flathead study

[nymphingmaniac]

Invasive flathead catfish impacting Susquehanna’s food chain, researchers find | Penn State University

Flathead catfish — native to the Mississippi River basin — were first detected in the Susquehanna River in Pennsylvania in 2002, according to the U.S. Geological Survey. In the two decades since then, the invasive species has spread throughout the river basin. The impact of the large predator on...

www.psu.edu

https://afspubs-onlinelibrary-wiley-com.ezaccess.libraries.psu.edu/doi/full/10.1002/tafs.10480

Kind of odd they used two methods to sequence, one modern, one "older". My best guess is that they generated data using the older method and then got on board to using the NGS method. Next generation seq (more sensitive, comprehensive and modern technique is the same used to sequence the human genome, for example)

 

[bringthepain]

Flatheads are bad news and need to be treated similar to snakeheads. Study seems to confirm that they indeed eat everything they can get their hands on

 

[Fredrick]

Flatheads are bad news and need to be treated similar to snakeheads. Study seems to confirm that they indeed eat everything they can get their hands on

Wait till the blue cats take hold

 

[poopdeck]

Flatheads and snakeheads have completely brought the SMB to their knees on the Delaware. Been saying it for years. This report is no surprise.

 

[Fredrick]

Flatheads and snakeheads have completely brought the SMB to their knees on the Delaware. Been saying it for years. This report is no surprise.

Snakeheads prefer different habits than smallmouth. Flatheads like to hide behind big rocks just like smallmouth.

 

[TimMurphy]

Dear board,

Maybe we need to realize that bucket biologists aren't solely responsible for all the invasives. Snakeheads, yes for they come from off the continent. But fish native to the US, just like animals, respond to changes in habitat and relocate as necessary. External factors force the changes. It's been happening since time began.

That said, there are many rivers in the Southern US that have largemouth, smallmouth, striped and spotted bass. Some of those same rivers have invasive brown and rainbow trout too. But they all have native blue and flathead catfish and somehow people manage to catch large specimens of all of the non-catfish with no population crashes. The exception seems to be with smallmouth because in many Southern rivers they are invasive, just like all of PA except for the Allegheny and Ohio drainages.

Stay tuned, I'm sure there is much to come before the next Ice Age hits.

Regards,

Tim Murphy 🙂

 

[poopdeck]

All I know is it’s been a long time since I caught 50 SMB in the morning on the Delaware and the only thing that has changed is the addition of flatheads and snakeheads. Them snakeheads are in the same section of river as where I fish for SMB so the habitat theory is a little weak.

 

[Nymph-wristed]

One they're here, they're here, yeah?

I may have missed something, but I still have not read or heard about a successful eradication of an invasive species once it's established. Please enlighten me if I am wrong. I may have read about poisoning entire watersheds and starting over? That seems like playing god to correct someone playing god?

 

[bringthepain]

Flatheads and snakeheads have completely brought the SMB to their knees on the Delaware. Been saying it for years. This report is no surprise.

Watched the same thing happen on the skuke years ago now. When dudes were catching undersized smallies to use for flathead bait i knew we were in deep doo doo. I havent fished the skuke in 15 years now but i suspect not much has changed. The area we used to fish was from where valley entered the river down to 422.

 

[Nymph-wristed]

I think folks would be surprised at the bass rebound on the Skuke despite those flatheads....

 

[Mike]

Watched the same thing happen on the skuke years ago now. When dudes were catching undersized smallies to use for flathead bait i knew we were in deep doo doo. I havent fished the skuke in 15 years now but i suspect not much has changed. The area we used to fish was from where valley entered the river down to 422.

That was the result of a substantial SMB reproduction problem (failure) from approximately Limerick downstream to at least Bridgeport. There was low reproduction from roughly Gibralter to Limerick, and good reproduction from Port Clinton to Gibralter.

 

[Mike]

Flatheads and snakeheads have completely brought the SMB to their knees on the Delaware. Been saying it for years. This report is no surprise.

Recommend that you check with your AFM or his staff. My recollection is that the population has rebounded in recent yrs based on night electrofishing at the same fixed sites for decades. Likewise, reproduction has been monitored for decades annually at fingerling sampling sites that either correspond with the adult sampling sites or are relatively close to the adult sites. Going back a decade or a little more there had been a series of below average year classes.

 

[TimMurphy]

Recommend that you check with your AFM or his staff. My recollection is that the population has rebounded in recent yrs based on night electrofishing at the same fixed sites for decades. Likewise, reproduction has been monitored for decades annually at fingerling sampling sites that either correspond with the adult sampling sites or are relatively close to the adult sites. Going back a decade or a little more there had been a series of below average year classes.

Dear Mike,

Wait, what, who knew that fish respond better to adversarial conditions than anglers?

Nature always seems to find a way to balance, much to the consternation of the folks who only want the balance tipped in THEIR favor. That was the point of my post way above when I stated that many Southern US rivers have two or 3, even 4 species of bass in them, and all the bad catfish, and yet fishing still remains good and outsized specimens of every fish are still caught annually.

On a side note, I'd be interested in your thoughts as to why flatheads and now blue catfish arrived in Pennsylvania. You can post in response on this thread if you'd like to, but I'd like to know more since you were still working as PAFC biologist when the catfish invasion began. I don't mean that as a call out, I'm genuinely interested in your thoughts.

Regards,

Tim Murphy 🙂

 

[poopdeck]

Recommend that you check with your AFM or his staff. My recollection is that the population has rebounded in recent yrs based on night electrofishing at the same fixed sites for decades. Likewise, reproduction has been monitored for decades annually at fingerling sampling sites that either correspond with the adult sampling sites or are relatively close to the adult sites. Going back a decade or a little more there had been a series of below average year classes.

Respectfully, I don’t need to. I have been boat fishing the same areas of the Delaware river for 40 years. I am intimately aware of the current and historical SMB numbers in the Bucks county area. These are my numbers based on many days of fishing over the years and decades and not data drawn from a handful of annual electro shocking surveys. If the PFBC is coming up with numbers indicating a rebound then I have to seriously question the data going in. If going from 50 bass to 5 bass in a morning of fishing by two experienced river anglers is considered natures balancing act then I guess I’m wrong. If going from a 5 bass morning to a 6 bass morning is a rebound then I’m wrong again. What I have seen is the average size of the fish going up but the numbers of smaller fish going down, way down, rock bottom down.

 

[caddisflyer]

We fished below Safe Harbor Dam on Susquehanna for many years starting in 1970s. The Walleye fishing was excellent and it attracted many fishermen. Gradually we began catching Flatheads and the Walleye were fewer. Eventually all the Walleye guys stopped coming. For about 10 years now that area has become a destination spot for Flatheads. I have no interest in that type of fishing. I never hear of anyone taking Walleye there anymore. The Smallmouth fishing went downhill there as well. Really a shame.
When my son started throwing the Flatheads on the bank the Fish Warden came down and was very angry about it which I thought was a strange response.

 

[Mike]

Respectfully, I don’t need to. I have been boat fishing the same areas of the Delaware river for 40 years. I am intimately aware of the current and historical SMB numbers in the Bucks county area. These are my numbers based on many days of fishing over the years and decades and not data drawn from a handful of annual electro shocking surveys. If the PFBC is coming up with numbers indicating a rebound then I have to seriously question the data going in. If going from 50 bass to 5 bass in a morning of fishing by two experienced river anglers is considered natures balancing act then I guess I’m wrong. If going from a 5 bass morning to a 6 bass morning is a rebound then I’m wrong again. What I have seen is the average size of the fish going up but the numbers of smaller fish going down, way down, rock bottom down.

Equally respectfully, the reasons why I suggested that you comtact the AFM were as follows:
The YOY SMB data would tell you whether or not yr to yr reproduction has continued to be spotty and whether the inconsistent reproductive success, if that’s still occurring, is widespread or more localized. Adult and YOY SMB data are recorded annually from representative sites over the stretch from Yardley to Upper Black Eddy for adults and Yardley to Raubsvillle, Northampton Co for YOY. The adult data would also provide a window telling you whether the adult population has slumped in some areas and not in others. I am not one to think that flatheads and snakeheads were causing the reproductive problems that we saw one to 1.5 decades ago since those problems were occurring in the absence or near-absence of the flatheads and snakeheads. That would not lead me to think that if such a problem still exists that the growth of the flathead and snakehead populations is today’s problem without some clearer evidence.

As for the subject flathead study, I will be reading the full text in the Trans Am Fish Soc when I receive my issue, but IF the horizontal bars shown in the figure above perhaps represent the frequency of occurrence of those species detected in the flathead stomachs, they’re not a strong argument for flatheads causing problems for SMB populations through direct predation on SMB. Competition for forage might be indicated, however.

 

[poopdeck]

No doubt the competition for forage is also a strong factor. However, over the last 1.5 decades I’ve watched the snakehead/flathead populations go up while simultaneously the SMB population has declined. I’ve also watched as officials and anglers have largely been dismissive of this very strong in your face correlation. Count all the YOY that you want but it’s the YOY that get eaten. To say invasive species are not the reason for the SMB decline simply because there are more overly abundant minnow species in the stomach is a nearsighted observation.

Also, the Delaware river is a completely different river. I can’t tell you the last time I saw a crayfish in the Delaware. I can’t tell you the last time I caught a bluegill or rock bass on the Delaware. I do seem to recall catching a sucker 10 or 15 years ago. Those species are long gone from the bucks county portion of the Delaware and soon the SMB will be gone. If the study was done on the Delaware it would also find less SMB in the stomach because of the dwindling numbers of SMB. So those stomach content studies only bolster and support my theory that the increased numbers of flatheads and snakeheads are directly responsible for the decline of SMB. And yes, nature will balance it out, it has to, because only a certain number of invasive can feast on what’s left. Make no mistake though, the SMB population will never recover and will remain paltry at best yet the invasive will level out. That’s not actually balancing in my book.