Growth, age at sexual maturity, longevity and natural mortality of Alpheus brasileiro (Caridea: Alpheidae) from the south-eastern coast of Brazil

Abstract

We estimated the growth patterns, age at the onset of sexual maturity, longevity, and natural mortality of the snapping shrimp Alpheus brasileiro Anker, 2012. The sampling occurred monthly from April 2015 to March 2016 in the estuarine intertidal zone of Cananéia, São Paulo, Brazil. To estimate the growth parameters, all cohorts were adjusted to the Bertalanffy growth model. Longevity was estimated by the inverse growth equation. Natural mortality was calculated following the decrease in abundance over time of each cohort. We obtained the following estimates: CL_∞ = 9.49 mm, k = 0.0077 day^-1 (1.64 year^-1), t₀ = - 0.7628 for males, and CL_∞ = 9.31 mm, k = 0.0095 day^-1 (1.32 year^-1), t₀ = 0.0374 for females. The estimated age at the onset of morphological sexual maturity was 94 and 74 days for males and females, respectively. Females take 89 days to reach functional maturity, and have a higher mortality (4.35 year^-1) than males (3.67 year^-1). We rejected the hypothesis that males and females of A. brasileiro have the same growth patterns, longevity, mortality and, reaches sexual maturity at the same age. Our results suggest that physiological aspects and energy allocation strategies modulate the growth, longevity, and mortality of these snapping shrimps.

Keywords:
Cananéia; intertidal zone; life history; sex allocation; snapping shrimp