Collaborative effort between fishers and scientists reveals first-time evidence of the smalltooth sandtiger shark (<i>Odontaspis ferox</i>) in Puerto Rico

Abstract Studying deep-water shark species presents inherent challenges stemming from the difficulty in accessing their habitats, coupled with factors such as low population densities, intricate behaviours, and complex biological attributes. The integration of citizen scientists, particularly fishers, offers a valuable avenue to make use of their life-long insights and expertise, thus facilitating the acquisition of crucial data that can effectively enhance the realm of shark research. Our collaborative engagement with fishers since 2017 has yielded an extensive documentation concerning elasmobranchs in the Caribbean region of Puerto Rico providing a unique opportunity to formally record species hitherto unreported. This is exemplified by the first documentation of the smalltooth sandtiger shark ( Odontaspis ferox (Risso, 1810)). Despite its broad geographic range and widespread distribution in temperate and tropical marine environments, there is a lack of comprehensive scientific understanding and limited available knowledge regarding this species. A noteworthy finding on December 30, 2020, near Rincón (northwest coast) in Puerto Rico, disclosed a large shark that an experienced fisher had captured as an unidentified by-catch at a depth of 325 m. Through an interdisciplinary approach using molecular (355 bp, Cytochrome Oxidase Subunit 1) and morphological techniques, we successfully confirmed the identity of the specimen as a female smalltooth sandtiger shark. Given the limited information available (e.g., diversity, abundance, behaviour, reproduction, distribution) on shark species in the coastal and deep waters of Puerto Rico, this report provides valuable new data that can significantly contribute to the conservation efforts to protect these enigmatic yet ecologically vital predators.