Kuykendall et al.: A management strategy evaluation for Spisula solidissima 
317 
Table 6 
Summary statistics for average proportion of change (shown in Fig. 8) in performance metrics used to evaluate the effect 
of closure location rule 2 on the Atlantic surfclam ( Spisula solidissima ) population and commercial fishery. Size of clams is 
given as shell length (SL) in millimeters, closure duration is measured in years, and LPUE means landings per unit of effort. 
N is the number of simulations where a significant difference exists between the performance metric using present-day or 
alternative management at present-day abundance. The maximum N is 9. 
Definition of a small clam 
104 mm SL 
93 mm SL 
80 mm SL 
64 mm SL 
Closure duration (yr) 
3 
5 
7 
3 
5 
7 
3 
5 
7 
3 
5 
7 
Stock density 
Present management 
N 
3 
1 
1 
2 
0 
2 
0 
1 
1 
3 
0 
1 
X 2 
0.04 
0.04 
0.03 
0.06 
- 
0.03 
- 
0.04 
0.04 
0.03 
- 
0.05 
Min 
0.03 
- 
- 
0.05 
- 
0.02 
- 
- 
- 
0.01 
- 
- 
Max 
0.04 
- 
- 
0.08 
- 
0.05 
- 
- 
- 
0.04 
- 
- 
Alternative management 
N 
3 
4 
5 
4 
3 
4 
4 
6 
5 
2 
5 
0 
X 2 
0.06 
0.04 
0.05 
0.04 
0.04 
0.07 
0.04 
0.04 
0.02 
0.05 
0.04 
- 
Min 
0.04 
0.02 
0.02 
0.02 
0.02 
0.04 
0.01 
0.01 
0.01 
0.02 
0.03 
- 
Max 
0.07 
0.05 
0.11 
0.08 
0.07 
0.11 
0.06 
0.07 
0.04 
0.09 
0.09 
- 
Number of clams per bushel 
Present management 
N 
6 
8 
8 
7 
8 
9 
6 
9 
9 
3 
8 
9 
X 2 
0.01 
0.02 
0.03 
0.01 
0.02 
0.03 
0.01 
0.02 
0.03 
0.01 
0.02 
0.03 
Min 
0.01 
0.01 
0.01 
0.01 
0.01 
0.01 
0.01 
0.01 
0.01 
0.01 
0.01 
0.01 
Max 
0.02 
0.04 
0.05 
0.02 
0.04 
0.05 
0.02 
0.04 
0.05 
0.02 
0.04 
0.05 
Alternative management 
N 
v2 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
X 
Min 
Max 
LPUE 
Present management 
N 
0 
0 
1 
0 
0 
1 
0 
0 
1 
1 
0 
1 
X 2 
- 
- 
0.04 
- 
- 
0.03 
- 
- 
0.03 
0.03 
- 
0.02 
Min 
Max 
Alternative management 
N 
5 
7 
4 
5 
4 
3 
8 
6 
6 
5 
7 
2 
X 2 
0.07 
0.06 
0.08 
0.08 
0.10 
0.12 
0.09 
0.08 
0.06 
0.08 
0.08 
0.06 
Min 
0.02 
0.04 
0.03 
0.04 
0.05 
0.07 
0.03 
0.04 
0.02 
0.03 
0.03 
0.03 
Max 
0.16 
0.09 
0.19 
0.14 
0.20 
0.21 
0.20 
0.18 
0.09 
0.20 
0.20 
0.08 
Number of 10' squares fished 
Present management 
N 
0 
1 
4 
0 
1 
2 
1 
2 
4 
0 
3 
4 
X 2 
- 
0.02 
0.03 
- 
0.02 
0.02 
0.01 
0.05 
0.02 
- 
0.05 
0.02 
Min 
- 
- 
0.01 
- 
- 
0.01 
- 
0.02 
0.01 
- 
0.02 
0.01 
Max 
- 
- 
0.08 
- 
- 
0.04 
- 
0.08 
0.04 
- 
0.07 
0.04 
Alternative management 
N 
3 
2 
0 
1 
0 
0 
2 
0 
0 
2 
0 
0 
X 2 
0.03 
0.04 
- 
0.01 
- 
- 
0.04 
- 
- 
0.04 
- 
- 
Min 
0.01 
0.01 
- 
- 
- 
- 
0.01 
- 
- 
0.01 
- 
- 
Max 
0.06 
0.08 
- 
- 
- 
- 
0.07 
- 
- 
0.06 
- 
- 
Total distance traveled 
Present management 
N 
v 2 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
X 
Min 
Max 
- 
- 
Alternative management 
N 
9 
9 
8 
9 
8 
7 
8 
8 
8 
8 
7 
9 
X 2 
0.05 
0.05 
0.04 
0.05 
0.04 
0.05 
0.04 
0.05 
0.05 
0.04 
0.04 
0.05 
Min 
0.03 
0.04 
0.02 
0.03 
0.03 
0.03 
0.03 
0.04 
0.02 
0.03 
0.02 
0.03 
Max 
0.07 
0.07 
0.07 
0.07 
0.06 
0.07 
0.07 
0.08 
0.08 
0.08 
0.07 
0.08 
