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22001155 SOUTHEASTERN NATURALIST 1V4o(3l.) :1442,5 N–4o3. 73
Movement, Homing, and Fates of Fluvial-Specialist Shoal
Bass Following Translocation into an Impoundment
Andrew T. Taylor1 and Douglas L. Peterson1,*
Abstract - Micropterus cataractae (Shoal Bass), an enigmatic fluvial specialist, has experienced
range-wide declines because of habitat fragmentation and other negative effects
of impounded rivers. In addition to these concerns, anglers often translocate Shoal Bass
from riverine habitats to impoundments following tournament weigh-ins. To investigate the
potential effects of this practice, we translocated adult Shoal Bass from riverine habitats to
a downstream impoundment and assessed their movements, homing abilities, and eventual
fates. All fish rapidly evacuated the impoundment in favor of lotic habitats, and the majority
of translocated fish returned upstream within about 3 weeks. Half of our translocated
fish also displayed homing to within 1 river km of their original capture site. Our results
demonstrate that fluvial-specialist Shoal Bass can survive translocation into impoundments,
but the differential effects of translocation associated with fishing tournaments should also
be considered in the management of Shoal Bass fisheries.
Introduction
Fluvial-specialist fishes—species that require lotic habitats for at least a portion
of their life cycles—are a diverse group that faces a suite of conservation challenges.
In the US, this group encompasses many native cyprinids, catostomids, percids,
and other taxa. Fluvial-specialist fishes feature a diverse array of adaptations to
dynamic lotic habitats, including various reproductive strategies, feeding guilds,
and morphologies (Bunn and Arthington 2002). Despite this diversity in life-history
strategies, fluvial-specialist species often become imperiled because of the specificity
of their habitat requirements (Moyle and Leidy 1992). The rapid loss of aquatic
biodiversity in North America, including freshwater fishes, is largely attributable to
the widespread alteration of fluvial habitats (Postel and Ricther 2003, Ricciardi and
Rasmussen 2001), which significantly complicates conservation of fluvial fishes.
Impounded river systems pose a variety of challenges to the conservation of
fluvial-specialist fishes. Downstream of dams, fluvial fishes and other sensitive taxa
are often unable to adapt to altered flow regimes (Poff and Zimmerman 2010), increased
water withdrawals (Freeman and Marcinek 2006), and altered temperature
regimes (Olden and Naiman 2009, Quinn and Kwak 2003). Upstream, impoundments
transform fluvial habitats into lentic habitats that may be unsuitable for
fluvial-specialist species. Impounded river systems also fragment fluvial-fish populations.
Dams typically impose 2 specific types of barriers to fluvial-fish migration.
The most obvious of these is the physical barrier that dams impose on upstream
and downstream movement. Although downstream migration through spillways
1Warnell School of Forestry and Natural Resources, University of Georgia, 180 East Green
Street, Athens, GA 30602. *Corresponding author - dpeterson@warnell.uga.edu.
Manuscript Editor: Jennifer Rehage
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(Schilt 2007) or hydroelectric turbines is sometimes possible, both pathways can
cause mortality (Coutant and Whitney 2000). In the upstream direction, dams often
create a completely impassable barrier unless fish ladders or another functional
fish-passage system is provided (Porto et al. 1999, Schilt 2007). Populations in
tributaries upstream from impoundments may experience an additional ecological
barrier to downstream or between-tributary migration created by large expanses
of unsuitable lentic habitat (sensu Pringle 1997). Impounded waters have been
shown to severely hinder gene flow among populations of fluvial fishes inhabiting
impoundment tributaries (Fluker et al. 2014, Herbert et al. 2003, Schwemm 2013).
Micropterus cataractae Williams & Burgess (Shoal Bass) is a fluvial-specialist
black bass species endemic to a heavily impounded river system. Shoal Bass are
native to the Apalachicola-Chattahoochee-Flint (ACF) Basin and are described as
fluvial, shoal-habitat specialists that are rarely observed in impoundments (Taylor
and Peterson 2014, Williams and Burgess 1999). Shoal Bass have declined
throughout much of their range primarily because of the negative effects of extensive
damming within the ACF Basin (Williams and Burgess 1999). Although Shoal
Bass are known to migrate distances greater than 200 km for spawning (Sammons
and Goclowski 2012), most populations appear to be fragmented. In a genetic
investigation of Shoal Bass in the upper Chattahoochee River Basin, mainstem
dams were found to limit genetic exchange in the downstream direction while
completely eliminating genetic exchange in the upstream direction (Dakin et al.
2007). These findings suggest that the long-term effects of habitat fragmentation
could seriously alter population genetic structure; however, a better understanding
of spawning habits, including any potential migration patterns, homing abilities,
and/or spawning-site fidelities, is needed to fully understand the potential effects
of fragmentation.
Despite being a relatively rare fluvial-specialist species, Shoal Bass are also a
popular sportfish. Shoal Bass attain relatively large sizes (up to 3990 g; International
Game Fish Association 2014) and support popular tournament and non-tournament
recreational and fisheries throughout much of their current range. Tournament anglers
on the Flint River system of Georgia typically target M. salmoides (Lacepède)
(Largemouth Bass) and Shoal Bass; participants often weigh in a mixed bag of both
species (A.T. Taylor, pers. observ.). Tournament fish must be released alive after
weigh-in, usually at boat ramps on the large impoundments where tournaments are
held. This practice results in the translocation of Shoal Bass from fluvial habitats in
the Flint River to downstream impoundments (see Ingram et al. 2013, Taylor 2012).
Translocating Shoal Bass into impoundments has prompted concern from both anglers
and resource managers (T. Ingram, Georgia Department of Natural Resources,
Albany, GA, pers. comm.) because the practice poses a potential threat to a species
that has declined throughout much of its native range (Taylor and Peterson 2014,
Williams and Burgess 1999).
To investigate how Shoal Bass respond to translocation into an impoundment,
we conducted a telemetry experiment on the Flint River, GA, with the following
objectives: 1) determine the prevalence of adult fish that return to riverine habitats
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after translocation to a downstream impoundment, 2) describe spatial and temporal
movement patterns of fish following translocation, and 3) identify the eventual fate
of each telemetered fish. Addressing these gaps in the current understanding of
Shoal Bass ecology and biology will better inform future management and conservation
efforts for Shoal Bass, and potentially, other fluvial-specialist fishes.
Methods
Field site description
Located in southwestern Georgia within the Southeastern Plains ecoregion, the
lower Flint River is characterized by limestone-bedrock outcrops, shoal complexes,
and influence from spring outflows. Our study area encompassed 50 river kilometers
(rkm) on the mainstem lower Flint River between Lake Blackshear and Lake
Worth (Fig. 1). Unlike free-flowing reaches upstream, this portion of the lower
Flint River is influenced by 2 mainstem hydroelectric dams. Crisp County Dam
(CCD) forms Lake Blackshear and is operated by Crisp County Power Commission
(Cordele, GA). Approximately 50 rkm downstream, the Georgia Power Dam (GPD)
is operated by Georgia Power (Atlanta, GA) and forms the 6-km2 Lake Worth. In
addition to the mainstem river between the 2 impoundments, our study area also
included the entirety of Lake Worth.
