Patagonian Shelf
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LME 14: Patagonian Shelf

Bordering countries:

Argentina, Falkland Islands, Uruguay

LME total area:

1,173,332 km²

LME overall risk:

This LME falls in the cluster of LMEs that exhibit medium numbers of collapsed and overexploited fish stocks, as well as very high proportions of catch from bottom impacting gear.
Based on a combined measure of the Human Development Index and the averaged indicators for fish & fisheries and pollution & ecosystem health modules, the overall risk factor is high.

Productivity

Chlorophyll-A:

The annual Chlorophyll a concentration (CHL) cycle has a maximum peak (1.22 mg.m^-3) in November and a minimum (0.518 mg.m^-3) during August. The average CHL is 0.839 mg.m^-3. Maximum primary productivity (386 g.C.m^-2.y^-1) occurred during 2002 and minimum primary productivity (314 g.C.m^-2.y^-1) during 2005. There is a statistically significant increasing trend in Chlorophyll of 19.9 % from 2003 through 2013. The average primary productivity is 351 g.C.m^-2.y^-1, which places this LME in Group 4 of 5 categories (with 1 = lowest and 5= highest).

Primary productivity:

Sea Surface Temperature:

Between 1957 and 2012, the Patagonian Shelf LME #14 has warmed by 0.06°C, thus belonging to Category 4 (slow warming LME). The most dramatic event occurred in 1961-62, when SST rose from the all-time minimum of 10.3°C to the all-time maximum of >11.3°C. A slight increase of SST from 1957 until 1998, when SST peaked at 11.2°C, gave way to a cooling down to 10.4°C in 2010. The most likely cause of the observed stability of the Patagonian Shelf is the constant influx of subantarctic waters with the Falkland/Malvinas Current. Another possible cause of the Patagonian Shelf’s thermal stability is an extremely rich pattern of oceanic fronts – sharp, narrow boundaries between relatively uniform water masses. Most fronts in this LME persist, albeit constantly evolving, year-round (Belkin et al., 2009). Moreover, the Patagonian Shelf is the only LME where rich frontal patterns exist year-round.

Fish and Fisheries

Fisheries in the Patagonian Shelf LME have undergone accelerated growth in the last decades involving mostly Argentine hake (Merluccius hubbsi), Argentine shortfin squid (Illex argentinus), southern blue whiting (Micromesistius australis), Patagonian grenadier (Macruronus magellanicus), and prawns (Pleoticus muelleri).

Annual catch:

Total reported landings have increased over the past three decades, recording 1.6 million tonnes in 1997 with Argentine hake and shortfin squid accounting for the majority share. The landings have since decline to about 1.3 million tonnes per year in recent years (2006 – 2010).

Catch value:

The value of the reported landings reached a peak of 6 billion US$ recorded in 1998.

Marine Trophic Index and Fishing-in-Balance index:

The MTI shows a decline since the late 1970s an indication of "fishing down" of the food web in the LME; over the same period, the FiB index has increased, implying that the increasing reported landings were due at least in part, to a geographic expansion of the fishery.

Stock status:

The Stock-Catch Status Plots shows that about 50% of commercially exploited stocks in the LME are either overexploited or have collapsed, with about 80% of the reported landings supplied by fully exploited stocks. However, the transition from fully exploited to overexploited stocks in the early 2000s was rather abrupt.

Catch from bottom impacting gear:

The percentage of catch from the bottom gear type to the total catch increased from around 35% in the 1950s to its maximum at 74% in 2000. This percentage range between 50 to 70% in the recent decade.

Fishing effort:

The total effective effort increased steadily from around 5 million kW in the 1960s to its peak at 100 million kW the early 2000s.

Primary Production Required:

The primary production required (PPR) to sustain the reported landings in this LME reached 25% of the observed primary production in the mid-1990s, but has declined to 20% in recent years.

Catch potential projections (under global warming):

Pollution and Ecosystem Health

Pollution

Nutrient ratio, Nitrogen load and Merged Indicator:

Human activities in watersheds are affecting nutrients transported by rivers into LMEs. Large amounts of nutrients (in particular nitrogen load) entering coastal waters of LMEs can result in high biomass algal blooms, leading to hypoxic or anoxic conditions, increased turbidity and changes in community composition, among other effects. In addition, changes in the ratio of nutrients entering LMEs can result in dominance by algal species that have deleterious effects (toxic, clog gills of shellfish, etc.) on ecosystems and humans. An overall nutrient indicator (Merged Nutrient Indicator) based on 2 sub-indicators: Nitrogen Load and Nutrient Ratio (ratio of dissolved Silica to Nitrogen or Phosphorus - the Index of Coastal Eutrophication Potential or ICEP) was calculated.

Nitrogen load:

The Nitrogen Load risk level for contemporary (2000) conditions was moderate (level 3 of the five risk categories, where 1 = lowest risk; 5 = highest risk). Based on a “current trends” scenario (Global Orchestration), this remained moderate in 2030 and increased to high by 2050.

Nutrient ratio:

The Nutrient Ratio (ICEP) risk level for contemporary (2000) conditions was moderate (3). According to the Global Orchestration scenario, this remained the same in 2030 and 2050.

Merged nutrient indicator:

The risk level for the Merged Nutrient Indicator for contemporary (2000) conditions was moderate (3). According to the Global Orchestration scenario, this remained the same in 2030 and increased to high in 2050.

POPs:

Data are available for two samples at one location from Uruguay and another from Buenos Aires, Argentina. The average concentration (ng.g^-1 of pellets) was 46 (range 0 – 93 ng.g^-1) for PCBs, 8 (range 0 – 16 ng.g^-1) for DDTs, and 0.2 (range 0.1 – 0.3 ng.g^-1) for HCHs. The PCBs and DDTs averages correspond to risk category 2 and HCHs to risk category 1, of the five risk categories (1 = lowest risk; 5 = highest risk). Minimal concentrations (ng.g^-1 of pellets) for all three indicators at the Uruguay location correspond to risk category 1, and this is due to the remoteness of the location. Moderate PCB concentration (93 ng.g^-1) in Argentina is probably due to the proximity to Buenos Aires. Pellets from more locations should be collected and analyzed to properly evaluate the LME.

Plastic debris:

Modelled estimates of floating plastic abundance (items km^-2), for both micro-plastic (<4.75 mm) and macro-plastic (>4.75 mm), indicate that this LME is in the group with the lowest plastic concentration. Estimates are based on three proxy sources of litter: shipping density, coastal population density and the level of urbanisation within major watersheds, with enhanced run-off. The low values are due to the remoteness of this LME from significant sources of plastic. The abundance of floating plastic in this category is estimated to be over 400 times lower than those LMEs with the highest values. There is very limited evidence from sea-based direct observations and towed nets to support this conclusion.

Ecosystem Health

Mangrove and coral cover:

Not applicable

Reefs at risk:

Not applicable

Marine Protected Area change:

The Patagonian Shelf LME experienced an increase in MPA coverage from 1,045 km² prior to 1983 to 3,076 km² by 2014. This represents an increase of 194%, within the low category of MPA change.

Cumulative Human Impact:

The Patagonian Shelf LME experiences below average overall cumulative human impact (score 2.98; maximum LME score 5.22), but which is still well above the LME with the least cumulative impact. It falls in risk category 2 of the five risk categories (1 = lowest risk; 5 = highest risk). This LME is most vulnerable to climate change. Of the 19 individual stressors, three connected to climate change have the highest average impact on the LME: ocean acidification (0.71; maximum in other LMEs was 1.20), UV radiation (0.68; maximum in other LMEs was 0.76), and sea surface temperature (0.97; maximum in other LMEs was 2.16). Other key stressors include sea level rise and demersal destructive commercial fishing.

Ocean Health Index:

The Patagonian Shelf LME scores below average on the Ocean Health Index compared to other LMEs (score 68 out of 100; range for other LMEs was 57 to 82). This score indicates that the LME is well below its optimal level of ocean health, although there are some aspects that are doing well. Its score in 2013 decreased 1 point compared to the previous year, due in large part to changes in the scores for food provision and clean waters. This LME scores lowest on food provision, tourism & recreation and lasting special places goals and highest on artisanal fishing opportunities and habitat biodiversity goals. It falls in risk category 4 of the five risk categories, which is a relatively high level of risk (1 = lowest risk; 5 = highest risk).

Socio-economics

Indicators of demographic trends, economic dependence on ecosystem services, human wellbeing and vulnerability to present-day extreme climate events and projected sea level rise, are assessed for the Patagonian Shelf LME. To compare and rank LMEs, they were classified into five categories of risk (from 1 to 5, corresponding to lowest, low, medium, high and highest risk, respectively) based on the values of the individual indicators. In the case of economic revenues, the LMEs were grouped to 5 classes of revenues from lowest, low, medium, high and highest, as revenues did not translate to risk.

