350 
Fishery Bulletin 96(2), 1998 
position would need to be reinvestigated if there was 
an unexpected change in mortality, such as that re- 
sulting from clams being washed ashore by a large 
typhoon or other storms (Sakurai et al., 1996). 
23456789 
Age (year) 
Figure 6 
Predicted age compositions for the harvestable-size sunray 
surfclams in April from 1991 to 1997. 
Year 
Figure 7 
Annual fluctuation of the measured (open circles) and predicted 
(solid circles) stock size of sunray surfclams. 
Acknowledgments 
We wish to express our appreciation to Y. 
Kanno and S. Goshima, Faculty of Fisheries, 
Hokkaido University, for their helpful advice 
and discussion. We are also grateful to the staff 
of Tomakomai Fisheries Cooperative Associa- 
tion for their kindness during this work. 
Literature cited 
Claereboudt, M. R., and J. H. Himmelman. 
1996. Recruitment, growth and production of giant 
scallops ( Placopecten magellanicus) along an envi- 
ronmental gradient in Baie des Chaleurs, eastern 
Canada. Mar. Biol. 124:661-670. 
Defeo, O., E. Ortiz, and J. C. Castilla. 
1992. Growth, mortality and recruitment of the 
yellow clam Mesodesma mactroides on Uruguayan 
beachs. Mar. Biol. 114:429-437. 
Dekker, R., and J. J. Beukema. 
1993. Dynamics and growth of a bivalve, Abra 
tenuis, at the northern edge of its distribution. J. 
Mar. Biol. Assoc. U. K. 73:497-511. 
Dillon, J. F., and G. R. Clark II. 
1980. Growth-line analysis as a test for contem- 
poraneity in populations. In D. C. Rhoads and R. 
A. Lutz (eds. ), Skeletal growth of aquatic organ- 
isms, p. 395-415. Plenum Press, New York, NY. 
Goshima, S., K. Nagamoto, K. Kawai, and 
S. Nakao. 
1991. Reproductive cycle and growth of the north- 
ern great tellin, Megangulus venulosus, in Shiri- 
uchi, Hokkaido. Benthos Res. 40:23-33. [In Japa- 
nese with English abstract.] 
Goshima, S., and T. Noda. 
1992. Shell growth of the North Pacific cockle 
Clinocardium californiense in Hakodate Bay, Hok- 
kaido. Benthos Res. 42:39-48. [In Japanese with 
English abstract.] 
Gunther, C. P. 
1992. Settlement and recruitment of Mya arenaria 
L. in the Wadden Sea. J. Exp. Mar. Biol. Ecol. 
159:203-215. 
Habe, T. 
1977. Systematics of Mollusca in Japan. Bivalvia 
and Scaphopoda. Hokuryukan, Tokyo, p. 178-180. 
[In Japanese.] 
Hanaoka, T. 
1972. Increase in number of animals. In S. Iwao 
and T. Hanaoka (eds.), Kyoritsu Shuppan, Tokyo, 
p. 88-91. [In Japanese.] 
Hanaoka, T., and T. Shimazu. 
1949. Studies on the morphometry and rate of 
growth in clam, Mactra suleataria Reeve, in Tokyo 
Bay. Nippon Suisan Gakkaishi 15:311-317. [In 
Japanese.] 
