As I say, in the natural world, fish live where competition is least, not where conditions are best.
So what limits the range of Pteronotropis welaka?
Welakas eat and grow like other Pteronotropis. Welakas do fine in Detroit city water. Welakas can be healthy and fertile in their second year.
And
Welakas can swim so fast that sunfish learn not to even try and eat them. Welakas even raid sunfish nests.
So why aren't Welakas everywhere?
What limits the range of Bluenose Shiners?
Started by
Guest_PhilipKukulski_*
, Jun 27 2010 10:32 PM
18 replies to this topic
#3
Guest_Mysteryman_*
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Posted 28 June 2010 - 09:42 AM
Yep.
The peninsular Florida populations along the St Johns drainage have been pretty much wiped out completely. The Longears which used to be common there have also been nearly wiped out completely. Coincidence? Probably not.
Agricultural runoff has also been a huge problem for them.
Bluenoses live in tiny scattered areas, as you know, but the waterways between these places are pretty inhospitable to them. In the Yellow River, for example, the deep holes are between very shallow waters only 2-3 inches deep with sandy bottoms and nowhere to hide. There are plenty of other fish found in those places, but not Bluenoses, and not many sunfishes, which certainly wouldn't try to make nests there anyway.
The spring heads where they are also found are not at all common, so with few springs, you'll have few populations. Again, for them to get anywhere else from these pools they would have to travel many miles to find another place they liked, tricky itself, but then they'd need there to be sunnies present in those places, and sunnies they could understand, at that. Also, the places where they are found tend to not have many other species in them, so avoiding competition is possibly a factor.
My guess is that they were once much easier to find across a much wider area, but being so darned picky, and faced with various indignities from humans like agricultural & timber runoff, dams, introductions of "gamefish" and road construction, their suitable habitat dwindled long before anybody ever paid any attention to them.
All in all, I'd say that the #1 thing that limits their distribution is their own stubbornness. Very picky, these guys.
The peninsular Florida populations along the St Johns drainage have been pretty much wiped out completely. The Longears which used to be common there have also been nearly wiped out completely. Coincidence? Probably not.
Agricultural runoff has also been a huge problem for them.
Bluenoses live in tiny scattered areas, as you know, but the waterways between these places are pretty inhospitable to them. In the Yellow River, for example, the deep holes are between very shallow waters only 2-3 inches deep with sandy bottoms and nowhere to hide. There are plenty of other fish found in those places, but not Bluenoses, and not many sunfishes, which certainly wouldn't try to make nests there anyway.
The spring heads where they are also found are not at all common, so with few springs, you'll have few populations. Again, for them to get anywhere else from these pools they would have to travel many miles to find another place they liked, tricky itself, but then they'd need there to be sunnies present in those places, and sunnies they could understand, at that. Also, the places where they are found tend to not have many other species in them, so avoiding competition is possibly a factor.
My guess is that they were once much easier to find across a much wider area, but being so darned picky, and faced with various indignities from humans like agricultural & timber runoff, dams, introductions of "gamefish" and road construction, their suitable habitat dwindled long before anybody ever paid any attention to them.
All in all, I'd say that the #1 thing that limits their distribution is their own stubbornness. Very picky, these guys.
#4
Guest_gerald_*
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Posted 28 June 2010 - 11:13 AM
Three thoughts/questions:
1) Do they successfully breed in nature in nests of most common Lepomis species, or only a few host species?
2) Are there certain common widespread fishes that are unusually rare or absent at sites with good welaka pops?
3) Maybe something to do with differences in small zooplankton communities and timing of blooms, which may in turn be related to groundwater vs surface water inputs at different sites.
1) Do they successfully breed in nature in nests of most common Lepomis species, or only a few host species?
2) Are there certain common widespread fishes that are unusually rare or absent at sites with good welaka pops?
3) Maybe something to do with differences in small zooplankton communities and timing of blooms, which may in turn be related to groundwater vs surface water inputs at different sites.
Yep.
The peninsular Florida populations along the St Johns drainage have been pretty much wiped out completely. The Longears which used to be common there have also been nearly wiped out completely. Coincidence? Probably not.
Agricultural runoff has also been a huge problem for them.
