. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 100 THOMAS L. BEITINGER. -100% - 75% 50% - 25% sx LD 1200 0000 1200 0000 1200 0000 1200 0000 1200 0000 1200 0000 1200 TIME (hrs) FIGURE 2. Median activity (, tunnel pass frequency) of 7 bluegill during the day experiment. The arrow indicates when photoperiod was switched from LD 12: 12 to 6:6:6:6. Activity patterns During the LD 12:12 (control) period, a distinct diurnal activity pattern was apparent (Figures Ic and 2). Day and night median activity levels (tunnel passes hr) ranged between 15-33 and 1-10, respect
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 100 THOMAS L. BEITINGER. -100% - 75% 50% - 25% sx LD 1200 0000 1200 0000 1200 0000 1200 0000 1200 0000 1200 0000 1200 TIME (hrs) FIGURE 2. Median activity (, tunnel pass frequency) of 7 bluegill during the day experiment. The arrow indicates when photoperiod was switched from LD 12: 12 to 6:6:6:6. Activity patterns During the LD 12:12 (control) period, a distinct diurnal activity pattern was apparent (Figures Ic and 2). Day and night median activity levels (tunnel passes hr) ranged between 15-33 and 1-10, respectively, and were highly significantly different (P < , Mann-Whitney U test). Fish demonstrated no obvious anticipation of dawn or dusk (Figure Ic). Activity levels varied sharply with illumination changes: activities increased during dawn and decreased following dusk. To facilitate discussion of the LD 6:6:6:6 experimental period, the fol- lowing time intervals were operationally defined: (1) abnormal dark—dark period from 1400-1900 hr; (2) normal dark—dark period from 0200-0700 hr; (3) abnormal light—light period from 2000-0100 hr; and (4) normal light—light period from 0800-1300 hr. Data collected during the hours when illumination intensity changed (, dawn and dusk) were omitted from analyses. In intervals 1 and 3 above, illumination levels were out-of-phase with the previous light/dark cycle; hence, responses during these intervals are of particular interest. Activities of fish during the first abnormal dark period did not follow the typical "dusk response" in which activity decreases sharply with decreases in illumi- nation (Figure 2). Median activity of fish during the first two out-of- phase dark intervals was increased significantly when compared to the activities of their successive in-phase dark intervals or any of the three LD 12:12 nights (Mann-Whitney U, P ).. Please note that these images are extracted from scanned page i
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
