Age and growth data are frequently used to monitor and manage important North American sport fishes such as Largemouth Bass Micropterus salmoides. Continental and regional growth standards have been developed for this species to assess fish growth over time and across space. However, Largemouth Bass age and growth data are infrequently collected in Arizona and the reliability of age estimates derived from typical structures (e.g., scales, otoliths) in the Southwest is uncertain. Our objectives were to 1) compare precision and bias of age estimates from scales with those from otoliths and 2) estimate Largemouth Bass growth in several southwestern warmwater reservoirs by using otoliths. We collected Largemouth Bass from three Arizona reservoirs—Alamo, Peña Blanca, and Roosevelt—by boat electrofishing in spring 2021. We removed scales and sagittal otoliths from fish and then prepared and independently aged them three times. We compared differences in precision and bias between scales and otoliths using reader agreement percentages, confidence ratings, average coefficients of variation, and age-bias plots. We used age estimates from Largemouth Bass otoliths to calculate mean lengths-at-age at capture and relative growth indices based on published growth standards in each reservoir. Largemouth Bass scale age estimates were less precise, overestimated ages of younger fish, and underestimated age of older fish compared with those of otoliths. Growth was lower in Peña Blanca Lake than in the other two reservoirs according to mean length-at-age estimates, and relative growth indices suggested that Largemouth Bass growth in all three reservoirs was above average at younger ages, but less so at older ages. The results from this study add to a growing body of literature supporting the use of otoliths for estimating age and growth of Largemouth Bass.

Collecting age and growth data is a primary component of fisheries management (Zale et al. 2012), and these data are frequently used to manage North American fishes, such as Largemouth Bass Micropterus salmoides (Maceina et al. 2007). Age information can be used to estimate fundamental demographics of Largemouth Bass populations, including rates of growth, mortality, and recruitment. Growth plays an important role in the survival of fishes and is an indication of resource availability in a body of water (Kerns and Lombardi-Carlson 2017). Age and growth data can also inform fisheries managers of the effectiveness of harvest regulations and other management decisions (Quist et al. 2012).

The widespread use of age and growth data has led to the development of regional and continental growth standards for Largemouth Bass and other important sport fishes (Hubert 1999; Quist et al. 2003; Jackson et al. 2008; Brouder et al. 2009). Growth standards can be used to evaluate growth rates in a population relative to other populations and can help identify factors affecting growth (e.g., environmental conditions, management actions). Nevertheless, age and growth information for Largemouth Bass is typically not collected in Arizona and the number of samples contributing to American Fisheries Society (AFS) southwestern ecoregion growth standards for the species is relatively small (comprise <12 data sets; Brouder et al. 2009). More growth data are needed to populate growth standards for the Southwest so that Largemouth Bass fisheries can be effectively evaluated over time and across space.

The effectiveness of growth standards in the southwestern United States is also complicated by the accuracy and precision of age structures from the region. A variety of age structures are used to estimate Largemouth Bass growth (Phelps et al. 2017), and their reliability has been tested in other regions. Scales have historically been the most prevalent structure for aging the species (Maceina et al. 2007), although more recent studies have reported biased estimates of age and growth and varying levels of precision (Maceina and Sammons 2006; Morehouse et al. 2013; Tyszko and Pritt 2017; Blackwell et al. 2019). Scales are of particular interest for Largemouth Bass age estimation in the Southwest because they are relatively easy to collect and process and do not require sacrificing fish (Quist et al. 2012). However, the accuracy and precision of scales in the Southwest’s unique geography and climate (long growing season, arid climate, high elevations) are uncertain. Otoliths require fish sacrifice, but they have been validated as an accurate and precise structure for aging Largemouth Bass (Taubert and Tranquilli 1982; Hoyer et al. 1985; Buckmeier and Howells 2003). However, otoliths have not been evaluated in the Southwest, and further development of regional growth standards for Largemouth Bass requires an assessment of the precision of age estimates from otoliths. We conducted this study to inform Arizona fisheries managers of the relative performance of two aging structures for developing and assessing management actions. Our objectives were to 1) compare precision and bias of age estimates from scales with those from otoliths and 2) estimate and assess Largemouth Bass growth in several southwestern warmwater reservoirs by using otoliths.

We collected Largemouth Bass from three reservoirs, representing a range of warmwater reservoir systems found in Arizona (Figure 1). Peña Blanca is a small reservoir (20 ha) at 1,219-m elevation formed by the impoundment of Peña Blanca Wash in the Coronado National Forest south of Tucson, Arizona (USFS 2022). Species found in the reservoir include Largemouth Bass, Bluegill Lepomis macrochirus, Redear Sunfish Lepomis microlophus, and Channel Catfish Ictalurus punctatus (Berg 2020).

Figure 1.

