. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SESARMA LARVAL RELEASE RHYTHM 315. 50-, O * 0 5. dehaani 1975 25 30 5 Jun Jul iiMmi 25 Jut. 30 JV^lJl 5 Aug 50-, O E 3 Z O O 1976 10 15 20 Jul 25 30 10 15 Aug. ••••!•••• 20 25 30 5 10 Sep FIGURE 2C. Number of Sesarma dehaani releasing larvae per night 21 June-9 July and 21 July- 8 August 1975; and 10 July 13 September 1976. Observations not carried out on 26, 27, and 30 June and 1, 2, and 5 July 1975. Each day of no observations was substituted by superposing data of 2 days examined in 1976; phase of larval release rhythm ca
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SESARMA LARVAL RELEASE RHYTHM 315. 50-, O * 0 5. dehaani 1975 25 30 5 Jun Jul iiMmi 25 Jut. 30 JV^lJl 5 Aug 50-, O E 3 Z O O 1976 10 15 20 Jul 25 30 10 15 Aug. ••••!•••• 20 25 30 5 10 Sep FIGURE 2C. Number of Sesarma dehaani releasing larvae per night 21 June-9 July and 21 July- 8 August 1975; and 10 July 13 September 1976. Observations not carried out on 26, 27, and 30 June and 1, 2, and 5 July 1975. Each day of no observations was substituted by superposing data of 2 days examined in 1976; phase of larval release rhythm can be regarded as identical (26 June replaced by 14 and 28 July; 27 June by 15 and 29 July; 30 June by 18 July and 1 August; 1 July by 19 July and 2 August; 2 July by 20 July and 3 August; and 5 July by 23 July and 6 August 1976, respectively. See Fig. 3C). 5-45% of S. intermedium zoeae died and all died within 70 h. S. dehaani zoeae had the highest tolerance of fresh water among the three species. However, a dead zoea was found 17 h after the treatment and all died within 96 h. Survival times grew longer as salinity increased (Fig. 5). Zoeae placed in natural sea water all lived at least 4 days, except one S. haematocheir zoea. Thus, zoeae released in fresh water are exposed to immediate danger of death. This may be particularly true for zoeae of S. haematocheir and S. intermedium. During low water, the river ran very slowly. Mud flats, stones, and dead trees were exposed to the air. Stagnant pools were common, and soon collected all corks; new or re-thrown corks soon entered another pool. At 150 m from the sea, they were borne upriver by the rising tide. However, during high water, stagnant pools were scarce. Two corks took 3 h 20 min and 3 h 30 min, respectively, to reach the sea with the receding tide, though they stopped at the water's edge* several times. DISCUSSION At the observation site, zoeae were released in fresh water (chlorinity ). As Fi
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
