71).;79

rev. 79- 

### 'el"'"""

TCJ 

# ~P~gB-SL

Mr. F. J. 

### Kee Director of Research .. ' 

# ontario hydro research division

RESPONSES OF GIZZARD SHAD (DOROSOMA CEPEDIANUM) TO DIFFERENT FLASH CHARACTERISTICS OF STROBE LIGHT



## H. Patrick

The responses of gizzard shad (Dorosoma cepedianum) to various discharge curves of strobe light were 

### investigated under laboratory conditions. 

## Flashcharacteristics such as rise time and peak duration appear critical in eliciting a fish avoidance 

## response. With increased duration of light flash there is less of a fish avoidance 

### response. Ablue filtered strobe, transmitting primarily bluegreen light, appears less effectve as a fish repellant compared to that of a yellow filtered 

## (yellow , orange, red light) strobe and white 

# strobe (all visible light). INTRODUCTION 30th laboratory and field research has indicated the potential of using strobe light alone or as part of a fish exclusion scheme (OHRDR 81- 61-K, 81- 190-K, 82- 

# 165-K). Although fish show an avoidance of this light source, the actual reasons or mechanisms involved in eliciting this response are only partly 

### known. Avoidance appears only partly related to light intensities (OHRDR 79- 104-K, 81- 190-K), and probably unrelated to the 

### spectral composition of the strobe light source (OHRDR 82- 

### 476-K). Flash rate appears to be important, however , with noticeable 

## avoidance occurring when frequency exceeds 200 flashes/minute (OHRDR 79- 

## 104-K, ~, 476-K. Still, other light sources such as incandescent and metal halide, when flashed at 200/minute and 

### higher, are generally ineffective as fish repellants (OHRDR 

### 82- 

# 476-K). These light sources differ mainly from strobe in that the duration of each flash is considerably 

### longer. It possible that fish avoidance of strobe light may be related to 

# its short flash duration. To test this hypothesis, a study was 

# ini tiated to determine the responses of fish to different strobe 

## discharge curves of varying durations.

iiOb 

### 740634- 526- 092 837 315 July 21, 1982 

### 82- 310-K file date report no.MJI_ 

### TERI;'.r.S A..'m Y~'I'HODS



## Species Investigated Adult shad , ranging in size from 25 to 40 cm, were used as test 

# species. Fish were collected by electro- fishing techniques in the winter of 1981 at both Pickering GS and Bruce 

# GS. Prior experimentation , fish were held in either 2. 4 or 3. 6 m circular pools under a controlled photoperiod of 10-14 h of 

# light. Water 

## temperatures ranged from approximately 7. 0 to 9. 5 O c throughout the testing period. Types of Discharge Curves Four different discharge curves of varying rise times and peak 

## durations were produced by changing the inductance and capaci tance of the strobe (Figure 1, Table 

# 1). These modifications and 

## curve- values are based on preliminary work conducted by Electrical 

## Research (OHRDR E81- 

# 75-H). Flash characteristics were measured using an oscilloscope (Phillips Model PM322) in conjunction with a photocell. Wi th increased capaci tance and inductance, the shape of the strobe discharge changed significantly 

# as both rise times and peak durations were altered. Rise time , de fined as the 

# period (ms) required to achieve peak output (measured between 

### 10- 

## 90% of pe ak output) ranged from 0. 

## 12 ms for curve B to 3. 0 ms for curve E, the latter being approximately 43 times slower than 

# that of a normal strobe discharge. Peak duration , or duration 

# of highest output (measured at 95% of peak output) ranged from 

## 20 ms for curve B to 4. 0 ms for curve 

# E. These peak durations were at least one order of magnitude longer than that of a normal 

### strobe flash 

### (curve A). Differences in total duration between normal ~~d modified discharge curves were less obvious 

## with discharge curve E' 

## only 2. 5 times longer than the normal 

## strobe. Curves B and C were similar in total duration to the normal 

## strobe (Curve A). 

## time

TABLE 1 CAPACITANCE k~D INDUCTANCE MODIFICATIONS

TO STROBE LIGHT 

## Modification Inductan ce (mH) Capaci tance 

### (llF) Area Under Curve (V.ms) 

### Curve 

### A Normal 0 . 0



### 1000 355 

### 351* 364 

### 361* 360* '., ' .

Intensi ty or 

### area under the curve has been 

## adj usted for curves 

# B. D. and E. by using clear filters, and by slight 

### adj ustmen t of strobe 

## ' s position in the experimental chambers. An incre ase in 

## inductance and capaci tance to the strobe unit resul ted in a reduced flash rate with a maximum rate of only 150 flashes/minute achieved for curves D and 

