1. Ilaria Spiga1, Joe Fox1, Robert Benson1, Addison Lawrence2, and David McKee1
1 Texas A&M‐Corpus Christi, Corpus Christi, USA.
2 AgriLife Research Mariculture Laboratory, Port Aransas, USA

2. Introduc)on
 Increases in human activity in the aquatic environment have
substantially increased background noise in the past 50 years
(Ross, 1973)
 likely to increase further (NRC, 2003)
 All motor‐driven boats, regardless of design, contribute to
ambient underwater noise
 frequencies and levels directly related to their size
(Richardson et al., 1995)
 In coastal waters, small vessels such as fishing and
recreational boats (high speed engines) are more common
 They add high frequency, broadband sounds to the
background noise (Richardson et al., 1995)

3. Importance of Sound
 Sound propagates much farther and faster underwater
than in air
 Underwater sound allows marine animals to gather
information and communicate at great distances and
from all directions (Richardson et al., 1995)
 Marine animals rely on sound
 to acoustically sense their surroundings
 communicate
 locate food
 and protect themselves underwater (Popper et al.,
2004)

4. Research to date
 Depending upon the magnitude of the signal:
 No impact on animals (Popper et al., 2007)
 Disruption of behavior (Vabo et al., 2002)
 Physiological damage (Popper et al., 2004; Smith et al.,
2004)
 Feeding behavior and survival (Wysocki et al., 2007;
Davidson et al., 2009)

5. Ra)onale for research
 Responses are diverse and species‐related
 More information is necessary
 Increase in number of recreational boats in Texas
since 2006 (NMMA, 2008)
 Increase in recreational fishing activity in Texas bays
and estuaries (Tseng et al., 2006)
 Can noise affect growth and survival in red drum and
spotted sea trout during their early life history?

6. Objec)ves
 To determine the effect of boat noise on growth,
survival, and condition factor on juvenile red drum
and spotted seatrout
 To evaluate by observation, potential of fish to
acclimate to anthropogenic noise

7. Fish targeted
Sciaenids: drums and croakers
 Red drum and spotted
seatrout
 Juvenile red drum (0.35 g ± 0.01)
and spotted seatrout 0.32 ± 0.01)
provided by Texas Parks and
Wildlife CCA/CPL Marine
Development Center (Corpus
Christi, TX, USA)

8. Research site and system
 Research conducted at
Texas AgriLife Research
Mariculture Laboratory,
Port Aransas, Texas, USA
 Semi‐closed recirculating
aquaculture system (RAS)
containing biofiltration
and artificial aeration

9. Experimental System and Design
System
 3 cylindrical tanks (5‐m
diameter) per species
 3 treatments:
1. Background noise
(control)
2. Continuous noise
3. Intermittent noise
 Stocking density 600 fish/
tank
 Completely randomized
design
 Fish exposed to noise for
8 wks

10. Acous)cs
Sound treatments
 Noise recorded from TCOON
station in Corpus Christi Bay
 Acquisition via hydrophone
located near the bottom (1.5 m
depth)
 Recording made of
approaching vessel passing
about 20 m from the recording
point (hydrophone)
 Dual channel digital sound file
structure:
1. Right channel carried
continuous sound
2. Left intermittent (30 min on,
30 min off)
50 sec long, highest amplitude 140 dB, 3 kHz.

11. Experimental protocol
 Dead fish removed daily
 Fish harvested after 8 wk
of noise exposure
 50 fish per subsample
 Growth determined as
mean final wet weight (g)
and mean final total
length (cm)
 Mean final condition
factor/tank/treatment

12. Sta)s)cal analysis
 One‐way ANOVA by species of mean final wet weight
(g), mean final Total length (cm), condition factor,
and survival.
 Level of replication: one tank per species/treatment
combination
 Tukey's HSD test
 One‐way block ANOVA with ranks of frequency
distributions for each dependent variable by
treatment, within species.
 Tukey’s HSD test

13. Results: growth variables following 8 wk
Red drum Spotted seatrout
Dependent
Variables
Background
noise
Continuous
noise
Intermittent
noise
Weight (g) 10.1±1.8 9.5±3.9 11.5±6.4
Total
length (cm) 8.4±1.6 1.0±1.6 10.4±1.4
Mean
Specific
growth rate
(%/day)
6.1 6.1 5.9
Condition
factor 1.3±1.1 0.9±0.1 0.9±0.1
Survival (%) 33.2 27 26.8
Dependent
Variables
Background
noise
Continuous
noise
Intermittent
noise
Weight (g) 10.5±3.2 11.5±5.5 10.9±3.6
Total
length (cm)
11.0±1.0 11.4±2.2 11.1±1.1
Mean
Specific
growth rate
(%/day)
6.50 6.47 6.49
Condition
factor 0.77±0.08 0.8±0.07 0.78±0.07
Survival (%) 22 24.8 26

14. Results: final total length and final wet weight
No significant difference No significant difference
Mean final wet weight (g) Mean final wet weight (g)
Mean final total length (cm) Mean final total length (cm)

15. Results: final wet weight distribu)ons
Red drum: no significant differences Spotted seatrout: no significant differences
WetweightfrequencyWetweightfrequencyWetweightfrequency
Wet weight frequency Wet weight frequency Wet weight frequency

16. Results: condi)on factor
 c.f.= weight *100/L3
 No significant differences
(α= 0.05)
Mean final condition factor Mean final condition factor

17. Results: condi)on factor frequency distribu)ons
Red drum: no significant differences Spotted seatrout: no significant differences
frequency frequency frequency
frequency frequency frequency
range range

18.  Red drum and spotted seatrout in the current study
acclimated to the increased sound
 Potentially, decrease immune efficiency and disease in the
presence of additional environmental stressors, such as poor
water quality, habitat losses, and predators.
 Therefore, noise should be considered as anthropogenic
variable co‐affecting the eco‐physiology of these 2 species.
 Effects of noise on fish are related to hearing sensitivity
 Red drum and spotted seatrout are considered “hearing
generalist” (100 ‐ 2000 Hz)
 Broadband, high frequency noise from recreational fishing
boats in estuaries may mask vocalizations and impair
communication
Discussion: from the tank into the wild

19. Discussion: from the tank into the wild
 Subtle responses found in Wysocki et. al (2007) and Davidson
et. al (2009):
 Rainbow trout (hearing generalist) reacted to long‐term
exposure to noise by slowing growth rate during the first month
 In estuary noise from recreational fishing boats does not have
a regular pattern as in the experimental study
 Chronic noise exposure from recreational fishing boats might
slow growth and, therefore, delay sexual maturation impairing
reproduction of red drum and spotted seatrout while in the
estuaries

20. Future Research Topics
 Use of trials to determine subtle responses during the
early exposure to noise
 Identification of the time in which adaptation to
increased noise occurs
 Multiple stressors (noise, T, pH, Ox) to determine
responses that might happen into the wild
 Otoliths to determine variation of growth

21. Conclusions
 There was no long term effect of noise exposure on red drum
and spotted seatrout growth
 Juvenile red drum and spotted seatrout were successful in
physiological adaptation to noise‐induced stress as evidenced
by levels of dependent variable shown following the 8‐wk study
 Behavioral observations: initial response to noise (either
continuous or intermittent) shown by both species as
swimming in tight circles around the center of the holding
tanks
 Adaptation was quite rapid
 Can adapt to pattern of noise as well (intermittent noise)

22. Acknowledgements
 AgriLife Research Mariculture Laboratory
 Texas Parks and Wildlife
 Harte Research Institute for Gulf of Mexico Studies
 Drs. Joe Fox, Robert Benson, Addison Lawrence, and
David McKee
 Nico Amalfitano, Shane Merryman, Adrian Bandolon,
and Leslie Adams