A static-renewal, seven day test was developed and utilized to study the effects of nutrition on the sensitivity of Mysidopsis intii Holmquist to zinc. It was found that juvenile growth was the most reliable and sensitive endpoint that could also reflect the subtle effects of low zinc concentrations and diet modifications. It was shown that even slight diet modifications could significantly alter growth over seven days. It was also shown that this small change in overall growth was accompanied by a heightened sensitivity to zinc. This heightened sensitivity was evident as a lowering of the Lowest Observed Effect Concentration of zinc in diets that suppressed growth. Though this shift in response to a toxicant is subject to variability, the fact that it was observed should make researchers and regulators aware of the potential significance of dietary influences on bioassays of pollutants. / Graduation date: 1995