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Laboratory Investigations on the Use of Strobe Lights and Bubble Curtains to Deter Dam Escapes of Age-0 Muskellunge


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The movement of Muskellunge Esox masquinongy over a dam to leave a reservoir is known as dam escape. It is common in Midwestern U.S. reservoirs and has been as high as 25% of the adult population. A variety of barrier and guidance systems have been used to control fish movement, but the success of such barriers has been mixed and appears to be very species dependent. We examined the effectiveness of a simple, relatively low-power and low-cost bubble curtain, strobe light, and bubble curtain with strobe light barriers to deter Muskellunge from escaping over spillways. In 15 replicate trials of each treatment type conducted in a simulated spillway, age-0 Muskellunge were more likely to escape during daytime trials (P Received September 18, 2013; accepted January 22, 2014
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North American Journal of Fisheries Management
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Laboratory Investigations on the Use of Strobe Lights
and Bubble Curtains to Deter Dam Escapes of Age-0
Heather A. Stewart
, Max H. Wolter
& David H. Wahl
Department of Natural Resources and Environmental Sciences, University of Illinois at
Urbana–Champaign, 1102 South Goodwin Avenue, Mail Code 047, Urbana, Illinois 61801, USA
Illinois Natural History Survey, Kaskaskia Biological Station, 1235 County Road 1000N,
Sullivan, Illinois 61951, USA
Published online: 22 May 2014.
To cite this article: Heather A. Stewart, Max H. Wolter & David H. Wahl (2014) Laboratory Investigations on the Use of Strobe
Lights and Bubble Curtains to Deter Dam Escapes of Age-0 Muskellunge, North American Journal of Fisheries Management,
34:3, 571-575
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North American Journal of Fisheries Management 34:571–575, 2014
American Fisheries Society 2014
ISSN: 0275-5947 print / 1548-8675 online
DOI: 10.1080/02755947.2014.892549
Laboratory Investigations on the Use of Strobe
Lights and Bubble Curtains to Deter Dam Escapes
of Age-0 Muskellunge
Heather A. Stewart*
Department of Natural Resources and Environmental Sciences,
University of Illinois at Urbana–Champaign, 1102 South Goodwin Avenue, Mail Code 047,
Urbana, Illinois 61801, USA
Max H. Wolter and David H. Wahl
Illinois Natural History Survey, Kaskaskia Biological Station, 1235 County Road 1000N,
Sullivan, Illinois 61951, USA
The movement of Muskellunge Esox masquinongy over a dam to leave a reservoir is known as dam escape. It is
common in Midwestern U.S. reservoirs and has been as high as 25% of the adult population. A variety of barrier
and guidance systems have been used to control fish movement, but the success of such barriers has been mixed and
appears to be very species dependent. We examined the effectiveness of a simple, relatively low-power and low-cost
bubble curtain, strobe light, and bubble curtain with strobe light barriers to deter Muskellunge from escaping over
spillways. In 15 replicate trials of each treatment type conducted in a simulated spillway, age-0 Muskellunge were
more likely to escape during daytime trials (P < 0.01), but the three barrier combinations did not reduce rates of
escape. Light and bubble curtain barriers will likely not be effective in reducing spillway escapes by Muskellunge.
Muskellunge Esox masquinongy are important sport fish in
the United States (Simonson and Hewett 1999) and stocking
is an important tool for enhancing populations in reservoirs
(Margenau 1992; Wahl 1999). Following introduction, Muskel-
lunge are frequently observed escaping over spillways after
high-water events. About 25% of a Muskellunge population in
an Illinois reservoir escaped in 1 year (Wolter et al. 2013). Es-
cape of Muskellunge appeared to be an active response as most
happened during peak activity times and in proximity to spawn-
ing. Escaped Muskellunge are s ubject to an uncertain fate and,
unless rescued, are lost to the reservoir fishery. Additionally, the
influx of these large piscivores into downstream systems could
contribute to a decline of native fishes that use the streams for
nurseries (Stanford et al. 1986). Reports of dam escapes have
generated interest in installing barrier nets to prevent fish es-
*Corresponding author:
Received September 18, 2013; accepted January 22, 2014
capes, but they are not always possible or effective due to debris
accumulation (Plosila and White 1970).
Electrical barriers, illumination, air bubble curtains, and
sonic devices are alternatives to barrier nets that deserve consid-
eration (McIninch and Hocutt 1987). Diverting fish with the use
of air bubbles has been suggested for decades (Von Brandt 1967;
Stewart 1982) and has the advantage of technical simplicity and
lower power consumption per unit area than electric barriers
(Stewart 1982). It has also been hypothesized that bubble cur-
tains have increased effectiveness if used with a light source
(Patrick et al. 1985). Previous studies using light and bubble
curtain barriers have proved successful in redirecting a num-
ber of different fishes. Strobe lights alone deterred Largemouth
Bass Micropterus salmoides, Chinook Salmon Oncorhynchus
tshawytscha, and Yellow Perch Perca flavescens (Richards and
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Chipps 2007). The highest deterrence occurred when a strobe
light and a bubble curtain were used in combination, as seen with
Atlantic Menhaden Brevoortia tyrannus, White Perch Morone
americana, and Spot Leiostomus xanthurus (Patrick et al. 1985;
McIninch and Hocutt 1987). However, other studies reported
that some fishes were attracted to such barriers (Patrick et al.
1985; Sager et al. 1987). Age-0 Rainbow Smelt Osmerus mor-
dax were repelled by strobe lights, whereas juveniles and adults
were not (Stafford-Glase and Homa 1997). Our objective was to
examine whether a bubble curtain, strobe light, or a combination
of these two would be effective in reducing dam escapes of age-
0 Muskellunge. We examined the potential of these approaches
using a scaled replica of a spillway in a controlled laboratory
Simulated dam and spillway.—In the laboratory, using flow
over a simulated barrier we examined a variety of variables
for their effect on age-0 Muskellunge movement. We created a
spillwayina460 × 100 × 50-cm fiberglass tank by blocking
one end with a notched (2 × 18 cm) board, simulating a dam
following the design of Wolter et al. (2013). Pumps (
0.76 L/s) were used to move water from below the spillway back
to the other end of the tank creating a closed loop (Figure 1).
