Morphometric analysis to aid fisheries management of two threatened guitarfish species (Pseudobatos horkelii and Pseudobatos percellens)

Abstract

This study aimed to provide data for fisheries management of two threatened guitarfish species, by using linear and geometric morphometric analyses. Linear morphometrics (LM) has limitations in determining minimum catch sizes, whereas geometric morphometrics offers a robust approach to quantifying body form variations with the potential to influence metrics set by legislation. Based on LM analysis, Pseudobatos horkelii were larger than Pseudobatos percellens. Based on geometric morphometric analysis body form differed between the two species, particularly in the head, disk, and posterior region. P. percellens were also sexual dimorphic in body form. Our findings provide valuable insights into permissible catch size limits of these threatened guitarfish and also contribute to improvement of fisheries management strategies where catch is still allowed. The study underscores the necessity of species-specific and sex-specific management directives to effectively ensure the population recovery of both guitarfish species.