Rights for the Patagonian Shelf

Image: onesharedocean.org

Image: onesharedocean.org

By Darlene Lee

The Patagonian Sea and the Patagonian Shelf 

Patagonia, a vast semi-arid plateau in South America, derives its name from “Patagones,” a Portuguese label for the region’s indigenous Tehuelche people.[1]

Famed for its wildlife, many species thrive in Patagonia, including several types of bat, hairy armadillos, red and gray foxes, weasels, and pumas. The unique Patagonian mara, a relative of the guinea pig, is common to the area. It looks like a jackrabbit and lives only in Argentina. Herds of guanaco, a pretty cousin of the camel, are also a common sight.

The surrounding marine region has one of the largest and most productive ecosystems in the Southern Hemisphere. Conservationists have given the name Patagonian Sea to this horseshoe of water wrapped around the southern cone of South America.


Marine conservationist Claudio Campagna, now partnering with Earth Law Center, pushed for the new name to highlight the sea’s stunning wildlife. In 2011 he said: “We invented the term ‘Patagonian sea’ in an attempt to shift the focus of attention towards the diversity of marine species: the wildlife spectacles in and around the sea.”[2] The name Patagonian Sea tells the world that the marine area is as wild and dramatic as its terrestrial counterpart.  

The term Patagonian Shelf refers specifically to the Atlantic side, alongside the coasts of Uruguay, Argentina and the Falkland Islands. The Shelf is nearly 3 million square kilometers and has a coastline of over 800 kilometers.[3]

Why is the Patagonian Shelf so important?

The Patagonian Shelf is a highly productive ecosystem due to the mixing of the warm saline waters of the Brazil Current and the cooler, nutrient rich sub-Antarctic waters.[4]

Home to nearly 4,000 known species,[5] 44 of the world’s 129 species of marine mammals can be found here. These include seven species of baleen whales, and 27 species of toothed whales (including dolphins, porpoises and killer whales). The La Plata River dolphin, Austral dolphin, and Commerson dolphin live only in this region.

The Commerson dolphin is also known as the skunk dolphin or the panda dolphin because of its sharply delineated black and white skin patterning. The smallest cetacean in the Antarctic Seas, adults grow to just 1.5m (5 feet).[6] Speedy, active swimmers, they often surf on breaking waves close to the shore and swim behind fast boats. Generally found in groups of 10 or less, their preference for living near the shore makes them particularly vulnerable to entanglement with fishing gear.[7]

The Patagonian Shelf is home to almost a third of the known species of pinnipeds, including the South American Sea Lion, the South American Fur Seal and, the largest carnivore in the world, the Southern Elephant Seal. Four of these species breed on the Uruguayan and Patagonian coasts and six have a frequent or occasional presence while migrating beyond their territories in Antarctic waters.


Among the area’s seabirds, penguins represent the largest biomass. Volunteer Point shelters the largest colony of King Penguins in the Falkland Islands. An estimated 1000 King Penguins breed here and forage in the Patagonian Shelf. Magellan Penguin colonies dot the coasts of Argentina, southern Chile and the Falkland Islands. One of the largest colonies is on the Isla Martillo in the Tierra del Fuego, Argentina.  Unfortunately, chicks visited and handled by tourists on Isla Martillo develop a stress response that weakens their immune system.[8]  

There are 147 recorded marine and coastal bird species nesting in the Patagonian Shelf region. [9]

The number of Falkland Skuas has dropped by half in just five years, according to a survey of their largest breeding ground on New Island, west of the Falkland Islands.[10] Dr Paulo Catry of Portugal’s Museum of Natural History, who conducted the survey, notes, "If something is not well with them, it may mean that something is not well with the rich Patagonian Shelf ecosystem.”[11]

The Patagonian Shelf also serves as a migration corridor for penguins, turtles and whales.[12]  From April to September Magellan Penguins migrate northward, wintering off the coasts of Uruguay, Brazil and Chile.[13] The migratory corridor of the Southern Right Whales ranges from the calving and nursing grounds in the Golfo Nuevo in the north to the Falkland Islands in the south.[14] (Hunted to near extinction, the Southern Right Whales gained protection and have recovered at a rate of 6 to 7 percent over the past 40 years.)

What are the threats to the Patagonian Shelf?

All species in Patagonia face threats from overfishing, chemical and plastic pollution, invasive species, and climate change.[15]


Fish populations have dramatically decreased in the last decade due to increased fishing and accidental bycatch. Fishery management has been motivated by political interests and not by the protection of marine resources. As a result, over 70 percent of fish stocks are either overexploited or have collapsed in the Patagonian Shelf.[16] These include hake, squid, mackerel, corvina and shore ray.

