The Río de la Plata — the world's widest river estuary at its mouth — drains the Paraná-Paraguay-Uruguay river system through Argentina and Uruguay. The basin encompasses the Pantanal, Gran Chaco, Atlantic Forest, and Pampas — extraordinary biodiversity facing intense agricultural pressure.
Conservation measures include: artisanal fisheries gillnet modifications; observer programs; area closures during high-risk seasons; and collaboration with fishing communities on alternative gear. Progress has been slower than needed given mortality rates. Brazil, Uruguay, and Argentina coordinate under regional conservation plans with limited enforcement capacity.
Capybara — the world's largest rodent — thrive along Paraná floodplains and other wetland edges. They are highly social (groups of 10-20), semi-aquatic animals. Welfare challenges include: commercial hunting in some areas for meat and hide; agricultural conflict as capybaras damage crops and are poisoned or shot; and tick-borne disease (Rocky Mountain spotted fever vectors) that leads to mass culling programs in periurban areas.
Capybara farming in Venezuela and Colombia provides an alternative to wild hunting, but farm welfare standards are poorly defined. Captive capybaras require social housing, water access for swimming, and adequate space — conditions not always provided.
The dorado (Salminus brasiliensis) — a powerful migratory fish reaching 30kg — is the Paraná's apex sport fish and an important protein source. Catch-and-release sport fishing has significant welfare implications: hooking injuries, air exposure, exhaustion from fighting, and handling stress. Best practice guidelines (wet hands, quick release, no removal from water) reduce post-release mortality but compliance varies widely among recreational fishers.
The Pampas wetlands — critical habitat for marsh deer, caimans, and waterbirds — have been drained at alarming rates for soy and rice agriculture. Marsh deer populations have declined as wetland habitat contracts. Animals pushed into remaining habitat patches face crowding, reduced food quality, and increased predator pressure. Esteros del Iberá in Argentina — a major rewilding project — is restoring wetland habitat and reintroducing giant anteater, tapir, peccary, and jaguar.
Rewilding Argentina's Iberá project represents one of South America's most ambitious wildlife welfare interventions. Jaguars — absent for 70+ years — were reintroduced from Pantanal stock beginning 2021. Giant anteaters, tapirs, and peccaries have been reintroduced to former ranges. Each successful reintroduction restores natural behavior, social structures, and life history patterns to species that evolved in these ecosystems — a direct welfare benefit over captive or fragmented populations.