200 
Fishery Bulletin 112(2-3) 
Table 1 
Individual cruise identification, vessel, schedule (beginning, ending, season), line-transect-survey effort in kilome- 
ters, and marine mammal visual observers of 16 California Cooperative Oceanic Fisheries Investigation (CalCOFI) 
surveys conducted from July 2004 to April 2008. Height of observer platform on the 3 research vessels from which 
these surveys were completed: 13.2 m on RV Roger Reuelle [RR], 8.1 m on RV New Horizon [NH], and 11.0 m on 
NOAA Ship David Starr Jordan [DSJ]. 
CalCOFI 
cruise ID 
Vessel 
Begin 
End 
Season 
Survey 
effort (km) 
Visual 
observers 1 
0407JD 
DSJ 
13-Jul-2004 
28-Jul-2004 
Summer 
1543 
RWB, ABD 
0411RR 
RR 
2-Nov-2004 
19-Nov-2004 
Fall 
1295 
ABD, AM, MS, SEY 
0501NH 
NH 
4-Jan-2005 
20-Jan-2005 
Winter 
1006 
DLC, EV 
0504NH 
NH 
15-Apr-2005 
30-Apr-2005 
Spring 
1485 
DLC, SMC 
0507NH 
NH 
l-Jul-2005 
16-Jul-2005 
Summer 
1571 
DLC, ABD, VI 
0511NH 
NH 
4-Nov-2005 
20-Nov-2005 
Fall 
1104 
DLC, SMC 
0602JD 
DSJ 
4-Feb-2006 
25-Feb-2006 
Winter 
1144 
GSC, SMC 
0604NH 
NH 
l-Apr-2006 
17-Apr-2006 
Spring 
1624 
DLC, ABD 
0607NH 
NH 
8-Jul-2006 
24-Jul-2006 
Summer 
1595 
DLC, AMH 
0610RR 
RR 
21-0ct-2006 
5-Nov-2006 
Fall 
1208 
ABD, AMH 
0701JD 
DSJ 
12-Jan-2007 
2-Feb-2007 
Winter 
1080 
GSC, ABD 
0704JD 
DSJ 
28-Mar-2007 
18-Apr-2007 
Spring 
911 
GSC, SMC 
0707NH 
NH 
28-Jun-2007 
13-Jul-2007 
Summer 
1502 
AMH, SEY 
0711NH 
NH 
02-Nov-2007 
18-Nov-2007 
Fall 
1109 
DLC, LJM 
0801JD 
DSJ 
07-Jan-2008 
23-Jan-2008 
Winter 
935 
DLC, GSC 
0803JD 
DSJ 
24-Mar-2008 
09-Apr-2008 
Spring 
884 
DLC, GSC 
Observers: R. W. Baird, D. L. Camacho, G. S. Campbell, S. M. Claussen, A. B. Douglas, A. M. Havron, V. Iriarte, A. 
Miller, L. J. Morse, M. Smith, E. Vazquez, and S. E. Yin. 
COFI cruises from July 2004 to April 2008 (Table 1). 
Covering an area of 238,494 km 2 , the study area con- 
sisted of coastal, shelf, and pelagic oceanic habitat from 
nearshore waters to waters 700 km offshore and up to 
4600 m deep. Observers used unaided eye or handheld 
7x50 reticle Fujinon 2 binoculars (Fujifilm Corp., Tokyo) 
to sight, identify, and estimate group sizes of cetaceans 
and pinnipeds encountered along the transect lines be- 
tween CalCOFI hydrographic sampling stations (Fig. 
1). The Southern California hydrographic sampling 
station sites are set along 6 parallel lines running 
southwest to northeast, with lines increasing in length 
from north to south (470-700 km). Stations occur ev- 
ery 37 km in coastal and continental shelf waters and 
every 74 km in offshore locations (Fig. 1). Occasionally, 
transect lines were interrupted by naval activity or 
adverse weather conditions; in these cases, the observ- 
ers discontinued effort until their vessel adjusted to a 
course that intersected with the interrupted transect 
line. Transit lines that ran along the CalCOFI tran- 
sect lines, as well as to and from the study area, were 
surveyed opportunistically in addition to the primary 
transect lines; however, these data were excluded from 
the analyses and results described here. Five northern 
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. 
lines were surveyed partially during 2 winter cruises; 
however, only a few sections of these lines were sur- 
veyed with acceptable sea conditions, and therefore 
these data also have been excluded from the analyses 
and results in this study. 
Three vessels were used for the line-transect sur- 
veys: the RV Roger Revelle (2 surveys) and RV New 
Horizon (8 surveys) of the Scripps Institution of Ocean- 
ography, University of California, San Diego, and the 
NOAA Ship David Starr Jordan (6 surveys) (Table 1). 
Survey speeds ranged from 18.5 to 22.2 km/h. Height 
of the observer platform varied by vessel from 8.1 to 
13.2 m, raising the possibility that there would be a 
vessel or a vessel-season bias. To test these biases, we 
ran single-factor analyses of variance (ANOVAs) to de- 
termine whether visual observers made initial sight- 
ings at significantly different distances for each vessel 
or vessel-season combination. Additionally, we ran tests 
to determine whether the number of transect line ki- 
lometers surveyed in good weather varied by season. 
Scanning from directly abeam to 10° past the bow on 
either side of the vessel, 2 observers recorded marine 
mammal sightings. During 2 survey cruises, an addi- 
tional person was available to record data and provide 
relief for observers at meal times (Table 1). Recorded 
sighting data included date, time, vessel latitude and 
longitude, vessel true heading, distance of animal from 
the vessel, sighting angle, 0, from the transect line, de- 
