History and ecology of wild‐captured crawfish in Louisiana

Abstract

The lower Mississippi River floodplain has historically been harvested for wild crawfish since the 1800s. Changes in seasonal hydrology align with the life history of the red swamp crawfish Procambarus clarkii and the white river crawfish P. zonangulus, making them primary targets for commercial and recreational harvesters. The goal of this study was to use over 20 years of long‐term data from Louisiana to evaluate the association of river stage and local precipitation with crawfish harvest.Crawfish landings data from 1999 to 2022, in addition to monthly Atchafalaya River stage height and monthly precipitation, were used to evaluate potential (delayed) effects of the environmental variables across a range of months.Annual wild crawfish landings averaged 5 million kg at a value of US$10 million, with 90% of statewide landings historically from the Atchafalaya River basin. We found two clusters of the effect of river stage on crawfish landings: (1) late‐fall (November and December) river stage significantly increased the early crawfish season (February) landings; and (2) winter (January and February) river stage significantly increased the March and April crawfish landings. Precipitation was only found to have an effect in one monthly combination.The wild crawfish fishery is viewed as an annual crop with little regulation, and this status may continue into the future. However, we have now quantified the effects of environmental variables associated with harvest, providing a deeper understanding of the river–crawfish relationship. These results may assist the future management of crawfish if harvest increases or if the river system experiences extreme (flow) conditions.