MEPS 139:119-125 (1996)  -  doi:10.3354/meps139119

Hemolymph ammonia and urea and nitrogenous excretions of Scylla serrata at different temperature and salinity levels

Chen JC, Chia PG

Hemolymph ammonia and urea levels and nitrogenous excretions of Scylla serrata (Forskal) (202 ± 18 g) were measured when the crabs were exposed to 9 different temperature and salinity regimes (15, 25, 35°C combined with 10, 25 and 40o/oo S). Hemolymph ammonia increased with a decrease in salinity, whereas hemolymph urea increased with an increase in salinity. Nitrogenous excretion increased with temperature. Excretion of ammonia-N, organic-N, nitrite-N, and nitrate-N and total nitrogen excretion (µg g-1 h-1) increased with a decrease in salinity, whereas urea-N excretion increased with an increase in salinity. At 25°C, ammonia-N excretion accounted for 82.0, 79.2 and 56.2% of total nitrogen excreted by the crabs at 10, 25 and 40o/oo S, whereas urea-N excretion accounted for 4.3, 9.1 and 30.1% respectively. It is concluded that the S. serrata at 40o/oo S shifts its excretory pattern from ammoniotelism to ureotelism.


Scylla serrata · Temperature · Salinity · Hemolymph · Ammonia · Urea · Nitrogenous excretion · Metabolism


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