Non-selective fishing methods, such as bottom trawling and longlines, are also leading to non-target species declining in the Shelf. The Consortium for Wildlife Bycatch Reduction notes that: “Longline bycatch is the principal cause of a global decline in albatross populations, including that of the endangered black-browed albatross. The species is the most common bycatch species in many longline fleets, including those fishing for swordfish off Chile, and for Argentine toothfish and kingclip on the Patagonia shelf. A significant decrease in black-browed albatross populations has been observed at the Falkland Islands, home to 80 percent of breeding pairs.”[17]

High shipping and oil tanker traffic has created “chronic oil pollution” in some areas of the Shelf. Major oil spills and contaminated ballast water discharge have particularly affected species such as penguins during their migratory movements along the coast. The Magellan Penguin is one of the most affected by oil contamination and thus a reliable indicator of the number of incidents. Oil spills kill 20,000 adults and 22,000 juveniles every year off the coast of Argentina. Displaced fish populations resulting from climate change also mean that new penguin parents must swim an extra 40 kilometers to find food, increasing the risk of their mates and chicks starving to death. The increase in rain storms also causes chick death because young birds haven’t yet grown waterproof feathers and are vulnerable to hypothermia when they get wet. As a result, 12 of 17 penguin species are experiencing rapid population declines.[18]

The Patagonian Shelf “experiences slight to moderate toxic chemical pollution.”[19] The following pollutants have been detected:

  • hydrocarbons derived from oil;
  • heavy metals;
  • persistently toxic substances (PCB); and
  • discharged urban effluents which kill animal life by eutrophication (lack of oxygen due to uncurbed plant growth from excessive nutrients) and solid waste.

These pollutants have not only been detected in the sea water but in the animals inhabiting the area. For example, high cadmium concentrations have been found in the Commerson dolphin.

Near cities, pollution from sewage, industry, and harbors adds to the ecosystem stresses and affects key marine mammals at their most vulnerable – for example, Southern Right Whales during their breeding and calving activities.[20] Southern Right Whales, like most whales, give birth in shallow warm waters[21] since newborns lack a thick layer of blubber leaving them vulnerable to cold and also lacking the buoyancy and strength for open ocean voyages.[22] Whale mothers stay in the same coastal waters for several months until their calf is strong enough for a migration – in the case of the Southern Right Whale, to feeding grounds in the Southern Ocean.[23] Raw sewage discharge into the Shelf has led to microbial pollution, exceeding international recommended levels and causing toxic red tides.


  • Severe contamination in ports can lead to malformation and local extinction of coastal species.  For example tributyltin (TBT) causes breeding problems in sea snails on the Argentine coast. TBT is a pollutant from the special paint used to coat ship hulls.[24]
  • Plastic causes malnutrition, mobility problems, disease and death when wild marine vertebrate species, especially turtles, birds and mammals, mistake plastic waste for food. Birds, seals, elephant seals and cetaceans also suffer from fatal entanglement in discarded fishing gear.

Invasive species

The accidental and intentional introduction of non-native species has led to decreased biomass of native and keystone species, endangering biodiversity.[25]

  • 41 non-native species have been reported in the Patagonian Sea. At least 20 living in coastal areas negatively impact ecosystems. Invaders include plants, sea worms, mussels, snails, barnacles, crabs, and fish.
  • Wakame (edible seaweed) covers large extensions of the seabed in gulfs and bays of the Argentine coast of central Patagonia, causing changes in biodiversity and economic losses owing to the degradation of bivalve banks.  
  • Possibly two non-native salmon species may have negative effects on penguin populations due to competition for food[26] including squid, hake, sprat and hagfish.[27]

Climate Change

The Shelf has experienced a gradual warming since the late 1950s, measuring 0.06 degrees centigrade warmer in 2012. Rising sea temperature is suspected to be the cause of the annually recorded high mortality of Southern Right Whale juveniles in the Patagonian Atlantic as warmer water has led to a scarcity of prey in the whales’ South Atlantic summer foraging area.

Rising sea temperatures have also reduced prey for adult female whales, potentially explaining the poor nutrition of whale calves in their first weeks of life.[28] Additionally, ocean acidification from increased carbon absorbed by the world’s oceans has resulted in harmful algal blooms (red tides). Toxins produced by these organisms have recently caused a sharp increase in seabird mortality.

What is being done to protect the Patagonian Shelf?

Recent decades have seen unprecedented advances in the science needed to design appropriate conservation plans for the Patagonian Sea. The scientific, civil society, and government sectors have effectively collaborated to identify the areas most important for ensuring that this seascape maintains its marine identity and ecological functions.

Such strategic and collaborative work, only possible through multinational and multidisciplinary alliances, has achieved unparalleled government commitments to making a long-lasting impact on the preservation of the Patagonia seascape. Countries are working to protect at least 10 percent of their national waters by 2020, in accordance with the Aichi Biodiversity Targets set by the Convention on Biodiversity.[29]

Why does the Patagonian Shelf need legal rights and what does that mean?

Marine protected areas are an important step forward in ocean protection, but humankind’s  dominant culture of wasteful consumption continues to pollute and degrade marine ecosystems. We now have the chance to go further by shifting the entire paradigm. When the Patagonian Shelf has legal rights the dominant culture will adapt to consider the ocean’s needs alongside human needs.

The drive for legal rights for the ocean emphasizes ocean health as the top priority. It means evaluating human activities by their impact on the ocean’s natural rhythms and cycles.

Legal Rights for the Patagonian Shelf means:

  • humans create a sustainable relationship with marine species and ecosystems; 
  • protection and restoration are legal responsibilities;
  • management boards (or ‘guardians’) ensure that human activities do not violate the rights of species and ecosystems.

Looking after the ocean now will save its wonders for future generations. Special thanks to Mission Blue who has designated the Patagonian Shelf project a Hope Spot, a place recognized for being critical to the health of the ocean—Earth‘s blue heart. Hope Spots are about recognizing, empowering and supporting individuals and communities around the world in their efforts to protect the ocean.

How can I help?

  • Share Earth Law news on social media
  • Research your local ocean protection organization and participate
  • Join the movement by volunteering and supporting Earth Law Center
  • Volunteer for this initiative by emailing dlee@earthlaw.org

Organizations who signed onto Earth Law Center’s Call to Action at the United Nations Ocean Conference in June 2017 featured below:


[1] https://www.britannica.com/topic/Tehuelche-people

[2] https://news.mongabay.com/2011/09/sowing-the-seeds-to-save-the-patagonian-sea/

[3] https://en.wikipedia.org/wiki/Patagonian_Shelf

[4] http://www.mpatlas.org/campaign/patagonian-shelf/

[5] http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0014631

[6] https://en.wikipedia.org/wiki/Commerson%27s_dolphin

[7] http://us.whales.org/species-guide/commersons-dolphin

[8] https://en.wikipedia.org/wiki/Magellanic_penguin

[9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3031619/

[10] http://news.bbc.co.uk/earth/hi/earth_news/newsid_9447000/9447159.stm

[11] http://news.bbc.co.uk/earth/hi/earth_news/newsid_9447000/9447159.stm

[12] https://marpatagonico.org/index.php/en

[13] https://www.researchgate.net/publication/226459043_Winter_migration_of_Magellanic_penguins_Spheniscus_magellanicus_from_the_southernmost_distributional_range

[14] http://icb.org.ar/Publicaciones/SC_66a_BRG_22.pdf

[15] http://us.whales.org/wdc-in-action/commersons-dolphins-and-other-species-of-southern-patagonia-argentina

[16] http://lme.edc.uri.edu/images/Content/LME_Briefs/lme_14.pdf

[17] http://www.bycatch.org/focus-species/black-browed-albatross

[18] https://en.wikipedia.org/wiki/Magellanic_penguin

[19] http://lme.edc.uri.edu/images/Content/LME_Briefs/lme_14.pdf

[20] http://wwf.panda.org/about_our_earth/ecoregions/patagonian_southwest_atlantic.cfm

[21] http://oceanadventures.co.za/southern-right-whales-distribution-and-reproduction/

[22] https://www.wildaboutwhales.com.au/whale-facts/about-whales/whale-migration

[23] https://data.marinemammals.gov.au/arwpic/index.php?route=information/information&information_id=9

[24] https://marpatagonico.org/index.php/en/patagonian-sea/threats

[25] http://lme.edc.uri.edu/images/Content/LME_Briefs/lme_14.pdf

[26] https://marpatagonico.org/index.php/en/patagonian-sea/threats

[27] http://animals.mom.me/magellanic-penguin-2467.html

[28] https://marpatagonico.org/index.php/en/patagonian-sea/threats

[29] https://medium.com/wcs-marine-conservation-program/scaling-up-marine-protection-in-patagonia-2c94001957b