Ushuaia City has been growing since 1980 and industrial and domestic effluents have been discharged along its
coasts. The present study evaluates the acute exposure of the rocky crab Halicarcinus planatus to three environmental
stressors (salinity, pH and ammonia) and to in situ coastal whole effluents (Industrial Zone (IZ), Yacht
Club (YC) and Encerrada Bay (EB)). Neither mortalities nor molting events were recorded during the study period.
The highest physiological rates were at salinity 25, at pH 9.5 and at 3 mg N–NH3 L−1 (174.38±17.76 μg
O2 h−1 g−1 and 12.80±4.54 μg N–NH3 h−1 g−1
; 199.45±11.86 μg O2 h−1 g−1 and 27.82± 6.88 μg
N–NH3 h−1 g−1
; and 232±43.5 μg O2 h−1 g−1 and 26.29±3.42 μg N–NH3 h−1 g−1
, respectively). Crabs exposed
to the studied areas also showed a tendency to increase physiological parameters. Acetylcholynesterase
(AChE) activity showed maximal inhibition in organisms from YC (0.14±0.07 nmol min−1 mg protein−1
).
H. planatus showed responses to both specific and complex environmental stressors and its use as a suitable
bioindicator of environmental changes is discussed.