Telemetry
To assess movement, homing ability, and eventual fates of Shoal Bass translocated
from upstream fluvial habitats to Lake Worth, we surgically implanted
radio transmitters into the body cavities of 12 adult fish captured at 3 distinct sites
within the free-flowing portion of the study area (Fig. 1). We collected fish by using
a boat-mounted, pulsed-DC electrofishing unit (7.5 Generator Powered Pulsator
[GPP], Smith-Root, Inc., Vancouver, WA) and recorded each capture location with
a handheld GPS unit. We held the captured fish in an aerated livewell while we collected
additional fish at each sampling site. At the conclusion of sampling at each
site, we surgically implanted an (ATS) F1840 or F1850 radio transmitter (Advanced
Telemetry Systems, Isanti, MN) into the body cavity of each fish using procedures
similar to Maceina et al. (1999). Transmitters had a minimum warrantied life of 333
d, weighed 20–25 g, and comprised no more than ~2% of each fish’s body weight,
which minimized the likelihood that movement and behavior of telemetered fish
was affected by the additional weight of the transmitter (Winter 1996). Following
the surgical procedure, we allowed fish to recover in the livewell for ~30 min, during
which time we transported them downstream to the release site at Cromartie
Landing in Lake Worth. The total handling time from initial capture to eventual
release was less than 2 hours for all fish.
We used a small boat equipped with a portable receiver (ATS R2000) and a handheld
directional antenna to locate transmittered fish approximately once per week
from 17 February 2011 to 2 June 2011 (105 d). We recorded GPS coordinates and
water temperature and depth and described the visible habitat whenever we located
a tagged fish. We also employed a stationary receiver (ATS R4500SD) positioned
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at the first shoal upstream of Lake Worth (~16 rkm upstream from Cromartie Landing)
to determine how long it took each fish to return to the river. The range of the
stationary receiver was more than double the width of the river; thus, we used the
Figure 1. A map of the study area that spanned of 50 rkm of the lower Flint River, GA, from
the base of Crisp County Dam (CCD) downstream to the Georgia Power Dam (GPD) that
forms Lake Worth. Circled areas indicate capture sites of transmittered and translocated
Shoal Bass.
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highest signal-strength recorded to approximate the time at which a telemetered
fish passed the receiver. We performed 1 final active-tracking survey of the study
area at the end of July 2011, separate from the weekly movement surveys, to determine
the eventual fate of each tagged fish.
At the conclusion of the study, we calculated daily movement rates of each fish
by dividing the minimum distance moved (m) between relocations by the amount
of time (d) elapsed during the relocation interval (Colle et al. 1989, Wilkerson and
Fisher 1997). We determined distance traveled between each subsequent relocation
event with the path tool within Google Earth version 7.1 (Google 2013), and
assumed paths between points followed the main river channel. We classified Shoal
Bass as having returned to their original capture site if we documented them within
1 rkm of that area and they remained there for 3 or more consecutive relocation
events. We determined these criteria for homing post hoc based on an abrupt difference
in the movement patterns of fish that never returned to their original capture
site compared to those that did. If we did not detect fish within the study area for
more than 2 consecutive weeks, we expanded our search to the first 2 rkm of river
below Lake Worth and GPD. Any fish that remained completely stationary for 3
or more consecutive weekly relocation events, and was also relocated in the same
location during the final tracking survey at the end of July 2011, was presumed
dead and subsequently removed from movement analyses after the first relocation
date on which we observed no movement. Although turbidity in our study area precluded
tag recovery or visual confirmation of mortality, we reasoned that a month or
more of subsequent relocations with no detectable movement was adequate to infer
mortality in Shoal Bass, which is a mobile species. Hightower et al. (2001) used a
similar methodology to infer mortality in Morone saxatilis Walbaum (Striped Bass).
Results
In total, we sampled, tagged, and translocated 12 adult Shoal Bass to Lake
Worth. On 16 February 2011, we translocated 3 fish from Abrams Shoals and 6
fish from Philema Shoals (Fig. 1). The following day, we translocated 3 fish from
the area just downstream of CCD. Mean body weight of translocated fish (prior to
surgical implantation of transmitters) was 1267 g (range = 825–1903 g); mean total
length (TL) was 414 mm (range = 367–480 mm) (Table 1).