Locations and approximate sizes of three Arizona reservoirs (Alamo, Peña Blanca, and Roosevelt) from which we collected Largemouth Bass Micropterus salmoides to compare precision and bias of age estimates from scales and otoliths and to assess Largemouth Bass growth in several southwestern warmwater reservoirs using otoliths.

Figure 1.

Locations and approximate sizes of three Arizona reservoirs (Alamo, Peña Blanca, and Roosevelt) from which we collected Largemouth Bass Micropterus salmoides to compare precision and bias of age estimates from scales and otoliths and to assess Largemouth Bass growth in several southwestern warmwater reservoirs using otoliths.

Close modal

Alamo Lake is a midsized reservoir (1,489 ha) at 343-m elevation located west of Phoenix, Arizona, in Alamo Lake State Park. The impoundment of the Bill Williams River in 1968 created the reservoir, and it has since become one of the premier Largemouth Bass fisheries in the state. In addition to the species found in Peña Blanca, Alamo Lake contains Black Crappie Pomoxis nigromaculatus, Common Carp Cyprinus carpio, Green Sunfish Lepomis cyanellus, Threadfin Shad Dorosoma petenense, Tilapia Oreochromis spp., and Yellow Bullhead Ameiurus natalis (Follmuth and D’Amico 2019).

Roosevelt Lake is a large reservoir (8,697 ha) at 648-m elevation formed by the damming of the Salt River and located northeast of Phoenix (SRP 2022). The reservoir is in the Tonto National Forest and is the largest reservoir found entirely within Arizona. Roosevelt Lake contains the same species as the other reservoirs (except Redear Sunfish and Tilapia) as well as Flathead Catfish Pylodictis olivaris, Gizzard Shad Dorosoma cepedianum, Smallmouth Bass Micropterus dolomieu, and Yellow Bass Morone mississippiensis (Gill 2019).

Data collection

We collected Largemouth Bass from reservoirs in the study site in spring (March–May) 2021. We collected fish by boat electrofishing at night (30 min after sunset and 30 min before sunrise) using AFS standard methods for sampling warmwater fishes in small (<200-ha) and large (>200-ha) standing waters (Miranda 2009; Miranda and Boxrucker 2009; Pope et al. 2009). We sampled with a 5.5-m boat equipped with an Apex electrofisher control box (Smith-Root, Vancouver, Washington) and standardized for power by adjusting peak current based on ambient water conductivity (Miranda 2009).

We measured total length of all captured Largemouth Bass to the nearest 1 mm, and we euthanized a subsample of 15 fish in each 25-mm length bin. We transported these euthanized fish in individually labeled Ziploc bags on ice in coolers. We stored the fish in a freezer and then thawed and processed them in a laboratory. We collected at least five scales from each fish from the area posterior to the tip of the pectoral fin when pressed down and below the lateral line (McInerny 2017) and pressed them onto acetate slides with a 110-H10 Ann Arbor roller press (Wildco, Yulee, Florida). We extracted both sagittal otoliths by accessing the otic chamber from the ventral surface of each fish (Schneidervin and Hubert 1986; Long and Grabowski 2017). We rinsed the otoliths with water, dried them, and stored them in labeled plastic vials. We then embedded the otoliths in an epoxy (West System, Bay City, Michigan) and sectioned them with an IsoMet 11-1280-160 low-speed saw (Buehler, Lake Bluff, Illinois). We made a 0.55-mm-wide section around the nucleus of each otolith and polished the sections before mounting them onto microscope slides (Long and Grabowski 2017).

We aged otoliths using digital photographs taken with a 14-megapixel camera mounted onto a trinocular stereomicroscope with transmitted light (United Scope, Irvine, California), and we aged scales using photographs taken of microfiche images (Micro Design, Inc., Hartford, Wisconsin) with a D3300 24-megapixel camera (Nikon, Tokyo, Japan). Three independent age estimates (in years) were made for each hard structure by readers who had no knowledge of fish length or estimates by other readers. All age readers had at least some experience aging fish, but the first age readings were done by a highly experienced reader, the second readings were done by an inexperienced reader, and the third readings were done by three different readers with varying (low, medium, and high) levels of aging experience. The three readers who combined to complete the third readings aged an equal number of structures from each lake and aged structures (i.e., otoliths and scales) from the same fish.

Age readers assigned an additional annulus to the outer edge of each structure to account for fish being collected during the growing season (i.e., spring). Readers also assigned a 0–3 confidence rating for each age estimate (Fitzgerald et al. 1997; Koch et al. 2008; Spiegel et al. 2010). A confidence rating of 3 corresponded to high confidence in a reader’s age estimate, whereas a rating of 0 corresponded to no confidence in an age estimate.

Data analyses

We compared precision and bias of age estimates derived from scales and otoliths by evaluating reader agreement, average coefficient of variation (ACV), confidence ratings, and age-bias plots. We expressed reader agreement for each structure type in terms of percent partial agreement (percent of all structures for which two or more readers agreed on the age of the fish) and percent complete agreement (percent of structures for which all readers agreed on the age of the fish). We estimated the ACV of age estimates from each structure type as follows:
formula
where sj is the standard deviation of age estimates for the jth fish, is the mean age estimate for the jth fish, and n is the number of fish aged (Ogle 2016). We calculated a mean confidence rating from the three ratings for each structure and averaged across all structures for both scales and otoliths.

For the age-bias plots, we considered otolith-derived age estimates to be the reference group (plotted on the x-axis) and plotted consensus age estimates (ages from structures that had partial reader agreement, i.e., two or more readers agreed on the age of the fish) from scales on the y-axis (Campana et al. 1995). At each age, we tested the difference between mean scale age and the otolith reference age with a one-sample t-test by using a Holm–Bonferroni-adjusted significance level (Ogle 2016). We also constructed age-bias plots between otolith and scale age estimates for each age reading to see whether bias between scales and otoliths was different depending on the age reader and the amount of age-reading experience.

We estimated Largemouth Bass mean lengths-at-age at capture in each reservoir by using total length and consensus age estimate data from otoliths and compared the estimates to AFS North American and ecoregional growth standards (Brouder et al. 2009) by using relative growth index (RGI) as follows:
formula
where Lt is the observed length-at-age t in a waterbody and Ls is the standard length-at-age (Quist et al. 2003; Jackson et al. 2008; Shoup and Michaletz 2017). Relative growth indices greater than 100 indicate above-average growth in a waterbody relative to range-wide averages, whereas values less than 100 indicate below-average growth. We performed all analyses and plotting by using the ‘base,’ FSA (Ogle et al. 2022), and ggplot2 (Wickham 2016) packages in R version 4.1.2 (R Core Team 2021).

In total, we sampled 1,004 Largemouth Bass with boat electrofishing in Alamo (n = 463 fish), Peña Blanca (n = 373), and Roosevelt (n = 168) lakes. We kept a subsample of 202 fish for age and growth analyses (65 fish from Alamo Lake, 74 from Peña Blanca Lake, and 63 from Roosevelt Lake). Total length of all Largemouth Bass sampled varied from 101 to 574 mm (Data S1, Supplemental Material), and age estimates varied from 1 to 9 y for otoliths and from 1 to 8 y for scales (Data S2, Supplemental Material).

Comparison of otolith and scale bias and precision

Age estimates from otoliths and scales differed in terms of partial and complete reader agreement, ACV, and confidence ratings (Table 1). Partial reader agreement was high for both scales (83.7%) and otoliths (100.0%); however, complete reader agreement was low for scales (17.8%) compared with otoliths (95.5%). Scale age readings had a 30.0% higher ACV than otolith readings. In addition, mean confidence rating was higher for age estimates from otoliths (2.3) than for age estimates from scales (0.8).

Table 1.

Comparison of the number of structures aged (n), partial and complete reader agreement percentages, average coefficient of variation (ACV), and mean confidence for age estimates from Largemouth Bass Micropterus salmoides otoliths and scales in three Arizona reservoirs. Partial reader agreement is the percentage of structures of a given type for which two or more readers agreed on the age of the fish, and complete reader agreement is the percentage of structures for which all three readers agreed on the age of the fish. The ACV is the coefficient of variation (standard deviation divided by the mean) of the three age readings for a given structure, averaged across all structures of that type. Mean confidence rating is a 0–3 rating that gives an indication of how confident readers were in their age estimates, with 0 indicating no confidence in an age estimate and a 3 indicating high confidence.

Comparison of the number of structures aged (n), partial and complete reader agreement percentages, average coefficient of variation (ACV), and mean confidence for age estimates from Largemouth Bass Micropterus salmoides otoliths and scales in three Arizona reservoirs. Partial reader agreement is the percentage of structures of a given type for which two or more readers agreed on the age of the fish, and complete reader agreement is the percentage of structures for which all three readers agreed on the age of the fish. The ACV is the coefficient of variation (standard deviation divided by the mean) of the three age readings for a given structure, averaged across all structures of that type. Mean confidence rating is a 0–3 rating that gives an indication of how confident readers were in their age estimates, with 0 indicating no confidence in an age estimate and a 3 indicating high confidence.
Comparison of the number of structures aged (n), partial and complete reader agreement percentages, average coefficient of variation (ACV), and mean confidence for age estimates from Largemouth Bass Micropterus salmoides otoliths and scales in three Arizona reservoirs. Partial reader agreement is the percentage of structures of a given type for which two or more readers agreed on the age of the fish, and complete reader agreement is the percentage of structures for which all three readers agreed on the age of the fish. The ACV is the coefficient of variation (standard deviation divided by the mean) of the three age readings for a given structure, averaged across all structures of that type. Mean confidence rating is a 0–3 rating that gives an indication of how confident readers were in their age estimates, with 0 indicating no confidence in an age estimate and a 3 indicating high confidence.

