? For Al

[Al Agnew]

AARRRGGHH!

The interbreeding did not HAVE to occur from an existing population in place. I caught three hybrids (actually it might have been just two, but that doesn't matter.) They were caught in the same year, same one mile of stream, same size, therefore probably from the same brood. Now, there are three possibilities as to how they got there. One is your idea, that they came from a resident spotted bass that spawned with a resident smallmouth. Since there are zero records of resident spotted bass anywhere in the Meramec River system to that point, I'd say that possibility is unlikely. Two is that they were spawned somewhere else, like maybe from the same group of fish who apparently had made it up to the Missouri/Mississippi confluence as well as the mouth of Isle du Bois Creek by 1969 (juvenile fish at that time, but their parents could have been there or they could have become adults in time to spawn the hybrids I caught). Those places bracket the lower end of the Meramec, so it's probably pretty likely that a few spotted bass had also made it to the lower end of the Meramec by 1969. They could have spawned with resident smallies in the lower end of the Meramec, and the hybrids migrated up into Big River. Three, one or more spotted bass could have migrated as far as lower Big River at that point, and produced the hybrids.

Spotted bass ARE migrators. Proof is that they spread rapidly up these streams until they came to mill dam barriers, which stopped their spread for several years. So if spotted bass had made it to the lower end of the Meramec by 1969, it makes perfect sense that at least one spotted bass could have made it to lower Big River by sometime in the early 1970s, and produced a brood of hybrids.

Keep in mind, however, that after that one year, I never saw another hybrid nor pure spotted bass in that area for the next fifteen years or so, and none were collected or reported from lower Big River during that time. So whatever spotted bass produced that brood, it apparently didn't survive afterwards, nor did any other spotted bass produce broods in that area. Now I'm not a vacuum cleaner when it comes to catching bass, but I fished the area enough that I'd say there would be at least a good chance I'd have caught spotted bass before and after that episode had there been a resident population.

So I'd say that it is far more likely that those hybrids came from a stray that had migrated far enough by three years before to have entered the Meramec system, rather than a resident which had lived there all its life, spawned from ancestors who lived there as well.

[drew03cmc]

OB, never once did I say native. I said there was a small population there, which would explain the hybrids Al was catching. Sampling is not an exact science. You can never sample EVERY fish in a body of water. You get a "representative" sample, which CAN exclude small or almost non-existent species due to a low population density.

I have my views and the "experts" as they call themselves have theirs. Oh well, nothing has changed.

[Tim Smith]

OB, never once did I say native. I said there was a small population there, which would explain the hybrids Al was catching.

??What's all the passion for if this isn't an argument over native vs. exotic origin??

Why does it matter if the fish came from a small remnant population or a few transients?

That's not really a question you can answer with certainty...although both you and OB have good points about sampling. They aren't completely inclusive as you say, but OB's right that over time they do approach the true representation of species using the system.

Either way, what are the repercussions of either scenario if the issue isn't over whether these fish are native or not? I don't see any.

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[Tim Smith]

So what was the limiting factor in the population then drew? Spotted bass have been expanding their range in both Illinois and Missouri during the timeline that AL has mentioned. Habitat on both sides of the Mississippi is suitable to spots and they were non existent on both sides of the Mississippi until the early 70's. That is 2 different states and another entity (Illinois natural history survey) that sample waterways and spotted bass did not start showing up in ANY surveys in Mississippi tributaries in Illinois until the early 60's and Missouri until the early 60's, 70's for the tributaties north of apple creek. If there had been a resident population, there was absolutely nothing holding it back from expanding rapidly, which is the exact reason that the population has exploded in the past 30 years. The habitat has been there the whole time for it to thrive. The Illinois natural history survey samples Illinois waterways on a yearly basis, and has done so for the past 100 years. Spots did not show up in any survey on the Illinois side (great spotted bass habitat) until the early 60's. This link shows the collection of all spotted bass found in Illinois and spotted bass started to show up in southern Illinois until the early 60's. They most likely have migrated from the Ohio river, or have traveled up from a lower mississippi river tributary. The Illinois natural history survey has been sampling southern Illinois Mississippi river tributaries since 1881 in Illinois waterways, I know that we have come light years in sampling technology since that time, but I find it really hard to believe that a population of fish has gone undetected and could just rapidly explode to where they are now, without a major alteration in species composition or habitat alteration. Drunken rant over.

http://ellipse.inhs.uiuc.edu:591/INHSCollections/FMPro

if that link doesn't work use this one

Type Micropterus punctulatus into the search function for species

http://ellipse.inhs.uiuc.edu:591/INHSCollections/FMPro?-db=INHSFish.fp5&-lay=web&-format=fishsearch.html&-view

Actually, no.

That data base is pretty spiffy, but it's incomplete. Philip Smith's Fishes of Illinois shows Micropterus punctulatus in the Embarras River (and 3 other Southeast Illinois drainages) prior to 1908, and Larimore and Smith's Fishes of Champaign County show it both the Embarras and the Vermilion (Wabash Drainage) before the turn of the century as well. There is no record of smallmouth in the Vermilion or the Embarras at that time but they have become the dominant Micropterus species in the Vermilion since that time (except in low gradient, fine substrate areas where spots take over). No smallmouth have ever occurred in the Embarras.