# E. All other 

## curves (including normal discharge) were adjusted to this flash 

# rate. Based on preliminary observations and earlier work (OHRDR 79- 104-K) this flash rate was probably at or near the 

### minimum level at which fish elicited marked 

## avoidance.

- 2 - 

### 82- 310Curve A Normal Curve Rise Time 

### Peak Total (ms) : Duration (ms) 

### Duration (ms) Normal 078

O. 72

74. 0 '0. :::=- I :::=-

Curve Curve

~ 3 '0' :::=-

Curve

Curve E :::=-

Durati on (ms) 

### FIGURE VARIOUS DISCHARGE CURVES OF STROBE LIGHT USED IN



### EXPERIMENTAL DESIGN 

# -3-
158042 RDSpectral compositions for each modified discharge curve varied

sligh tly 

### from that of the normal strobe 

### (Figure 2). 

## Generally light was transmitted throughout the entire visible range, with slightly higher energy output in the orange and red regions of the spectrum (especially curves B and 

# C). Because of an increased orange-red content of the discharge, increased fish avoidance could be expected for these discharge curves (OHRDR 78- 

### 516-K) . Chambered Experimen ts Both short 

## (5, 15 minutes) and long (12 h) term experiments wereused to determine the responses of gizzard shad to various discharge curves produced by strobe 

# light. All experimen ts were conducted in a 2. 4 m diameter circular tank which was divided equally into three 

## areas, each approximately 1. 5 m 

## 2 (Figure 3). In the design 

## , one chamber was ill umina ted with strobe source which was the sole source of illumination during the testing 

# period. For each experiment, the strobe light source 

## (modified or normal) was projected downwards in the tank producing concentric 

### zones of varying light intensities. Light output in curves B 

### D and E were higher than that of the normal strobe 

## (Figure I, area under curve), and had to be adjusted using clear plexiglass 

# filters , and by slight adjustment of the strobe 

## s position in the experimental chamber. These fil ters had no noticeable effect on the spectral output of the 

# strobe. Intensity, measured as area under each discharge curve, varied less than 10% among all 

## discharge curves (Table 1). Strobe light intensities, for all



## (zlO%) ranged from approximately 333 lux (7. llEom :) n~ar the light source to approximately l~ lux 

### (0. 3 llE'm 2 .S 1 ) at the edge of the light 

# zone. Light recorded near the outer wall was approximately 2. 0 lux (~O. l llEo The illuminated chamber had no influence on the other two chambers
which were in darkness during the testing period. In the long term tests, closed circuit 

### T. V. was used to monitor fish numbers in the lighted chamber (for each discharge 

## curve) at 10 minute intervals (freeze frame) over the 12 hour monitoring 

# period. One replicate (n = 15 fish) was performed for each 

## discharge curve (except curve E) * The number of shad that entered 

### the same experimental chamber (strobe source off) over a similar 

### 12 h period under low level light (~3 lux, ~0. 

### 01 llE'm 

## served as a control. Short term tests consisted of moni toring fish numbers and distribution in the lighted chamber following both 5 and 

### 15 minute 

# illumination periods. Ten replicates 

# (n = 15 fish/replicate) were performed for both modified and normal discharge 

## curves 

# (total 80 replicates). After each selected time period , chutes which divided the chambers were closed and the number of shad in 

### each chamber recorded.
Because of technical difficulties, modified curve E could not 

### produce light for more 

## than. a 30 minute period.

- 4 - 

### 82- 310

# -- ....,

'0 20 :::=-

oW 15 :=! ....,

10 Normal Curve A

Curve

Curve

Curve

Curve E



### 410 430 450 

## 470 490 510 530 550 

## 570 590 610 

## 630 650 670 690 Wave 1 

## ength (nm)



### FIGURE 2 

### SPECTRAL COMPOSITION OF VARIOUS DISCHARGE 

### CURVES OF STROBE LIGHTS (C. W. - 

### QUANTUM METER 3500)

c:- 

### ....0""" 01'"\

### 2.4m CIRCULAR TANK Light Source
0 (0) 0 (0) 0(0::1.3) 0(0::1.3) ...... ........ ........ ........

1(6. 0::0, 1 (2. 

### Chute

Opening 1(5. 0::0. 1(2,

Chamber



### FIGURE 3 

### LIGHT INTENSITIES MEASURED AS ILLUMINANCE 

### (LUX, IN BRACKET) AND QUANTUM FLUX (~E. m ':'1



### FOUND IN EXPERIMENTAL CHAMBER

- 6 - 158176 RD~ 10



## ~ 8-

Q..

~ 18

Q.. 

### lue Filter

Yellow Filter



## 410 430 450 470 490 

## 510 530 550 570 

## 590 610 630 

## 650 670 690 Wave length Cnm) 

### FIGURE 4 SPECTRAL COMPOSITION OF A , BLUE 

### AND B YELLOW 

### FILTERED STROBE LIGHT 

### SOURCES (C. 

### I.W. QUANTUM



# METER 3500) 158044 RDObservations were also made on the distribution of shad wi 

## thin

each chamber rela 

## ti ve to the light source after closing the 

# chutes. Ten control tests (15 fish/replicate) were also per

### formed for each experimental condition (total 80 replicates) in complete darkness to assess fish numbers in each chamber in the absence of strobe 

# light. Control and experimental tests were alternated to reduce any temporal bias. 

### Addi tional tests were also conducted to determine the responses of shad to a normal strobe light source covered with blue or 

### yellow filters. The blue filter transmitted light primarily in the 410 and 630 nm visible range, with maxima occurring in the blue- green region (450- 530 nm , Figure 

# 4). The yellow filter transmi tted all 

### visible light beyond 470 nm , with highest output in the yellow (577- 

## 597 nm), orange (597- 622 nm) and red (622- 690) 

# regions of the visible spectrum. Experimental procedure was 

### similar to that described above for short term (5 and 15 min) 

# tests. RESULTS AND DISCUSSION Response of Shad to Various Strobe Discharge Curves 

### In the long term tests (12 h), an increase in the number of shad in the lit chamber occurred with an increase in peak duration 

# of the flash (Figure 5). Statistically, the lowest number of fish 

### was observed in the chamber lit with a normal strobe (curve A) or with discharge curve B , indicating that shad showed strongest avoidance of these light sources over the monitoring period (F4,36o = 195 , p~0. 

### , Appendix C). The number of shad observed in the chamber lit with discharge curves C and D over the 12 h 

### moni toring period are not significantly different from the control 

# test (Multiple Range Test , Appendix C) . 

## , There was no noticeable evidence of a change in fish numbers in the experimental chamber over a 12 h monitoring period for either normal or modified 

# discharge curves (Figure 6). Generally, there appeared to be fewer fish observed as the monitoring period progressed, suggesting a slight avoidance of the lit area for all discharge 

## curves. Al though discharge curve 

# B (rise time 0. 

## 12 ms, peak duration 0.ms) appeared similar in effectiveness to the normal strobe in ex

# cluding shad (averaged over a 12 h period , Figure 5), this avoidance response was not evident in 

### the initial 5 and 

## 15 minutes of 

## experimentation (Figure 7). During these illumination 

## periods, the lowest mean number of shad was consistently recorded only for 

# the normal strobe discharge curve (Table 2 , Multiple Range 

## Test) . Relative to control tests , fewest shad numbers were observed in 

### the chamber lit with normal strobe (curve A) and discharge curve in the 5 minute tests, and only with the normal strobe following 

### 15 minutes of illumination (Figure 7 , Table 

## 3). These results indicate that strobe flash duration is critical in 

# elici ting an initial fish avoidance response. Distribution of fish in the lighted chamber following 5 and 15 minute illumina

### tion periods supplemented these data. 

## Fish were frequently observed near the light source in all modified curve tests, whereas they were generally located near the edge of the tank where intensi ties 

### were lowest in the normal strobe 

# tests.

- 8 - 

### 82- 3100 25

~ 20 c..
::) 10 J: 5

t'3 15 ::)



### 25 -

)- 15 ::)

u.. NORMAL 80Ws PEAK DURATION 

### X= 1.8 :: 1.1



### CURVE B 200 )JS



### CURVE C 700 lJS.



### CURVE D 2 OOO~



### CONTROL 

### 1.6



### NUMBER OF SHAD OBSERVED. IN LIGHTED CHAMBER



### FIGURE 5 

### FREQUENCY OF SHAD OBSERVED IN EXPERIMENTAL LIT ZONE



### OVER A 12- HOUR PERIOD

- 9 - 158094-~~

Normal Curve A

Curve 

# . 'A.~J.v
~A_ 

# NA H'

Time (hours) 

# 11 0400 1600



### FIGURE 6 NUMBER OF SHAD RECORDED IN 

### EXPERIMENTAL CHAMBER

10- 158045 RDA. 5- 

### MINUTE ILLUMINATION PERIOD NORMAL STROBE 11 r

c::: 5 Iu.J (;J ::2: 4 - 

# -::(

...:..



### CURVE A

t- 80 \-lS 

### Peak 

### - Duration
8 -
7 -6 r

### CURVE B

200 II 5 

### CURVE C

700 II 5 

### - - - -

iJ') 

## u:
c::: B 15- MINUTE ILLU, \~INATION !!J ::2: :::::J 76 t### 5 f### 4 f3: - . ~



# -f-- ill:

!!!!!!!!!!!I!!~!! PERIOD - -



# Ii
I-- 

### CURVE D

2 000 \-lS

- r- 

## -I-- :~:j::: -"-



# I'"

I E 

## I C

FIGURE 7 RESPONSES OF GIZZARD SHAD TO 

### VARIOUS STROBE DISCHARGE CURVES (E = EXPERIMENTAL , C = 

### CONTROL) ,-- I'-



## I E I C



### -11- CURVE E
4000 fl 

### 5 -



# Iii :):E): ....

- r

# I E I C

158095-

### TABLE 2

STATISTICAL COMPARISON OF SHAD NUMBERS RECORDED IN EXPERI~ENTAL

CHAMBER LIT WITH VARIOUS STROBE DISCHARGES 

## III umina tion 

# Period (min) 

# F-statistic



# d. f. Multiple Range (S. lowest ~ highest numbers Discharge Curves 

### :lOrmal \ C (A) Discharge Curves 

### \'norma 

## l D 

# , C B / 

# (A) ' P~0.

TABLE 3 STATISTICAL COMPARISON (t- VALUES) OF SHAD NUMBERS RECORDED IN 

### EXPERIMENTAL LIT CHAMBER RELATIVE TO CONTROL TESTS 

## (Figure Illumination Discharge Curve 

## Period (min) 

### (Normal) 9 * 3. 7 * 

## (avoidance) (avoidance)

6 * 1. 0 2. 8 * 1. 9 3. 4 * 

## (avoidance) 

# (attraction) (attraction)

- 12 - 

### 82- 310Shad Response to Blue and Yellow Filtered Strobes

Shad showed an initial attraction to blue filtered strobe 

# light (after 5 minutes , Table 

# 4). Mean shad numbers observed in the experimental lit chamber were significantly higher than that observed in control 

# tests. In one replicate 

### 13 of 15 fish 

## (or 86% of total) was observed in the lighted 

## chaIT~er (Appendix A) . 

### However , following 15 minutes of illumination , there was a reduction in the number of shad recorded in the experimental Ii t chamber, 

## suggesting a delayed avoidance response 

## (Table 4). TABLE 4 COMPARISON OF MEAN SHAD NUMBERS RECORDED IN EXPERIMENTAL LIT CHAMBER RELATIVE TO CONTROL TESTS



### 1.2 YELLCW F I L TER 

## Control IExperimental; Response 

## u X S. (X~ X S. (X)!Response 

### ! Attract-iI3. 1 1.6 ; 4. 

### 1.9 

# , ion 1.9 : avoid- 

# 3 2. 

# 4 2. 2* 

# 1.7 avoid

# i once 

# :ance Illumination Per iod 

### (min) BUJE FILTER



# Control i ExDerirrental 

# X S. D. (X)! 

# X S. D. (X) .;,

i? ~O.
In the yellow filtered 5 minute strobe tests, there was no significant difference between shad numbers recorded between experimental and control tests , indicating nei ther attraction 

## nor 

## avoidance (Table 4). However, similar to the blue filtered strobe resul ts, an avoidance was observed with prolonged illumination (15 min u te s) . Effect of Strobe Flash Duration on Shad Behaviour Flash duration appears to significantly influence shad behaviour wi th less of an avoidance response occurring with increased 

## flash 

# duration. These results confirm the speculation that 

## fish avoidance of strobe light may be related to the flash characteristics 

### of the strobe (OHRDR 82- 

### 476-K). However , it should be emphasized that rise time and peak duration are probab ly more critical than 

# the total duration of the flash in elici ting this avoidance. Although curves B and C had similar total durations as the normal 

# strobe (curve A), thev were relatively ineffective as a fish 

# repellant (Figures 1 

# 7). Flashing light of short peak duration 

### such as that produced by a normal strobe (~lOO~s) is foreign to most fresh-water pelagic species, and generally results i~ 

## disorientation , confusion and avoidance (as observed under - 13 - 

### 82- 310

### laboratory conditions). In marine environments, several

organisms (algae, vertebrates, fish) have evo Ived the ability 

### (bioluminescence) to repel 

## (or escape from) potential predators 

### by emitting light of short duration (Herring 1978 , Morin 1982, 

### pers comm). It is noteworthy that the shape of the flash produced by these organisms (ie rapid rise time, slow exponential 

### decay) is almost identical to the discharge curve of strobe 

# light (although the total duration is much 

## longer). In addition to flash duration, flash rate has also consistently been found to be important in eliciting a fish avoidance response (OHRDR 79- 104-K, OHRDR 82- 

# 476-K). The flash rate used in these 

# tests (150 flashes/min) is probably the minimum at which avoidance 

# will occur. For field applications a lightly higher rate would be recommended (200- 

## 250 flashes/minute). Experiments with filtered strobe light have shown that if the 

## blue- green content of the emissions is increased there is 

### evidence suggesting an attraction 

# (at least ini 

# tially). Attraction by fish to these wavelengths tends to override their avoidance of a rapid 

# flash. This can have important implications in field situations where blue- green light penetrates far in the water column, since a far field attraction to a strobe light 

## source may potentially exist when unfiltered light sources are used. 

### However, as fish move closer to the light source , and other 

### wavelengths become apparent, an 

### avoidance response should occur. It is expected that spectral composi tion of a strobe probably plays a limited role in 

## repelling fish.
SUMMARY 

# 1. Flash characteristics of strobe light such as rise time and peak duration appear critical in eliciting a fish 

## avoidance 

## response. 

# 2. With an increase in duration of light flash, there is less of a fish avoidance re 

## sponse. 

# 3. A blue-filtered strobe light appears less effective as a 

### fish repellant compared to that of yellow (filtered) and white 

## strobes.

j-A~ 

# ;lh ~C. H. Clark 

### Manager Chemi cal 

## ! ~ I Approved: ,.' ...

Research Dept . Patrick Research Biologist Biological Research Section PEP : kwk

- 14 - 

### 82- 310REFERENCES

Herring, P. 

### S., 1978 (ed), Bioluminescence in Action , Academic Press. 570 pp. 

### Morin, J., 1982 (per comm) University of California at Los 

### Ange les . OHRDR 78- 

### 516-K , Response of fish to light, P. 

## H. Patrick, December 29 , 1978. OHRDR 79- 104-K, Response of gizzard shad to strobe light H. Patrick, March 26 , 1979. OHRDR 81- 190-K, Responses of fish to diversion 

# barriers, H. Patrick, July 29 , 1981. 6 . OHRDR 81- 61-K, American eel response to white strobe light

H. Saunders 1980 , R. 

### S. Sheehan and B. Sim October 14 , 1981. OHRDR 82- 165-K, Use of filtered mercury vapour lights in 

## association wi th a modified fish handling pump at Nanticoke GS. G. T. Haymes, May 14 , 1982. OHRDR 82- 

## 4 76-K, Responses of fish to flashing 

# lights, H. Patrick. 9 . OHRDR E81- 75-H, Extending the flash duration of 

## strobes, M. Staelter.

- 15 - 

### 82- 310APPENDIX A

NUMBER OF GIZZARD SHAD KECORDED IN EXPERIMENTAL &~D CONTROL

CHAMBERS IN 5 AND 15 MINUTE TESTS


### Time 

## Replicate Type 

### (min) 

## Control Chamber 1 Normal Chamber 2 

### Strobe Chamber 3



### Exp


## Control Normal 

### Strobe Exp * 1



## Control Exp * 1

Con tro 1 

### Exp * 1


## Control Exp :~ 1


## Control Exp * 1

Chamber 1 lit in experimental - 16 - 

### 82- 310

### Time



### Type 

### (min) 

## Control Chamber 1 Chamber 2 Chamber 3 

### Exp * 1 3 extra
Con 

# trol Exp * 1


## Control Exp * 1


## Control Exp * 1


## Control (yellow) 

# fil ter 11 9



### Exp * 1

Con tro 1 

## (yellow)

fil 

# ter Exp * 1 11 9 11 5

- 17 - 

### 82- 310

### Time 

## Replicate

rrvpe 

### (min) 

## Control Chamber 1 

### (Blue) Exp



## Control Exp * 1

- 18 - 

### 82- 310APPENDIXNUMllEH OF SIIADHECOHDED IN EXPERIMENTALCIlAMllER FOR EACIIDISCIIAHGE CUlM'OVER A 12 h PERIODN umbe rl1trO 1- --'r-maT StroDTime(lOin)1st 6 hr 2nd6 hr1sDhr 2nd 6 hr1st 6 hr 2nd 6 hr1st 6 hr 2nd 6 hr1st 6 hr 2nd 6 hr0 6100200.--.3001 (j400500tJ 0 uAPPENDIX CANOVA COMPARISON OF MEAN NUMBER OF SHAD RECORDED IN LIGHTED CHAMBEROVER A 12 h MONITORING PERIOD FOR VARIOUS STROBE DISCHARGE CURVESAnalysis of VarianceSourceSum ofSquaresDegreesOf FreedomMeanSquareRatioSignificanceProbabili tyGroupsWithin GroupsTotal6001.101467.677.8146.3603656001.0959366.80141. 8825318719400000000MeanMULTIPLE RANGE (S0 N .K. )NormalCurve BCurve CCurve DControl1. 81. 9I-'. "--- -,"'..,,- ,Table l.Swimming speed (Vs) required of fish passing line of louvers for givenapproach velocities(V~and selected angles(0)of t~e line of louvers,(Vs .. Va Sin 0)0 f1. 221.461.691. 93I~. 020:::5 I1.131. 351.571. 79III;c.0 I1.041. 251.451. 651.853 00"TJ"TJ':1\1 ,11~1.331.521.701.88;I:0 871.041. 211.381. 531. 71:3.Y2.1. 241.391, 51~1. 900, 8~1. 241 ,li9..1...lQ.l.:H(t)1.081. 201.481. 75~ 0"TJ(t)1. 031. 271.501. 721. 93(t)5 I-L..Q2..1. 251.431. 611. 770 I...L.QQ..2..:l5...1. 29r;:-\ 0,1.5..2..:.22...J....QQ.1.042 0,'\..,ANGLE OF LINE OF LOUVERS(degrees) 0jo., " "~':" """""":""."-~"':"--"""""~""i-")"""""""'""".'::""""""'O"""'O"""~"""""-""'~'~""""""""""""""'r"--~,.,.-...........o ."""""="""""'~-, -"..--.. .', ,-' -...,........,.~, '~-"':~"~"""""',~"."-r.c...,,,~.