Mean consensus scale age was significantly different from otolith age at ages 1, 2, 4, 8, and 9 (Figure 2A). Scale age estimates tended to overestimate ages of younger Largemouth Bass (less than or equal to age 2) and underestimate ages of older individuals (greater than or equal to age 8) compared with otoliths; we did not observe a significant difference (P > 0.01) between mean consensus scale and otolith age at ages 3 and 5–7. Scale-based age bias was the same at all ages when only using estimates from the first age reading (by a highly experienced reader; Figure 2B); however, the results changed slightly for the second and third age readings. There was no significant difference between mean scale age and otolith age at age 2 when only using the second age readings (by a less experienced age reader; Figure 2C). For the third age readings (by readers with varying levels of experience), there was a significant difference between mean scale age and otolith age at age 3 (Figure 2D).

Figure 2.

Age-bias plots comparing mean age estimates from Largemouth Bass Micropterus salmoides scales (y-axis) and otoliths (x-axis) using (A) consensus age estimates from all readers, (B) age estimates from age reading 1, (C) age estimates from age reading 2, and (D) age estimates age reading 3. Age estimates from scales were either significantly (white dot) or not significantly (black dot) different from otolith ages based on one-sample t-tests. Error bars represent 95% confidence intervals for mean scale ages, and the dashed lines represent 1:1 agreement lines where mean scale age would equal otolith age (Ogle 2016).

Figure 2.

Age-bias plots comparing mean age estimates from Largemouth Bass Micropterus salmoides scales (y-axis) and otoliths (x-axis) using (A) consensus age estimates from all readers, (B) age estimates from age reading 1, (C) age estimates from age reading 2, and (D) age estimates age reading 3. Age estimates from scales were either significantly (white dot) or not significantly (black dot) different from otolith ages based on one-sample t-tests. Error bars represent 95% confidence intervals for mean scale ages, and the dashed lines represent 1:1 agreement lines where mean scale age would equal otolith age (Ogle 2016).

Close modal

Growth assessments

Estimated mean length was smaller at all ages in Peña Blanca Lake than in the other two reservoirs (Table 2). Relative growth indices indicated that Largemouth Bass growth in all three reservoirs was above average at most observed ages (RGI > 100) and near or below average at older ages (Table 3). In particular, growth was below average in Peña Blanca Lake at older ages (i.e., after age 5 relative to continental standards and after age 8 relative to regional standards). In addition, RGIs were higher in all reservoirs when we assessed mean lengths-at-age with regional rather than continental growth standards.

Table 2.

Mean length at each observed Largemouth Bass Micropterus salmoides age in three Arizona reservoirs (Alamo, Peña Blanca, and Roosevelt) estimated with otoliths. We aged each otolith three times and used the consensus age (agreed on by two or more readers) to estimate the age of each fish.

Mean length at each observed Largemouth Bass Micropterus salmoides age in three Arizona reservoirs (Alamo, Peña Blanca, and Roosevelt) estimated with otoliths. We aged each otolith three times and used the consensus age (agreed on by two or more readers) to estimate the age of each fish.
Mean length at each observed Largemouth Bass Micropterus salmoides age in three Arizona reservoirs (Alamo, Peña Blanca, and Roosevelt) estimated with otoliths. We aged each otolith three times and used the consensus age (agreed on by two or more readers) to estimate the age of each fish.
Table 3.

Relative growth indices (RGIs) for Largemouth Bass Micropterus salmoides in three Arizona reservoirs by using age estimates from otoliths and North American and Ecoregion 10 (North American deserts) lentic water length-at-age growth standards. The RGI is a ratio between an observed length-at-age in a waterbody and a standard length-at-age and gives an indication of whether fish are growing fast (>100) or slow (<100) compared with the standard. Growth standard sample size indicates the number of data sets used to generate the growth standard at each age (Brouder et al. 2009). We calculated the RGIs for ages observed in each reservoir.

Relative growth indices (RGIs) for Largemouth Bass Micropterus salmoides in three Arizona reservoirs by using age estimates from otoliths and North American and Ecoregion 10 (North American deserts) lentic water length-at-age growth standards. The RGI is a ratio between an observed length-at-age in a waterbody and a standard length-at-age and gives an indication of whether fish are growing fast (>100) or slow (<100) compared with the standard. Growth standard sample size indicates the number of data sets used to generate the growth standard at each age (Brouder et al. 2009). We calculated the RGIs for ages observed in each reservoir.
Relative growth indices (RGIs) for Largemouth Bass Micropterus salmoides in three Arizona reservoirs by using age estimates from otoliths and North American and Ecoregion 10 (North American deserts) lentic water length-at-age growth standards. The RGI is a ratio between an observed length-at-age in a waterbody and a standard length-at-age and gives an indication of whether fish are growing fast (>100) or slow (<100) compared with the standard. Growth standard sample size indicates the number of data sets used to generate the growth standard at each age (Brouder et al. 2009). We calculated the RGIs for ages observed in each reservoir.

The potential influence of structure type on Largemouth Bass growth estimates was evident in the precision and bias comparisons between otoliths and scales. We found that age estimates from otoliths were more precise (Table 1) and that scale age estimates were biased at older (greater than or equal to age 8) and younger (less than or equal to age 2) ages compared to otoliths. Bias in estimates from scales did not change drastically across readers and experience levels, but small differences among age-bias plots (Figure 2), combined with lower reader agreement and confidence ratings for scales (Table 1), suggest that scales were more difficult for readers to age. Nevertheless, scale-based age bias was generally consistent across readers and experience levels and age reader experience did not appear to influence the precision of age estimates from Largemouth Bass scales as it did in Long and Fisher (2001).

Bias and precision of age readings from Largemouth Bass scales were consistent with assessments in other regions. In North Carolina, age estimates from scales were less precise and there was low agreement between age estimates from scales and sectioned otoliths, especially for larger fish (Besler 1999). Morehouse et al. (2013) found low complete reader agreement and high estimated ACV for scale age estimates of Largemouth Bass from lakes in Indiana. In two different studies in New York, age estimates from scales had lower reader agreements; higher average percent error than estimates from otoliths (Maceina and Sammons 2006); and higher ACV than estimates from dorsal spines, otoliths, and opercles (Sotola et al. 2014). Blackwell et al. (2019) found that age estimates from Largemouth Bass scales in South Dakota had low complete reader agreement and higher ACV, and were bias at older ages compared to otoliths. Biased age estimates from scales can lead to an underestimation of growth at younger ages and an overestimation of growth at older ages, which could mislead management decisions based on these estimates (Tyszko and Pritt 2017).

Relative growth indices suggested that Largemouth Bass growth in all three reservoirs was above average at most ages, but these values could also be the result of small sample sizes used to develop growth standards and discrepancies caused by age structure choice. Approximately half of the data contributing to the AFS North American growth standards for Largemouth Bass (n; Table 3) are from the eastern United States (Ecoregion 8, eastern temperate forests) and approximately 30% are from the Great Plains (Ecoregion 9; Brouder et al. 2009). Conversely, data from the Southwest (Ecoregion 10, North American deserts) constitute approximately 5% of all North American data (n < 12 for all ages; Table 3). North American growth standards for Largemouth Bass may be more of a reflection of growth in other regions, whereas the amount of data used to develop southwestern standards may be too small to reliably evaluate populations in the region. In addition, Starks and Rodger (2020) attributed differences in RGIs between two different Smallmouth Bass growth standards to the use of potentially biased age structures. This could also be the case in the present study because AFS growth standards for Largemouth Bass (Brouder et al. 2009) do not specify structure type, whereas we only used otoliths to estimate growth in our study.

Age and growth information is a fundamental component of sport fish management (Zale et al. 2012) that is regularly used to manage populations of Largemouth Bass across North America (Maceina et al. 2007). However, age and growth information is not routinely used to guide management decisions in Arizona. Age-length keys and von Bertalanffy growth functions based on age estimates from otoliths can be used to estimate Largemouth Bass growth in southwestern reservoirs, identify potential factors affecting growth, and develop and assess subsequent management actions. Furthermore, otoliths appear to provide more precise estimates of age and growth of Largemouth Bass in the Southwest and in other regions. There is evidence that scales can be reliable for aging Largemouth Bass at younger ages (Maraldo and MacCrimmon 1979; Maceina and Sammons 2006; Taylor and Weyl 2012; Morehouse et al. 2013; Blackwell et al. 2019), but this was not the case in our study. The main limitation of using otoliths is that fish must be sacrificed, and, if this is not an option, the reliability of other nonlethal structures, such as dorsal fin spines and pectoral fin rays, could also be assessed. Studies in other regions have reported mixed results with these structures (Maraldo and MacCrimmon 1979; Morehouse et al. 2013; Sotola et al. 2014; Klein et al. 2017; Blackwell et al. 2019), but these evaluations have not taken place in the southwestern United States. The results from this study build on a growing body of literature supporting the standardized use of otoliths for Black Bass Micropterus spp. age and growth estimation (Long and Fisher 2001; Klein et al. 2017; Tyszko and Pritt 2017; Blackwell et al. 2019; Starks and Rodger 2020). However, future use of otoliths, in the Southwest and elsewhere, would benefit from further validation of otoliths as age structures by using known-age fish or other methods (Buckmeier et al. 2017) so that the timing of increment formation can be confirmed and the accuracy of age estimates can be quantified.

Please note: The Journal of Fish and Wildlife Management is not responsible for the content of functionality of any supplemental material. Queries should be directed to the corresponding author.

Data S1. We sampled length and age data for all Largemouth Bass Micropterus salmoides obtained in three Arizona reservoirs (Alamo, Peña Blanca, and Roosevelt) in spring 2021. Data for each fish include unique identifiers across all lakes (fish_ID) and within each lake (Lake_ID); the lake from which we collected the fish (lake); the total length of the fish in millimeters (TL_mm); and consensus age (age agreed on by two or more readers), in years, from otoliths (oto.C).

Available: https://doi.org/10.3996/JFWM-23-006.S1 (24 KB)

Data S2. We collected length and age data from a subsample of Largemouth Bass Micropterus salmoides for age and growth analyses from three Arizona reservoirs (Alamo, Peña Blanca, and Roosevelt) in spring 2021. Data for each fish include unique identifiers across all lakes (fish_ID) and within each lake (Lake_ID); the lake from which we collected the fish (lake); the total length of the fish in millimeters (TL_mm); age estimates, in years, from otoliths by readers 1, 2, and 3 (oto.1, oto.2, and oto.3, respectively); age estimates from scales by readers 1, 2, and 3 (sca.1, sca.2, and sca.3, respectively), consensus age from otoliths and scales (oto.C and sca.C, respectively; age agreed on by two or more readers; NA entered when fewer than two readers agreed on the age of a structure); and a confidence rating (0–3 rating) for each otolith (oto.cr1, oto.cr2, and oto.cr3) and scale (sca.cr1, sca.cr2, and sca.cr3) age reading.

Available: https://doi.org/10.3996/JFWM-23-006.S2 (11 KB)

Reference S1.Berg N. 2020. Peña Blanca Lake fisheries management plan 2020–2030. Phoenix: Arizona Game and Fish Department.

Available: https://doi.org/10.3996/JFWM-23-006.S3 (1.048 MB) and https://azgfd-portal-wordpress-pantheon.s3.us-west-2.amazonaws.com/wp-content/uploads/archive/Copy-of-Pena-Blanca-Lake-Fisheries-Management-Plan-2020-2030.pdf

Reference S2. Follmuth R, D’Amico T. 2019. Alamo Lake fisheries management plan 2019–2029. Phoenix: Arizona Game and Fish Department.

Available: https://doi.org/10.3996/JFWM-23-006.S4 (1.136 MB) and https://azgfd-portal-wordpress-pantheon.s3.us-west-2.amazonaws.com/wp-content/uploads/archive/Alamo-Lake-Fisheries-Management-Plan-2019-2029.pdf

Reference S3. Gill CJ. 2019. Roosevelt Lake fisheries management plan 2019–2029. Phoenix: Arizona Game and Fish Department.

Available: https://doi.org/10.3996/JFWM-23-006.S5 (1.069 MB) and https://azgfd-portal-wordpress-pantheon.s3.us-west-2.amazonaws.com/wp-content/uploads/archive/Roosevelt-Lake-Management-Plan-2019-2029-1.pdf

We thank University of Arizona students Andrew Wong, Jared Farquhar, Annie Dixon, and Stephen Ferrar for assisting with fieldwork. We thank Alex Loubere, Ty Hardymon, Delilah Bethel, Chris Cantrell, Julie Carter, and Andy Clark from the Arizona Game and Fish Department for assisting with equipment, permitting, and logistics. We thank the journal reviewers and Associate Editor, Zachary Jackson, and Christopher Jenney for comments on drafts of the manuscript. The Arizona Game and Fish Department (grant 1434-13HQRU1580) provided funding for this project, with additional support by the U.S. Geological Survey and the University of Arizona. We conducted all research in accordance with protocol 20-658 approved by the Institutional Animal Care and Use Committee at the University of Arizona.