Bluenoses live in tiny scattered areas, as you know, but the waterways between these places are pretty inhospitable to them. In the Yellow River, for example, the deep holes are between very shallow waters only 2-3 inches deep with sandy bottoms and nowhere to hide. There are plenty of other fish found in those places, but not Bluenoses, and not many sunfishes, which certainly wouldn't try to make nests there anyway.
The spring heads where they are also found are not at all common, so with few springs, you'll have few populations. Again, for them to get anywhere else from these pools they would have to travel many miles to find another place they liked, tricky itself, but then they'd need there to be sunnies present in those places, and sunnies they could understand, at that. Also, the places where they are found tend to not have many other species in them, so avoiding competition is possibly a factor.
My guess is that they were once much easier to find across a much wider area, but being so darned picky, and faced with various indignities from humans like agricultural & timber runoff, dams, introductions of "gamefish" and road construction, their suitable habitat dwindled long before anybody ever paid any attention to them.
All in all, I'd say that the #1 thing that limits their distribution is their own stubbornness. Very picky, these guys.
#5
Guest_Dustin_*
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Posted 28 June 2010 - 11:32 AM
Another factor that I think is involved is a reasonably constant water temperature. Most of the populations are associated with springs where the temperature fluctuates very little between the seasons. If the fish are maintained indoors in aquariums I would suspect the temperature would remain fairly constant as well.
I am suspicicous of which sunfish these guys utilize. I have only caught them once and they were found with redspotted sunfish. Obviously, they also use dollar and longears, but would bluegill or warmouth work?
I am suspicicous of which sunfish these guys utilize. I have only caught them once and they were found with redspotted sunfish. Obviously, they also use dollar and longears, but would bluegill or warmouth work?
#6
Guest_Irate Mormon_*
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Posted 28 June 2010 - 10:17 PM
Another factor that I think is involved is a reasonably constant water temperature. Most of the populations are associated with springs where the temperature fluctuates very little between the seasons.
Truth. Plus, they like a particular microhabitat in which to spawn.
#7
Guest_Mysteryman_*
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Posted 29 June 2010 - 09:39 AM
Ooh! Temperature, of course. They like the deep and shady spots, which like springs are more stable.
Since most areas are dominated by a particular Lepomis, the Bluenoses in a given area respond best to that species.
Moving to an area dominated by a different sunnie may be a problem for them. It's just a guess on my part, but I do know this:
--The ones southeast of Dothan react strongly to Bluegill milt exposure, since that pond is stocked with them. However, they don't react much at all to Warmouth milt. Longears set them right off just fine.
--The ones nearest me use Warmouth nests, since the lower Yellow River has Warmouths aplenty and little else but Greens. Todd & I also found some near some Warmouths in spawning color. I haven't kept those, though, and haven't experimented with them.
--The ones from the place most of the ones in captivity came from use Redspots, and don't react at all to Warmouth milt ( much to my annoyance since it's so much easier for me to get ) and Longear milt didn't get them going, either. ( I gotta get some redspots next time, if ever there is a next time )
--I don't know what's going on in Mississippi. I think they use Longears in the Pearl River.
I would hazard a guess that over a fairly short time the bluenoses could adapt to new sunfish species, since they can obviously use them, but I'm assuming that they simply don't want to bother when they can stick with their preferred species. It would be a neat experiment, but one heck of a pain to conduct.
Certain species rare or absent in areas with good welaka populations?
Wow. Tough question.
I find that most welaka spots generally have only a small handful of fish species in them, even when nearby waters have many more. There's usually one dominant sunfish, usually a darter or two, one or two topminnows, and often only one other shiner, maybe two.. and that's about it. The big, best spot has bowfin & gar as well, and Elassoma zonatum.
Gambusia! I don't recall seeing Gambusia at any welaka site. There may be some, but I don't remember any. The topminnows probably keep them repelled.
Water inputs and food blooms? Yeah, I can see that. In fact, I'd guess they were critical.
Since most areas are dominated by a particular Lepomis, the Bluenoses in a given area respond best to that species.
Moving to an area dominated by a different sunnie may be a problem for them. It's just a guess on my part, but I do know this:
--The ones southeast of Dothan react strongly to Bluegill milt exposure, since that pond is stocked with them. However, they don't react much at all to Warmouth milt. Longears set them right off just fine.
--The ones nearest me use Warmouth nests, since the lower Yellow River has Warmouths aplenty and little else but Greens. Todd & I also found some near some Warmouths in spawning color. I haven't kept those, though, and haven't experimented with them.
--The ones from the place most of the ones in captivity came from use Redspots, and don't react at all to Warmouth milt ( much to my annoyance since it's so much easier for me to get ) and Longear milt didn't get them going, either. ( I gotta get some redspots next time, if ever there is a next time )
--I don't know what's going on in Mississippi. I think they use Longears in the Pearl River.
I would hazard a guess that over a fairly short time the bluenoses could adapt to new sunfish species, since they can obviously use them, but I'm assuming that they simply don't want to bother when they can stick with their preferred species. It would be a neat experiment, but one heck of a pain to conduct.
Certain species rare or absent in areas with good welaka populations?
Wow. Tough question.
I find that most welaka spots generally have only a small handful of fish species in them, even when nearby waters have many more. There's usually one dominant sunfish, usually a darter or two, one or two topminnows, and often only one other shiner, maybe two.. and that's about it. The big, best spot has bowfin & gar as well, and Elassoma zonatum.
Gambusia! I don't recall seeing Gambusia at any welaka site. There may be some, but I don't remember any. The topminnows probably keep them repelled.
Water inputs and food blooms? Yeah, I can see that. In fact, I'd guess they were critical.
Edited by Mysteryman, 29 June 2010 - 09:44 AM.
#8
Guest_PhilipKukulski_*
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Posted 02 July 2010 - 08:51 PM
Thanks all for your expertise.
I have never seem where Welaka spawn. I assume in May and June. Too late for a Jim Graham trip, and too early for summer vacation.
You(s) may be right in some critical water parameters for spawning. Soft-water, live food bloom, stabilized temperature.
The fry also may be the weak link. After 4 weeks, tank raised Welaka fry are where 2 week old Hypselopterus would be; then they match growth. I am very nervous about killing Welaka fry by netting or water changes.
Competition with adults? Ponce de Leon seems to have many fish species.
I have never seem where Welaka spawn. I assume in May and June. Too late for a Jim Graham trip, and too early for summer vacation.
You(s) may be right in some critical water parameters for spawning. Soft-water, live food bloom, stabilized temperature.
The fry also may be the weak link. After 4 weeks, tank raised Welaka fry are where 2 week old Hypselopterus would be; then they match growth. I am very nervous about killing Welaka fry by netting or water changes.
Competition with adults? Ponce de Leon seems to have many fish species.
#9
Guest_Mysteryman_*
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Posted 03 July 2010 - 09:15 AM
Competition with adults? Ponce de Leon seems to have many fish species.
Ponce de Leon? Hmmm.. I don't recall seeing welakas in Cypress or Vortex springs. I've never dived in Ponce de Leon Spring or Morrison Spring, either, but I think I read that Redeyes are in Morrison. They really do seem to prefer places with few neighbors. There are numerous very minor springs around there, though, which I've never checked out, and they look like they might be good spots. Not far from there ( ~25 miles )is Florida's very best spot for them, being a place very very much like Alabama's best spot. Surrounding it are many little spots which are likely good welaka spots, and which also probably don't hold many fish species. Most of the fish species are probably concentrated in the numerous lakes in the area, but that's just my guess. Anyway, between the two areas are oodles of places where welakas might abound, but I just don't know, so I couldn't tell you how many other species they swim with in those places.
Ponce de Leon? Hmmm.. I don't recall seeing welakas in Cypress or Vortex springs. I've never dived in Ponce de Leon Spring or Morrison Spring, either, but I think I read that Redeyes are in Morrison. They really do seem to prefer places with few neighbors. There are numerous very minor springs around there, though, which I've never checked out, and they look like they might be good spots. Not far from there ( ~25 miles )is Florida's very best spot for them, being a place very very much like Alabama's best spot. Surrounding it are many little spots which are likely good welaka spots, and which also probably don't hold many fish species. Most of the fish species are probably concentrated in the numerous lakes in the area, but that's just my guess. Anyway, between the two areas are oodles of places where welakas might abound, but I just don't know, so I couldn't tell you how many other species they swim with in those places.
