A New Device for Collecting Drifting Semibuoyant Fish Eggs

Abstract

Several fish species in lotic systems are pelagic broadcast spawners that produce nonadhesive, semibuoyant eggs that drift downstream. This reproductive strategy and egg type appear to be common in Plains stream cyprinids in the west-central United States. Although it is relatively easy to capture semibuoyant eggs, the inability to provide species-specific identification of this life stage has hindered studies on the reproductive ecology and life history of these fishes. While drift nets have been used to collect semibuoyant eggs, the process of separating the reproductive products from other organic drift was time consuming and usually fatal for eggs. We developed a field sampling device, the Moore egg collector, that allowed for the efficient, quantitative, and nondestructive collection of large numbers of semibuoyant fish eggs and that could aid in the study of a variety of organisms that employ drift as a dispersal strategy during a portion of their life history.