Agulhas Current
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LME 30: Agulhas Current

Bordering countries:

Comoros, Madagascar, Mayotte, Mozambique, South Africa, Swaziland, United Republic of Tanzania

LME total area:

2,615,294 km²

LME overall risk:

This LME falls in the cluster of LMEs that exhibit high percentages of rural coastal population, high numbers of collapsed and overexploited fish stocks, as well as 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 very high.

Productivity

Chlorophyll-A:

The annual Chlorophyll a concentration (CHL) cycle has a maximum peak (0.208 mg.m^-3) in July and a minimum (0.110 mg.m^-3) during December. The average CHL is 0.151 mg.m^-3. Maximum primary productivity (204 g.C.m^-2.y^-1) occurred during 2002 and minimum primary productivity (172 g.C.m^-2.y^-1) during 2009. There is a statistically insignificant decreasing trend in Chlorophyll of -11.4 % from 2003 through 2013. The average primary productivity is 186 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:

From 1957 to 2012, the Agulhas Current LME #30 has warmed by 0.72°C, thus belonging to Category 3 (moderate warming LME). The Agulhas Current’s slow, steady long-term warming was punctuated by relatively small-scale cold/warm events with a magnitude of about 0.5°C. The Agulhas Current does not significantly affect the adjacent Benguela Current LME #29, although a certain degree of leakage can be expected from the Agulhas Current into the Benguela Current. The Agulhas Current originates in the southwestern Indian Ocean, where it is fed by the southward coastal flow from the Somali Coastal Current LME #31 and also by the South Equatorial Current and by the East Madagascar Current. The Somali-Agulhas oceanic connection explains the observed synchronism between the Somali and Agulhas LMEs. For example, the all-time minimum of 1964-1965 occurred simultaneously in the Somali and Agulhas LMEs, as well as the near-all-time maxima of 1983 in these two LMEs.

Fish and Fisheries

Annual catch:

Total reported landings in this LME peaked at just under 700,000 t in 1974 with record landings of Cape anchovy and South American pilchard. However, with the collapse of these fisheries in the mid-1970s, the reported landings were diminished down to 180,000 t and have remained at this low level for some time. Some signs of growth can be seen in recent years, particularly in the landings of South American pilchard, and total landings reached 320,000 t in the 2000s.

Catch value:

The trend in the value of the reported landings has mirrored that of the landings, peaking at just over 650 million US$ (in 2005 real US$) in 1968.

Marine Trophic Index and Fishing-in-Balance index:

The sharp increase in the MTI in the mid-1970s reflects the collapse of the pilchard and anchovy fisheries, two species with low trophic levels. Although the MTI has declined over the last few years, likely due to the increased pilchard landings, there is no observable decline indicative of ‘fishing down’ of the food web in this LME. Over the same period, the FiB index showed at best a minor decline, suggesting that the increasing catches over this period may not compensate for the decline in the MTI.

Stock status:

The Stock-Catch Status Plots show that the number of collapsed stocks is about the same as overexploited (just under 30%), while the two groups altogether contribute to just under 20% of the catch biomass.

Catch from bottom impacting gear:

The percentage of catch from the bottom gear type to the total catch increased from 2% in the 1950s to its first peak at around 34% in 1980. Then, this percentage kept decreasing and fluctuated around 13% in recent decade.

Fishing effort:

The total effective effort continuously increased from around 7 million kW in the 1950s to its peak around 200 million kW in the 2000s.

Primary Production Required:

The primary production required (PPR) to sustain the reported landings in the LME reached close to 8% of the observed primary production in 1968, when the highest landings was recorded. With the collapse of the Cape anchovy and South American pilchard fisheries in the mid-1970s, the PPR declined to around 2% in the 1980s; however, PPR has returned to about 5% in recent year.

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 the same in 2030 and 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 2050.

POPs:

Twelve samples from 11 locations are available. Average concentrations (ng.g^-1 of pellets) were 35 (range 1-97 ng.g^-1) for PCBs, 27 (range 2-129 ng.g^-1) for DDTs and 10 (range 0.3 -36.4 ng.g^-1) for HCHs, corresponding to risk categories 2, 3, and 4, respectively, of the five risk categories (1 = lowest risk; 5 = highest risk). Large spatial and temporal variations are noticeable. Average PCB concentrations were moderate in South Africa (60 ng.g^-1) and low (11 ng.g^-1) in Mozambique. This is probably due to different degrees of industrialization in these countries. High concentrations of DDTs (up to 129 ng.g^-1 of pellets) and HCHs (up to 36.4 ng.g^-1 of pellets) were sporadically observed. Most of them were for the samples from 2007 – 2011; such high concentrations were not observed in 2012 or later, suggesting an improvement of the pollution situation. Continuous monitoring is recommended to determine the temporal trend.

