South Brazil Shelf
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LME 15: South Brazil Shelf

Bordering country:

Brazil

LME total area:

566,397 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 (0.403 mg.m^-3) in August and a minimum (0.154 mg.m^-3) during January. The average CHL is 0.235 mg.m^-3. Maximum primary productivity (267 g.C.m^-2.y^-1) occurred during 1998 and minimum primary productivity (201 g.C.m^-2.y^-1) during 2004. There is a statistically insignificant increasing trend in Chlorophyll of 5.61 % from 2003 through 2013. The average primary productivity is 233 g.C.m^-2.y^-1, which places this LME in Group 3 of 5 categories (with 1 = lowest and 5= highest).

Primary productivity:

Sea Surface Temperature:

Between 1957 and 2012, the South Brazil Shelf LME #15 has warmed by 1.07°C, thus belonging to Category 2 (fast warming LME). The thermal history of this LME consisted of two epochs. The relatively cold epoch of the 1960s-1970s lasted through 1982, followed by abrupt transition to the warm epoch of the 1980s -1990s that culminated in the all-time maximum of >23.1°C in 2001. The recent SST reversal resulted in a cooling of >0.8°C over 10 years. The SST range between the near absolute minimum of 21.5°C in 1979 and the absolute maximum of >23.1°C in 2001 was >1.6°C in 22 years, similar to other Category 2 (fast warming) LMEs. The thermal history of the South Brazil Shelf LME #15 and adjacent East Brazil Shelf LME #16 are different despite these LMEs’ proximity to one another. Divergent ocean currents east of Brazil explain this difference.

Fish and Fisheries

The South Brazilian Bight contributes about half of Brazil’s commercial fisheries yield. Sardines and anchovies represent the most important groups in shelf catches, while the important demersal species are Argentine hake (Merluccius hubbsi), croakers (Umbrina canosai, Micropogonias furnieri) and shrimp. There is increasing expansion and importance of the oceanic fisheries in Brazil, particularly for tuna.

Annual catch:

Total reported landings showed an increase up to 1967, when landings peaked at 250,000 tonnes, but have since declined to 110,000 tonnes in recent years.

Catch value:

The value of the reported landings reached about 480 million US$ (in 2005 real US$) in 1986, with crustaceans accounting for a significant fraction of this.

Marine Trophic Index and Fishing-in-Balance index:

Both the MTI as well as the FiB index show an increase from the late 1950s. This pattern is indicative of the geographical expansion of the fisheries in the LME. These trends may imply that the targeting of higher trophic-level species could be masking any ‘fishing down’ effect in the catch.

Stock status:

The Stock-Catch Status Plots indicate that about 40% of commercially exploited stocks in the LME are either overexploited or have collapsed, with almost 50% of the reported landings supplied by fully exploited stocks.

Catch from bottom impacting gear:

The percentage of catch from the bottom gear type to the total catch reaches its maximum at 60% in 1958 and then this percentage fluctuated between 30 to 55% in these few decades

Fishing effort:

The total effective effort increased from around 4 million kW in 1950 to its peak at 80 million kW in 2003.

Primary Production Required:

The primary production required (PPR) to sustain the reported landings in this LME reached 12% of the observed primary production in the mid-1980s, and has fluctuated between 6 to 9% in recent years. This is probably an underestimate due to unreported landings.

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 low (level 2 of the five risk categories, where 1 = lowest risk; 5 = highest risk). Based on a “current trends” scenario (Global Orchestration), this remained low in 2030 and increased to moderate by 2050.

Nutrient ratio:

The Nutrient Ratio (ICEP) risk level for contemporary (2000) conditions was low (2). According to the Global Orchestration scenario, this increased to moderate in 2030 and increased further to high in 2050.

Merged nutrient indicator:

The risk level for the Merged Nutrient Indicator for contemporary (2000) conditions was low (2). According to the Global Orchestration scenario, this remained the same in 2030 and increased to high in 2050.

POPs:

Eleven samples at 10 locations are available, mostly from the Sao Paulo coast. The coast is heavily impacted by PCBs (averaged concentration of PCBs of 1,759 ng.g^-1 of pellets). This is one of the highest concentrations among all the locations sampled worldwide. It is worth noting that PCB concentrations rapidly increased from about 300 ng.g^-1 in 2009 to about 3,000 ng.g^-1 in 2012. The pollution level of PCBs in 2012 corresponds to category 5 of the five risk categories (1 = lowest risk; 5 = highest risk) and poses a high risk for consumption of seafood. There is urgent need to understand the latest pollution status, identify the sources of PCBs, and take necessary actions depending on the sources. The average DDTs concentration (25 ng.g^-1 of pellets) is moderate in this LME, corresponding to risk category 3.

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 relatively high levels of 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 high values are due to the relative importance of these sources in this LME. The abundance of floating plastic in this category is estimated to be on average over 100 times higher that those LMEs with lowest values. There is limited evidence from sea-based direct observations and towed nets to support this conclusion.

Ecosystem Health

Mangrove and coral cover:

0.12% of this LME is covered by mangroves (US Geological Survey, 2011).

Reefs at risk:

Not applicable

Marine Protected Area change:

The South Brazil Shelf LME experienced an increase in MPA coverage from 55 km² prior to 1983 to 3,296 km² by 2014. This represents an increase of 5,903%, within the medium category of MPA change.

Cumulative Human Impact:

The South Brazil Shelf LME experiences an above average overall cumulative human impact (score 3.89; maximum LME score 5.22), which is well above the LME with the least cumulative impact. It falls in risk category 4 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 (0.94; maximum in other LMEs was 1.20), UV radiation (0.60; maximum in other LMEs was 0.76), and sea surface temperature (1.46; maximum in other LMEs was 2.16). Other key stressors include commercial shipping, sea level rise, ocean based pollution, and demersal destructive commercial fishing.

Ocean Health Index:

The South Brazil Shelf LME scores below average on the Ocean Health Index compared to other LMEs (score 69 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 increased 2 points compared to the previous year, due in large part to changes in the scores for coastal livelihoods and clean waters. This LME scores lowest on mariculture, natural products, tourism & recreation and iconic species goals and highest on artisanal fishing opportunities, carbon storage, coastal economies, lasting special places 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 South Brazil 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 Rio de Janeiro in the north to Rio Grande do Sul in the south and covers a total of 214,895 km². A current population of 57 million is projected to almost double to 108 million in 2100, and density increasing from 264 persons per km² in 2010 to 504 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 21% of the LME’s coastal dwellers. The South Brazil Shelf LME places in the high-risk category based on percentage and absolute number of coastal poor (present day estimate).

Revenues and Spatial Wealth Distribution:

Fishing and tourism depend on ecosystem services provided by LMEs. The South Brazil Shelf LME ranks in the low revenue category in fishing revenues based on yearly average total ex-vessel price of US 2013 $223 million for the period 2001-2010. Fish protein accounts for 5% of the total animal protein consumption of the coastal population. Its yearly average tourism revenue for 2004-2013 of US 2013 $113,066 million places it in the very 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 South Brazil 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 South Brazil Shelf LME HDI belongs to the medium HDI and medium-risk category. Based on an HDI of 0.739, this LME has an HDI Gap of 0.261, 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 South Brazil 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 South Brazil Shelf LME is within the high-risk (high threat) category. The combined contemporaneous risk due to extreme climate events, degrading LME states and the level of vulnerability of the coastal population, is high. In a sustainable development scenario, the risk index from sea level rise in 2100 is very low, and increases to very high risk under a fragmented world development pathway.

Governance

Governance architecture:

For this LME neither of the two transboundary arrangements have any formal linkages although they both address highly migratory pelagic species, one of high commercial value and one for conservation purposes. There may be interaction amongst the arrangements through participation in each other’s meetings, but this appears to be informal.
The overall scores for the ranking of risk were: