Fig. 1

Food intake and morphology change of gills in response to the sudden drop in salinity in S. paramamosain. a, Food intake change in Scylla paramamosain. The juvenile crab with a body weight of ~ 30 g eat about two Sinonovacula constricta (Lamarck) in 24 h, so three Sinonovacula constricta (Lamarck) per crab were feed every day and cleaned up the leftovers regularly to prevent the water going bad. b, the phenotypic changes of gill filaments within 120 h after the salinity drop: 23‰ in CK group, others were the phenotypes of 12, 24, 48, 72, 96, and 120 h after salinity dropped to 3‰. c, changes of gills in length; “0” indicated CK group, and the others were the gill length at 12, 24, 48, 72, 96, 120 h after salinity dropped to 3‰. Bars are 300 μm in b