Rocky reefs from Patagonia argentina
Temperate rocky reefs in Patagonia Argentina are productive areas that support highly diverse communities of invertebrates, algae and fishes. Rocky outcrops form complex structures which offer a great variety of microhabitats, this in turn, leads to a great variety of species co-existing. As such, these rocky reefs provide important marine ecosystem services for the recreational fishing and scuba diving activity in the region, and have educational and scientific research value as well.
Why they are important?
Temperate rocky reefs in Patagonia Argentina are productive areas that support large communities of invertebrates, algae and fishes. Even though the total area of rocky bottoms is considerably lower than soft bottoms in the Patagonian shallow shelf (<30 m depth), many species including macroalgae depend exclusively on the hard substrate to settle. Complex structures on rocky reefs offer a great variety of microhabitats, this in turn, leads to a larger variety of species co-existing. Small rock caves also give shelter to fish species that reside in rocky reefs all their adult life. Therefore, we can consider rocky reefs as an “oasis” of biodiversity among large extensions of homogeneous soft bottoms coastal ecosystems. Despite its high ecological importance, these habitats have received limited attention.
In the last 19 years only 4 studies (Genzano et al., 2011; Irigoyen et al., 2011; Rechimont et al., 2013; Bravo et al., 2015) include benthic communities of hard subtidal shallow bottoms of Argentina. From these none of them were focused on describing the entire benthic community of rocky reefs in Patagonia Argentina. There is only one baseline study that was done 50 years ago on some shallow reefs in Nuevo Gulf, but the communities of the overhang areas and deeper than 5 m were not described. Most of the available information along the Patagonian coast is about rocky intertidal communities (Bertness et al., 2006; Liuzzi and López Gappa, 2008; Liuzzi et al., 2011; Rechimont et al., 2013; Adami et al., 2018) or rocky reefs fish communities (Irigoyen, 2006; Venerus, 2006; Galván et al., 2009; Venerus et al., 2014).
We must start studying Patagonian rocky reef benthic communities in more detail because understanding the present state of local and regional benthic biodiversity is critical to detect future changes in species composition that may occur in those areas. The majority of the known species that are present in rocky reefs have a restricted temperature ranges that determine the optimum region to live in. If sea temperature increases in the upcoming years due to global warming, species range shifts may occur. The results of this study will advance the knowledge of rocky reef species distribution and will be useful to create mathematical models to predict changes. These models can give us an idea of potential species range shifts (which species and geographical distribution) if the sea temperature increase 3.1 ± 0.6 °C, which is estimated for 2100 (RCP8.5 scenario).
Sub-aquatic tourism areas (STA)
Rocky reefs within Nuevo Bay, where Puerto Madryn is located, are utilized as ‘sub-aquatic tourism areas’ (STA). STAs are of interest for sustainable tourism development and conservation. These areas are chosen because of desirable characteristics such as clear waters, shallow rocky reefs (<15 m depth), proximity to the city, impressive underwater scenery and high biodiversity. The local government has established a legislation (Decreto No 1998/13 2013) where only recreational and scientific diving is allowed inside STAs.