Effects upon selected marine organisms of explosives used for sound production in geophysical exploration.

Survival rate and extent and nature of injury were monitored for red drum (Sciaenops ocellatus), black drum (Pogonias cromis), blue crab (Callinectes sapidus), white shrimp (Penaeus setiferus), and American oyster (Crassostrea virginica) held in cages at logarithmic distances (one to 46 meters) from where a strand of commercially available explosive (Primacord with 100 grams of powder per 33 centimenters), commonly used to produce sound waves for seismic exploration, was detonated in a shallow water environment. Survival of test organisms varied with species, depth of cage, and distance from detonation site. Fish held at the surface exhibited low mortality, whereas those in bottom cages closest to site of detonation (one and 23 meters away) exhibited mortality rates between 40 and 100%. The swimbladder, kidney, and peritoneum were the most frequently damaged organs in fish. Shrimp exhibited modest mortality rates at all station and water depths. Survival of shrimp did not appear to be directly related to distance from detonation. Blue crab survival appeared to be directly related to distance from detonation site. Survival of oysters was high at all stations and inversely proportional to distance and sound source. Varying results among test organisms were attributed to pressure wave characteristics associated with charge detonation. Comparable testing is needed during summer months to determine effects under worse case conditions when greater numbers and life stages of organisms are present and ambient condition more stressful in these shallow water environments.