Oil spill dispersants cause bradycardia in a marine fish

The symptoms of detergent poisoning have been observed to be similar to those of asphyxic hypoxia (Marchetti, 1965). If hypoxia is in any way involved in the toxicity of detergents the sublethal physiological effects of the detergents in oil dispersants would be expected to be similar to the effect of hypoxia alone. When subjected to hypoxia fish decrease their heart rate and increase the ventilation volume (Holeton & Randall, 1967; Butler & Taylor, 1975; Randall, 1966). Heart rate in fish is precisely controlled and compensated (Kiceniuk, 1975; Kiceniuk & Jones, in press). This study was undertaken to determine (a) whether heart rate of a marine fish is affected by oil dispersants and if so, (b) what components of oil dispersants are effective in producing the response, and (c) at what relative concentrations?