ESR prepress abstract  -  DOI: https://doi.org/10.3354/esr00868

Insights into reproduction and behavior of the smalltooth sawfish Pristis pectinata

Kevin A. Feldheim*, Andrew T. Fields, Demian D. Chapman, Rachel M. Scharer, Gregg R. Poulakis

*Email: kfeldheim@fieldmuseum.org

ABSTRACT: Sawfishes (Family Pristidae) constitute one of the most threatened families of marine fish and substantial management efforts are required to stabilize and recover their populations worldwide. Philopatry is common in marine animals, including sharks and rays, and can be a key driver of population structure, which in turn determines the most appropriate scale required for effective population assessment and management. We examined philopatry at 2 known smalltooth sawfish Pristis pectinata nursery sites in the Charlotte Harbor estuarine system, Florida (i.e. Caloosahatchee and Peace rivers) by reconstructing parental genotypes based on composite genotypes from dorsal fin clippings of offspring captured within the nurseries between 2004 and 2015. Of 55 reconstructed females, 45 clearly exhibited philopatry, most on a biennial cycle, to these nursery sites. Thirty-four females gave birth in the Caloosahatchee River, 19 gave birth in the Peace River, and 2 females used both nurseries for parturition. Nine females have been giving birth at these sites for a decade or more. Two females produced offspring with the same male over consecutive breeding seasons and one other pair of parents was identified at a 6-year interval, suggesting that females store sperm, use an unknown mating aggregation site, or both. Male genotypes (n = 192) were rarely seen more than once at these nurseries (n = 7). However, some males mated in consecutive years and successfully with multiple females within years. Evidence of parturition site-fidelity by smalltooth sawfish in Florida likely extends the time before range expansion would be expected.