Movements and behavior of satellite-tagged yellownose skate (Dipturus chilensis) and roughskin skate (Dipturus trachyderma) in southern Chile

Dipturus chilensis and D. trachyderma are two species of skates found on the continental shelf and slope around the southern tip of South America. As another batoids, their life traits make them more susceptible to overfishing. In Chile, the skate fishery covers around twenty latitudinal degrees and is captured as a target species by artisanal vessels from the central-south zone to the Patagonian fjords (south of 41°S). Seven individuals of D. chilensis and three of D. trachyderma, 75-110 cm total length (TL), were tagged with pop-up satellite tags programmed to detach 60 days post-tagging. The skates were tracked in two areas of southern Chile, one exposed to the Pacific Ocean (Bahía Mansa) and another within the Patagonian fjords of the Chiloe inland sea (Comau Channel). Bathymetric ranges of 9-512 m and temperatures of 7.7-11.5°C for D. chilensis and depths of 111-513 m with temperatures of 10.5-11.5°C for D. trachyderma were detected. The minimum horizontal movement varied between 0.84 and 35.95 km in D. chilensis and 2.59 and 33.90 km in D. trachyderma. Notably, D. chilensis was found at significantly shallower depths at night, with differences between zones and higher levels of vertical activity in Comau. Both species showed daily vertical movements of up to 1.4 km, displaying movement patterns associated with different modalities of foraging. The median vertical speed was up to 0.18 TL s-1, suggesting that both species could primarily utilize nektobenthic diel vertical migration to move to and from the coast.