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Fishery Bulletin 108(3) 
the most susceptible owing to targeting, and priority 
is therefore given to the collection of data for valuable 
target fisheries). 
The degree of consistency within the productivity and 
susceptibility scores was determined from correlations 
of a particular attribute to its overall productivity or 
susceptibility score (after removal of the attribute being 
evaluated). In this analysis, susceptibility attributes 
related to management were separated from other sus- 
ceptibility attributes. All but two of the attributes had 
relatively high correlation coefficients, with an overall 
average correlation of 0.43 and ranging from -0.21 to 
0.80 (Table 4). The correlation coefficients for recruit- 
ment pattern (-0.21) and seasonal migration (0.06) were 
unusually low and could reflect the narrow range of ob- 
served recruitment patterns or seasonal migrations, as 
is evident from each attribute being scored 90% of the 
time as a moderate risk. Although these attributes were 
not informative for the majority of the stocks we exam- 
ined, we anticipate that these attributes may prove to 
be more useful for other fisheries. As previously noted, 
in these cases the attribute weight can be adjusted to 
reflect its utility. 
□ Allantic shark complex ★ Nf siroundfish 
A CA nearshore groundfish © Ml swordfish longline 
( A current pelagics HI tuna longlinc 
Figure 3 
A subset of the stocks from the example applications 
(n=50) for which the status (stock is either overfished 
^ current ^ msy ^ or being overfished \B CURRENT <B MSY ]) 
could be determined between 2000 and 2008. Produc- 
tivity and susceptibility analysis scores increase with 
distance from the origin, as does the vulnerability score. 
The dashed line references the minimum vulnerability 
scores observed among the 162 stocks evaluated in the 
applications. 
Relationship of stock vulnerability to fishing pressure 
To evaluate the efficacy of the PSA in identifying stocks 
that are vulnerable to overfishing, we examined a subset 
(n = 50) of the example stocks for which status determina- 
tion criteria were available to assess whether the stock’s 
maximum sustainable fishing mortality rate (i.e., whether 
it is being overfished) or minimal stock size threshold (i.e., 
whether it was overfished) had been exceeded between 
the years of 2000 and 2008 (Fig. 3). Kruskal-Wallis 
tests indicated significant differences in susceptibility 
(P=0.001) and vulnerability (P=0.002) scores between 
stocks that had been overfished or that were being over- 
fished in the past (i.e., Northeast groundfish multispecies 
and highly migratory Atlantic shark complexes) and 
those that had not. However, productivity scores were 
not found to be significantly different (P= 0.891). Stocks 
that had been overfished or that were being overfished 
in the past generally had susceptibility scores greater 
than 2.3 and vulnerability scores greater than 1.8. 
To further examine the efficacy of the PSA to iden- 
tify vulnerable stocks, we evaluated four lightly fished 
nontarget species (i.e., minor bycatch species) that were 
unlikely to be impacted by fishing activities in their 
region according to their average landings (<5 metric 
tons/yr), price value (< $ 1 .00/lb ), and suspected high 
productivity rates. These minor bycatch species, from 
the South Atlantic and Gulf of Mexico snapper-grouper 
longline fishery, represented stocks that should have 
substantially lower vulnerability scores (< 1.0) com- 
pared to the other species that are considered either 
targeted species or major bycatch species. Three of the 
four nontarget species received vulnerability scores of 
less than 1.0 (Fig. 1), but the other stock (sand tilefish, 
Malacanthus plumieri ) received a vulnerability score 
of 1.1 because of its moderate productivity (2.1) and 
susceptibility (1.9). 
These post hoc results involving stocks with status 
determinations and lightly fished nontarget species, 
although limited, indicate that the PSA can differ- 
entiate between low- and highly vulnerable stocks. 
However, a fixed threshold for delineating between the 
varying levels of vulnerability was not observed in all 
situations because a gradient of vulnerabilities existed. 
Therefore, determination of appropriate thresholds 
for low-, moderate-, and highly vulnerable stocks will 
likely reflect the nature of each particular fishery and 
the management action that will be applied. In some 
cases, managers may prefer to use the results of the 
PSA in a contextual or qualitative manner to deter- 
mine management decisions rather than as a basis for 
specifying rigid decision rules. When thresholds are 
desired, we recommend that managers and scientists 
jointly determine appropriate thresholds on a fishery- 
by-fishery basis. 
Comparisons between target and nontarget stocks 
Comparisons of productivity and susceptibility between 
target and nontarget stocks were made in the Hawaii- 
