410 
Fishery Bulletin 115(3) 
Table 1 
Average values of MeanCount, the mean number of fish counted in a sample of frames from a video, for black sea bass 
( Centropristis striata) observed in the 3 classified habitat types (sand, sand+rock, live bottom) in videos collected from 14 
June to 4 August 2011 at 6 sampling sites in waters off the coast of Maryland. Values are given for 2 categories: all black 
sea bass and nuchal black sea bass (or fish that were distinguishable from other individuals by a darker body coloration, 
a nuchal hump, and white fin stripes). Average values of MeanCount, with 95% confidence intervals in parentheses, and 
mean depths (in meters), with standard deviations (SDs) in parentheses, for all daily deployments (4 per day) are provided 
for each site and date. 
Site 
Date 
Depth (SD) 
All black sea bass 
Nuchal black sea bass 
Sand 
Sand+rock 
Live bottom 
Sand 
Sand+rock 
Live bottom 
1 
14 Jun 2011 
22.1 (0.3) 
0.19 (-0.21-0.40) 
0.00 (0.00-0.00) 
0.00 (0.00-0.00) 
0.01 (-0.01-0.03) 
0.00 (0.00-0.00) 
0.00 (0.00-0.00) 
2 
16 Jun 2011 
25.9 (2.1) 
0.11 (-0.01-0.23) 
0.07 (0.00-0.00) 
0.00 (0.00-0.00) 
0.03 (0.00-0.06) 
0.02 (0.00-0.00) 
0.00 (0.00-0.00) 
3 
23 Jun 2011 
30.8 (0.5) 
0.70 (-0.25-1.65) 
0.00 (0.00-0.00) 
9.28 (8.84-9.72) 
0.43 (-0.17-1.03) 
0.00 (0.00-0.00) 
1.38 (0.87-1.89) 
2 
28 Jun 2011 
25.9 (2.6) 
0.15 (0.07-0.23) 
0.00 (0.00-0.00) 
0.00 (0.00-0.00) 
0.05 (0.00-0.10) 
0.00 (0.00-0.00) 
0.00 (0.00-0.00) 
4 
8 Jul 2011 
29.1 (2.6) 
0.00 (0.00-0.00) 
0.20 (0.00-0.00) 
12.17 (1.85-22.49) 
0.00 (0.00-0.00) 
0.08 (0.00-0.00) 
1.83 (0.43-3.23) 
4 
18 Jul 2011 
29.1 (2.5) 
0.11 (-0.10-0.32) 
4.38 (-0.93-9.69) 
0.00 (0.00-0.00) 
0.03 (-0.04-1.0) 
1.05 (0.23-1.87) 
0.00 (0.00-0.00) 
5 
20 Jul 2011 
29.7 (2.4) 
0.00 (0.00-0.00) 
1.02 (-0.07-2.11) 
0.00 (0.00-0.00) 
0.00 (0.00-0.00) 
0.11 (-0.02-0.24) 
0.00 (0.00-0.00) 
6 
26 Jul 2011 
30.4 (1.8) 
2.12 (0.00-0.00) 
3.78 (0.73-6.83) 
2.47 (0.00-0.00) 
0.00 (0.00-0.00) 
0.48 (0.46-0.50) 
0.50 (0.00-0.00) 
6 
1 Aug 2011 
30.3 (1.6) 
1.85 (1.16-2.45) 
0.00 (0.00-0.00) 
2.54 (1.48-3.60) 
0.47 (0.14-0.80) 
0.00 (0.00-0.00) 
0.35 (0.12-0.58) 
6 
4 Aug 2011 
30.1 (1.3) 
0.00 (0.00-0.00) 
8.93 (2.23-15.63) 
3.90 (0.00-0.00) 
0.00 (0.00-0.00) 
0.88 (0.32-1.44) 
0.77 (0.00-0.00) 
out prior knowledge about the distribution or extent 
of the bottom topography in the sampling region, we 
consulted with commercial trap fishermen of black sea 
bass regarding locations where fish might be observed. 
Because the goal of this study was to use underwater 
video to observe and count black sea bass on natural 
habitats, sampling locations were not selected at ran- 
dom. Instead, 6 hard bottom sites ranging in depth 
from 22 to 31 m (Table 1, Fig. 1) were chosen because 
they were primarily characterized by hard bottom sub- 
strates or other natural structures that offered the best 
chance to observe and count fish; sites were visited 1-3 
times during the study period. 
At each sampling site, videos were collected during 
daylight hours (0900 to 1500 Eastern Daylight Sav- 
ings Time) by using a camera system that incorporat- 
ed a rectangular fish trap as a base (dimensions: 107 
cm lengthx53 cm widthx31 cm height; 3.8-cm 2 mesh, 
12-gauge plastic coated wire) (Fig. 2). A frame (di- 
mensions: 107 cm lengthx53 cm width x 86 cm height) 
constructed of galvanized and zinc-plated slotted steel 
angle was bolted to 15-cm sections of slotted angle po- 
sitioned inside the trap at each corner. This fixed the 
frame height at 71 cm above the bottom of the trap 
and 38 cm from the top. Weight was added to the trap 
(with 4 bricks weighing ~2.7 kg each) to ensure that 
it landed flat on the bottom so that the frame stood 
upright. Five GoPro HD Hero l 2 digital video cameras 
(720-pixel resolution, 170° angle of view) were bolted 
to the steel frame with tripod mounts, 38 cm above 
the top of the trap. Four cameras faced outward, one 
2 Mention of trade names or commercial companies is for iden- 
tification purposes only and does not imply endorsement by 
the National Marine Fisheries Service, NOAA. 
on each side at a 45° angle to obtain a standardized 
view of fish and the bottom habitat near the trap dur- 
ing each deployment. An additional camera looking j 
downward at a 45° angle over the top of the trap was 
mounted to capture any behavioral responses (e.g., en- 
tries, escapes) of black sea bass to the trap that may 
have occurred during each deployment (Cullen and Ste- 
vens, 2017). 
Because hard bottom habitats in the coastal waters 
of Maryland are patchy and sparsely dispersed among jj 
soft bottom habitats (e.g., sand), we were concerned 1 
that the number of videos depicting black sea bass on \ 
these habitats would be limited. Therefore, to account 
for the potential spatial variation in habitat at sam- 
pling sites and to help ensure that we obtained obser- 
vations of fish on hard bottom habitats, four 60-min 
continuous deployments of the video camera system j 
were made at a given site per day (n=10 d). Deploy- 
ment locations for the camera system were based on 
observations from a fish finder (FCV-582L; Furuno 
Electric Co. Ltd., Nishinomiya City, Japan) and incor- 
porated a flat bottom area, adjacent to structure. The 
system was then lowered to the bottom slowly, from the 
deck of a chartered commercial vessel, with a rope that 
was attached to a marker buoy and flag at the surface. 
After 1 h, the system was lifted to the surface with a I 
hydraulic pot-hauler. The vessel was then moved -200 
m to the north, south, east, or west from the deploy- 
ment site and repositioned over new bottom habitat. 
The system was then dropped down for the next video 
sample. After the first 2 deployments, the system was 
hauled to the vessel where the camera batteries were j 
changed. The final 2 samples of video were collected 
in the same manner as that described previously, and 
with a distance of -200 m between deployment loca- 
