. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 4 i -§ 3, o. 1 2H o 0 J 60 90 120 Time (min) emarginata 150 180. 30 60 90 120 Time (min) Figure 4. Cleaning of the mouthparts in 16 crabs (mean ± SEM) during 3-h exposure to 100%, 75%. 50%, and 25% seawater: (a) Callinecles sapitlus. (b) Curcinus maenas, (c) Cancer magister, and (d) Libinia emarginata. process, rather than the extension and fanning of the abdo- men seen in the other species. Discussion Callinectes sapidus hyper-regulated its body fluids in all salinities, including 100% SW (Fig. 1); this has been re- ported
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 4 i -§ 3, o. 1 2H o 0 J 60 90 120 Time (min) emarginata 150 180. 30 60 90 120 Time (min) Figure 4. Cleaning of the mouthparts in 16 crabs (mean ± SEM) during 3-h exposure to 100%, 75%. 50%, and 25% seawater: (a) Callinecles sapitlus. (b) Curcinus maenas, (c) Cancer magister, and (d) Libinia emarginata. process, rather than the extension and fanning of the abdo- men seen in the other species. Discussion Callinectes sapidus hyper-regulated its body fluids in all salinities, including 100% SW (Fig. 1); this has been re- ported previously (Tan and Van Engel, 1966). In all the other species, hemolymph was iso-osmotic with 100% SW. Carcimts maenas, which is classed as an efficient osmoreg- ulator, had hemolymph osmolality levels (Fig. 1) similar to previous reports (Lucu et ai, 1973; Rankin and Davenport. 1981). All Carcinus used in the present study were green- colored male crabs. Red-colored individuals, which are in a prolonged intermolt (McGaw et ai, 1992), are poorer os- moregulators (Reid et ai. 1989: McGaw. 1991) and have different behavioral responses to low salinity (McGaw and Naylor. 1992a. c). Cancer magister is classed as a weak osmoregulator (Jones, 1941) and the levels of hemolymph osmolality reported here (Fig. 1) agree closely with the data of Hunter and Rudy (1975). Cancer magister is able to survive in salinities as low as 12 ppt (36% SW; Cleaver, 1957); however, in the present study all survived short-term exposure (24 h) to 25% SW (8 ppt) (Fig. 1). Libinia emar- ginata is an osmoconformer, with ion levels closely follow- ing those of the external medium (Gilles. 1970). This was also seen in the present study (Fig. 1), except in the lowest salinity. Libinia emarginata can withstand dilution of the medium only to 40% SW (Gilles, 1970). Mortality was high after 12-h exposure to 25% SW, and the short acclimation time (10 h) used would not have allowed hemolymph os- molality to decline
Size: 1794px × 1393px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