Population:

The littoral area extends from Uruguay in the north to Tierra del Fuego in the south and covers a total of 463,855 km². A current population of 21 million is projected to almost double to 39 million in 2100, and density increasing from 44 persons per km² in 2010 to 83 per km² by 2100. About 10% of coastal population lives in rural areas, and is projected to increase in share to 19% in 2100.

Coastal poor:

The indigent population makes up 13% of the LME’s coastal dwellers. The Patagonian Shelf LME places in the low-risk category based on percentage and in the medium risk category using absolute number of coastal poor (present day estimate).

Revenues and Spatial Wealth Distribution:

Fishing and tourism depend on ecosystem services provided by LMEs. The Patagonian Shelf LME ranks in the very high revenue category in fishing revenues based on yearly average total ex-vessel price of US 2013 $2,486 million for the period 2001-2010. Fish protein accounts for 3% of the total animal protein consumption of the coastal population. Its yearly average tourism revenue for 2004-2013 of US 2013 $41,973 million places it in the high revenue category. On average, LME-based tourism income contributes 10% to the national GDPs of the LME coastal states. Spatial distribution of economic activity (e.g. spatial wealth distribution) measured by night-light and population distribution as coarse proxies can range from 0.0000 (totally equal distribution and lowest risk) to 1.0000 (concentrated in 1 place and most inequitable and highest risk). The Night Light Development Index (NLDI) thus indicates the level of spatial economic development, and that for the Patagonian Shelf LME falls in the category that is of high economic development, thus with low risk.

Human Development Index:

Using the Human Development Index (HDI) that integrates measures of health, education and income, the present-day Patagonian Shelf LME HDI belongs to the high HDI and low-risk category. Based on an HDI of 0.799, this LME has an HDI Gap of 0.201, the difference between present and highest possible HDI (1.000). The HDI Gap measures an overall vulnerability to external events such as disease or extreme climate related events, due to less than perfect health, education, and income levels, and is independent of the harshness of and exposure to specific external shocks.
HDI values are projected to the year 2100 in the contexts of shared socioeconomic development pathways (SSPs). The Patagonian Shelf LME is projected to assume a place in the very low risk category (very high HDI) in 2100 under a sustainable development pathway or scenario. Under a fragmented world scenario, this LME is estimated to place in the very high-risk category (very low HDI) because of reduced income level and increased population size compared to estimated income and population values in a sustainable development pathway.

Climate-Related Threat Indices:

The Climate-Related Threat Indices utilize the HDI Gaps for present-day and projected 2100 scenarios. The contemporary climate index accounts for deaths and property losses due to storms, flooding and extreme temperatures incurred by coastal states during a 20-year period from 1994 to 2013 as hazard measures, the 2010 coastal population as proxy for exposure, and the present day HDI Gap as vulnerability measure.
The Contemporary Threat Index incorporates a Dependence Factor based on the fish protein contribution to dietary animal protein, and on the mean contribution of LME tourism to the national GDPs of LME coastal states. The HDI Gap and the degree of dependence on LME ecosystem services define the vulnerability of a coastal population. It also includes the average of risk related to extreme climate events, and the risk based on the degrading system states of an LME (e.g. overexploited fisheries, pollution levels, decrease in coastal ecosystem areas).
The 2100 sea level rise threat indices, each computed for the sustainable world and fragmented world development pathways, use the maximum projected sea level rise at the highest level of warming of 8.5 W/m² in 2100 as hazard measure, development pathway-specific 2100 populations in the 10 m × 10 km coast as exposure metrics, and development pathway-specific 2100 HDI Gaps as vulnerability estimates.
Present day climate threat index to the Patagonian Shelf LME is within the low-risk (low threat) category. The combined contemporaneous risk due to extreme climate events, degrading LME states and the level of vulnerability of the coastal population, is medium. In a sustainable development scenario, the risk index from sea level rise in 2100 is very low, and increases to high risk under a fragmented world development pathway.

Governance

Governance architecture:

The two arrangements for high seas southern bluefin tuna and the large pelagics in the Atlantic (CCBST and ICCAT) are separate arrangements, as is the arrangement for sea turtles (IAC). However, the fisheries, pollution and biodiversity arrangements in the areas within the EEZ of Uruguay and Argentina appear to be well integrated as a result of the Treaty of the Rio de la Plata.
The overall scores for the ranking of risk were: