200 
Fishery Bulletin 11 7(3) 
permutations. The PE RM AN OVA F- ratio test statistic is 
based on the expectations of mean squares and is directly 
analogous to the construction of the E-statistic for multi¬ 
factorial univariate models but should be thought of as a 
pseudo /'-test statistic because it does not have a known 
distribution under a true null hypothesis (Anderson et al., 
2008). To estimate statistical significance between regions 
and between size categories, pairwise PERMANOVA 
tests were run. These tests included a Type II (condi¬ 
tional) sum of squares, with fixed effects summed to zero 
for mixed terms, and permutation of residuals under a 
reduced model. The pairwise PERMANOVA pseudo t-test 
statistic is a direct multivariate analogue to the univari¬ 
ate t-statistic (Anderson et al., 2008). Exact permutation 
P-values are reported. 
Canonical analysis of principal coordinates (CAP) 
was used to further examine differences among parasite 
communities by measuring the distinctiveness of groups 
through cross validation (Anderson et al., 2008). Over¬ 
parameterization was prevented by choosing the number 
of principal coordinate analysis (PCO) axes that maxi¬ 
mized a leave-one-out allocation success to groups (Ander¬ 
son and Robinson, 2003). The CAP analyses were based 
on abundance data and used a Bray-Curtis dissimilarity 
coefficient. A permutation “trace” ( tr) test (sum of squared 
canonical eigenvalues) was used to test for significant 
differences. 
We determined which parasite taxa contributed the 
greatest percent contributions to distinctiveness of par¬ 
asite communities by using the similarity percentage 
(SIMPER) procedure in PRIMER and performed a shade 
plot analysis (Clarke et ah, 2014b) on the 7 most abun¬ 
dant parasite taxa to provide a visual display of the para¬ 
site taxa most responsible for differences or trends among 
sizes of Pacific sardine and regions of collection. 
For the parasite communities of northern anchovy, for 
which a less complex data set was available, a one-way 
multivariate analysis of similarities (ANOSIM) permuta¬ 
tion test was used to identify differences in parasite mean 
abundances among regions. The ANOSIM test, based on 
rank similarities, provides R values. An R value close to 
or equal to one indicates that all communities within a 
group are more similar to each other than to communities 
from different groups, and an R value approximating zero 
indicates that similarities within and between groups are 
the same (Clarke and Green, 1988). 
Results 
Pacific sardine: parasite taxa recovered 
A total of 14 trophically transmitted parasite taxa were 
recovered from Pacific sardine (Table 3). We recovered 
Table 3 
Prevalence (P) and mean intensity (I), with 95% confidence intervals (95% CIs), of parasites recovered from 1388 Pacific sardine 
(Sardi?iops sagax ) caught in 5 regions of the California Current System from 2005 through 2008. n=sample size. Asterisks (*) 
denote that only 2 infected fish were collected. 
British Washington and Northern California Central California Southern California 
Parasite taxa 
Columbia (n=219) 
Oregon (n= 532) 
(n=281) 
(n=188) 
(n= 168) 
P(%) 
I (95% Cl) 
P(%) 
I (95% Cl) 
P(%) 
I (95% Cl) 
P(%) 
I (95% Cl) 
P(%) 
I (95% Cl) 
NEMATODA 
Anisakis spp. 
25.1 
1.4 (1.2—1.6) 
24.2 
1.7 (1.4—2.0) 
11.4 
1.0 (0.9-1.1) 
6.4 
1.3 (0.7-1.6) 
12.0 
2.3 (1.3-3.3) 
Contracaecum 
0.0 
0.0 
0.0 
0.0 
1.2 
1.5* 
rnargolisi 
C. rudolphii 
0.0 
0.0 
0.0 
0.0 
1.8 
1.0 
Hysterothylacium sp. 
18.7 
1.3(1.1-1.5) 
19.0 
1.5(13-1.7) 
24.9 
1.4 (1.2-1.6) 
9.6 
1.2 (0.9-1.5) 
31.5 
1.5 (1.3-1.7) 
Unknown nematode 
0.9 
1.0 
2.4 
1.2 (1.0-1.4) 
3.2 
1.2 (0.9-1.5) 
2.1 
1.0 
3.0 
1.0 
TREMATODA 
Lampritrema sp. 
0.0 
0.0 
0.0 
0.5 
1.0 
0.0 
Lecithaster gibbosus 
48.4 
4.9 (3.7-6.1) 
8.1 
2.9 (1.8-3.0) 
1.1 
1.0 
0.0 
0.0 
Myosacciurn ecaude 
5.0 
1.6 (0.6-2.6) 
8.1 
1.2 (0.8-1.6) 
28.8 
2.2 (1.6-3.0) 
29.8 
2.1 (1.6-2.6) 
41.7 
2.3 (1.5-3.1) 
Parahemiurus merus 
25.1 
1.8 (1.4-2.2) 
5.3 
1.0 (0.9-1.1) 
5.3 
1.3 (0.9-1.7) 
16.0 
1.1 (0.9-1.3) 
19.0 
1.3(1.1-1.5) 
Pronoprymna petrowi 
8.7 
7.0 (2.8-11.2) 
0.4 
1.5* 
0.0 
0.0 
0.0 
Unknown trematode 
0.5 
1.0 
0.0 
0.4 
1.0 
0.0 
0.6 
1.0 
ACANTHOCEPHALA 
Rhadinorhynchus sp. 
0.5 
2.0 
1.9 
1.3 (0.9-1.7) 
0.7 
1.0 
1.6 
1.0 
1.8 
1.0 
CESTODA 
Tetraphyllidea 
0.0 
0.2 
1.0 
0.0 
0.0 
0.0 
Unknown cestode 
0.5 
5.0 
0.0 
0.0 
0.0 
0.0 
