Celtic-Biscay Shelf
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LME 24: Celtic-Biscay Shelf

Bordering countries:

France, Guernsey, Ireland, Isle of Man, Jersey, United Kingdom

LME total area:

766,550 km²

LME overall risk:

This LME falls in the cluster of LMEs that exhibit medium to high numbers of collapsed and overexploited fish stocks, high levels of demersal non-destructive low bycatch fishing, as well as very high shipping pressure.
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 (0.978 mg.m^-3) in May and a minimum (0.369 mg.m^-3) during December. The average CHL is 0.641 mg.m^-3. Maximum primary productivity (329 g.C.m^-2.y^-1) occurred during 1999 and minimum primary productivity (248 g.C.m^-2.y^-1) during 2006. There is a statistically significant decreasing trend in Chlorophyll of -4.11 % from 2003 through 2013. The average primary productivity is 272 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 Celtic-Biscay Shelf LME #24 has warmed by 0.51°C, thus belonging to Category 3 (moderate warming LME). After the sharp drop around 1960, SST remained relatively cold until it bottomed out at 12.2°C in 1986. An abrupt rebound has followed, resulting in SST exceeding 13.4°C in 1989, a 1.2°C jump in just 3 years. Except of the cold spell in 1991-1994, SST remained relative warm until it has peaked at 13.6°C in 2007. Measured from the absolute minimum of 12.2°C in 1986 to the absolute maximum of 13.6°C in 2007, the rate of SST increase was 1.4°C in 21 years. The subsequent cooling between 2007 and 2012 resulted in SST decrease of 0.6°C. This is the longest interrupted decrease of SST in this LME since 1957.

Fish and Fisheries

The natural environmental variability in this LME adds a high degree of uncertainty to the management of marine resources. Cyclical oscillations, such as the North Atlantic Oscillation, have been linked to fluctuations in the abundance of albacore and bluefin tuna. Many stocks in the LME are intensively exploited or depleted and Total Allowable Catch (TAC)-based regulations have been implemented for anchovy, hake and blue whiting.

Annual catch:

Total reported landings in this LME show changes in biomass and catch composition. The landings recorded a peak of 1.6 million t in 1976, and declined to 1 million t in recent years.

Catch value:

The value of the reported landings reached 4.8 billion US$ (in 2005 real US$) in 1979.

Marine Trophic Index and Fishing-in-Balance index:

The MTI declined over the three decades from 1950 to 1980. In the early 1980s, however, it experienced a strong increase, while the FiB index reached a new plateau. These trends indicate that ‘fishing down’ of the food web occurred from 1950 to the 1980s, after which the effect was masked by expansion of the fisheries into new stocks (e.g., blue whiting).

Stock status:

The Stock-Catch Status Plots indicate that collapsed stocks make up 30% of all stocks exploited in the LME, but that fully exploited stocks contribute almost 50% of the reported landings biomass.

Catch from bottom impacting gear:

The percentage of catch from the bottom gear type to the total catch fluctuated between 25 and 47% from 1950 to 2010. This percentage reached its peak at 47% in 1995. In the recent decade, this percentage fluctuated around 30%.

Fishing effort:

The total effective effort continuously increased from around 100 million kW in the 1950s to its peak at 540 million kW in the mid-2000s.

Primary Production Required:

The primary production required (PPR) to sustain the reported landings in this LME reached 50% of the observed primary production in the mid-1990s, but has declined to 40% 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 high. (level 4 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 risk level for the Nutrient Ratio Sub-Indicator (ICEP) for contemporary (2000) conditions was high (4). According to the Global Orchestration scenario, the risk category remained the same in 2030 and 2050.

Merged nutrient indicator:

The risk level for the Merged Nutrient Indicator for contemporary (2000) conditions was high (4). According to the Global Orchestration scenario, the risk category remained the same in 2030 and 2050.

