. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. , June 10 Low tide 10 30 40 ] Inno 19 Low tide JUllc \L n 1 m A n n- A ^/276^ v 10 20 30 40 Shore -"-Position Figure 3. The fraction of the population found at each position along transects perpendicular to the shoreline, on a beach at low tide on several days. The vertical black bar marks the average position of the sea's edge at low tide. (The meter markers were not in the same location each day. the profile of the beach changes daily.) The vertical height of each low tide is given beside th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. , June 10 Low tide 10 30 40 ] Inno 19 Low tide JUllc \L n 1 m A n n- A ^/276^ v 10 20 30 40 Shore -"-Position Figure 3. The fraction of the population found at each position along transects perpendicular to the shoreline, on a beach at low tide on several days. The vertical black bar marks the average position of the sea's edge at low tide. (The meter markers were not in the same location each day. the profile of the beach changes daily.) The vertical height of each low tide is given beside the vertical line. The total number of clams counted is given in the shaded area. Most days, the population is found shoreward of the sea's edge at low tide, out of reach of any swash. Usually, the clams do not migrate at all within I h of low tide. Clams chose waves that moved relatively large distances in the shoreward direction. They jumped for such large swash before the swash reached them. How do they predict the size of incoming swash? One testable hypothesis is that there are patterns to the waves. For instance, if the size of incoming swash is correlated with the excursion of the previous backwash, then the excursion of the pre- ceding backwash, Ep, could be a cue. I found that Ep is not correlated with the next excursion of the swash. E, (R2 = , , , on the 4 days), so it would be a poor predictor of E. Indeed the clams are not using Ep since C/T does not increase with increasing Ep (Fig. 4B). Two variables determine the excursion of the swash, E, the variables Bm and Sm (Fig. 1). On some days clams rode swash that moved significantly farther shoreward (Bm) than swash they did not ride (P < , F-test, multiple regression with dummy variables, Weisberg, CfT 0-2 2-4 . . . E/Emax CAT B. Please note that these images are extracted from scanned page images that may have been digitally en
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
