Johansson et al.: Seasonal distribution and environmental associations of larval and juvenile Sebastes spp. 
273 
1.5 
1.0 
Sn 0.5 
CO 
O 
CM 
CO 
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0.0 
-0.5 
- 1.0 
Month 
A May 
▼ June 
♦ July 
• August 
■ September 
+• October 
T 
S. pinniger * 
▼ SPRING 
M 
4 S. aleutianus 
S babcocki ^ 
\ • 
Temperature • Distance from shore 
♦ Ul • SSS 
PDO S. elongatus^' ^ SUMMER 
Sal i SST 
S crameri" 
NPGO' 
^S. entomelas' 
\ * 
S helvomaculatus ' 
• ■ 
/ 
- 1.5 
-r- 
- 1.0 
- 0.5 
0 0 
0 5 
10 
Axis 1 = 28.3% 
Figure 4 
Nonmetric multidimensional scaling ordinations showing axes 1 and 3 for 
larval rockfishes (Sebastes spp.) identified visually after collection off Wash¬ 
ington and Oregon during 2005-2008 and environmental covariates. Envi¬ 
ronmental data include sea surface temperature (SST) and salinity (SSS) at 
1 m, and at a depth of 30 m, Upwelling Index (UI), Pacific Decadal Oscilla¬ 
tion (PDO) index, and North Pacific Gyre Oscillation (NPGO) index. Aster¬ 
isks (*) denote species with coefficients of correlation >0.15. Each symbol 
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. 
catches. At offshore stations, we were more likely to 
encounter redbanded rockfish, whereas greenstriped 
rockfish were identified closer to the shelf break. 
The NMS ordination of the proportion of rockfish 
identified by genetics (Figs. 5 and 6) contained 24 spe¬ 
cies caught in 126 of 143 tows where we had genetic 
data (excluding the station sampled 185 km offshore) 
and described 87.3% of the variation in the data set 
(axis 1=38.9%, axis 2=29.5%, and axis 3=18.9%). The 
stress for the final solution was 15.7% (instability=0, 
131 iterations). The largest variation in community 
structure was also explained by seasonal differenc¬ 
es along axis 1 (Suppl. Table 2) (online only). Summer 
months (r=0.729) and warmer SSTs (r=0.416, r 2 <0.15) 
were positively associated with axis 1 along with red- 
stripe rockfish (S. proriger), greenstriped rockfish, and 
yelloweye rockfish (S. ruberrimus ) ( r : 0.513, 0.482, 
and 0.445, respectively). Axis 1 was negatively associ¬ 
ated with spring months (r= -0.761) and canary) and 
widow rockfish (r\ -0.688 and -0.592). These were 2 
of the species that were also identified in spring us¬ 
ing visual identification, indicating that there was good 
agreement between visual and genetic identifications. 
Axis 2 showed a positive association with redstripe 
rockfish (r=0.776) and a negative association with ros- 
ethorn rockfish (r- -0.745, r 2 <0.15), which was associ¬ 
ated with warm, summer months based on the visual 
identification criteria. There were no physical variables 
associated with axis 2 or 3, but splitnose rockfish was 
negatively associated with axis 3 (r= -0.552). 
Rockfish parturition timing varies seasonally by spe¬ 
cies. To better understand some of this variation, we 
