Effects of Marsh Management on Fisheries Organisms: The Compensatory Adjustment Hypothesis

An overview of data including numbers of species, numbers of individuals, biomass, and average weight per individual from three studies of differing marsh management systems in southwestern Louisiana indicate that populations of managed systems are generally maintained despite partial restrictions on organism movements due to water control structures. At some high level of restriction, perhaps in systems completely leveed and managed for specific target organisms, recruitment and subsequent export may be drastically reduced. However, we suggest that below a critical level of restriction, recruitment, growth, and eventual export approach normal levels. Restrictions may select for or against certain species, but the replacement of those selected against may maintain the overall fishery productivity of the system.