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 moderate 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 12 times lower that those LMEs with lowest values. There is very limited evidence from sea-based direct observations and towed nets to support this conclusion.

Ecosystem Health

Mangrove and coral cover:

0.21% of this LME is covered by mangroves (US Geological Survey, 2011) and 0.3% by coral reefs (Global Distribution of Coral Reefs, 2010).

Reefs at risk:

This LME has a present (2011) integrated threat index (combining threat from overfishing and destructive fishing, watershed-based and marine-based pollution and damage) of 257. 22% of coral reefs cover is under very high threat, and 31% under high threat (of the 5 possible threat categories, from low to critical). When combined with past thermal stress (between 1998 and 2007), these values are 36% and 31% for very high and high threat categories respectively. By year 2030, 52% of coral cover in this LME is predicted to be under very high to critical level of threat from warming and acidification; this proportion increases to 53% by 2050.

Marine Protected Area change:

The Agulhas Current LME experienced an increase in MPA coverage from 1,547 km² prior to 1983 to 23,967 km² by 2014. This represents an increase of 1,449%, within the low category of MPA change.

Cumulative Human Impact:

The Agulhas Current LME experiences an above average overall cumulative human impact (score 3.84; maximum LME score 5.22), which is also well above the LME with the least cumulative impact. It falls in risk category 3 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 (1.09; maximum in other LMEs was 1.20), UV radiation (0.64; maximum in other LMEs was 0.76), and sea surface temperature (1.68; maximum in other LMEs was 2.16). Other key stressors include commercial shipping, sea level rise, and ocean based pollution.

Ocean Health Index:

The Agulhas Current 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 coastal livelihoods and clean waters. This LME scores lowest on mariculture, coastal protection, tourism & recreation, and sense of place goals and highest on artisanal fishing opportunities, coastal economies, 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 this 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 coastal area stretches over 754 317 km². A current population of 40 698 thousand in 2010 is projected to increase to 75 018 thousand in 2100, with a density of 54 persons per km² in 2010 increasing to 99 per km² by 2100. About 66% of coastal population lives in rural areas, and is projected to decrease in share to 62% in 2100.

Coastal poor:

The indigent population makes up 51% of the LME’s coastal dwellers. This LME places in the very high-risk category based on percentage and in the very high-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. This LME ranks in the medium-revenue category in fishing revenues based on yearly average total ex-vessel price of US 2013 $576 million for the period 2001-2010. Fish protein accounts for 20% of the total animal protein consumption of the coastal population. Its yearly average tourism revenue for 2004-2013 of US 2013 $12 598 million places it in the low-revenue category. On average, LME-based tourism income contributes 9% 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 this LME falls in the category with very high risk.

Human Development Index:

Using the Human Development Index (HDI) that integrates measures of health, education and income, the present-day LME HDI belongs to the very low HDI and very high-risk category. Based on an HDI of 0.551, this LME has an HDI Gap of 0.449, 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). This LME is projected to assume a place in the low risk category (high HDI) in 2100 under a sustainable development pathway. Under a fragmented world scenario, the LME is estimated to place in a very high-risk category (very low HDI) because of reduced income levels and increased population values from those estimated in a sustainable development scenario.

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 of this LME is within the very high-risk (very 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 very high. In a sustainable development scenario, the risk index from sea level rise in 2100 is medium, and increases to very high risk under a fragmented world development pathway.

Governance

Governance architecture:

In this LME, the two transboundary arrangements for fisheries in the areas within national jurisdiction (SWIOFC) and demersal resources in ABNJ (SIOFA) are supposed to be closely connected but given the fact that the latter is not fully operational, it is difficult to tell if this is happening. The arrangements for pollution and biodiversity that fall under the Nairobi Convention are also linked. However neither of these sets appears to be integrated with each other or with the tuna arrangement (IOTC). Further, no integrating mechanisms, such as an overall policy coordinating organisation for the LME, could be found. However, the ASCLME Project appears to be performing that role. 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: