Smallmouth Bass Page - Revision history

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-[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase (duration of daylight) is long and increasing and water temperatures are between 15°C to 25°C. Under controlled laboratory conditions, she found that spawning could be induced from January to the end of June independently of the photophase. Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings (occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
+[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase (duration of daylight) is long and increasing and water temperatures are between 15°C to 25°C. Under controlled laboratory conditions, she found that spawning could be induced from January to the end of June independently of the photophase. Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
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-[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase (duration of daylight) is long and increasing and temperatures between 15°C to 25°C. Under controlled laboratory conditions, she found that spawning could be induced from January to the end of June independently of the photophase. Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings (occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
+[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase (duration of daylight) is long and increasing and water temperatures are between 15°C to 25°C. Under controlled laboratory conditions, she found that spawning could be induced from January to the end of June independently of the photophase. Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings (occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
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-[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase (duration of daylight) is long and increasing and temperatures between 15°C to 25°C. Under controlled laboratory conditions, spawning could be induced  from January to the end of June independently of the photophase. Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings (occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
+[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase (duration of daylight) is long and increasing and temperatures between 15°C to 25°C. Under controlled laboratory conditions, she found that spawning could be induced from January to the end of June independently of the photophase. Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings (occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
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-[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase is long and increasing and temperatures between 15°C to 25°C. Under controlled laboratory conditions, spawning could be induced  from January to the end of June independently of the photophase (duration of daylight). Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings (occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
+[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase (duration of daylight) is long and increasing and temperatures between 15°C to 25°C. Under controlled laboratory conditions, spawning could be induced  from January to the end of June independently of the photophase. Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings (occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
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-[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase is long and increasing and temperatures between 15°C to 25°C. Under controlled laboratory conditions, spawning could be induced  from January to the end of June independently of the photophase. Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings (occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
+[https://storre.stir.ac.uk/handle/1893/29308 Cantin (1994)] found that natural spawning occurs in spring (April to July) when the photophase is long and increasing and temperatures between 15°C to 25°C. Under controlled laboratory conditions, spawning could be induced  from January to the end of June independently of the photophase (duration of daylight). Individual spawnings indicated that the same female can spawn more than once per season and at different times of the year if the right developmental and spawning conditions are met. At the end of the experiments, the fish left from all the groups were stocked, in mid-July, into a lake. August and September spawnings were then observed. These spawnings (occurred with temperature fluctuations between 15-18°C and decreasing photoperiod.
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 Difficulty arises when trying to compare the number of smallmouth bass being caught from year to year due to changes in capture methodologies. For example, if one were to focus removal efforts in an area where smallmouth bass are concentrated like in a backwater or a slough, the catch per unit effort (or CPUE) would be higher that the CPUE of normal monitoring which by design is done at sites that are selected more at random.
-Additionally, the level of effort changes from year to year and those changes are not well reflected when presenting the number of fish being caught. For example, if one caught a certain number of fish one year using a certain level of effort and then the next year they doubled the level of effort but only caught a third more fish, the CPUE (and relative abundance) would be smaller the second year even though more fish were caught. Both capture methodologies and level of effort has changed from year to year with the numbers of smallmouth bass listed above.
+Additionally, the level of effort can change from year to year and those changes may not be reflected when presenting the number of fish being caught. For example, if one caught a certain number of fish one year using a certain level of effort and then the next year they doubled the level of effort but only caught a third more fish, the CPUE (and relative abundance) would be smaller the second year even though more fish were caught. Both capture methodologies and level of effort has changed from year to year with the numbers of smallmouth bass listed above.
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 '''2024'''
-*[https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1304&context=etd2023 Friesen, Barrett T., "Invasion Potential of Nonnative Fishes Through a Large Western Dam Into a Prized and Vulnerable Ecosystem" (2024). All Graduate Theses and Dissertations, Fall 2023 to Present. 288. https://digitalcommons.usu.edu/etd2023/288 ]
+*[https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1304&context=etd2023 Friesen, Barrett T., "Invasion Potential of Nonnative Fishes Through a Large Western Dam Into a Prized and Vulnerable Ecosystem" (2024). All Graduate Theses and Dissertations, Fall 2023 to Present. ]
 *[[Media:LTEMP_SEIS_Cool_Mix_Flow_Summary_Report_Draft4.docx|2024 Cool Mix Flow Summary Report]]
 *[https://qcnr.usu.edu/coloradoriver/files/research/2024-SMB-Report-3.pdf Review of Smallmouth Bass Management in the Colorado River Ecosystem]

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 *[https://www.youtube.com/watch?v=50m8DoiKVVU Video 1]
 *[https://www.youtube.com/watch?v=zBDDliPHdVk Video 2]
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-! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #a3b0bf; text-align:left; color:#000; padding:0.2em 0.4em;"> What is the risk of smallmouth bass establishment below Glen Canyon Dam to humpback chub in Grand Canyon? </h2>
+! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #a3b0bf; text-align:left; color:#000; padding:0.2em 0.4em;"> What is the likelihood of smallmouth bass establishment below Glen Canyon Dam and what risk might that pose to humpback chub in Grand Canyon? </h2>
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-==[https://academic.oup.com/tafs/article/154/5/469/8209825 Pine et al. 2025. Assessing the potential for Smallmouth Bass population establishment in Grand Canyon]==
+=='''[https://doi.org/10.1093/tafafs/vnaf027 William E Pine, Josh Korman, Richard A Valdez, Carl J Walters. 2025. Assessing the potential for Smallmouth Bass population establishment in Grand Canyon. Transactions of the American Fisheries Society, Volume 154, Issue 5, September 2025, Pages 469–489]'''==
-The expansion of nonnative Smallmouth Bass (Micropterus dolomieu) into the Grand Canyon ecosystem downstream of Glen Canyon Dam is widely seen as a potential threat to native fishes, particularly the Humpback Chub (Gila cypha), which is listed as threatened under the Endangered Species Act. This concern stems from observations in the Green and upper Colorado rivers, where dam- modified habitats and reservoir introductions have allowed Smallmouth Bass to become established and impact native fish species. Our objective was to compare habitat conditions between a Smallmouth Bass population center in the Green River— where Humpback Chub are rare— and two major Humpback Chub population centers in the Colorado River in Grand Canyon, where Smallmouth Bass invasion is a conservation concern, to help assess invasion risk and inform management actions downstream of Glen Canyon Dam.
-==Methods==
+The expansion of nonnative Smallmouth Bass (Micropterus dolomieu) into the Grand Canyon ecosystem downstream of Glen Canyon Dam is widely seen as a potential threat to native fishes, particularly the Humpback Chub (Gila cypha), which is listed as threatened under the Endangered Species Act. This concern stems from observations in the Green and upper Colorado rivers, where dam-modified habitats and reservoir introductions have allowed Smallmouth Bass to become established and impact native fish species. Our objective was to compare habitat conditions between a Smallmouth Bass population center in the Green River— where Humpback Chub are rare— and two major Humpback Chub population centers in the Colorado River in Grand Canyon, where Smallmouth Bass invasion is a conservation concern, to help assess invasion risk and inform management actions downstream of Glen Canyon Dam.
-We developed a conceptual model of Smallmouth Bass recruitment potential emphasizing the roles of temperature, turbidity, and the timing of these conditions, based on literature for Smallmouth Bass and Largemouth Bass Micropterus nigricans. Using U.S. Geological Survey gauge station data, we summarized daily temperature and turbidity patterns near a known Smallmouth Bass population center in the middle Green River (near Jensen, Utah) and compared those with conditions in the Colorado River in Glen Canyon and Grand Canyon downstream from Glen Canyon Dam. We then used our conceptual model of Smallmouth Bass early life history, along with observed turbidity and temperature patterns, to explore how irregular recruitment could affect Smallmouth Bass population dynamics and individual growth potential using an age- structured population model and a bioenergetics model.
-==Results==
+We developed a conceptual model of Smallmouth Bass recruitment potential emphasizing the roles of temperature, turbidity, and the timing of these conditions, based on literature for Smallmouth Bass and Largemouth Bass (Micropterus nigricans). Using U.S. Geological Survey gauge station data, we summarized daily temperature and turbidity patterns near a known Smallmouth Bass population center in the middle Green River (near Jensen, Utah) and compared those with conditions in the Colorado River in Glen Canyon and Grand Canyon downstream from Glen Canyon Dam. We then used our conceptual model of Smallmouth Bass early life history, along with observed turbidity and temperature patterns, to explore how irregular recruitment could affect Smallmouth Bass population dynamics and individual growth potential using an age-structured population model and a bioenergetics model.
-Although warm reservoir releases due to low water storage in Lake Powell has made temperature regimes in Glen and Grand canyons more similar to those of the middle Green River, the Colorado River ecosystem in Grand Canyon has a very different turbidity regime from that of the middle Green River. The Colorado River in Grand Canyon becomes very turbid during late summer and fall, when tributaries experience flash floods during the North American monsoon season. These periods of high turbidity coincide with critical early life stages of Smallmouth Bass, likely limiting foraging efficiency, growth, and overwinter survival. Our population model indicates that rapidly growing and sustained Smallmouth Bass populations require successful recruitment at least once every 2 years, but empirical data suggest that these conditions occur only every 5–7 years in Grand Canyon. This would make long- term establishment of self- sustaining Smallmouth Bass populations in Grand Canyon unlikely or at least highly uncertain.
-==Conclusions==
+Although warm reservoir releases due to low water storage in Lake Powell has made temperature regimes in Glen and Grand canyons more similar to those of the middle Green River, the Colorado River ecosystem in Grand Canyon has a very different turbidity regime from that of the middle Green River. The Colorado River in Grand Canyon becomes very turbid during late summer and fall, when tributaries experience flash floods during the North American monsoon season. These periods of high turbidity coincide with critical early life stages of Smallmouth Bass, likely limiting foraging efficiency, growth, and overwinter survival. Our population model indicates that rapidly growing and sustained Smallmouth Bass populations require successful recruitment at least once every 2 years, but empirical data suggest that these conditions occur only every 5–7 years in Grand Canyon. This would make long-term establishment of self-sustaining Smallmouth Bass populations in Grand Canyon unlikely or at least highly uncertain.
 Despite the presence of nonnative predators, Humpback Chub populations in Grand Canyon have expanded during the past 10–15 years, very likely due to favorably warm river temperature. While Smallmouth Bass in Glen or Marble canyons (between Glen Canyon Dam and the Little Colorado River) may pose a downstream dispersal risk (and potentially a threat to Humpback Chub populations), high turbidity conditions downstream of the Little Colorado River reduce the likelihood of persistent local Smallmouth Bass recruitment. These results suggest that Smallmouth Bass invasion risk to Humpback Chub is not uniform across the Colorado River basin and should be evaluated in the context of the different site- specific water quality and flow regime conditions, other known risks to Humpback Chub, and Humpback Chub population size in different parts of the basin.
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