Sampling variability of ichthyoplankton surveys—Exploring the roles of scale and resolution on uncertainty

Abstract

We examine the accuracy of predictions from a conceptual model dealing with survey design in a variable environment using data collected from a number ichthyoplankton collections carried out off Newfoundland, Canada. We test predictions concerning the effects of spatial scale, survey resolution, as well as the impacts which variations in environmental forcing and survey duration have on the precision of population estimates. Although the size of the survey area does not appear to influence the precision of population estimates, the distance between stations, the variability in wind forcing of currents, and the time taken to cover the area of interest all have notable effects on precision. The significance which each of these variables may have on the ability to detect changes in population abundance is likely to vary depending on the underlying circulation that characterizes different ecosystems. Our findings, however, point to the potential benefits that may be derived from evaluating the possible influence of such variables on the precision of population estimates based on long standing monitoring programs. This may serve to explain why it has been so difficult to detect substantial changes in vital rates obtained in process-oriented research.