Any use of trade, product, website, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Berg
N.
2020
.
Peña Blanca Lake fisheries management plan 2020–2030
.
Phoenix
:
Arizona Game and Fish Department
(see Supplemental Material, Reference S1)
.
Besler
DA.
1999
.
Utility of scales and whole otoliths for aging Largemouth Bass in North Carolina
.
Proceedings of the Southeastern Association of Fish and Wildlife Agencies
53
:
119
129
.
Blackwell
BG,
Kaufman
TM,
Moos
TS.
2019
.
Evaluation of anal spines, dorsal spines, and scales as potential nonlethal surrogates to otoliths for estimating ages of Largemouth Bass and Smallmouth Bass
.
North American Journal of Fisheries Management
39
:
596
603
.
Brouder
MJ,
Iles
AC,
Bonar
SA.
2009
. Length frequency, condition, growth, and catch per effort indices for common North American fishes. Pages
231
282
in
Bonar
SA,
Hubert
WA,
Willis
DW
, editors.
Standard methods for sampling North American freshwater fishes
.
Bethesda, Maryland
:
American Fisheries Society
.
Buckmeier
DL,
Howells
RG.
2003
.
Validation of otoliths for estimating ages of Largemouth Bass to 16 years
.
North American Journal of Fisheries Management
23
:
590
593
.
Buckmeier
DL,
Sakaris
PC,
Schill
DJ.
2017
. Validation of annual and daily increments in calcified structures and verification of age estimates. Pages
33
79
in
Quist
MC,
Isermann
DA
, editors.
Age and growth of fishes: principles and techniques
.
Bethesda, Maryland
:
American Fisheries Society
.
Campana
SE,
Annand
MC,
McMillan
JI.
1995
.
Graphical and statistical methods for determining the consistency of age determinations
.
Transactions of the American Fisheries Society
124
:
131
138
.
Fitzgerald
TJ,
Margenau
TL,
Copes
FA.
1997
.
Muskellunge scale interpretation: the question of aging accuracy
.
North American Journal of Fisheries Management
17
:
206
209
.
Follmuth
R,
D’Amico
T.
2019
.
Alamo Lake fisheries management plan 2019–2029
.
Phoenix
:
Arizona Game and Fish Department
(see Supplemental Material, Reference S2)
.
Gill
CJ.
2019
.
Roosevelt Lake fisheries management plan 2019–2029
.
Phoenix
:
Arizona Game and Fish Department
(see Supplemental Material, Reference S3)
.
Hoyer
MV,
Shireman
JV,
Maceina
MJ.
1985
.
Use of otoliths to determine age and growth of Largemouth Bass in Florida
.
Transactions of the American Fisheries Society
114
:
307
309
.
Hubert
WA.
1999
.
Standards for assessment of age and growth data for Channel Catfish
.
Journal of Freshwater Ecology
14
:
313
326
.
Jackson
ZJ,
Quist
MC,
Larscheid
JG.
2008
.
Growth standards for nine North American fish species
.
Fisheries Management and Ecology
15
:
107
118
.
Kerns
JA,
Lombardi-Carlson
LA.
2017
. History and importance of age and growth information. Pages
1
8
in
Quist
MC,
Isermann
DA
, editors.
Age and growth of fishes: principles and techniques
.
Bethesda, Maryland
:
American Fisheries Society
.
Klein
ZB,
Bonvechio
TF,
Bowen
BR,
Quist
MC.
2017
.
Precision and accuracy of age estimates obtained from anal fin spines, dorsal fin spines, and sagittal otoliths for known‐age Largemouth Bass
.
Southeastern Naturalist
16
:
225
234
.
Koch
JD,
Schreck
WJ,
Quist
MC.
2008
.
Standardised removal and sectioning locations for shovelnose sturgeon fin rays
.
Fisheries Management and Ecology
15
:
139
145
.
Long
JM,
Fisher
WL.
2001
.
Precision and bias of Largemouth, Smallmouth, and Spotted Bass ages estimated from scales, whole otoliths, and sectioned otoliths
.
North American Journal of Fisheries Management
21
:
636
645
.
Long
JM,
Grabowski
TB.
2017
. Otoliths. Pages
189
219
in
Quist
MC,
Isermann
DA
, editors.
Age and growth of fishes: principles and techniques
.
Bethesda, Maryland
:
American Fisheries Society
.
Maceina
MJ,
Boxrucker
J,
Buckmeier
DL,
Gangl
RS,
Lucchesi
DO,
Isermann
DA,
Jackson
JR,
Martinez
PJ.
2007
.
Current status and review of freshwater fish aging procedures used by state and provincial fisheries agencies with recommendations for future directions
.
Fisheries
32
:
329
340
.
Maceina
MJ,
Sammons
SM.
2006
.
An evaluation of different structures to age freshwater fish from a northeastern US river
.
Fisheries Management and Ecology
13
:
237
242
.
Maraldo
DC,
MacCrimmon
HR.
1979
.
Comparison of ageing methods and growth rates for Largemouth Bass, Micropterus salmoides Lacépède, from north latitudes
.
Environmental Biology of Fishes
4
:
263
271
.
McInerny
MC.
2017
. Scales. Pages
127
158
in
Quist
MC,
Isermann
DA
, editors.
Age and growth of fishes: principles and techniques
.
Bethesda, Maryland
:
American Fisheries Society
.
Miranda
LE.
2009
. Standardized electrofishing power for boat electrofishing. Pages
223
230
in
Bonar
SA,
Hubert
WA,
Willis
DW
, editors.
Standard methods for sampling North American freshwater fishes
.
Bethesda, Maryland
:
American Fisheries Society
.
Miranda
LE,
Boxrucker
J.
2009
. Warmwater fish in large standing waters. Pages
29
42
in
Bonar
SA,
Hubert
WA,
Willis
DW
, editors.
Standard methods for sampling North American freshwater fishes
.
Bethesda, Maryland
:
American Fisheries Society
.
Morehouse
RL,
Donabauer
SB,
Grier
AC.
2013
.
Estimating Largemouth Bass age: precision and comparisons among scales, pectoral fin rays, and dorsal fin spines as nonlethal methods
.
Fisheries and Aquaculture Journal
4
:
1
7
.
Ogle
DH.
2016
.
Introductory fisheries analyses with R
.
Boca Raton, Florida
:
CRC Press
.
Ogle
DH,
Doll
JC,
Wheele
P,
Dinno
A.
2022
.
FSA: simple fisheries stock assessment methods. R package version 0.9.3
.
Phelps
QE,
Tripp
SJ,
Hamel
MJ,
Koenigs
RP,
Jackson
ZJ.
2017
. Choice of structure for estimating fish age and growth. Pages
81
105
in
Quist
MC,
Isermann
DA
, editors.
Age and growth of fishes: principles and techniques
.
Bethesda, Maryland
:
American Fisheries Society
.
Pope
KL,
Neumann
RM,
Bryan
SD.
2009
. Warmwater fish in small standing waters. Pages
13
27
in
Bonar
SA,
Hubert
WA,
Willis
DW
, editors.
Standard methods for sampling North American freshwater fishes
.
Bethesda, Maryland
:
American Fisheries Society
.
Quist
MC,
Guy
CS,
Schultz
RD,
Stephen
JL.
2003
.
Latitudinal comparisons of Walleye growth in North America and factors influencing growth of Walleyes in Kansas reservoirs
.
North American Journal of Fisheries Management
23
:
677
692
.
Quist
MC,
Pegg
MA,
DeVries
DR.
2012
. Age and growth. Pages
677
731
in
Zale
AV,
Parrish
DL,
Sutton
TM
, editors.
Fisheries techniques
. 3rd edition.
Bethesda, Maryland
:
American Fisheries Society
.
R Core Team
.
2021
.
R: a language and environment for statistical computing
.
Vienna
:
R Foundation for Statistical Computing
.
Available: https://www.R-project.org (June 2023)
Schneidervin
RW,
Hubert,
WA.
1986
.
A rapid technique for otolith removal from salmonids and catostomids
.
North American Journal of Fisheries Management
6
:
287
.
Shoup
DE,
Michaletz
PH.
2017
. Growth estimation: summarization. Pages
233
264
in
Quist
MC,
Isermann
DA
, editors.
Age and growth of fishes: principles and techniques
.
Bethesda, Maryland
:
American Fisheries Society
.
Sotola
VA,
Maynard
GA,
Hayes-Pontius
EM,
Mihuc
TB,
Malchoff
MH,
Marsden
JE.
2014
.
Precision and bias of using opercles as compared to otoliths, dorsal spines, and scales to estimate ages of Largemouth and Smallmouth Bass
.
Northeastern Naturalist
21
:
565
573
.
Spiegel
JR,
Quist
MC,
Morris
JE.
2010
.
Precision of scales and pectoral fin rays for estimating age of Highfin Carpsucker, Quillback Carpsucker, and River Carpsucker
.
Journal of Freshwater Ecology
25
:
271
278
.
[SRP] Salt River Project
.
2022
.
Daily water report: February 21, 2022
.
Tempe, Arizona
:
Salt River Project
.
Starks
TA,
Rodger
AW.
2020
.
Otolith and scale‐based growth standards for lotic Smallmouth Bass
.
North American Journal of Fisheries Management
40
:
986
994
.
Taubert
BD,
Tranquilli
JA.
1982
.
Verification of the formation of annuli in otoliths of Largemouth Bass
.
Transactions of the American Fisheries Society
111
:
531
534
.
Taylor
GC,
Weyl
OLF.
2012
.
Otoliths versus scales: evaluating the most suitable structure for ageing Largemouth Bass, Micropterus salmoides, in South Africa
.
African Zoology
47
:
358
362
.
Tyszko
SM,
Pritt
JJ.
2017
.
Comparing otoliths and scales as structures used to estimate ages of Largemouth Bass: consequences of biased age estimates
.
North American Journal of Fisheries Management
37
:
1075
1082
.
[USFS] U.S. Forest Service
.
2022
.
Pena Blanca Lake
.
Tucson, Arizona
:
U.S. Forest Service
.
Wickham
H.
2016
.
ggplot2: elegant graphics for data analysis
.
New York
:
Springer-Verlag
.
Zale
AV,
Sutton
TM,
Parrish
DL.
2012
. Conducting fisheries investigations. Pages
1
14
in
Zale
AV,
Parrish
DL,
Sutton
TM
, editors.
Fisheries techniques
. 3rd edition.
Bethesda, Maryland
:
American Fisheries Society
.

The findings and conclusions in this article are those of the author(s) and do not necessarily represent the views of the U.S. Fish and Wildlife Service.

Author notes

Citation: Ingram SJ, Grant JD, Beard ZS, Berg N, Ringelman AM, Bonar SA. 2023. Estimating age and growth of largemouth bass in southwestern reservoirs by using otoliths and scales. Journal of Fish and Wildlife Management 14(2):315–323; e1944-687X. https://doi.org/10.3996/JFWM-23-006

Supplemental Material