Kuykendall et al.: A management strategy evaluation for Spisula solidissima 
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Create sets of cases with: 
1 . Varying states of nature 
-distribution/patchiness 
2. Varying commercial procedures 
-captain type 
-definition of a small clam 
Use sets of cases to simulate present-day and alternative management strategies 
including: 
1 . Present-day management 
-no closures 
2. A range of closure durations 
-3, 5, 7 years 
3. Two closure location options to close the ten-minute squares with the highest 
rule specified value 
-Rule 1: ratio of number of small clams to number of market-sized clams 
-Rule 2: number of small clams per square meter 
Figure S 
Diagram of the procedure used to compare performance of present-day management 
(no closures) with alternate management (3 closure durations and 2 closure location 
rules) in the management strategy collection for Atlantic surfclam ( Spisula solidis- 
sima) in the Mid-Atlantic Bight. 
from 3 to 7 years, the average percentage of simula- 
tions with significant increases in stock density under 
area management increased across all definitions of a 
small clam. The 3-year closure duration resulted in an 
average increase in stock density of 5% (Fig. 7, Table 
4); 44% (Table 3) of simulations showed a significant 
increase in stock density compared to present-day 
management. The 5-year closure duration resulted in 
an average 4% increase in stock density over all defi- 
nitions of a small clam (Fig. 7, Table 4). The greatest 
average percentage of simulations that showed a sig- 
nificant increase in stock density compared with that 
under present-day management is seen with the 5-year 
closure duration (range: 33 - 67 %; average: 47%; Table 
3). The 7-year closure duration resulted in a 7% aver- 
age increase in stock density (Fig. 7, Table 4), the larg- 
est average stock density increase across all definitions 
of a small clam. The 7-year closure duration showed 
a significant increase in stock density in an average 
of 44% (range: 33-56%; Table 3) of the simulations in 
comparison with present-day management. When the 
imposed incidental mortality on clams not retained 
