Canelones-Maldonado is located off the coast of Canelones and Maldonado departments in Uruguay. The area is situated in the Joint Regime Area of Argentina and Uruguay (Flanders Marine Institute 2023). It sits on the continental shelf around La Plata River. It is characterised by turbid waters and sandy substrates with mud patches. The area is influenced by a vertical stratification in salinity, which can vary from 15–30 ppt depending on wind force and freshwater discharge (Jaureguizar et al. 2003). Mean bottom water temperature is 20°C during the warm period (December–March) and 10–12°C during the cold period (June–September). During each period, estuarine waters are almost fully thermally homogeneous both vertically and horizontally (Guerrero et al. 1997). Other environmental conditions, such as salinity and turbidity are highly influenced by neighbouring surface marine currents (Brazil Current and Patagonic Coastal Current) (Jaureguizar et al. 2016). The location of the Rio de la Plata plume (i.e., freshwater with high turbidity) across the South Atlantic Coastal System exhibits important and significant seasonal and inter-annual variation. This variation is associated not only with the interaction between the shelf water masses and the discharge pattern of the plume but is also highly influenced by wind seasonality (Jaureguizar et al. 2023).

This Important Shark and Ray Area is benthic and pelagic and is delineated from inshore and surface waters (0 m) to 50 m based on the bathymetry of the area