Table 3 Summary of parametric coefficients (linear terms) and smoothing terms from GAM used to determine if detection efficiency was related to distance from transmitter (tag distance, in meters), direction of robot travel relative to transmitter (toward or away), robot depth (depth, in meters from water surface), or robot pitch (pitch, in degrees from horizontal)

(Intercept)

− 4.282

− 7.363

1.79E−13

dir = toward

5.322

8.965

3.11E-19

s(rt_distance): dir = away

6.48E−04

4.85E−04

0.265

s(rt_distance): dir = toward

1.642

4.345

5.84E−04

s(rt_distance): run = 17–1

2.152

6.651

3.07E−04

s(rt_distance): run = 18–1, 18–2

2.466

44.738

4.25E−13

s(rt_distance): run = 18–3

1.118

2.699

5.27E−03

s(pitch): dir = away

0.570

1.087

0.152

s(pitch): dir = toward

2.416

33.366

3.15E−09

s(depth): dir = away

1.212

9.468

8.55E−04

s(depth): dir = toward

0.209

0.255

0.247