Gulf of Thailand
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LME 35: Gulf of Thailand

Bordering countries:

Cambodia, Malaysia, Thailand, Viet Nam

LME total area:

391,665 km²

LME overall risk:

This LME falls in the cluster of LMEs that exhibit low to levels of economic development (based on the night light development index) and high pollution from plastic debris.
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 (0.437 mg.m^-3) in December and a minimum (0.236 mg.m^-3) during April. The average CHL is 0.312 mg.m^-3. Maximum primary productivity (431 g.C.m^-2.y^-1) occurred during 2003 and minimum primary productivity (369 g.C.m^-2.y^-1) during 2013. There is a statistically insignificant decreasing trend in Chlorophyll of -1.84 % from 2003 through 2013. The average primary productivity is 401 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:

From 1957 to 2012, the Gulf of Thailand LME #35 has warmed by 0.42°C, thus belonging to Category 3 (moderate warming LME). The Gulf of Thailand LME is wide open to the South China Sea LME #36, so their thermal regimes are linked. The relative magnitude of corresponding peaks and troughs is however different between these LMEs. The Gulf of Thailand’s steady warming was modulated by relatively strong interannual variability with year-to-year variations exceeding 0.5°C. The SST peak of 1998 stands out. This event was likely related to the El Niño 1997-98. Other pronounced events are: (1) near-all-time minimum of 1963, simultaneous with a SST minimum in the South China Sea LME #36; (2) absolute minimum of 1976, which corresponds to a minimum in the South China Sea.

Fish and Fisheries

The catch composition of the Gulf of Thailand LME is a tropical multi-species mix and includes food fish, trash fish, squid and cuttlefish, shrimp, shellfish and crab. Until the early 1960s, the fisheries were dominated by small pelagics (mainly Indian mackerels, Rastrelliger spp. and anchovies, Stolephorus spp.), caught by artisanal fishers for local markets. In the 1960s, the introduction of trawl gear led to the development of demersal trawl fisheries targeting various demersal fishes, shrimps and squid.

Annual catch:

Total reported landings rose to over a million t in 1969, but this is probably due to misreporting of fish caught outside the Gulf. After 1969, the landings declined to less than 500,000 t by the late 1970s, but gradually returning to just under 900,000 t by 2003. Again, a large fraction of the increased landings in recent years was probably caught outside of the LME, notably tuna. Note the high level of ‘mixed group’ in the reported landings.

Catch value:

The value of the reported landings peaked at about 1.1 billion US$ (in 2005 real US$) in 2006.

Marine Trophic Index and Fishing-in-Balance index:

The trends in the MTI and the FiB are indicative of growing fisheries in the LME. However, due to the poor taxonomic details in the underlying landings statistics it is highly likely that such diagnosis is incorrect.

Stock status:

The Stock-Catch Status Plots indicate that almost 30% of the stocks in the LME are either collapsed or overexploited, and that they contribute less than 15% of the catch. Again, the high degree of taxonomic aggregation in the underlying statistics must be noted in regards to problems in the interpretation of these plots.

Catch from bottom impacting gear:

The percentage of catch from the bottom gear type to the total catch increased from 14% in the 1950s to its first peak at around 29% in 1972. Then, this percentage kept decreasing and fluctuated around 25% in recent decade.

Fishing effort:

The total effective effort continuously increased from around 10 million kW in the 1950s to its peak around 200 million kW in 1999.

Primary Production Required:

The primary production required (PPR) to sustain the reported landings in this LME peaked in the early 1970s at 30% of the observed primary production, and following a period of low PPR, has again reached this level 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 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 very low (1). According to the Global Orchestration scenario, this increased to low in 2030 and increased further to moderate 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 moderate in 2050.

POPs:

Data are available only for one sample at one location in Thailand. This location shows minimal concentration (ng.g^-1 of pellets) of 5 ng.g^-1 for PCBs and 0.2 ng.g^-1 for HCHs, while moderate concentration of 26 ng.g^-1 for DDTs. These correspond to risk categories 1 for PCBs and HCHs, and 3 for DDTs, of the five risk categories (1 = lowest risk; 5 = highest risk). Recent application of DDT pesticide for Malaria control might have occurred. Extensive monitoring is necessary in this 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 highest 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 relative importance of these sources in this LME. The abundance of floating plastic in this category is estimated to be on average over 400 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:

0.46% of this LME is covered by mangroves (US Geological Survey, 2011) and 0.17% 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 253. 16% of coral reefs cover is under very high threat, and 24% 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 increase to 24% and 47% for very high and high threat categories respectively. By year 2030, 27% 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 41% by 2050.

Marine Protected Area change:

The Gulf of Thailand LME experienced an increase in MPA coverage from 721 km² prior to 1983 to 1,927 km² by 2014. This represents an increase of 167%, within the low category of MPA change.

Cumulative Human Impact:

The Gulf of Thailand LME experiences an above average overall cumulative human impact (score 4.03; maximum LME score 5.22), which is also 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, all four connected to climate change have the highest average impact on the LME: ocean acidification (0.48; maximum in other LMEs was 1.20), UV radiation (0.38; maximum in other LMEs was 0.76), sea level rise (0.66; maximum in other LMEs was 0.71), and sea surface temperature (0.99; maximum in other LMEs was 2.16). Other key stressors include commercial shipping, nutrient runoff from land, ocean based pollution, invasive species, and all three types of demersal commercial fishing (demersal destructive, non-destructive low-bycatch, and non-destructive high-bycatch).

Ocean Health Index:

The Gulf of Thailand 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 1 point compared to the previous year, due in large part to changes in the scores for natural products and coastal livelihoods. This LME scores lowest on fisheries, coastal protection, carbon storage and iconic species goals and highest on artisanal fishing opportunities and coastal economies goals. It falls in risk category 3 of the five risk categories, which is an average 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 230 482 km². A current population of 38 106 thousand in 2010 is projected to increase to 62 702 thousand in 2100, with a density of 165 persons per km² in 2010 reaching 272 per km² by 2100. About 54% of coastal population lives in rural areas, and is projected to increase in share to 58% in 2100.

Coastal poor:

The indigent population makes up 15% of the LME’s coastal dwellers. This LME places in the medium-risk category based on percentage and in the 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 high-revenue category in fishing revenues based on yearly average total ex-vessel price of US 2013 $1 143 million for the period 2001-2010. Fish protein accounts for 38% of the total animal protein consumption of the coastal population. Its yearly average tourism revenue for 2004-2013 of US 2013 $33 128 million places it in the high-revenue category. On average, LME-based tourism income contributes 17% 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 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 medium HDI and medium-risk category. Based on an HDI of 0.717, this LME has an HDI Gap of 0.283, 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 very low risk category (very 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 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 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 very low, and increases to high risk under a fragmented world development pathway.

Governance

Governance architecture:

The two transboundary arrangements for fisheries (APFIC and WCPFC) in the area each cover high seas highly migratory tuna and tuna-like fisheries and the fisheries within national jurisdiction. There does not appear to be any formal connection between the two arrangements, possibly since they have different areas of competence. However, the arrangement for the Regional Seas Programme cover both for pollution and biodiversity, falling under the Coordinating Body of the Seas of South east Asia (COBSEA), with linkages to the Partnership in Environmental Management for the Seas of East Asia (PEMSEA). Also, the “within national jurisdiction” arrangements for fisheries, pollution and biodiversity do not appear to be integrated with each other or with the tuna arrangement. Similarly, the specific biodiversity arrangement for turtles does not appear to be integrated with the other arrangements in the LME. No integrating mechanisms, such as an overall policy coordinating organization for the LME, could be found. There may be interaction amongst the arrangements through participation in each other’s meetings, but this appears to be informal.
The overall scores for ranking of risk were: