“…Thus, fine‐scale changes in somatic growth, or fish size‐at‐age, can be back‐calculated from otolith increment measurements [17]. Otoliths of some atherinid species, such as Atlantic silversides ( Menidia menidia ), have been validated for use in age and growth studies [18]; however, to our knowledge, validation has not been completed for otoliths of topsmelt ( Atherinops affinis ), a model marine species used in the growth and survival tests required by the U.S. Environmental Protection Agency (U.S. EPA) in effluent toxicity studies [6]. Otoliths have been used to investigate how environmental stressors, such as temperature, oceanographic processes, and food availability, alter fish growth rates [4,19,20], but to our knowledge, otolith growth rate analysis has not been applied to studies of toxicant effects on the growth rates of toxicity test species.…”