What Factors influence the Smallmouth population

[timinmo]

The best way is to go to the Stream Team site and in the blue above the green headings there is a topic marked "interactive map" it is to the right.  That will bring up a map of Missouri with test sites all over the map.  You can zoom into the area you are interested in and click on the emblem.  Some of these sites are inactive, that is,  someone tested there once and never went back or there is no current data.

What I thought you might find interesting is "we" MSA Stream Team 509 participated in a year long project to sample 20 sites in the Meramec Basin.  509 sampled two of these sites once a month for a year, other teams sampled other sites.  We tested turbidity, nitrates and phospates in this study.  Normal Water Quality Monitoring test for some other things as well.  If you send me your E-mail I will forward the results to you, it is about twenty pages.  In my eyes the project did not answer any questions but I don't believe it was designed to.

As a disclaimer I will tell you I am not a scientist and do the WQM as an excuse to get out on the river.

Is water quality part of the spotted bass issue?  I don't think anyone can answer that with any degree of certainty, but poor quality can not help.  I'm just not sure it hurts.  If the quality is bad it is bad for all the bass varieties.  Habitat could be a different thing but I don't mind admitting that I do not have an answer.  As a person who fished the Bourbeuse  in the sixties and seventies I can tell you to my untrained teenage eyes it was in much worst shape then than now.  I caught the biggest MIssouri smallmouth I have ever caught in the sixties and while I do not keep records, I can not recall catching a spotted bass until years later.  As others have stated the Meramec basin is full of them now.

I will leave it to others to argue the how and why but no one can dispute their presence. 

 

 

   

[Al Agnew]

Of course, this isn't scientific but anecdotal, but I have not observed these streams getting more murky over the many years I've fished them, with the exception of more silt being stirred up by jet boat wakes on the middle Meramec on warm weather weekends.  Remember that jet boats didn't get popular enough to be significant until the mid to late 1980s...which is also when spotted bass were appearing. Coincidence? In my opinion, jet boats did adversely affect smallmouth numbers, but I noticed that in stretches farther up the Meramec where spots had not yet reached. 

As for all the other ills of urbanization, it's not like spotted bass are more tolerant of pollution than smallmouth. All that chemical laced run off from urban areas is probably bad for both.  And maybe detailed chemical analysis would show things I can't eyeball, but I see little difference in the water quality of these rivers over the years, and actually the difference I've seen has been some improvement with better sewage treatment in the smaller towns farther up the rivers.  (More later, I'm tired of typing on my phone😁

[Chief Grey Bear]

I don't think anyone is claiming it is a cesspool of poison.  But water quality  has obviously changed.    To deny that is being disingenuous. Did it change to favor the smallmouth?  Or did it change to favor the spotted bass?  We all know what the results say.

 

[Johnsfolly]

1 hour ago, Al Agnew said:

As for all the other ills of urbanization, it's not like spotted bass are more tolerant of pollution than smallmouth. All that chemical laced run off from urban areas is probably bad for both.  

Does anyone on this thread know if smallmouth bass are more susceptible than spotted bass to intersex development (development of both testicular and ovarian tissues within the same gonad; also know as ovatestis) due to endocrine active substances or endocrine disruptive compounds (EDC's)? I have not done a whole lot of research and the only thing that I could quickly find was this statement in a recent study in Maryland by the US Fish and Wildlife. These statements seem to suggest that their may be potential differences between smallmouth and largemouth in terms of their susceptibility for male fish to develop intersexuality.

"The Results

We found female germ cells (oocytes) in the testes of 82% to 100% of the male smallmouth bass and in 23% of the males from the single largemouth bass collection near the Blue Plains Wastewater Plant in Washington, DC. The baseline prevalence of testicular oocytes in male smallmouth is uncertain but may be in the range of 14% to 22%; baseline for male largemouth may be closer to 0%."

With spotted and smallmouth bass considered by taxonomists to be more closely related to each other than in comparison to the largemouth wasn't sure if anything is really know about whether the two species respond differently to the presence of EDC's in the environment. It is likely for EDC's to increase due to urbanization (i.e., introduction of herbicides, pesticides, birth control hormones, etc.).

Al - what is the differences in growth rate or better yet maturation rate between smallmouth and spotted bass. One could theorize that if smallmouth reach sexual maturity at a later age, then they would be more likely to be affected by EDC's due to the length of their exposure. The higher incidence of intersex in the population will likely cause a decline in viable reproduction.

[MOPanfisher]

Many things change over time, water flow, temps, chemistry, population make up.  If spotted bass are more adapted to some areas, and are more aggressive and are present then harvest or stocking isn't going to change much.  They are still going to be there and be numerous, certainly it won't hurt to harvest them but it's not going to bring back the golden days no matter what we would like.

[timinmo]

Well guys I guess I did not say it in so many words but I think water quality probably has improved since the sixties for several reasons.  The Clean Water Act being the biggest.

If you are looking to blame the influx of spots on something I don't thing you will find it water quality.  The habitat might have went down hill but if we had the data I would bet that in most cases the chemistry of the water has improved.

[Chief Grey Bear]

23 minutes ago, Johnsfolly said:

Al - what is the differences in growth rate or better yet maturation rate between smallmouth and spotted bass. One could theorize that if smallmouth reach sexual maturity at a later age, then they would be more likely to be affected by EDC's due to the length of their exposure. The higher incidence of intersex in the population will likely cause a decline in viable reproduction.

I'm not Al, but they both mature and start spawning at about the same time.  Usually by the third or fourth year. 

 

[Johnsfolly]

Thanks Chief. I should have thrown out that question to the larger audience.

[Chief Grey Bear]

Always glad to help when I can. 

[Al Agnew]

Johnsfolly, I wonder if the EDC problem is anywhere close to as big in these streams as it is in the streams studied in Maryland.  I know it's a huge problem in several eastern streams, but the human population throughout their watersheds is probably much denser than in the Ozarks, and thus there would be more endocrine disruptors getting into the waterway.  The fortunate thing the Meramec River system has going for it is that most of its urbanization is toward the lower ends of the streams, so it doesn't affect all of them.  The Bourbeuse is affected by agricultural chemicals and practices throughout its length, but the only major, growing town along it is Union, close to the downstream end.  Big River has a significant urbanized area on the upper portion, however, and a lot of scattered by extensive development in its lower watershed in Jefferson County.  The Meramec, of the three, probably has the healthiest watershed, with less row-cropping and grazing than the Bourbeuse, more intact timber than both the Bourbeuse and Big.

By the way, spotted bass appear to grow slightly faster than smallmouth in Ozark streams until they reach their fifth year, then grow more slowly from then on.  Top end size, of course, is significantly less than smallmouth.

We can argue all night about how the spots got there and why they got there when they did.  They are there.  They have had a huge effect on the smallmouth population.  Really, the only important questions are, CAN we do anything to help the smallmouth against the spots, SHOULD we do anything, and WHAT can or should we do?

If you want to study a very detailed investigation of the health of the streams of the Meramec Basin, search "Meramec River Conservation Action Plan".  You can download the whole thing.  It's a cooperative effort spearheaded by the Nature Conservancy, with participation by a whole bunch of educational and environmental institutions.  It makes for very interesting reading if you're a river geek like me.