Johansson et al.: Seasonal distribution and environmental associations of larval and juvenile Sebastes spp. 
275 
sP 
cn 
co 
<n 
2 0 
1.5 
1.0 
0.5 
0.0 
-0 5 
Month 
A May 
▼ June 
♦ July 
• August 
■ September 
+ October 
S. aleutianus 
S nebulosus 
* S. paucispinis 
~S. reedi 
T3. melanosticus 
S. alutus 
S entomelas' 
S. jordani 
♦ •_ u 
■ ff S. ensifer 
WS rosaceus0 S. ruberrimus' 
S. crameri 
^ S. flavidus 
I | 
• UI -B DQJ 
NPGO“W^ 
SPRING Distance from shore'__„. 
Salinity • SSS, 
^S. pinniger' 
X 
A 
Temperature # 
S. helvomaculatus‘ w S proriger’ 
S. babcocki 
SUMMER 
S. elongatus' 
mmiatus 
y 
«*■ S. 
SST • 
S. I 
| • S. melanostomus 
brevispims 
S^aurora g 
f*0 m 
S. diploproa’ 
S. maliger 
0 
T= 
T 
- 2.0 - 1.5 - 1.0 - 0.5 0.0 0.5 1.0 1.5 
Axis 1 = 38.9% 
Figure 6 
Nonmetric multidimensional scaling ordinations showing axes 1 and 3 for 
larval rockfishes (Sebastes spp.) identified by cytochrome b sequencing after 
collection off Washington and Oregon during 2005-2008 and environmental 
covariates. Environmental data include sea surface temperature (SST) and 
salinity at the sea surface (1 m; SSS), Upwelling Index (UI), Pacific Decadal 
Oscillation (PDO) index, and North Pacific Gyre Oscillation (NPGO) index. 
Asterisks (*) denote species with coefficients of correlation >0.15. Each sym¬ 
bol represents the species composition of larvae collected in a single complete 
haul of a midwater trawl ordinated in species space. The arrows indicate 
the directionality and strength (by length of arrow) of physical correlations 
between hauls and physical variables measured during the collection period. 
Discussion 
Before the widespread use of DNA-based identifica¬ 
tions, much of what was known about larval and ju¬ 
venile rockfishes off the west coast of North America 
came from bycatch in multiyear seasonal surveys made 
in the 1960s and 1970s by using strictly visual identi¬ 
fications (Richardson and Laroche, 1979; Laroche and 
Richardson, 1980, 1981). These authors used a variety 
of gear to sample both pelagic larvae and juveniles, as 
well as settled juveniles, providing useful information 
on the sizes and dates of occurrence and some infor¬ 
mation on spatial distribution for 7 common species, 
including several examined here. Using a similar ap¬ 
proach, we were able to identify a total of 3266 rockfish 
from 17 species, using visual methods alone, acknowl¬ 
edging that visual identification is more commonly ap¬ 
plicable for larger size classes. Previous studies found 
seasonal patterns similar to those we observed, in that 
darkblotched, canary, widow, and yellowtail rockfish 
were generally present early in the summer and settled 
by the end of June, whereas rosethorn rockfish reached 
peak catches later in the summer (July and August) 
(Richardson and Laroche, 1979; Laroche and Richard¬ 
son, 1980, 1981). Building on the earlier studies, we 
were able to provide information on a larger number of 
taxa (24) by using both genetic and visual approaches 
than by visual identifications alone (17) and to capture 
a broader size range of juveniles given the larger nets 
used in our study compared with those used in earlier 
studies. Because the list of species identified with the 
2 methods did not overlap completely, the combined ap- 
