West Bering Sea
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LME 53: West Bering Sea

Bordering countries:

Russian Federation, United States of America

LME total area:

2,182,768 km²

LME overall risk:

This LME falls in the cluster of LMEs that exhibit low to medium levels of economic development (based on the night light development index) and medium levels of collapsed and overexploited fish stocks.
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 medium.

Productivity

Chlorophyll-A:

The annual Chlorophyll a concentration (CHL) cycle has a maximum peak (1.22 mg.m^-3) in May and a minimum (0.250 mg.m^-3) during February. The average CHL is 0.606 mg.m^-3. Maximum primary productivity (298 g.C.m^-2.y^-1) occurred during 1998 and minimum primary productivity (161 g.C.m^-2.y^-1) during 2007. There is a statistically insignificant increasing trend in Chlorophyll of 14.1 % from 2003 through 2013. The average primary productivity is 234 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 West Bering Sea LME #53 has warmed by 0.47°C, thus belonging to Category 3 (moderate warming LME). The long-term cooling of the late 1950s-early 1970s culminated in the all-time minimum of 3.7°C in 1976. The North Pacific regime shift of 1976-77 (Mantua et al., 1997; Hare and Mantua, 2000) has transpired in the West Bering Sea with the utmost clarity and was extremely abrupt. It manifested as a rapid 0.6°C SST rise between 1976 and 1978. This rise was followed by a steady SST increase until present. Thus, the regime shift of 1976-77 was a switch from a long-term cooling to a long-term warming, separated by a step-like SST increase. The all-time maximum of >5.2°C in1996 is bizarre since it occurred before the El Niño 1997-98 and before a similar warm event in the East Bering Sea. The cold event of 1999 occurred simultaneously across the entire Bering Sea.

Fish and Fisheries

The West Bering Sea LME has the largest biomass of cod-like fishes in the world. Other species fished include Alaskan pollock, Pacific saury, salmon, flatfish, rockfish, halibut, flounder, herring, squid and a variety of crab species and other crustaceans. A major problem is unreported fishing in the West Bering Sea and in the ‘Donut Hole’, a high seas area that does not come under the jurisdiction of either Russia or the USA (Alaska). Catches have been illegally transferred to Russian carrier vessels bound for ports in Japan, South Korea, China, the U.S.A. and Canada. There is evidence of fishing in prohibited areas. The rise of industrial fishing has also had a major impact.

Annual catch:

Total reported landings recorded 2.4 million t in 1988 but have since declined by about half, with only 1.2 million t reported in the most recent year.

Catch value:

Marine Trophic Index and Fishing-in-Balance index:

The MTI has declined since the early 1960s to the late 1980s, suggesting a ‘fishing down’ of the food webs in the LME, though the decline in the mean trophic level appears to have been compensated for by the increased landings as evident in the positive trend of the FiB index. As the landings in the LME became dominated by Alaska pollock, a high-trophic level species, the mean trophic level began to increase, but with catches and FiB decreasing.

Stock status:

The Stock-Catch Status Plots indicate that more than 25% of the exploited stocks in the LME have collapsed, with another 10% overexploited. The reported landings in the region are mostly supplied by the overexploited and fully exploited stocks (about 80% of the total catch).

Catch from bottom impacting gear:

The percentage of catch from the bottom gear type to the total catch fluctuated between 3 and 17% from 1950 to 2010. This percentage fluctuated around 9% in the recent decade.

Fishing effort:

The total effective effort continuously increased from around 1 million kW in the 1950s to its peak around 13 million kW in 2005.

Primary Production Required:

The primary production required (PPR) to sustain the reported landings in this LME reached 12 % of observed primary production in the late 1980s, but has declined 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 very low. (level 1 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 very low (1). 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 very low (1). According to the Global Orchestration scenario, this remained the same in 2030 and 2050.

POPs:

No pellet samples were obtained from 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 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 West Siberian Sea LME experienced an increase in MPA coverage from 1,327 km² prior to 1983 to 12,098 km² by 2014. This represents an increase of 812%, within the low category of MPA change.

Cumulative Human Impact:

The West Bering Sea LME experiences average overall cumulative human impact (score 3.44; maximum LME score 5.22), but which is still 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 (0.65; maximum in other LMEs was 1.20), UV radiation (0.69; maximum in other LMEs was 0.76), and sea surface temperature (1.69; maximum in other LMEs was 2.16). Other key stressors include commercial shipping, ocean based pollution, and demersal destructive commercial fishing.

Ocean Health Index:

The West Bering Sea 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 remained unchanged compared to the previous year. This LME scores lowest on food provision, natural products, and tourism & recreation goals and highest on artisanal fishing opportunities, coastal protection, 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 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 232 827 km². A current population of 311 thousand in 2010 is projected to decrease to 196 thousand in 2100, with a density of 13 persons per 10 km² in 2010 decreasing to 8 per 10 km² by 2100. About 31% of coastal population lives in rural areas, and is projected to decrease in share to 25% in 2100.

Coastal poor:

The indigent population makes up 17% of the LME’s coastal dwellers. This LME places in the high-risk category based on percentage and in the low-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 $715 million for the period 2001-2010. Fish protein accounts for 14% of the total animal protein consumption of the coastal population. Its yearly average tourism revenue for 2004-2013 of US 2013 $378 million places it in the very low-revenue category. On average, LME-based tourism income contributes 6% 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 high-risk category.

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 high HDI and low-risk category. Based on an HDI of 0.782, this LME has an HDI Gap of 0.218, 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 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 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 medium. In a sustainable development scenario, the risk index from sea level rise in 2100 is very low, and increases to low under a fragmented world development pathway.

Governance

Governance architecture:

Transboundary issues of concern in this LME are addressed by the Arctic Council, primarily due to its integrative nature. However, while it does appear that the Arctic Council has the potential to develop into an informal overall policy coordinating organization; its policy coordination role with respect to fisheries is weak.
The overall scores for ranking of risk were: