Work

Age, growth, maturity, and natural mortality of the smalltooth sawfish (Pristis pectinata) in Florida waters

Year: 2025

Type: article

Abstract: Accurate estimates of age, somatic growth, maturity, and natural mortality are essential for effective conservation of endangered species. This study resulted in updated growth data and the first direct assessments of length at maturity and age at maturity for the endangered smalltooth sawfish (Pristis pectinata). A Bayesian approach using the von Bertalanffy growth function was used to combine vertebral band counts, mark-recapture data, and results from increment analysis to estimate somatic growth and to derive age at maturity and natural mortality rates. Smalltooth sawfish grow rapidly in their first 3 years, reaching 235 cm stretch total length (STL), 3.2 times their mean length at birth (73.7 cm STL), before growth slows. Asymptotic length was 446 cm STL for males and 484 cm STL for females, with a Brody growth coefficient of 0.178 year−1 for males and 0.170 year−1 for females. We directly estimated median age at maturity as 6.9 years for males and 7.9 years for females, similar to previous indirect assessments. Constant natural mortality was estimated to be between 0.151 and 0.278 on the basis of life history surrogates. The oldest individual examined in this study was a 30.1-year-old female, confirming that the species exceeds 30 years in the wild. These results are vital for refining population recovery models, and they underscore the need for ongoing monitoring and data collection to support long-term recovery efforts.

Source: Fishery Bulletin

DOI: 10.7755/fb.123.3.5