Following translocation into Lake Worth, 10 of 12 (83%) Shoal Bass eventually
returned to fluvial habitats upstream of the impoundment. We later found
alive the 2 fish that did not return to fluvial habitats upstream in fluvial habitats
downstream of GPD. The 10 fish that returned to the river took an average of 21 d
(range = 12–35 d) to traverse the 16 rkm between Cromartie Landing and the first
shoal habitat upstream of Lake Worth. Fish generally proceeded upstream after reentering
fluvial habitats; 1 fish paused near the stationary receiver before moving
farther upstream towards its original capture site. Movement rates of translocated
fish were variable, and fish size did not appear to af fect movement pattern.
Translocated Shoal Bass appeared to experience 3 general phases of movement
after their release in Lake Worth: river re-entry, spawning season, and reduced
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summer discharge (Fig. 2). Following translocation, fish moved sporadically in
Lake Worth for a few weeks before beginning to move upstream within the river
channel. Average daily-movement rates peaked at 23 d post-translocation (early
March), with fish averaging 955 m/d (range = 16–1784 m/d) as 10 of 12 telemetered
fish returned upstream to fluvial habitats (Table 2). After returning to the
river, movement rates appeared to vary with the spawning season. Between 35
and 72 d post-translocation (late March to early May 2011), we observed other
adult Shoal Bass sampled in the study area to be in spawning condition (Taylor
2012), and water temperatures at that time (16–23 °C) were conducive to spawning
in this species (Hurst 1969, Wright 1967). Near the middle of spawning season,
movement rates of telemetered Shoal Bass decreased noticeably, averaging
160 m/d (range = 19–434 m/d; Fig. 2). Also during this period, 7 telemetered fish
remained in or near Philema Shoals, the largest shoal complex in the study area.
Between 72 and 106 d post-translocation (early May through early June 2011),
other Shoal Bass sampled in the study area were no longer in spawning condition
(Taylor 2012) and river discharge dropped by ~85 cubic meters per second
(cms; Fig. 2). During this time, telemetered Shoal Bass had much lower averagemovement
rates of ~20 m/d, and the majority of transmittered fish moved slightly
downstream to deeper areas within the shoals (Table 2).
Half (6 of 12) of the translocated Shoal Bass returned to within 1 rkm of
their capture location, each remaining there for at least 3 weeks during our study
(Table 1). Two of 3 Shoal Bass displaced from Abrams Shoals returned back to
their capture area within 3 weeks, and thereafter, we regularly located them in close
proximity to that shoal. Of the 6 fish displaced from Philema Shoals, 4 returned to
Table 1. Capture location, total length (TL), weight, time required to re-enter the first shoal habitat
upstream of Lake Worth (time [days]; see Fig. 1), number of relocations after initial translocation (#),
overall average-movement rate (avg rate [m/day]), whether each fish homed to its original capture site,
and eventual fate of each telemetered fish translocated from the lower Flint River, GA. * indicates that
fish left study area after several weeks in Lake Worth and never re-entered the shoal habitats upstream
of Lake Worth from where they were displaced. These fish were later discovered alive downstream of
the Georgia Power Dam (GPD) and Lake Worth. ** indicates fish returned upstream to the river following
translocation into Lake Worth, but were translocated a second time by tournament anglers in
June 2011. Both fish were later presumed dead near Cromartie Landing.
Tag # Capture area TL (mm) Weight(g) Time # Avg rate Homing? Eventual fate
701 Philema 386 1003 12 9 132 Yes Alive
711 Philema 410 1174 17 11 74 Yes Alive
721 Below CCD 457 1743 14 9 227 No Alive
731 Philema 385 906 35 10 309 No Dead**
741 Abrams 376 825 20 13 216 Yes Alive
751 Abrams 390 1092 19 10 375 Yes Alive
761 Below CCD 458 1753 21 13 643 No Dead
771 Philema 407 1185 15 11 306 Yes Alive
781 Below CCD 367 962 33 11 318 No Dead**
791 Abrams 376 838 * 4 102 No Left
820 Philema 480 1903 22 10 375 Yes Alive
931 Philema 475 1821 * 2 111 No Left
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this area and rarely ventured away. The first of these returned to Philema Shoals
within 3 weeks; however, the other 3 took approximately 5–6 weeks. In contrast,
the 3 Shoal Bass displaced from below CCD did not return to their capture sites.
One fish from below CCD had the highest overall average-movement rate (643 m/d;
Table 1) as it moved sporadically between the stationary receiver and to within 12
rkm of its capture location. Two others moved as far upstream as Philema Shoals
and eventually situated themselves in smaller shoal areas between Philema and
Abrams shoals.
Eventual fates revealed that 5 of 12 (42%) telemetered fish had left the population
or were dead at the end of our study (Table 1). One fish from Abrams
Figure 2. Minimum, average, and maximum observed-movement rates in meters per day
(m/d) of telemetered adult Shoal Bass following translocation into Lake Worth (primary yaxis)
along with average daily discharge in cubic meters per second (cms) of the lower Flint
River at USGS stream gage 02350512 at Hwy 32 bridge near Philema Shoals (secondary
y-axis). Note the timing of biologically relevant events during the movement study: re-entry
to river, spawning period, and reduced summer dischar ge.
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Shoals and another from Philema Shoals left the study area within 1 month after
translocation into Lake Worth, and we later found both alive downstream of GPD.
Near the end of our study, 1 fish that had returned to the river was presumed dead
after we observed no movement over consecutive relocation events from late April
through the end of the movement study in June. The July survey to confirm fish fates
corroborated this conclusion, because we observed no discernable fish movement.
Interestingly, 2 fish that had returned to the river were eventually presumed dead
near Cromartie Landing following a second translocation into Lake Worth by tournament
anglers in June 2011. One of these fish was discovered in early June near the
dock at Cromartie Landing the morning after a fishing tournament; the other was
observed being released following a tournament weigh-in at Cromartie Landing in
mid June (see Taylor 2012). We relocated both of these telemetered fish at the dock
on a weekly basis until the end of July with no discernable movement. The second
translocation of these fish by tournament anglers occurred after our movement
study was completed; thus, these angler-induced movements did not influence the
results of our movement analyses.
Discussion
Our study provided a direct test of Shoal Bass responses to translocation
downstream into an impoundment. Our results showed that all adult Shoal Bass
translocated into Lake Worth vacated the impoundment within 2–4 weeks, even
though 2 fish left the study area to do so. In fact, the highest movement rates were
observed as 10 of 12 Shoal Bass left the impoundment and re-entered upstream,
Table 2. Telemetry data summarized by observation date for 12 adult Shoal Bass that were captured
from 3 areas of the lower Flint River, GA, and translocated into Lake Worth in early February 2011.
Number = number of individual fish located, time = time since translocation (days), interval = interval
between observation dates (days), and percentage = % of fish moving upstream (+) and downstream
(-)
Mean movement rates
Date Number Time Interval (min-max) during interval (m/d) Percentage
24 Feb 11 7–8 7–8* 150 (66–327) +81.8, -18.2
3 Mar 11 14–15 7 592 (22–1949) +54.5, -45.5
11 Mar 7 22–23 8 955 (16–1784) +71.4, -28.6
16 Mar 7 27–28 5 878 (44–2489) +85.7, -14.3
23 Mar 10 34–35 7 730 (64–2072) +90.0, -10.0
1 Apr 10 43–44 9 256 (19–1258) +60.0, -40.0
7 Apr 10 49–50 6 242 (5–1513) +60.0, -40.0
15 Apr 9 57–58 8 160 (19–434) +66.7, -33.3
20 Apr 8 62–63 5 181 (17–559) +62.5, -37.5
29 Apr 9 71–72 9 106 (0–562) +44.4, -44.4
18 May 8 90–91 19 23 (1–45) +12.5, -87.5
26 May 7 98–99 8 23 (0–50) +14.3, -71.4
2 Jun 6 105–106 7 20 (1–83) +33.3, -50.0
*7 days for the fish translocated on 17 February 2011 from Philema and Abrams shoals and 8 days for
fish translocated on 16 February 2011 from the area just downstream of Crisp County Dam (CCD).
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fluvial habitats. The return of 6 of 12 Shoal Bass back to where they were sampled
illustrated a previously unreported homing ability in the species. Our results also
demonstrate that adult Shoal Bass are capable of surviving translocation to a lentic
environment; however, the effects of angling and other sublethal effects of translocation
should also be considered when managing Shoal Bass fisher ies.
Following translocation into lentic habitats, all 12 Shoal Bass displayed a rapid
evacuation of lentic habitats, the motivation for which is currently unclear. Despite
subsets of translocated fish moving both upstream (10) and downstream (2) of
the translocation impoundment, all 12 eventually returned to lotic habitats within
several weeks of their translocation. The rapid evacuation from the impoundment
suggested that fish were avoiding lentic habitats, which supports reports that Shoal
Bass are rarely encountered in impoundments (Williams and Burgess 1999). Alternatively,
fish could have simply been moving to shoal habitats for the imminent
onset of the spawning season. Future studies are needed to evaluate the seasonal
movements of Shoal Bass translocated into impoundments to better understand the
factors that motivate their movements.
Once adult Shoal Bass returned to fluvial habitats, their movements during the
spawning season illustrated several adaptations typical of other fluvial-specialist
fishes. The pattern of movements observed during the spawning season (Fig. 2)
was consistent with Wright’s (1967) hypothesis that, like many other fluvial fish -
es, Shoal Bass spawn during discharge pulses in the spring months (e.g., Taylor
and Miller 1990, Tyus and Karp 1990). Our results also emphasize the importance
of large shoal-complexes for Shoal Bass spawning (Goclowski et al. 2013, Taylor
and Peterson 2014) because the majority of transmittered fish spent much of the
spawning season in the largest available shoal complexes previously identified as
likely spawning areas (Taylor 2012). Spawning aggregations of Shoal Bass within
large shoal complexes appear to occur throughout most of the species’ range,
including the upper Flint River (Goclowski et al. 2013), lower Flint River (Ingram
et al. 2013, Taylor 2012), and tributaries of the middle Chattahoochee River
(Sammons 2011). Shoal Bass are not unique in this adaptation; many other fluvial
species are shoal-dependent or rely on shoal habitats at some point in their development
(e.g., Hagler 2006).
Our study provides direct qualitative evidence of homing ability in Shoal Bass.
In a probabilistic sense, translocated fish had 5 general locations they could have
eventually occupied: Muckalee Creek (tributary), Kinchafoonee Creek (tributary),
the Flint River downstream of Lake Worth, the Flint River upstream of Lake Worth
(their home tributary), or they could have remained in Lake Worth. The Flint River
above and below Lake Worth is known to harbor robust Shoal Bass populations
(Taylor and Peterson 2014), and Auburn University Natural History Museum (Auburn
University, AL) records confirm that Shoal Bass have been collected in both
Muckalee Creek and Kinchafoonee Creek. Not only did 10 of 12 translocated fish
return upstream into the Flint River, but half (6 of 12) returned and remained within
1 rkm of their original capture site. In doing so, all 6 passed through several smaller
shoal habitats and those that returned to Philema Shoals passed by another large
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shoal complex at Abrams Shoals. Similar patterns of homing behavior have also
been observed in fluvial populations of both M. dolomieu Lacepède (Smallmouth
Bass; Langhurst and Schoenike 1990, VanArnum et al. 2004) and Largemouth Bass
(Richardson-Heft et al. 2000).