The upper meter of the tank was partitioned with a net so that
fish in the trial arena could not encounter the area where pumps
discharged water. Spillway overflow height has been identified
as an important determinant of escape (Lewis et al. 1968; Paller
et al. 2006), so overflow height in this system was greater than
the body depth (1.25–1.75 cm) of an age-0 Muskellunge, and
water velocity at the face of the simulated dam (6 cm/s) was
comparable to velocities observed at the mouth of the spillway
at Lake Sam Dale, Illinois (4 cm/s) at similar levels of overflow.
Water depth was 34 cm in the trial arena when pumps were
running, whereas the water level in the catch basin was 24 cm,
which prevented fish from moving back into the test arena after
escaping. Flow was low enough that a refuge was not needed
as some fish did not pass over the dam. The trial arena was
378 L in volume and 198 cm long, an approximate distance of
15 body lengths for an average fish used in the trials. Three
identical tanks were used for replication and housed indoors.
Tanks were surrounded by opaque curtains to prevent fish from
being disturbed during the trials. A single age-0 Muskellunge
(120–165 mm TL) was randomly selected from one of four
pools of fish (200 individuals) and was placed into the arena
and allowed to acclimate for 1 h under trial conditions with
no flow over the barrier. After acclimation, the pumps were
activated to begin the 2-h trial. Treatments included the presence
and absence of a strobe light, presence and absence of a bubble
curtain, both in combination, and a control with no barriers.
Muskellunge escapes over the 2-h trial period was recorded.
Because diel period is an important factor of escape (Wolter
et al. 2013), we conducted day and night trials. Each of the
three barrier treatments, as well as day and night trials, were
replicated 15 times in a fully factorial design. Controls were run
with no strobe light or bubble curtain both during the day and
at night. After a trial, individuals were placed in a separate tank
so they would not be reused within 48 h.
Bubble curtain and strobe light.—The bubble curtain, which
was placed 110 mm from the spillway was created with a sec-
tion of PVC tubing, 500 mm long and 20 mm diameter, that
had 0.39-mm holes spaced 16 mm apart. The curtain was con-
nected by tubing to an air compressor delivering 984.3 kg/m
of pressure. The strobe light used was a Zeagle Underwater
Strobe with a xenon flash (60 flashes per minute) and visibility
of 3.2 km. The strobe light was angled to point into the bubble
curtain 390 mm from the spillway ( Figure 1), similar in scale to
FIGURE 1. Schematic of the simulated spillway system used to examine the effects of bubble curtain, strobe light, and their combination for reducing escapes
of Muskellunge. Dimensions of the system were 4.6 m long × 1.0 m wide × 0.5 m deep. The bubble curtain was 110 mm from the spillway and 500 mm across,
and had a width of 20 mm. The strobe was placed 390 mm from the spillway. Escape was determined when a fish passed over the dam into the catch basin as
monitored by a closed-circuit television camera, except for bubble curtain trials.
Downloaded by [Heather Stewart] at 20:28 04 June 2014
laboratory studies by Sager et al. (1987, 250 mm) and McIninch
and Hocutt (1987, 300 and 850 mm). A single-plane wall of
bubbles was created that was illuminated by the strobe light.
Behavior trials were recorded using video cameras (AUC-75;
Atlantis Camera, Englewood, New Jersey) positioned 2 m above
the water surface of the simulated dam. Cameras were connected
to camera junction boxes, which sent video feed to video cas-
sette recorders (VCRs) to assess behavior during movement
of Muskellunge. The bubble curtain disrupted the surface of the
water so only control and strobe light trials were video-recorded
during the day. Trials were assessed using frame-by-frame anal-
ysis (30 frames/s) (Wagner et al. 2009). The behaviors assessed
were number of approaches before escape (defined as an indi-
vidual coming within one body length of the spillway), time
to escape, and activity prior to escape. A fish was classified as
making multiple approaches if it was observed to retreat before
approaching again. For activity prior to escape, both distance
from the spillway and body orientation of each individual ap-
proach was evaluated. Body orientation was recorded as degrees
from spillway, and as either head first or sideways. Head first
was defined as an angle of 45–135
to the spillway and sideways
was defined as a 0–45
or 135–180
angle. Time to escape and
number of approaches were both quantified with two-sample
t-tests between escaping and nonescaping fish assuming equal
variances. For night and bubble curtain trials, visual observa-
tions were recorded to determine whether the fish went over the
spillway and, if so, at what time. Approaching behavior was not
recorded for night and bubble curtain trials.
Logistic multiple regression analysis (PROC LOGISTIC
SAS 9.2) was used to determine the variables that had an effect
on rates of escape. Categorical variables—diel period, strobe
light, and bubble curtain—were coded as either 1 or 0 based on
presence or absence, respectively. Length was used as a contin-
uous covariate. Fish were classified as having either “escaped”
or “not escaped” during the 2-h trials resulting in a binomial
response variable, 1 or 0 to code escape or no escape, respec-
tively, and significance was determined at α = 0.05. Percent
concordance was used as a measure of goodness of fit.
Fish length varied over a relatively narrow range and did
not differ between treatments (chi-square = 0.31, df = 1, P =
0.58). Diel period had an effect on escape and rates of escape
were higher during the day than at night (chi-square = 29.43,
df = 1, P < 0.01; Table 1). An explanatory model determining
the probability of escape under various conditions demonstrated
how diel period affected the probability of escape, with escapes
occurring more than twice as frequently during the day than at
night (Figure 2). There was also an effect of strobe on escape
with presence causing increased probability of escape compared
with a control (chi-square = 4.21, df = 1, P = 0.04; Table 1; Fig-
ure 2). The presence of bubbles did not reduce escapes compared
with controls (chi-square = 0.29, df = 1, P = 0.60; Table 1) nor
TABLE 1. Results of logistic regression analysis on Muskellunge escapes
during trials in a simulated spillway. The equation predicts a logit with a prob-
ability (p) that can be computed as p = 1/[1 + exp(logit)]. Presence–absence
of ambient light, strobe light, and bubbles were examined as factors influenc-
ing escape. Statistical significance is indicated by p-values in bold text with an
asterisk (*); no interactions were statistically significant (α = 0.05).
Wald chi p > chi
Parameter df Estimate SE square square
Intercept 1 1.20 0.45 7.28 <0.01*
Diel period 1 2.73 0.50 29.43 <0.01*
Strobe light 1 0.96 0.47 4.21 0.04*
Bubble curtain 1 0.25 0.46 0.29 0.60
did the strobe light–bubble curtain combination (chi-square =
0.08, df = 1, P = 0.78). Escape was not affected by any interac-
tion of variables, including between diel period and strobe light
presence (chi-square = 0.62, df = 1, P = 0.43). Although not
statistically different, night time rates of escape were 47% with
strobe light (SD = 18.0) and 25% without strobe (SD = 12.5).
Fish Behavior
All escapes that were observed occurred within the first
20 min of the 2-h trials. Type and number of approaches did
not differ between strobe trials and control. The time to escape
after a trial began was similar for both strobe (mean, 8.9 min)
and no strobe (mean, 5.1 min; t-test: P = 0.15). Number of ap-
proaches to the spillway prior to escape did not differ between
strobe (mean, 1.3) and no strobe (mean, 2.0) trials (t -test: P =
0.15). Most (90%) escaping fish approached head first with the
body perpendicular to the spillway. The majority of the individ-
uals that escaped swam parallel to the spillway, then stopped
FIGURE 2. Probability of Muskellunge escape from the simulated spillway
during day and night with and without the strobe barrier present. Diel period
had an effect on escape (P < 0.01), and there was also an effect of strobe on
escape (P = 0.04); however, there was no significant interaction (P = 0.43).
Downloaded by [Heather Stewart] at 20:28 04 June 2014
and hovered before turning their head towards the spillway and
swimming over.
Strobe lights, bubble curtains, or their combination in a sim-
ulated spillway did not serve as a successful barrier to age-0
Muskellunge. In fact, the strobe light increased the number of
age-0 Muskellunge escapes. Positioning of the strobe light and
bubble curtain left a portion of the trial arena opposite of the
spillway as a refuge for fish that wanted to avoid these stimuli,
suggesting that the Muskellunge approaching were not merely
trying to escape the stimulation. Fishes at lower trophic lev-
els such as Alewife Alosa pseudoharengus, Rainbow Smelt,
Gizzard Shad Dorosoma cepedianum, White Perch, Spot, and
Atlantic Menhaden can be deterred by strobe light–bubble bar-
riers (Patrick et al. 1985). Muskellunge may react differently to
these stimuli than do other fishes as a result of species-specific
behavioral patterns (Bibko et al. 1974; Patrick et al. 1985;
McIninch and Hocutt 1987; Sager et al. 1987). Striped Bass
M. saxatilis have been observed to have only a temporary de-
terrence from strobe light (Bibko et al. 1974). Several other
studies have documented patterns of strobe light attraction in
select fishes, indicating that light may increase foraging effi-
ciency for visually foraging fishes (Brett and McKinnon 1953;
Alveras 1974; Hocutt 1980; Fiest and Anderson 1991; John-
son et al. 2003; Richards and Chipps 2007). Muskellunge are
visual predators (New and Kang 2000), which could explain
the observed attraction response to strobe light. There are many
factors that could account for the disparity in escapes among
fishes. Responses to light barriers may be species-specific due
to differences among feeding strategies, swimming activity and
ability, differences in visual systems, diel activity patterns, and
habitat selection (Patrick et al. 1985; McIninch and Hocutt 1987;
Sager et al. 1987). Variation in response to artificial illumination
can depend on light intensity, color, order of color presentation,
length of exposure, and mode of intensity change (Fields and
Finger 1956; Patrick 1982; Patrick et al. 1985; Sager et al. 1987;
Marchesan et al. 2004). Strobe lights have proven to be the most
successful of flashing lights, but the flash frequency is important
to be effective (Sager et al. 1987). Strobe light efficacy in causing
a startle response depends on a flash frequency distinguishable
from any natural light fluctuations observed underwater due to
waves or cloud movement (McFarland and Loew 1983; Schech-
ner and Karpel 2004). Because no previous studies using strobe
lights had been performed on Muskellunge, we used a flash rate
of 60 per minute to assess avoidance response. The Muskellunge
were not deterred by the low frequency strobe light, so future
studies should assess avoidance of higher flash frequencies.
Muskellunge escaped more often during daylight hours than
at night. Similar daylight escape patterns have been observed
with Largemouth Bass, whereas Black Bullhead Ameiurus
melas in the same study showed increased escapes at night
(Lewis et al. 1968). These escape patterns may be related to
foraging behavior and activity levels of the different fishes. The
escaping bullheads were primarily age-0 fish, which exhibit two
feeding periods, one at dawn and one at dusk, and the majority
of escapes were at these times (Darnell and Meierotto 1965;
Lewis et al. 1968). Largemouth Bass have higher foraging suc-
cess during daylight hours (McMahon and Holanov 1995), thus
the higher rate of escape during the day may be related to for-
aging activity. Since Muskellunge are primarily visual foragers,
it might be expected that they would exhibit similar behavior in
terms of daytime escape as other visual hunters such as Large-
mouth Bass (New et al. 2001).
The level of avoidance Muskellunge would exhibit towards
bubble barriers was uncertain given the limited research on Es-
ocidae with nonphysical barriers. Previous literature also pro-
vided little insight to possible responses due to the few trials
with predatory fishes. Piscivorous fishes such as White Perch
and Striped Bass were observed to have limited avoidance of
bubble barriers alone (Sager et al. 1987), which suggests that
these responses could be based on foraging behavior. However,
pelagic fishes such as Alewife, Rainbow Smelt, and Gizzard
Shad were found to be repelled by bubble barriers, whereas some
demersal fishes such as White Sucker Catostomus commersonii
and Spot were attracted (Patrick et al. 1985). The combination
of strobe light with bubble curtain barriers has demonstrated an
improved avoidance for some pelagic fishes (Sager et al. 1987).
We used age-0 Muskellunge that may not exhibit the same es-
cape behaviors as older adult fish. However, Wolter et al. (2013)
found a correlation between escapes in laboratory studies of
immature Muskellunge and field trials of adult Muskellunge,
suggesting our results on effects of nonphysical barriers could
also be applied to adult fish.
Muskellunge in these trials behaved similarly as they did
during tank acclimation, where fish were suspended in the wa-
ter column and moved slowly about the tank. Darting or other
types of burst swimming behavior were very rare. Observations
of Muskellunge behavior suggest that active swimming was in-
volved in escapes and it was not just the flow pulling the fish
over the spillway (Wolter et al. 2013). The majority of the indi-
viduals that escaped swam parallel to the spillway, before they
turned and swam over the barrier. Similar approach behavior
has been observed in flatfishes (Lemon Sole Microstomus kitt,
European Plaice Pleuronectes platessa, and Common Dab Li-
manda limanda) when electrified barriers were used (Stewart
1982). Frequently, the fish would swim parallel to the barrier,
turn away to retreat, and then approach the barrier again. These
behaviors were thought to be testing the barrier to find out if
it was harmless, and when no harm appeared to come from
the barrier, the fish quickly escaped. A similar response was
observed in age-0 Muskellunge.
Before installing light and bubble curtain barriers, response
to a range of stimuli and intensity for targeted fishes should
be understood to maximize barrier effectiveness. Future studies
should also assess sound barriers for Muskellunge, as some
fishes are more sensitive than others to particular wavelengths
Downloaded by [Heather Stewart] at 20:28 04 June 2014
and frequencies (Sager et al. 1987; Mann et al. 2007). Strobe
light and bubble curtain barriers have attracted interest from
fish managers because of their simplicity and low costs, but our
study suggests these barriers will not be effective at reducing
spillway encounters for age-0 Muskellunge.
Funding for this project was provided by the Hugh C.
Becker Memorial Foundation and from Federal Aid in Sportfish
Restoration Act Project F-151-R. We thank L. Dunham and S.
Pallo who coordinated activities with the Illinois Department of
Natural Resources. We thank Steve Miranda for his statistical
help. We also thank L. Einfalt for the care of fish and laboratory
assistance, as well as C. DeBoom for assistance with experimen-
tal design and three anonymous reviewers for providing helpful
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Fisheries Management 33:829–838.
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... Channel catfish also showed low sensitivity to strobe lights when compared to largemouth bass, chinook salmon, and yellow perch [15]. Previous literature as suggested that foraging schedules and activity rates may be linked to the efficacy of non-physical barriers [32]. For example, largemouth bass had higher foraging success during daylight hours while also having greater escape rates during that time [33]. ...
... In escape studies, fish often swim parallel to the barrier, turn away and retreat, and then approach the barrier again [32]. These behaviours were thought to be testing the barrier and when no harm was encountered individuals escaped confinement [32]. Cohesive behaviour among animals is an attempt to dilute predation risk [30]. ...
... As the strobe-light barrier provides no harm to individuals, it is possible that experimental individuals evaluated their interactions with the barrier. In escape studies, fish often swim parallel to the barrier, turn away and retreat, and then approach the barrier again [32]. These behaviours were thought to be testing the barrier and when no harm was encountered individuals escaped confinement [32]. ...
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The movement of fish can be regulated by behavioural manipulation through non-physical barrier systems. Aquatic invasive species are becoming one of the major management issues in North America, and threaten native aquatic ecosystems, including freshwater fish. Placements of non-physical barriers in waterways can help disrupt the movement of invasive fish. This study examined the effect of a strobe-light stimulus on the avoidance behaviour of two proxy species, juvenile common carp (Cyprinus carpio) and juvenile channel catfish (Ictalurus punctatus), in a controlled laboratory environment. For each species, three sequential treatments of pre-stimulus, strobe-light stimulus, and post-stimulus for 30 min periods were recorded on acclimated groups of 5 juvenile common carp and 5 juvenile channel catfish using 15 and 13 replicates, respectively. The distribution of juvenile common carp individuals throughout the tank did not change significantly with treatment, nor did cohesive grouping behaviour. Similarly, there were no significant differences across experimental treatments in average location/distance of juvenile channel catfish relative to the strobe light or degree of cohesion in response to the strobe light. Non-physical barriers have been widely reported to vary between species and environmental conditions. These results suggest that strobe lights evoke no avoidance or attractive responses in juvenile common carp and juvenile channel catfish, and will likely not be an effective barrier to inhibit movements of juvenile invasive fishes.
... All rights reserved. Accepted Article behaviour (Flammang et al., 2014;Mussen et al. 2014;Stewart et al. 2014;Miehls et al. 2017; Table I). The efficacy of strobe lights affecting fish behaviour most likely depends on the species' visual and spectral sensitivity and environmental conditions, such as ambient light and water turbidity. ...
... Temporal reduction in visual sensitivity could explain why studies have reported varied results in the efficacy of strobe lights in modulating fish swimming behaviour (Hamel et al., 2011;Flammang et al., 2014;Mussen et al., 2014;Stewart et al., 2014;Kim & Mandrak, 2017;Miehls et al., 2017). Many of these studies also examined the effect of a multi-modal non-This article is protected by copyright. ...
... For instance, in a laboratory experiment Flammang et al. (2014) determined that strobe lights reduced the efficacy of a bubble-strobe-light barrier in preventing walleye Sander vitreus (Mitchill 1818) escapement from a simulated reservoir. Furthermore, Stewart et al. (2014) and Miehls et al. (2017) concluded that a bubble-strobe-light system was ineffective in altering the swimming behaviour of muskellunge Esox masquinongy Mitchill 1824 and sea lamprey Petromyzon marinus L. 1758, respectively. Alternatively, Perry et al. (2014) found that a combined bubble-strobe-light system was effective in diverting migrating Chinook salmon Oncorhynchus tshawytscha (Walbaum 1792). ...
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Non‐physical barriers, including the use of underwater strobe lights alone or paired with sound or bubbles, are being considered as a means to prevent the upstream migration of invasive silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis. To optimize potential optical deterrents, it is necessary to understand the visual sensitivity of the fishes. Dark‐adapted H. molitrix and H. nobilis were found to possess broad visual sensitivity between 470 nm to 620 nm with peak spectral sensitivity at 540 nm for H. molitrix and 560 nm in H. nobilis. To assess the effect of a strobe light on vision, dark‐adapted H. molitrix, H. nobilis and common carp Cyprinus carpio, were exposed to three different 5 s trains (100, 200, or 500 ms on–off flashes) of white light and the recovery of visual sensitivity was determined by measuring the b‐wave amplitude of the electroretinogram (ERG). For all species, the longest recoveries were observed in response to the 500 ms flash trains (H. molitrix mean ± SE = 702.0 ± 89.8 s; H. nobilis 648.0 ± 116.0 s; C. carpio 480 ± 180.0 s). The results suggest that strobe lights can temporarily depress visual sensitivity, which may render optical barriers less effective. This article is protected by copyright. All rights reserved.
... Muskellunge (Esox masquinongy) are a popular sport fish that occur only in North America, being both ecologically and economically important to the fishery (Bozek et al. 1999;Stewart et al. 2014). Anglers enjoy Muskellunge due to their large sizes (Gillis et al. 2010) and ...
... Also, one individual was found in a nearby gravel pit after a large rain event, potentially facilitating this movement. Fish located on the southern half of the reservoir appeared to travel towards the dam after large precipitation events that increased the reservoir water level, potentially causing Muskellunge to be flushed through the dam (Wolter et al. 2013;Stewart et al. 2014). Several of these fish were tracked by the dam one week, but were never found again. ...
... Although the configuration of the dam may not be comparable to similar structures in the Midwest, Muskellunge have been flushed through these dams, particularly during daylight hours (Wolter et al. 2013;Stewart et al. 2014). Unfortunately, tracking below the dam to confirm this movement of fish was not possible due to liability and private property restrictions. ...
... Bubbles introduced underwater generate sound and create turbulence that is influenced by bubble density and rise velocity (Brevik and Kristiansen, 2002). Furthermore, they can create a visual barrier by obscuring a fish's line of sight (Flammang et al., 2014;Stewart et al., 2014), although guidance efficiencies are generally higher at night for species such as walleye Sander vitreus (Flammang et al., 2014), muskellunge Esox masquinongy (Stewart et al., 2014), largemouth bass Micropterus salmoides (Lewis et al., 1968), and sockeye salmon Oncorhynchus nerka (Brett and MacKinnon, 1953). This might be because fish can detect gaps during daylight hours through which they can pass, as suggested for Atlantic salmon smolts (Welton et al., 2002). ...
... Bubbles introduced underwater generate sound and create turbulence that is influenced by bubble density and rise velocity (Brevik and Kristiansen, 2002). Furthermore, they can create a visual barrier by obscuring a fish's line of sight (Flammang et al., 2014;Stewart et al., 2014), although guidance efficiencies are generally higher at night for species such as walleye Sander vitreus (Flammang et al., 2014), muskellunge Esox masquinongy (Stewart et al., 2014), largemouth bass Micropterus salmoides (Lewis et al., 1968), and sockeye salmon Oncorhynchus nerka (Brett and MacKinnon, 1953). This might be because fish can detect gaps during daylight hours through which they can pass, as suggested for Atlantic salmon smolts (Welton et al., 2002). ...
Acoustic bubble curtains have been marketed as relatively low cost and easily maintained behavioural deterrents for fisheries management. Their energy efficiency can be improved by reducing air flow and exploiting bubble resonance. In a series of three flume experiments, we: (1) investigated the reactions of carp to a low air flow bubble curtain, (2) compared the effectiveness of resonant versus non-resonant insonified bubble curtains (for the same volume flux of gas injected through the nozzles) to deter passage, and determined the stimuli responsible for eliciting deterrence, and (3) included the effect of visual cues generated by the bubble curtain. This study showed that bubble curtains with a higher proportion of resonant bubbles deterred carp relatively better. Passage rejection was likely influenced by multiple cues at distances within a body length of the fish - specifically the rate of change in both particle motion, and flow velocity caused by rising bubbles. All acoustic bubble curtains were less effective in the presence of daylight, suggesting that vision plays an important role at mediating carp reactions. We discuss the importance of ascertaining the bubble size distribution, in addition to the gas flow rate and aperture size, when characterising acoustically active bubble curtains.
... Non-physical barriers can use behavioral and/or physiological stimuli to control fish movements, since fish may exhibit attraction or repulsion behavior, caused by various environmental stimuli including sound [15,22,23], light [20,21,24,25], electric [26,27], chemical [28,29], and mixed [30,31]). The efficiency of these non-physical barriers depends on the fish species, the environmental conditions, and the potential habituation to a particular stimulus [32,33]. ...
... Sager et al. [32] reports that the repulsive efficacy of stroboscopic light in fish depends greatly on the frequency used (flashes/minute), and Coutant [51] adds that most strobe lights tested are set at frequencies of 300 flashes/minute or higher. The literature refers to the use of light stimuli in fish with strobe light at various frequencies: 60 flashes/minute [31,54], 86 flashes/minute [36]; 300 flashes/minute [35,37], and considering the evaluation of both the day-time period and the nocturnal period [29,35,55]. ...
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A repulsive effect, that some induced primary stimuli, like sound and light, is known to be provoked in fish behavior. In the present study, two strobe light frequencies, 350 flashes/minute and 600 flashes/minute, were tested in laboratorial conditions, using three native freshwater fish species of northern Portugal: Brown trout (Salmo trutta), Northern straight-mouth nase (Pseudochondrostoma duriense) and Iberian barbel (Luciobarbus bocagei). The results showed a differential repulsive behavior of the fish species to light stimulus, and particularly to a frequency of 600 flashes/minute. S. trutta presented the most repulsive behavior, whereas the L. bocagei showed less repulsion to the light stimulus. No relevant differences were found between pre-test and post-assessments, confirming a rapid recovery of natural fish behavior after the deterrent effect. The results highlighted the potential of behavioral barriers, particularly in salmonid streams, based on strobe light stimulus.
... The majority of nonphysical barrier evaluations were laboratory studies (four studies), whereas one was a combined laboratory and field study and one was strictly a field study (Supplemental Materials). A bubble barrier and an electric barrier reduced Walleye escapement (Flammang et al. 2014;Weber et al. 2016), and strobe lights repelled Rainbow Smelt (Hamel et al. 2008); however, neither sound nor strobe lights were effective at reducing the escapement of Walleye (Smith and Andersen 1984) or Muskellunge (Stewart et al. 2014). A number of nonphysical barrier reviews concluded that no one technology is a panacea and individually tailoring the method to each case and to the specifics of the species' physiology would best benefit managers and researchers to manage escapement (Noatch and Suski 2012;Putland and Mensinger 2019;Jesus et al. 2021). ...
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Downstream escapement of fishes from reservoirs via release structures can represent a loss to populations comparable to natural and harvest mortality. Consequently, quantifying and managing fish escapement is a critical component of sustainable reservoir fish management. We reviewed existing literature to assess the state of knowledge of reservoir fish escapement and found 57 unique papers published from 1942 through 2021. Early studies of escapement sought to evaluate escapement by directly capturing fish below release structures. More recently, advances in technology have enabled more detailed studies on factors influencing escapement and the influence it has on regulating reservoir fisheries. Evaluations have occurred throughout North America, assessing escapement of 49 species through a number of different outlet structures. Annual escapement estimates ranged from 0‐100% and escapement tended to be higher from spillways and surface release outlets compared to other outlets. Further, smaller bodied individuals tended to escape at higher rates than larger fish and escapement was generally positively related to reservoir discharge metrics. Sixteen papers assessed benefits of physical and non‐physical barriers for reducing reservoir fish escapement and determined barriers were effective for retaining fish in reservoirs. We conclude by describing management options to address escapement as well as three pressing research needs that will broaden the existing knowledge base regarding fish escapement. In light of predicted changes in precipitation events and subsequent adaptations to reservoir management, quantifying and mitigating fish escapement will be a critical component of sustainable reservoir fish management in the future.
... The same system blocked up to 60% of downstream swimming juvenile carp in a stream connecting a wetland and a lake (Zielinski and Sorensen, 2015;Figure 9). Avoidance responses to bubble curtains appear to be species specific as both walleye and muskellunge were shown to be minimally deterred by bubble curtain systems (Flammang et al., 2014;Stewart et al., 2014). Ultimately, bubble curtains are an inexpensive tool for sites where reductions in common carp movement, not total elimination, is the goal. ...
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Aquatic invasive species (AIS) are of concern in North America due to their devastating impacts on ecosystems and economies. The Great Lakes region is particularly vulnerable to AIS introduction and establishment with at least 184 nonindigenous species reported in this region from a large number of taxa including viruses, bacteria, diatoms, protozoa, arthropods, mollusks, fish, and plants. Representative species from these groups were explored, describing the features of their natural history and current efforts in prevention and control. Specifically, five AIS that are expected to spread to novel areas in the region are discussed: viral hemorrhagic septicemia virus and heterosporis (pathogens affecting fish), starry stonewort (an alga), zebra mussels (a bivalve), and carps (fishes). Novel strategies for AIS control include next-generation sequencing technologies, gene editing, mathematical modeling, risk assessment, microbiome studies for biological control, and human-dimension studies to address tensions related to AIS management. Currently, AIS research is evolving to adapt to known technologies and develop novel technologies to understand and prevent AIS spread. It was found that AIS control in this region requires a multidisciplinary approach focusing on the life history of the species (e.g., pheromones), adaptive management of anthropogenic structures (e.g., bubble curtains), and the integration of human dimensions to develop efficient management plans that integrate local citizens and management agencies.
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The use of non-physical barriers, particularly based on acoustic and luminous stimuli has been historically used to influence the behavior of fish, mainly for fishing purposes. Nowadays, behavioral barriers and guidance systems have been developed, not only to deter movements of fish, but also to promote behavioral responses with the objective of native fish protection, in particular the potamodromous species, reducing their mortality in the hydraulic structures of dams and guiding them towards transposition systems or to replacement habitats in regularized water bodies. This review details the use of acoustic and luminous systems and their evolution in recent years (Scopus 2012–2019) for the development of selective behavioral barriers for fish. We found that recent technologies try to identify new acoustic and luminous sensory ranges. Ambient sound, sound of predators or luminous spectral bands with different wavelengths have been used to selectively stimulate target and non-target species, in order to improve the effectiveness of repulsive/attractive systems for fish. Guidelines for future research in the area are also present.
Technical Report
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Les quatre espèces de carpe asiatique sont des espèces aquatiques envahissantes (EAE) qui représentent une menace sérieuse pour l’intégrité écologique du fleuve Saint-Laurent et de ses tributaires. Bien que nous considérons que la carpe de roseau (Ctenopharyngodon idella) fréquente les eaux du fleuve et de deux de ses tributaires, au moment de rédiger ce rapport, son niveau d’abondance est inconnu. Quant aux trois autres espèces, elles n’y ont pas été détectées à ce jour. Il est donc encore possible d’agir pour prévenir l’arrivée ou la dispersion de ces espèces dans les eaux intérieures. La protection de ces eaux est d’ailleurs un des objectifs du Programme québécois de lutte contre les carpes asiatiques. L’objectif du rapport est de procéder à une première évaluation des risques de dispersion des carpes asiatiques dans le fleuve Saint-Laurent et ses tributaires en considérant leur capacité pour franchir des obstacles artificiels et naturels entre le fleuve Saint-Laurent et l’amont des tributaires et, le cas échéant, d’évaluer les options pour freiner leur progression vers l’amont. L’évaluation des risques de dispersion implique aussi l’acquisition de connaissances sur les caractéristiques des habitats propices aux carpes asiatiques et de connaître leur capacité de nage. Ces aspects sont également traités dans le rapport. Finalement, certaines options de gestion liées notamment à la configuration des obstacles sont proposées.
Disruption of movement patterns due to alterations in habitat connectivity is a pervasive effect of humans on animal populations. In many terrestrial and aquatic systems there is increasing tension between the need to simultaneously allow passage of some species while blocking the passage of other species. We explore the ecological basis for selective fragmentation of riverine systems where the need to restrict movements of invasive species conflicts with the need to allow passage of species of commercial, recreational, or conservation concern. We develop a trait‐based framework for selective fish passage based on understanding the types of movements displayed by fishes and the role of ecological filters in determining the spatial distributions of fishes. We then synthesize information on trait‐based mechanisms involved with these filters to create a multi‐dimensional niche space based on attributes such as physical capabilities, body morphology, sensory capabilities, behavior, and movement phenology. Following this, we review how these mechanisms have been applied to achieve selective fish passage across anthropogenic barriers. To date, trap‐and‐sort or capture‐translocation efforts provide the best options for movement filters that are completely species selective, but these methods are hampered by the continual, high cost of manual sorting. Other less effective methods of selective passage risk collateral damage in the form of lower or higher than desired levels of passage. Fruitful areas for future work include using combinations of ecological and behavioral traits to passively segregate species; using taxon‐specific chemical or auditory cues to direct unwanted species away from passageways and into physical or ecological traps while attracting desirable species to passageways; and developing automated sorting mechanisms based on fish recognition systems. The trait‐based approach proposed for fish could serve as a template for selective fragmentation in other ecological systems. This article is protected by copyright. All rights reserved.
Laboratory feeding trials were conducted to determine how light intensity affects foraging success by the visual piscivore, the largemouth bass (Micropterus salmoides). Foraging success was greater than 95% at light levels ranging from low intensity daylight (2·43×10 2 lx) to moonlight (3×10 -3 lx), but declined significantly to 62% at starlight (2×10 -4 lx) and near 0% in total darkness. Over a range of low to high water clarities (0·5, 2·0, and 4·0 m Secchi depth), estimated depth limits for feeding during the day ranged between 5·5 to 44 m and from 1·6 to 13 m at night during a full moon. At starlight, light intensity rapidly attenuated to a level below the feeding threshold within 0·5 m of the surface at all water clarities. The depth of the water column available for feeding in low clarity water (0·5 m Secchi) was 67 and 75% less than at moderate (2·0 m Secchi) and high (4·0 m Secchi) water clarities. The findings illustrate how differences in the light environment can have important ramifications for predator-prey interactions.
Muskellunge Esox masquinongy occur in many Midwestern reservoirs where dam escapement is often reported. Because densities of Muskellunge in many reservoirs are low, escapement is a concern. Little is known regarding the factors that influence rates of Muskellunge dam escapement or the proportion of reservoir populations that escape annually. We used controlled laboratory experiments to examine how juvenile Muskellunge interact with flow over a barrier at varying levels of turbidity, flow rate, habitat availability, and periods in the diel cycle. In the field we inserted PIT tags into juvenile and adult Muskellunge, monitored their escapement over a dam with an antenna array, and then compared escapement among demographic groups and described escapement in relation to precipitation events, water temperature, and water clarity. Both laboratory and field studies found Muskellunge were more likely to escape during the day than at night. We estimated that 25% of a reservoir Muskellunge population escaped within the 1-year period of this study, with escapement occurring during late spring but not during fall. Adults were more likely to escape than juveniles, and both sexes escaped at equal rates. Methods developed here can be used to provide useful information to managers and develop mitigation practices to limit escapement in situations where it is not desirable.Received March 19, 2013; accepted June 3, 2013
Since 1995, the Colville Confederated Tribes have managed the Chief Joseph Kokanee Enhancement Project as part of the Northwest Power Planning Council's (NWPPC) Fish and Wildlife Program. Project objectives have focused on understanding natural production of kokanee (a land-locked sockeye salmon) and other fish stocks in the area above Grand Coulee and Chief Joseph Dams on the Columbia River. A 42-month investigation concluded that entrainment at Grand Coulee Dam ranged from 211,685 to 576,676 fish annually. Further analysis revealed that 85% of the total entrainment occurred at the dam's third powerplant. These numbers represent a significant loss to the tribal fisheries upstream of the dam. In response to a suggestion by the NWPPC's Independent Scientific Review Panel, the scope of work for the Chief Joseph Kokanee Enhancement Project was expanded to include a multiyear pilot test of a strobe light system to help mitigate fish entrainment. This report details the work conducted during the first year of the study by researchers of the Colville Confederated Tribes in collaboration with the Pacific Northwest National Laboratory (PNNL). The objective of the study was to determine the efficacy of a prototype strobe light system to elicit a negative phototactic response in kokanee and rainbow trout. Analysis of the effect of strobe lights on the distribution (numbers) and behavior of kokanee and rainbow trout was based on 51, 683 fish targets detected during the study period (June 30 through August 1, 2001). Study findings include the following: (1) Analysis of the count data indicated that significantly more fish were present when the lights were on compared to off. This was true for both the 24-hr tests as well as the 1-hr tests. Powerplant discharge, distance from lights, and date were significant factors in the analysis. (2) Behavioral results indicated that fish within 14 m of the lights were trying to avoid the lights by swimming across the lighted region or upstream. Fish were also swimming faster and straighter when the lights were on compared to off. (3) The behavioral results were most pronounced for medium- and large-sized fish at night. Medium-sized fish, based on acoustic target strength, were similar to the size of kokanee and rainbow trout released upstream of Grand Coulee Dam. Based on this study and general review of strobe lights, the researchers recommend several modifications and enhancements to the follow-on study in 2002. The recommendations include: (1) modifying the study design to include only the 24-hr on/off treatments, and controlling the discharge at the third powerplant, so it can be included as a design variable; and (2) providing additional data by beginning the study earlier (mid-May) to better capture the kokanee population, deploying an additional splitbeam transducer to sample the region close to the lights, and increasing the number of lights to provide better definition of the lit and unlit region.
