The Patagonian Sea is one of the most productive coastal-oceanic areas in the Southern Hemisphere, providing a great abundance of food for huge breeding aggregations of penguins, albatross, whales, dolphins, elephant seals, and sea lions. This ecosystem has global importance as a source of food for migratory species of birds, fish including sharks, turtles and marine mammals.
This seascape falls within the Southwest Atlantic Ocean (SWA), which has been identified as a hotspot for chondrichthyans — the class of cartilaginous fish that includes sharks, rays and chimaeras — due to the large number of native and endangered species found there. Several colleagues and I recently evaluated the conservation status of sharks, rays and chimaeras in the Patagonian Sea according to criteria identified by the International Union for the Conservation of Nature (IUCN) Red List of threatened species.
The assessment — to establish a baseline for further conservation actions — showed that more than the half of Patagonian Sea’s cartilaginous fishes are threatened with extinction.
Critically Endangered species in the region included the endemics (or those that live specifically in the SWA): guitarfishes (Pseudobatos horkelii and Zapteryx brevirostris), the narrownose smoothhound (Mustelus schmitti) and the Striped smoothhound (Mustelus fasciatus). Other Critically Endangered species were the sandtiger (Carcharias taurus) and the tope shark (Galerhinus galeus), the last of our species of focus in the region. All populations had declined by more than 80 percent in the last 40 years due to overfishing.
The principle activities threatening sharks, rays, and chimaeras include illegal, unreported and unregulated (IUU) fishing captures; by-catch or discarded species by bottom trawlers, gillnet fisheries, longline fisheries, and recreational fisheries; and other minor impacts resulting from contamination and habitat loss of coastal nursery grounds from aquaculture development.
“The Patagonian Sea ecosystem has global importance as a source of food for migratory species of birds, fish including sharks, turtles and marine mammals.”
Chile, Uruguay, Argentina, and Brazil have adopted their own National Plan of Action (NPOA) for Sharks, skates, rays and chimaeras. Argentina and Uruguay have also recently launched a Binational Plan of Action. Although the first NPOA was adopted in the region more than a decade ago, in order to protect these species, it seems like other measures and tools are urgently needed to reverse this decline.
Argentina is one of the top skate-landing countries but these capture statistics are not identified by species. This is a serious problem in most jurisdictions of the region as well, making it difficult to estimate skate catches and therefore create proper management measures at species level. Currently however, the level of extraction is monitored as an assemblage and regulated through the setting of fishing effort limits within different zones, with the observer data providing the detail on the species composition.
To improve the current conservation status of threatened species in the Patagonian Sea, we recommend the following measures among others:
· Create a Regional Fisheries Management Organization, focused in chondrichthyans species and with an ecosystem approach for the Patagonian Sea and influence areas, particularly between Argentina, Uruguay and Brazil.
· Implement traceability projects for imperiled commercial fishes shared by Patagonian Sea countries, enlisting NGOs to promote these initiatives and assist key stakeholders.
· Highlight threatened and endemic landed species in discussions via the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
· Strengthen and improve implementation of National Action Plans at the country level — with particular focus on improving the current coordination between different national and provincial fishery agencies, research institutions, fishing community and NGOs in Argentina.
· Argentina and Uruguay should sign the Convention on Migratory Species Memorandum of Understanding for highly migratory shark and ray species in order to develop a Patagonian Sea Regional Conservation Plan.
· Argentina and Brazil should sign the UN FAO’s Port State Measures Agreement to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated fishing (PSMA).
· Argentina should improve the skate catch species level reports as well as the export identification of all products from the commercial skate assemblage.
“Chile, Uruguay, Argentina, and Brazil have adopted their own National Plan of Action (NPOA) for Sharks, skates, rays and chimaeras. Argentina and Uruguay have also recently launched a Binational Plan of Action.”
· Create a Regional MPA Network focus on improving the current conservation status of most imperiled and endemic species of the Patagonian Sea.
With these actions adopted and implemented in the region and the information we have collected through our assessment, we believe we can significantly improve and strengthen protections for sharks, rays, and chimaeras in the Patagonian Sea.
Juan Martín Cuevas is a marine conservationist with the Argentina program at WCS (Wildlife Conservation Society). Since late 2015, he has been working to develop and implement a conservation plan for sharks and rays in the Patagonian Sea.