OCEAN AMBIENT NOISE IS USUALLY CONSIDERED AS AN INTERFERING BACKGROUND FOR UNDERWATER ACOUSTIC SYSTEMS. THESE SOUNDS HAVE A SERIOUS EFFECT ON SONAR. FROM LOW FREQUENCY BAND (10HZ-500HZ) TO MID-FREQUENCY RANGE (500HZ-25KHZ), MARINE ANIMALS SIGNIFICANTLY INCREASES OCEAN AMBIENT NOISE. RESULTS REVEAL THAT BIOLOGICAL NOISE FROM MARINE INVERTEBRATES LIKE SNAPPING SHRIMPS DROPS DETECTION RANGE FROM 35 KM TO 2-11 KM BY INCREASE IN 20-25 DB OF NOISE. THESE LONG PROPAGATING SOUND OF MARINE ANIMALS INFLUENCES PASSIVE SONAR DETECTION. HENCE, IT DETERIORATES THE SONAR’S EFFICIENCY BY 80%.