We evaluated the effects of fin-clipping on the foraging behavior and growth of age-0 muskellunge Esox masquinongy. Fish were subjected to one of six fin-clipping treatments (one or both pectoral and pelvic fins, all paired fins, and a nonclipped control) and allowed to forage on golden shiners Notemigonus crysoleucas in laboratory pools (1.7 m in diameter). Observations of foraging behavior showed that muskellunge required a similar number of stalks, follows, and strikes to capture prey regardless of fin clip. Capture efficiencies (56%) were also similar among treatments. In outdoor pools (1.5 m in diameter), the growth and food conversion efficiency of fin-clipped muskellunge feeding on golden shiners over a 1-month period did not differ from those of unclipped controls. Fin removal did not compromise foraging behaviors and growth for juvenile muskellunge foraging on moderately evasive prey, and fish showed immediate behavioral compensation.
From an ecological perspective, predation, competition or resource partitioning, and abiotic factors interact to affect species distribution and abundance. To make management recommendations, I review research dealing with the relative influence of these factors in determining stocking success of muskellunge Esox masquinongy. Survival of stocked muskellunge is affected by losses to resident predators. Prey preference and composition are also important, and better muskellunge survival and growth occurs in systems with soft-rayed or fusiform prey rather than in centrarchid-dominated systems. However, potential for competition with resident fishes has not been carefully considered. Abiotic factors, particularly temperature, can influence stocking mortality and subsequent growth. Survival increases with size and is maximized with large muskellunge fingerlings (>240 mm), but cost-effectiveness can vary substantially with predator and prey populations. Hatchery rearing techniques can also affect muskellunge stocking success. Pellet-reared fish have lower survival than minnow-reared fish because predation mortality is higher, but both groups exhibit similar food consumption and growth. The parental population can affect survival and growth because temperature-related differences in bioenergetic variables occur among muskellunge populations. In addition to compromising genetic integrity, the mixing of populations with different physiological characteristics may have negative consequences for native populations. Thermal regimes of recipient waters should be considered in choosing the most appropriate population for stocking outside the native range. Muskellunge stocking should be pursued within an ecological context that integrates the relative importance of predation, competition, and abiotic factors. This framework provides a guide for making management decisions concerning populations, hatchery rearing techniques, sizes, and timing of muskellunge introductions into systems with specific characteristics.
The hearing thresholds of eight fish species from northern Canada were measured using auditory evoked potential techniques. The species with the best hearing was the lake chub Couesius plumbeus, followed by the longnose sucker Catastomus catastomus, both which had relatively sensitive hearing over the frequency range tested from 100 to 1600 Hz. The remaining species (troutperch Percopsis omiscomaycus, nine-spined stickleback Pungitius pungitius, pike Esox lucius, spoonhead sculpin Cottus ricei, burbot Lota lota and broad whitefish Coregonus nasus) all showed most sensitivity to low frequencies ( Keywords: audiogram; evoked potential; freshwater fishes; hearing Document Type: Regular Paper DOI: Affiliations: 1: Department of Fisheries and Oceans Canada, 101, 5204–50th Avenue, Yellowknife, NT, X1A 1E2 Canada and 2: Department of Biology, Neuroscience and Cognitive Science Program, and Center for Comparative and Evolutionary Biology of Hearing, University of Maryland, College Park, MD 20742, U.S.A. Publication date: January 1, 2007 $(document).ready(function() { var shortdescription = $(".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\\n/g, ''); if (shortdescription.length > 350){ shortdescription = "" + shortdescription.substring(0,250) + "... more"; } $(".descriptionitem").prepend(shortdescription); $(".shortdescription a").click(function() { $(".shortdescription").hide(); $(".originaldescription").slideDown(); return false; }); }); Related content In this: publication By this: publisher In this Subject: Zoology By this author: Mann ; Cott ; Hanna ; Popper GA_googleFillSlot("Horizontal_banner_bottom");
Aquarium and field experiments were conducted to investigate the ability of electrified barriers and bubble curtains to confine flatfish and roundfish. The experiments demonstrated that a relatively weak electrical stimulus applied to a clearly marked barrier could successfully confine flatfish and that a bubble curtain could successfully confine roundfish. Electrified barriers failed to confine roundfish in the sea. It was found that flatfish were hesitant about passing through unenergised barriers, implying that the visual effect of the barriers was significant.