Cardisoma carnifex (Herbst, 1796)

Chang, Chung-Chieh, Hatch, Kent A., Hsu, Chia-Hsuan, Hwang, Wenbe, Liu, Hung-Chang & Chang, Yuan-Mou, 2023, Tripedalia maipoensis Sun & Tsui & Wong & Cheung & Ng & Or & Qiu 2023, sp. nov., Zoological Studies 62 (22), pp. 1-14 : 7-8

C. carnifex

Similar to the migration rhythmicity of ovigerous females, the peak timing of larval release also occurred about 3 days after the new and full moon (3.2 ± 1.3 days) during the intermediate amplitude nocturnal high tide (10.2 ± 6.2 days after the maximum amplitude nocturnal high tides) ( Table 1) and lasted for about one week. The timing of larval release seemed to occur around the maximum amplitude diurnal high tides (3.9 ± 6.3 days after the maximum amplitude diurnal high tides), but the r value was 0.56 ( Table 1). This suggests that the timing of larval release was less consistent with maximum amplitude diurnal high tides. Relative to the diel rhythm, all females released larvae during the first half of the night and a majority of larval release was between 2000H and 2259H (78%, mean = 21:18 ± 1.2 h, Table 1, Fig. 4A ). Relative to the tidal rhythm, all females released larvae during the flood tide and most individuals released larvae within 5 hours before the high slack tide (87%, mean = 4.1 ± 1.4 h, Table 1, Fig. 4B ).

E. notatus

Similar to the migration rhythmicity of ovigerous females, the peak timing of larval release also occurred about 20 days after the new moon (20.0 ± 1.3 days) during the intermediate amplitude diurnal/nocturnal high tide ( Table 1; Fig. 3B ) and lasted for about one week. Relative to the diel rhythm, all females released larvae during the first half of the night and a majority of larval release was between 2000H and 2259H (90%, mean = 20:42 ± 1.0 h, Table 1, Fig. 4C ). Relative to the tidal rhythm, all females released larvae during the flood tide and most individuals released larvae within the 6 hours before the high slack tide (99%, mean = -4.6 ± 1.1 h, Table 1, Fig. 4D ).

Figures

Fig. 4. Temporal change in the number of females releasing larvae between 1800H and 0200H along with the time of the nighttime high tide for Cardisoma carnifex (A, B) and Epigrapsus notatus (C, D). The total number of female C. carnifex and E. notatus are 311 and 204, respectively.

Fig. 3. Temporal pattern of migrating ovigerous female Epigrapsus notatus recorded on the embankment flood control road of Chengxi windbreaks between September and November in 2020 (A) and 2021 (B). Solid lines (─) and dash lines (---) represent nocturnal (1800-0559H) and diurnal (0600-1759H) high tides, respectively. The breaks in the lines indicate a lack of data on tidal height for the observation days. Closed and open circles represent new and full moons, respectively.