Age, growth, and reproduction of the yellow-edged lyretail Variola louti (Forssakal, 1775)

Abstract

Groupers (Family Epinephelidae) are important to commercial, subsistence, and recreational fisheries throughout the world. Grouper species have complex life histories that make them more vulnerable to exploitation. While there has been extensive research on some, the majority of groupers lack sufficient life history information for proper management. The yellow-edge lyretail grouper, Variola louti, has life history gaps that need to be filled and lacks regional life history information for Guam. Age, growth, and reproduction were assessed from fishery-dependent samples collected from around Guam from 2010 to 2017. Variola louti ranged from 19.4 to 49.7 cm fork length (FL) and 2 to 17 years old. Due to the size selectivity of the fishery, a Bayesian von Bertalanffy growth model was applied. The von Bertalanffy growth parameters were L∞ = 43.7 cm FL, k = 0.28, and t0 = − 0.2. Protogynous hermaphroditism was confirmed with females reaching reproductive maturity at 26.0 cm FL (L50) and 2.6 years (A50) and female to male sex change at 35.3 cm FL (LΔ50) and 6.1 years (AΔ50). Sex ratio was 1.5 females per male, excluding transitional individuals. Using Hoenig’s method, natural mortality was estimated at 0.37 year−1. The life history of Variola louti suggests that it is a relatively fast growing and early maturing grouper that is not as vulnerable to exploitation as larger bodied, slower growing groupers. However, future monitoring of sex ratio, size at maturity, and size at sex change is recommended to track and manage fishery effects, such as the recent scuba spear ban in Guam, on the life history and population status of this species.