Sharks and skates in the Comau Fjord, northern Patagonia, Chile: an elasmobranch species checklist with biological aspects

Fjord ecosystems serve as crucial habitats for elasmobranchs, supporting them across all life stages. Chilean Patagonia provides one of the most complex and extensive networks of fjord ecosystems in the world, displaying high marine biodiversity, including elasmobranchs. However, little is known about this ecologically important group of fishes in these ecosystems. This study investigates the biodiversity of elasmobranchs in the Comau Fjord over a period of 6 months by combining morphological and molecular data. In total, 309 specimens within a radius of 7.5 km were recorded, belonging to six families and nine species: Hexanchus griseus (77.5-178 cm L_T), Notorynchus cepedianus (180.6 cm L_T), Schroederichthys bivius (35-65.2 cm L_T), Scymnodon macracanthus (37.3 cm L_T), Centrophorus squamosus (87.4 cm L_T), Deania calceus (58.3-98.6 cm L_T), Squalus acanthias (25.5-101.1 cm L_T), Dipturus chilensis (62.9-152 cm L_T), and Dipturus trachyderma (69.8-194 cm L_T). This included records of three species previously unknown in the fjord and was equivalent to nearly 20% of the elasmobranch richness found in Southern Chile. The results further suggest that the Comau Fjord could be a primary nursery ground for several species of elasmobranchs. This is the first time that a species inventory of elasmobranchs is conducted in a Chilean fjord system. The outcomes of this research provide an elasmobranch species checklist with biological aspects from the Comau Fjord, which are essential data to inform decision makers, conservation managers, and future research.