Also, while the INHS samples every year, it doesn't sample every system every year. In the late 19th and eary 20th century, the spatial and temporal spacing between samples was pretty wide. At that time the sampling effort primarily consisted of Stephen Forbes and a few others and they were stretched quite thin. It would be pretty hard to exclude spotted bass from many Illinois systems based on Stephen Forbes effort simply because he couldn't get around to them.

And to be frank, sampling technologies for abundance have not advanced tremendously. We have a variety of electrofishing packages now, but those leave gaps in the sampling record and you're better off with a minnow seine if you're sampling for things like darters. You're badly limited in water over 10 feet deep with electrofishing. Rotenone has been around for a long time as has dynamite, bottom trawls, fish weirs, fyke nets, trammel nets, cast nets, pop nets, hook and line...I guess underwater cameras and acoustic gear are new but those aren't much help in Illinois' murky water even today and acoustics aren't useful for species ID unless you know what you're looking for. It takes multiple gears over multiple years and a little bit of luck to get a complete record of the species in a system.

Discussions about reasons for expansions are important and a lot of fun but they require a significant grain of salt.

[aftersh0ck]

sorry for the hornets nest

[drew03cmc]

??What's all the passion for if this isn't an argument over native vs. exotic origin??

Why does it matter if the fish came from a small remnant population or a few transients?

That's not really a question you can answer with certainty...although both you and OB have good points about sampling. They aren't completely inclusive as you say, but OB's right that over time they do approach the true representation of species using the system.

Either way, what are the repercussions of either scenario if the issue isn't over whether these fish are native or not? I don't see any.

Al has been promoting his theory as gospel about the Diversion Channel causing the spotted bass increase. He follows that by saying that he caught 3 hybrids in the 70s, and then says that spotted bass didn't begin invading until the 80s. I am sorry, there is a gap there, in which the spots were there already, as is evident by the hybrids. They don't just appear. Smallmouth x smallmouth does not produce meanmouth. Sorry. That is not the way genetics would work in that situation. I can see the possibility of his theory, but everyone else is wrong. Nothing else holds water if it came from someone on the other side of the Ozarks, or someone who does not take what is said as gospel.

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[Tim Smith]

I was speaking of Mississippi river drainages Tim, I know that they were native to the Ohio river tributaries in southeast Illinois. Interesting to hear that they have expanded they're range in the vermillion. Where spotted bass native to all wabash tributaries? INHS actually shows a collection of smallmouth in the embarras in 1966. Someone needs to do some genetic testing to determine where the spots have migrated from.

I see your point better now, SIU. Thanks for being patient while I get up to speed on the details.

According to Fishes of Champaign County they were in the Vermilion from the first time Forbes sampled them. I don't see evidence the Wabash tribs were carefully sampled until well into the 20th century so I couldn't comment on how widespread they were then. Interestingly too, smallmouth have always been in the Kaskaskia, and spots have always been in the Embarras right next door. Neither species has poked their nose into their neighboring drainages.

I hope the people who are making decisions about inland fisheries research and "Voldemort" adaptation are thinking about how to deal with future range expansions of this species.

[Al Agnew]

Drew, just keep in mind that I fished that same section, along with most of the rest of the river, for years before and after I caught those hybrids, without ever seeing either a pure spotted bass or a hybrid. It simply doesn't make sense that there was a tiny population of spotted bass there, in perfect spotted bass habitat, so small that neither I nor any of my friends who also fished that stretch ever caught one, and that never gained in population until all of a sudden they exploded. I don't know why you are so nettled that I'm "promoting" my theory, but all I'm doing is telling what I have seen in extensively fishing the eastern Ozarks since about 1970, and making some educated guesses.

Siusaluki, thanks for the info on Illinois. The Illinois fish in the tribs running into the Mississippi seem to show a similar time line to those on the west side of the river, though maybe a little earlier. I know when spots first started showing up on Saline Creek and upstream, but they were in lower Apple Creek when I first started fishing it so they could have been there by the early 1960s. I don't know offhand when the dams were built on the upper Missouri, but as soon as the floodgates closed and the lakes up there started filling up, the silt load in the Missouri would have been greatly reduced. Perhaps, if my theory is correct, that was the major factor that allowed spotted bass spread.

Spotted bass have always been native to the Ohio River system, mainly limited by the habitat in the tributaries and probably by latitude--they couldn't go too far north in the northern tributaries because of water temps. But the Ohio historically had much less of a silt load than the Missouri, and the Mississippi between the Missouri and the Ohio, so spots could have moved up and down it to populate the tribs in Illinois naturally, but not be able to move up the Mississippi from the mouth of the Ohio--therefore no early records of spotted bass in the Mississippi tribs. If the Missouri dams theory is correct, by the time the dams were in place they could have moved up the Mississippi finally and colonized those streams. And...I don't know how likely it is that they would cross the Mississippi, since the main channel isn't very hospitable to bass, but the Ohio is a plausible source for the Illinois fish and the Missouri fish could have possibly come from the Ohio as well. And...the Illinois fish could have possibly come from the Diversion Channel. It would be very interesting to do detailed genetic studies on spots in the Ohio tribs, spots in the Diversion Channel, and spots in the Mississippi tribs on both sides of the river, to get a much better idea on where those fish came from.

At any rate, unless Drew is right, it's an interesting study in the spread of a fish species due to environmental factors. I just wish the results hadn't been so disastrous for my rivers.