Growth lines in bivalve mollusks have been thought to reflect solar days, circadian rhythms and/or tides. Tides seem to be the dominating influence in some intertidal species. This study provides laboratory evidence suggesting that tides are a major influence in the number of growth lines in the clam Protothaca staminea.
Clams were grown under 4 different "tidal" regimes, (0, 1, 2 and 3 tides per day) for forty-one days. Acetate peels of shell cross sections were used for growth line counting. Photomicrographs and measurements showed a striking difference in the growth and number of growth lines between the 4 tidal groups. Generally, those with the least number of tidal emersions showed the least number of lines. Presence of lines in specimens grown with no tidal exposure suggests that in P. staminea the lines may be endogenously controlled but entrained by the tides.
Conrad D. Clausen
Ariel A. Roth
Raymond E. Rychman
Master of Arts (MA)
Year Degree Awarded
Date (Title Page)
Library of Congress/MESH Subject Headings
Clams; Tide pool ecology
Loma Linda University Libraries
This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Irsula, Orlando, "Effect of Simulated Tidal Patterns on Growth and Growth Line Formation in the Little Neck Clam, PROTOTHACA STAMINEA" (1981). Loma Linda University Electronic Theses, Dissertations & Projects. 1036.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives