343 
National Marine 
Fisheries Service 
NOAA 
Fishery Bulletin 
fb> established in 1881 •<?. 
Spencer F. Baird 
First U.S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Quantifying the behavior of fish in response to a 
moving camera vehicle by using benthic stereo 
cameras and target tracking 
Email address for contact author: dsomerton4@gmail.com 
1 Resource Assessment and Conservation Engineering Division 
Alaska Fisheries Science Center 
National Marine Fisheries Service, NOAA 
7600 Sand Point Way NE 
Seattle, Washington 98115 
2 Mississippi Laboratories 
Southeast Fisheries Science Center 
National Marine Fisheries Service, NOAA 
3209 Frederic Street 
Pascagoula, Mississippi 39567 
Abstract— ’Underwater cameras in- 
creasingly are being used on remote- 
ly operated, autonomous, or towed 
vehicles to provide fishery-indepen- 
dent survey data in areas unsuitable 
for bottom trawls. To observe and 
quantify avoidance and attraction 
behaviors of fish to these vehicles, 
we developed an observational test 
bed consisting of 3 benthic stereo 
cameras, set in a straight line, on 
a coral reef in the Gulf of Mexico. 
During one pass of a towed camera 
vehicle, one of the benthic cameras 
viewed a school of vermilion snap- 
per ( Rhomboplites aurorubens ) that 
exhibited a variety of avoidance be- 
haviors. Stereo analysis was used to 
position some these fish, and target 
tracking was used to estimate their 
swimming performance and school- 
ing characteristics for each second 
from the time the research vessel 
had passed the benthic cameras to 
the time of arrival of the towed un- 
derwater vehicle. The fish showed 
little reaction to the tow vessel 
but responded to the tow cable by 
swimming laterally and downward, 
then rapidly increased their swim- 
ming speed and avoidance behavior 
when the towed vehicle came into 
view. The use of observational test 
beds, stereo photography, and target 
tracking allows quantification of the 
avoidance response and provides a 
means to determine which stimuli 
produced by the sampling process 
elicit fish avoidance behaviors. 
Manuscript submitted 20 July 2016. 
Manuscript accepted 24 April 2017. 
Fish. Bull. 115:343-354 (2017) 
Online publication date: 16 May (2017). 
doi: 10.7755/FB.115.3.5 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
David A, Somerton (contact author ) 1 
Kresimir Williams 1 
Matthew D. Campbell 2 
For most commercial and recreation- 
al marine fish species in the United 
States, bottom trawl surveys provide 
fishery-independent indices of abun- 
dance needed for stock assessment 
modeling. However, bottom trawl sur- 
veys cannot be used in areas that are 
too steep or rocky, have fragile epib- 
enthos, such as coral, or are legally 
closed to trawling. As an alternative 
to bottom trawling in such areas, op- 
tical assessment increasingly is being 
used, especially with the use of cam- 
era systems on stationary platforms 
(Campbell et al., 2015) or mobile 
platforms, such as remotely operated 
vehicles (Adams et al., 1995), autono- 
mous underwater vehicles (Clarke et 
al., 2009), towed vehicles (Lembke et 
al., 2013), and manned submersibles 
(Yoklavich et al., 2007). 
One concern that has been raised 
about fish density or abundance esti- 
mates produced by such camera sys- 
tems is that they could be biased as 
a result of attraction, avoidance, and 
incomplete detection of fish (Trenkel 
et al., 2004; Stoner et al., 2008; Ryer 
et ah, 2009; McIntyre et al., 2015). 
Studies have addressed such sam- 
pling bias by quantifying fish behav- 
ior as seen from the camera vehicles 
themselves. (Lorance and Trenkel, 
2006; Yoklavich et al., 2007) or by 
estimating the relative sampling ef- 
ficiency of different camera vehicles 
(Laidig et al., 2013). However, there 
have been few attempts to obtain in- 
dependent estimates of sampling ef- 
ficiency of camera vehicles or to con- 
duct in situ observational studies of 
fish behavior in response to camera 
vehicles by using an independent ob- 
servational method that is unlikely 
to elicit behavioral responses. 
Similar concerns about sampling 
efficiency have been raised concern- 
ing survey bottom trawls. However, 
bottom trawls have been in use much 
longer than camera vehicles, and a 
variety of techniques have been de- 
veloped to estimate components of 
trawl sampling bias, such as herding 
(Engas and Godp, 1989a) and escape- 
ment under the footrope (Engas and 
God0, 1989b). In some cases, these 
