Shad spit up by or found in a flatheads stomach. FE, you're the resident flathead expert on the site, have you ever seen or heard of a flathead spitting up an American Shad, adult or juvenile?

In the spring, flatheads are just coming out of an almost complete catatonic state from the winter when they essentially lie on the river bottom not moving. Here's a link if you're interested. They're stacked up like cord wood on the river bottom and essentially don't feed or move.

https://www.in-depthoutdoors.com/com...c/cats_857786/

In the spring when the shad run is in full swing, flatheads are just getting active and I don't believe at the rate shad are moving upriver, usually following the main current of the river, many succumb to flatheads. Does that mean some don't get picked off, no. But I don't believe it's of any significance since most shad will be upriver where there's a significantly lesser population of flatheads to matter by the time flatheads become aggressive leading up to their spawn which usually occurs between May and June dependent on water temperature.

If in the fall you believe flatheads are keying in on 2-3" juvenile shad high in the water column during their downstream migration to the sea then you don't understand the feeding habits of flatheads preparing for the long winter ahead when they virtually go dormant. I would expect stripers, walleye and smallmouths kill significantly more juvenile shad than flatheads ever will.

As far as your catch this spring in the Raritan, I'm going to guess most of the flatheads you saw caught were below the dam. This year because of an extremely mild winter with no snow, everything started early. Flathead will start moving upriver in anticipation of their spawn in the spring, are most schooled up that time of year and most vulnerable. They also have more of a tendency to feed during the day than the hot summer months when they spend the day in the deep cooler pools and cruise the shallows at night in search of forage. In my experience, spring is the one time of year you'll see flatheads hit a slow moving weighted swim shad or something fished close to the bottom in an area with good cover or rubble. Based on your pictures, you were fishing below a dam where baitfish, stripers and migrating shad were probably stacked up. There's no dams on the Delaware and it's a much wider river which is a completely different dynamic and again in my opinion why I don't believe flatheads are having any measurable impact on American Shad either during the adult run in April / May or when the juveniles are heading back to the sea in the fall.

[thmyorke1]

Good points, i see what you mean now. Probably for the better that I dont compare the two rivers. Especially if the delaware stays cooler through the spring.

Back to snakeheads,
Maybe same can be said about snakeheads and shad, they just dont happen to cross paths as much?

[Broad Bill]

Can't comment about snakeheads as I've never fished for them, don't know enough about their feeding habits or the habitat they frequent. I always thought snakeheads preferred slow moving or stagnant water more than the current they'd have to tolerate in systems like the Delaware River. Again from what I've read there appears to be a pretty nasty virus associated with snakeheads and if that's true I'd be more concerned about them spreading that into the Delaware system for all the indigenous species as opposed to the impacts predation might have on the shad population. More details in attached link.

https://www.usgs.gov/news/national-n...20of%20animals.

[Broad Bill]

https://www.nj.com/times-sports/2011...e_smallmo.html

We don't need another virus like this which absolutely decimated the smallmouth population and other species in the Susquehanna River and Delaware River a few decades ago. Scary stuf! Fish dying within days of being infected. It's as devastating as what happened 5 or 6 years ago with the steelhead population in Lake Ontario the result of a change in winter feeding habits due to the lake freezing up resulting in a vitamin B deficiency in steelies that killed 90% of the steelhead population. If snakeheads in any way are capable of spreading their own bacterial infections in a system that could have this magnitude of impact, every effort should be made to remove the species from the watershed.

Another article where snakeheads have been found to spread large mouth bass virus (LMBV) which is another deadly and devastating disease.

https://www.chesapeakebay.net/news/b...ern-snakeheads

[bulletbob]

Got a deal for all you NJ guys.. We'll take all the snakeheads up here, and you guys can have the zebra mussels and gobies.. THEN we can discuss "decimated fisheries"... bob