Predicting the abundance of white shrimp ( Litopenaeus setiferus) from environmental parameters and previous life stages

Abstract

White shrimp ( Litopenaeus setiferus) landings in Louisiana display substantial intra- and inter-annual variability. This variability reflects the stochastic impacts of environmental factors that influence growth, mortality, and subsequent survival in a given year, a situation that frustrates attempts by fisheries managers to predict future abundance. We developed a recursive three-equation model for predicting Louisiana white shrimp abundance and subsequent catch based on lagged life-stage counts and environmental parameters such as temperature, river discharge, and cumulative wetland loss. The estimated model demonstrated a significant and positive relationship between early life stage abundance and temperature and salinity. At the same time, wetland loss and high river discharges were related to lower abundance. Biological factors such as numbers of juvenile shrimp at early life stages predicted late juvenile abundance, with a similar relationship existing between late juveniles and adult catch per unit effort (CPUE).