The effect of water quality on the respiration and excretion rates of the Copepod Paracalanus parvus collected from the coastal waters of the Gulf was tested through short-term laboratory experiments. Copepods were subjected to industrial discharge, hypersaline water as well as harbor water. The respiration rate of the copepod is significantly lowered [down to 2.8 x 10-2 μl O2/Cop./hr] when exposed to hypersaline water rather than industrial discharge[7.9 x 10-2 μl O2/Cop./hr] when compared to its original habitat [range 6.6-8.2 x 10-2 μl O2/Cop./hr]. The excretion rate of ammonia and phosphorus, likewise the respiration rate, depends mainly on the levels of ammonia, phosphorus and oxygen in the incubation water. Rates of ammonia excreted from industrial water incubated copepods were significantly high during the first 36hrs reaching the maximum i.e. 29 x10-3 μg N/Cop./hr after 24 hrs. Ammonia excretion increased gradually during the first 24 hrs for the hypersaline water incubated copepods followed by a constant rate between 38-42 x 10-3 μg N/Cop./hr to the end of the experiment. Phosphorus excretion was higher for the hypersaline > industrial water > harbor water incubated copepods, compared to their original habitat [45-55 x 10-5 μg P/Cop./hr]. Metabolic disorders were generally observed during the first 24 hrs. Derived N/P [Nitrogen/ Phosphorus] and O/P[ Oxygen/ Phosphorus] ratios are higher for hypersaline water > industrial discharge > harbor water incubated animals.