Interestingly, Ingram et al. (2013) translocated Shoal Bass from a spawning
aggregation in the lower Flint River downstream to Lake Seminole and reported
that no fish returned back to the capture area during their 90-d study. In their study,
however, fish were displaced during and after the spawn, whereas in our study all
fish were displaced just prior to spawning. Consequently, the homing behavior we
observed may have simply reflected the seasonal tendency of Shoal Bass to move
toward shoal complexes at the onset of the spawning season. The distance displaced
may also affect Shoal Bass homing ability. In Ingram et al.’s (2013) study, fish were
displaced approximately 90 rkm, whereas those in our study were only displaced
20–50 rkm. Despite the relatively small sample size of telemetered fish in our study,
the 3 fish displaced the farthest (50 rkm) did not return to their original capture site,
while many of the others did.
The eventual fates of our fish revealed that fluvial-specialist Shoal Bass are capable
of surviving translocation into lentic habitat in the short-term; however, the
long-term effects of tournament-related translocation should be further evaluated.
All 12 of our Shoal Bass survived the initial translocation into the impoundment,
but our fish also had return access to riverine habitats. Whether or not Shoal Bass
can survive translocation to a lentic habitat without return access to a lotic habitat
remains unknown. Translocated fish may also emigrate from their original population,
as was the case with 2 of 12 study fish that passed downstream of GPD.
Although these fish were lost from the study population, their movement also illustrates
that translocation into an impoundment may facilitate gene flow among populations
fragmented by impoundments. Unfortunately, translocation associated with
tournament angling during the summer months may increase post-release mortality
of Shoal Bass because environmental conditions during the summer months may
be particularly unfavorable. During our study, anglers translocated 2 of the telemetered
fish into Lake Worth a second time during summer fishing tournaments, and
both were eventually presumed dead near the weigh-in site at Cromartie Landing.
Although the effects of angler-handling time and high water-temperatures have not
been well-studied in Shoal Bass, previous studies on other Micropterus spp. have
shown that both are positively correlated with post-release mortality of tournamentcaught
fish (Edwards et al. 2004, Wilde 1998). In addition to being translocated into
a suboptimal lentic environment, these factors could significantly increase the tournament-
associated mortality of Shoal Bass. Of the 10 fish that returned upstream,
3 died within 6 months of their return (Table 1). Our findings were consistent with
those of Ingram and Kilpatrick (2015) who estimated a 49% annual-mortality rate
for adult Shoal Bass in the lower Flint River .
Our study has several important conservation and management implications.
The observed homing ability and the apparent importance of shoals as spawning
habitat suggests that connectivity among these habitats is vital to effective
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conservation of Shoal Bass and other fluvial species. Additional investigation
is warranted concerning the severity of fragmentation among populations in the
heavily impounded native range of the Shoal Bass. Future studies of homing and
spawning-site fidelity in Shoal Bass will help improve our current understanding
of the critical linkages between habitat connectivity and the population dynamics
of these and other fluvial-specialist fishes. Until such research is completed, we
suggest that precautionary regulations regarding the translocation of Shoal Bass
during fishing tournaments should be considered. For example, managers may wish
to consider limiting the timeframe that tournament-related translocation is allowed.
Post-release mortality of translocated Shoal Bass may be particularly problematic
during the warmer summer months when water temperatures reach their seasonal
highs. Likewise, translocation of adults during the spawning season may negatively
affect spawning success. Other regulations that address the distance displaced and
the potential for return access to shoal habitat may also be prudent. Although further
research is needed to evaluate the effectiveness of such management actions,
precautionary regulations like those suggested should help ensure the long-term
sustainability of these important fisheries until a better understanding of their overall
conservation status has been achieved.
Acknowledgments
We would like to thank the Georgia Department of Natural Resources for logistical support
for this project, including the individual efforts of T. Ingram, J. Tannehill, and R. Weller
with the Wildlife Resources Division, Fisheries Management Section. This manuscript was
greatly improved by comments from Dr. James M. Long and 2 anonymous reviewers. We
also thank D. Higginbotham, J. Swearingen, J. Keltner, F. Mathis, T. Faircloth, and H. Seymour
for their assistance with data collection and field logisti cs.
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