#11
Guest_gerald_*
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Posted 05 July 2010 - 10:00 AM
'spose they imprint on the smell of the sunfish whose nest they hatched in, like anadromous salmon?
>> Mysteryman wrote: I would hazard a guess that over a fairly short time the bluenoses could adapt to new sunfish species, since they can obviously use them, but I'm assuming that they simply don't want to bother when they can stick with their preferred species. It would be a neat experiment, but one heck of a pain to conduct.
>> Mysteryman wrote: I would hazard a guess that over a fairly short time the bluenoses could adapt to new sunfish species, since they can obviously use them, but I'm assuming that they simply don't want to bother when they can stick with their preferred species. It would be a neat experiment, but one heck of a pain to conduct.
#14
Guest_fundulus_*
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Posted 05 July 2010 - 02:54 PM
That's true, welaka ranching isn't big business. Whatever the details of a given experimental design, it's in the realm of the possible to demonstrate what might be one factor stabilizing welaka reproduction in nature. Given that fish can detect molecules in the water at concentrations far below what we can smell in the air, it could be exciting path of research. I mean, what's not to like about having aquaria full of welaka and various sunfishes?You might need a hundred replications
considering I am the only one to raise more than 20 Welaka.
(I should mention here that I'm happy after seining several longears this morning in Estill Fork in Jackson Co., AL. We were only interested in telescope and scarlet shiners, so we let them go.)
#15
Guest_ashtonmj_*
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Posted 05 July 2010 - 03:56 PM
You might need a hundred replications
considering I am the only one to raise more than 20 Welaka.
When are that many replicates ever obtained in ecology. I don't mean sample size either, I mean true replicates. While I get your point Phil, it wouldn't be a ecological and statitsical conclusion (with some level of uncertainty in the claim made about the hypothesis) if every expirement had that kind of replication.
#16
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Posted 05 July 2010 - 04:23 PM
What experimental design would we want to use? A block ANOVA, with negative controls and different sunfish species milt using welaka from different locations? It's cumbersome but possible with enough experimental tanks (and people, too).
#17
Guest_ashtonmj_*
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Posted 05 July 2010 - 05:04 PM
I'd personally use small ponds say 0.25 acre each, which are readily available or easily made, but under utilized at universities with agricultural extensions or aquaculture programs. Well water is cheap and cool. You could not only block by water quality, but by sunfish species, and habitat variables (depth, cover, etc.) . Has anyone ever used milt from one sunfish species but visual cues from another?
#18
Guest_gerald_*
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Posted 06 July 2010 - 12:54 PM
Seems to me the possible Pteronotropis welaka Host-selection Theories could include:
1) They may be opportunistic, hosting on whichever sunfish lets them approach the nest without being attacked. Host selection may be based on host size and behavior rather than species. Groups of spawning welaka might act differently from pairs, and 2-yr olds might use different hosts than 1-yr olds.
2) They may be imprinted as eggs/larvae on the smell of their host's nest. (Or maybe visual cues as Matt suggests, but somehow I doubt that with larvae).
3) They may be imprinted sometime later, perhaps as the gonads mature, on the smell and/or appearance of sunfish species that spawn in habitats where welaka like to spawn.
4) There is no developmental imprinting, but populations are genetically pre-disposed to host on certain sunfish species based on smell and/or visual cues. (If so, there's probably some genetic polymorphism to confuse us. Otherwise they'd be pitifully un-adaptable.)
5) ??? ... add your theories.
1) They may be opportunistic, hosting on whichever sunfish lets them approach the nest without being attacked. Host selection may be based on host size and behavior rather than species. Groups of spawning welaka might act differently from pairs, and 2-yr olds might use different hosts than 1-yr olds.
2) They may be imprinted as eggs/larvae on the smell of their host's nest. (Or maybe visual cues as Matt suggests, but somehow I doubt that with larvae).
3) They may be imprinted sometime later, perhaps as the gonads mature, on the smell and/or appearance of sunfish species that spawn in habitats where welaka like to spawn.
4) There is no developmental imprinting, but populations are genetically pre-disposed to host on certain sunfish species based on smell and/or visual cues. (If so, there's probably some genetic polymorphism to confuse us. Otherwise they'd be pitifully un-adaptable.)
5) ??? ... add your theories.
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