LeCiair et al.: Seasonal changes in abundance and migration of Sebastes auriculatus and 5. caurinus 
307 
Length class 
Figure 2 
Total numbers (summed over 3 transects) by length class (total lengths in 
centimeters) of brown and copper rockfish (Sebastes auriculatus and S. cari- 
nus, respectively) observed during seasonal surveys at Point Heyer Artificial 
Reef, Puget Sound, Washington, from summer 2005 through summer 2012. 
summer, fall, or winter; summer was significantly dif- 
ferent from fall and winter; and fall was significantly 
different from winter. 
For each species and for any given year, the sum- 
mer fish density summed over all length classes was 
more than twice that for winter, and the densities did 
not vary greatly over time. To evaluate the potential 
impact of seasonal juvenile recruitment on overall sea- 
sonal abundances, we combined the 2 smallest length 
classes (<5 and 5<10 cm) and examined the relative 
proportion of these fish to the overall counts, by season, 
and summed over all surveys for both brown and cop- 
per rockfish. The number of juveniles encountered was 
greatest during the summer for both species, as was 
the relative proportion of juvenile copper rockfish to 
the total number of copper rockfish encountered (14%). 
Brown rockfish juveniles, however, represented the 
greatest proportion during the winter (9%) (Fig. 4). We 
used a two-tailed z-test for comparison of 2 proportions 
to determine whether juvenile rockfishes composed a 
significantly greater proportion of the total number 
of fish observed during either summer or winter. The 
proportion of juvenile brown rockfish was significantly 
greater in the winter (^=2.2, P<0.05), but the propor- 
tions did not differ significantly between summer and 
winter for copper rockfish ( 2 = 1 . 6 , P>0.05) (satisfactory 
n*Pi >5 and /z[l-pj>5 sample-size tests where n=sample 
size and p=proportion). 
To determine whether there were qualitative differ- 
ences between brown and copper rockfish that occupied 
the reef in the summer and winter we divided them 
into 2 length classes, small (<20 cm) and large (>20 
cm). Summed over all surveys, the densities of both 
small and large fish were greatest during the summer, 
and large fish were more abundant than small fish year 
round (Fig. 5). For both species, the proportion of large 
fish to the total numbers observed was significantly 
greater in the winter ( 2 = 2.5 [brown rockfish] and 4.2 
Table 2 
Summary of analysis of variance (ANOVA) comparisons between generalized linear mixed model (GLMM) null models (fish 
count as the response variable, and year and transect as random effects) and full models (season added as explanatory 
variable) for seasonal counts of brown and copper rockfish at Point Heyer Artificial Reef, Puget Sound, WA.; AIC=Akaike 
information criteria; BIC=Bayesian information criteria; df =degrees of freedom. 
Model 
df 
AIC 
BIC 
Log-likelihood 
Deviance 
y} df P (>y}) 
Brown rockfish Null model 
Brown full 
3 
1032.33 
1039.93 
-513.17 
1026.33 
Full model 
6 
651.69 
666.89 
-319.85 
639.69 
386.64 
3 <0.001 
Copper rockfish Null model 
Copper rockfish 
3 
1003.44 
1011.04 
-498.72 
997.44 
Full model 
6 
795.36 
810.55 
-391.68 
783.36 
214.09 
3 <0.001 
