Laidig et at. : Reactions of fishes to a manned submersible and a remotely operated vehicle 
65 
Table 4 
Number of fishes reacting within 3 m or >3 m from the front of the manned submersible and the remotely operated 
vehicle (ROV). “Position” refers to the location where each fish taxon was most frequently observed. S=on the seafloor, 
N=near the seafloor, M=in midwater (>1 m above seafloor). The total number of fishes (n) observed is indicated for 
each vehicle. 
Position 
Submersible (n = 10,550) 
ROV ( «= 16, 158 ) 
Number of reacting fishes 
Number of reacting fishes 
<3 m 
>3 m 
Total 
<3 m 
>3 m 
Total 
Bank Rockfish 
N 
8 
38 
46 
14 
3 
17 
Blackeye Goby 
S 
0 
74 
17 
91 
Blue Rockfish 
M 
2 
179 
181 
0 
2 
2 
Bocaccio 
N 
57 
8 
65 
30 
5 
35 
Canary Rockfish 
N 
18 
2 
20 
32 
3 
35 
Cowcod 
S 
3 
2 
5 
2 
1 
3 
Dover Sole 
S 
0 
10 
11 
21 
Greenblotched Rockfish 
S 
2 
1 
3 
5 
0 
5 
Greenspotted Rockfish 
S, N 
10 
6 
16 
55 
32 
87 
Greenstriped Rockfish 
s 
2 
3 
5 
66 
10 
76 
Hagfishes 
s 
1 
0 
1 
4 
2 
6 
Halfbanded Rockfish 
N, M 
84 
134 
218 
1258 
5173 
6431 
Pacific Hake 
M 
11 
6 
17 
13 
2 
15 
Pink Seaperch 
N, M 
0 
211 
8 
219 
Pygmy Rockfish 
N 
0 
1201 
581 
1782 
Rosethorn Rockfish 
M 
0 
4 
4 
2 
1 
3 
Rosy Rockfish 
N 
7 
2 
9 
11 
0 
11 
Shortspine Combfish 
S 
1 
0 
1 
23 
4 
27 
Splitnose Rockfish 
S, N, M 
14 
40 
54 
29 
10 
39 
Spotted Ratfish 
N 
10 
6 
16 
4 
2 
6 
Squarespot Rockfish 
N, M 
301 
111 
412 
68 
44 
112 
Stripetail Rockfish 
S 
2 
3 
5 
2 
2 
4 
Thornyheads 
S 
0 
4 
6 
10 
Widow Rockfish 
N, M 
26 
41 
67 
4 
46 
50 
Yellowtail Rockfish 
N, M 
12 
4 
16 
37 
82 
119 
YOY Rockfishes 
S, N 
0 
0 
Total 
571 
590 
1161 
3159 
6047 
9206 
Percentage of fish reactions 
49 
51 
34 
66 
Percentage of all fishes 
5 
6 
20 
37 
Sablefish ( Anoplopoma fimbria) and 39% of all Pacific 
Hake. Lorance and Trenkel (2006) observed that all 
8 taxa seen in the Bay of Biscay, in habitat types rang- 
ing from flat to gentle slopes and from fine sediments 
to boulders, reacted to a large working-class ROV 
with rates from 10% to 90%. Uiblein et al. (2003), also 
in the Bay of Biscay, worked with a 3-person submers- 
ible to study fish behavior and found that most of 
the 7 more abundant taxa reacted to the vehicle by 
markedly changing their activity level. Two species 
observed in both of these studies (Roundnose Grena- 
dier [ Coryphaenoides rupestris] and Orange Roughy) 
reacted more often to the ROV than to the submers- 
ible. 
In our study, fishes that lived in the midwater above 
the seafloor reacted to both the Delta submersible and 
the Phantom ROV at a higher rate than did fishes 
on the seafloor. Similar results have been reported in 
other studies. Krieger and Ito (1999) observed that 
all Shortraker ( Sebastes borealis) and Rougheye (S. 
aleutianus) Rockfishes that occurred above the sea- 
floor reacted by swimming toward the seafloor as the 
Delta submersible approached, but only 5 out of the 
531 recorded fishes of these 2 species moved when 
initially seen on the seafloor. Lorance and Trenkel 
(2006) examined the reactions of 8 fish taxa in the 
Bay of Biscay and observed that most species reacted 
to the working-class ROV; only the seafloor-dwelling, 
deep-sea Atlantic Thornyhead ( Trachyscorpia cristula- 
ta echinata) had little reaction to the vehicle. In that 
study, 2 of the 3 taxa that had the greatest reactions 
(shark species of the order Squaliformes and the fami- 
ly Scyliorhinidae) were commonly encountered as they 
swam high in the water column. Adams et al. (1995) 