POPs:

Fifteen samples were available from this LME. The average concentration (ng.g^-1 of pellets) was 423 (range 9 –2,970 ng.g^-1) for PCBs, 13 (range 1–86 ng.g^-1) for DDTs, and 5.1 (range 0.2- 21.1 ng.g^-1) for HCHs. The PCBs average corresponds to risk category 4, DDTs to category 2 and HCHs to category 3, of the five risk categories (1 = lowest risk; 5 = highest risk). Distinct spatial difference in pollution status was observed between the United Kingdom side (9 - 46 ng.g^-1 of pellets for PCBs and 1 - 3 ng.g^-1 of pellets for DDTs) and the French side (64 - 2,970 ng.g^-1 of pellets for PCBs and 4 - 86 ng.g^-1 of pellets for DDTs), especially in Normandy. PCB concentration (ng.g^-1 pellet) in the pellets from Le Havre, at the mouth of Seine River, exhibited one of the highest concentrations among all samples worldwide (2,970 ng.g^-1). This region is a historically developed industrial area and has one of the biggest harbours in France. The resultant highly contaminated bottom sediments act as legacy sources of PCBs. High concentrations of DDTs in Le Havre could be also legacy pollution arising from runoff from the catchment of the Seine River where DDT might have been used in the past. Higher concentrations of HCHs (up to 21.1 ng.g^-1 of pellets) could be related to the current usage of pesticide Lindane in northern France. This is consistent with monitoring results of atmospheric HCHs (Pozo et al., 2006). Continuous monitoring in this area, especially northern France, is recommended.

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 moderate 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 Celtic-Biscay Shelf LME experienced an increase in MPA coverage from 4,967 km² prior to 1983 to 11,206 km² by 2014. This represents an increase of 126%, within the low category of MPA change.

Cumulative Human Impact:

The Celtic-Biscay Shelf LME experiences well above average overall cumulative human impact (score 4.64; maximum LME score 5.22). It falls in risk category 5 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 (0.87; maximum in other LMEs was 1.20), UV radiation (0.65; maximum in other LMEs was 0.76), and sea surface temperature (1.67; maximum in other LMEs was 2.16). Other key stressors include commercial shipping, sea level rise, ocean based pollution, invasive species, pelagic low-bycatch commercial fishing, and all three types of demersal commercial fishing (demersal destructive, non-destructive low-bycatch, and non-destructive high-bycatch).

Ocean Health Index:

The Celtic-Biscay Shelf LME scores above average on the Ocean Health Index compared to other LMEs (score 75 out of 100; range for other LMEs was 57 to 82), but still relatively low. 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 mariculture, coastal protection, carbon storage, and tourism & recreation goals and highest on artisanal fishing opportunities, coastal economies and lasting special places goals. It falls in risk category 2 of the five risk categories, which is a moderate 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 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 389 613 km². A current population of 68 611 thousand in 2010 is projected to increase to 76 595 thousand in 2100, with a density of 176 persons per km² in 2010 increasing to 197 per km² by 2100. About 21% of coastal population lives in rural areas, and is projected to increase in share to 23% in 2100.

Coastal poor:

The indigent population makes up 2% of the LME’s coastal dwellers. This LME places in the very 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. This LME ranks in the very high-revenue category in fishing revenues based on yearly average total ex-vessel price of US 2013 $2 742 million for the period 2001-2010. Fish protein accounts for 10% of the total animal protein consumption of the coastal population. Its yearly average tourism revenue for 2004-2013 of US 2013 $233 075 million places it in the very high-revenue category. On average, LME-based tourism income contributes 11% 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 low 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 high HDI and very low risk category. Based on an HDI of 0.892, this LME has an HDI Gap of 0.108, 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 high-risk category (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 medium-risk (medium 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 medium risk under a fragmented world development pathway.

Governance

Governance architecture:

In this LME, the policy cycles relating to the key issues of fisheries and pollution are associated with well-established transboundary arrangements that are among the strongest globally. However, there does not appear to be much integration among these processes. Given that all coastal countries in this LME are within the European Union, the EU CFP may provide integration among fisheries bodies and between fisheries and environmental issues. Further, this LME has been assigned an overall integration score of 1.0 due to the presence of the European Union Maritime Policy with its ability to function as an overall policy coordinating organization for the key transboundary issues within the LME.
The overall scores for the ranking of risk were: