. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. E 3- o o o o o 0 -J 30 60 90 120 150 180 Time (min) Libinii emarginata. 30 60 90 120 Time (min) 150 180 Figure 2. Locomotor activity of 16 crabs (mean ± SEM) during 3-h exposure to seawakr Loncentrations of 100%, 75%, 50%, and 25% sea- water; (a) Carcinus inarmis, (b) Canter magister, and (c) Libitria emar- ginata. pronounced in Carcinus nuieiius. There was a significant increase after 15-30 min in 50% and 25% seawater (Fig. 2a; F = , P < ), and activity remained elevated above levels in 100% and 75% seawater. f
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. E 3- o o o o o 0 -J 30 60 90 120 150 180 Time (min) Libinii emarginata. 30 60 90 120 Time (min) 150 180 Figure 2. Locomotor activity of 16 crabs (mean ± SEM) during 3-h exposure to seawakr Loncentrations of 100%, 75%, 50%, and 25% sea- water; (a) Carcinus inarmis, (b) Canter magister, and (c) Libitria emar- ginata. pronounced in Carcinus nuieiius. There was a significant increase after 15-30 min in 50% and 25% seawater (Fig. 2a; F = , P < ), and activity remained elevated above levels in 100% and 75% seawater. for the duration of the experiment. Both Cancer magister (Fig 2b) and Libinia emarginata (Fig. 2c) showed an immediate and significant increase in activity as the salinity was lowered (F = and , P < ). However, the pattern was somewhat different than in Callinectes sapidus and Carcinus maenas. The activity levels of Cancer magister declined during the first hour of low-salinity exposure, and Libinia emarginata was largely inactive after 45 min. Individuals of both spe- cies buried themselves in the gravel and moved infrequently thereafter. Each species also responded to a decrease in salinity with an increase in frequency of mouthpart movements; each set of mouthpart movements (3-8 movements per set) was associated with a ventilatory reversal (not shown). In Cal- linectes sapidus, there was a clear increase in mouthpart movements as the seawater was lowered to 25% (Fig. 3a; F = , P < ). In 100% seawater this species only occasionally opened its mouthparts, but in 50% and 25% seawater the frequency of mouthpart movements was ele- vated for the 3-h experimental period. Carcinus maenas exhibited a similar behavior pattern, with increasing mouth- part movements in the lower salinities (Fig. 3b; F = P < ). In 50% and 25% SW there was a significant increase in frequency of mouthpart movements compared to levels in 100% and 75% SW (Table I)
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
