North Terceira is an important area for undefined aggregations of one shark species.

In the Azores Exclusive Economic Zone, scientific surveys were conducted annually using benthic longlines divided into depth strata of 50 m intervals across 0–1,200 m and consisting of a mainline unit composed of four skate sides ~45 m long with ~30 hooks with soak times between 4–6 hours (Pinho et al. 2020; Das et al. 2022). Between 2010–2017, 256 fishing sets (554,360 hooks) were deployed in the depth range where the species have been recorded regionally in the longline surveys (0–650 m; E Giacomello & D Das unpubl. data 2025). Of the 256 fishing sets deployed, 13 (5.1%) were inside this area and of 286 Tope captured between 2010–2017 in 69 sets, 113 (39.5%) were caught inside this area (E Giacomello & D Das unpubl. data 2025). Six of these fishing sets recorded >10 Tope caught on a single fishing set, of which four were recorded in this area (E Giacomello & D Das unpubl. data 2025). Catch-per-unit-effort (individuals/1,000 hooks) in this area was the highest across the Azores and ranged between 0.7–8.5 (average = 2.9), while outside this area ranged 0–7.9 (average = 0.3; E Giacomello & D Das unpubl. data 2025). Within the Azores, it has been reported that Tope catches increase in shallow waters (<150 m) with larger catches of smaller sharks in nearshore habitats (Santos et al. 2020).

In addition, local ecological knowledge supports the importance of this area for aggregations of Tope. Of 163 fishers interviewed in 2020 on all nine islands of the Azores Archipelago, 56 reported observing Tope aggregations (36 from São Miguel Island and 20 from Terceira Island). Among the 20 that observed aggregations around Terceira Island, 14 identified specific locations, with half of them explicitly indicating this area, while the remaining indicated the west coast (n = 3) and the southwest coast (n = 4). These aggregations were described as occurring year-round, typically involving around 10–20 individuals, including both juveniles and adults (Soares 2021). Fishers reported the presence of aggregations here more frequently than in other islands of the archipelago (Soares 2021). Aggregations of juvenile and adult Tope have been recorded in coastal areas where high catches of the species occur (Lucifora et al. 2004; Nosal et al. 2021). Additional information is required to understand the nature and function of these aggregations.