Ecological plasticity and habitat connectivity in Pristis pectinata: Life-history reconfiguration across the freshwater-estuarine-marine continuum

The smalltooth sawfish, Pristis pectinata, exhibits a highly specialized association with shallow estuarine environments while retaining the capacity to occupy freshwater-influenced and adjacent coastal habitats. Here, we synthesize the ecological plasticity, reproductive biology, nursery dependence, ontogenetic habitat use, population decline, and conservation of P. pectinata across the freshwater–estuarine–marine continuum. This species-specific synthesis was derived from a broader comparative review of coastal elasmobranchs and integrates evidence from the literature on distribution, reproduction, habitat use, movement ecology, nursery environments, and conservation. Pristis pectinata is characterized by an estuarine-centered life-history strategy: juveniles occupy shallow mangrove shorelines, tidal creeks, river mouths, and protected embayments, while responding dynamically to salinity, freshwater inflow, and other environmental conditions. Rather than exhibiting a simple freshwater-to-marine transition, individuals maintain prolonged estuarine residency before progressively expanding their spatial use toward coastal marine habitats. Low fecundity, relatively large neonates, prolonged juvenile development, and strong nursery fidelity further increase the demographic importance of these connected habitats. The resulting pattern indicates that ecological plasticity in P. pectinata is expressed not primarily through extensive freshwater dependence, but through dynamic habitat use within an interconnected estuarine-centered system. Within the Dynamic Environmental Reconfiguration Hypothesis framework, the species provides an example in which environmental transitions form an active component of life-history organization, linking reproduction, nursery residency, ontogenetic development, and coastal expansion. Conservation of P. pectinata therefore requires not only reduction of direct anthropogenic mortality but also maintenance of the functional connectivity among freshwater-influenced habitats, estuarine nurseries, and coastal marine environments.