Understanding the feeding ecology of the broadnose sevengill shark (Notorynchus cepedianus) in Patagonia, Argentina

The broadnose sevengill shark (Notorynchus cepedianus) is classified as Vulnerable by the IUCN, and its population in the Southwest Atlantic is declining. Despite some progress in understanding the ecological requirements of the sevengill shark, there are still several information gaps. Essential aspects of its trophic ecology, such as main prey items or key feeding grounds, remain uncertain and this information is essential for developing effective conservation strategies. Stable isotopes and spontaneous regurgitations were analyzed to describe the trophic ecology of sevengill sharks within a marine protected area (MPA) of Peninsula Valdés in Patagonia, Argentina. Analysis of spontaneous regurgitations revealed that the southern elephant seal (Mirounga leonina) was the primary prey item (70%) for the sevengill shark, during abundance peaks of both species in the MPA. However, the stable isotope analysis indicated that the teleosts were the main prey item, and the overall contribution of the elephant seal to the diet of the sevengill shark was around 30%. In addition, the contribution of each prey group varied with the size of the individuals. The estimated trophic position was 4.43, placing the species among the apex predators of the region. This study confirmed the use of the MPA as an essential foraging ground and contributed to identifying its main prey items. Also, it reflects the need to expand conservation tools beyond this particular coastal protection.

Fil: Funes, Manuela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Fil: de Wysiecki, Agustín María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina

Fil: Bovcon, Nelson Darío. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; Argentina

Fil: Jaureguizar, Andrés Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina

Fil: Irigoyen, Alejo Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina