Gulf of California
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LME 4: Gulf of California

Bordering country:

Mexico

LME total area:

216,344 km²

LME overall risk:

This LME falls in the cluster of LMEs that exhibit high rates of increase in MPA coverage.
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 (0.996 mg.m^-3) in March and a minimum (0.308 mg.m^-3) during August. The average CHL is 0.572 mg.m^-3. Maximum primary productivity (594 g.C.m^-2.y^-1) occurred during 2000 and minimum primary productivity (424 g.C.m^-2.y^-1) during 2013. There is a statistically insignificant increasing trend in Chlorophyll of 24.6 % from 2003 through 2013. The average primary productivity is 502 g.C.m^-2.y^-1, which places this LME in Group 5 of 5 categories (with 1 = lowest and 5= highest).

Primary productivity:

Sea Surface Temperature:

Between 1957 and 2012, the Gulf of California LME #4 has warmed by 1.13°C, thus belonging to Category 1 (super-fast warming LME). The semi-landlocked Gulf of California shares some similarities with the California Current. The global cooling of the 1960s-1970s manifested here as a 2°C drop from 1958 to 1975. After a 2°C rebound in 1979-1983, the Gulf of California remained warm until present. The sharp SST peak of 1983 was synchronous with similar peaks in the Central American Pacific LME #11, where SST reached the all-time maximum of 28.2°C, and in the Humboldt Current LME #13, where SST reached 17.3°C, second only to the 1997 all-time record high of 17.6°C. The California Current SST also peaked in 1983. The 1983 SST peak in four East Pacific LMEs (#3, 4, 11, and 13) is attributed to the El Niño 1982-1983. Since 1983, the Gulf of California’s thermal history is strongly correlated with that of the California Current LME #03, including major events (peaks) of 1992 and 1997, likely associated with major El Niños.

Fish and Fisheries

Historically, this LME has supported numerous fisheries of commercially valuable species. Fisheries resources in the Gulf are targeted by the commercial, artisanal, and recreational fishing sectors.

Annual catch:

In terms of weight caught, the major fisheries are dominated by small pelagic fish, namely Californian anchovy and Pacific sardine, as well as penaeid shrimps (blue, white and brown shrimp, Litopenaeus stylirostris, Litopenaeus vannamei, Farfantepenaeus californiensis, respectively, together with other less important species). The total annual catch of tuna-like resources increased rapidly from the late 1970s to peak in the mid-1980s. Total reported landings in this LME recorded a peak of 300,000 t in 1982 driven by record catches of anchovy.

Catch value:

Crustaceans, mainly in the form of penaeid shrimps account for a large portion of the value of the reported landings, which peaked at 200 million US$ (in 2005 real US$) in 1997.

Marine Trophic Index and Fishing-in-Balance index:

The MTI has increased from 1950 to the early 1970s, and then declined slightly and remained relatively steady thereafter, except for a more recent increase. The FiB index suggests a spatial expansion of the fisheries until the early 1980s, and has remained relatively level since, suggesting that natural limits may have been reached.

Stock status:

The Stock-Catch Status Plots indicate that the number of collapsed and overexploited stocks have been increasing in the LME, to about 40% of the commercially exploited stocks. The majority of the reported landings is supplied by fully exploited stocks.

Catch from bottom impacting gear:

The percentage of catch from the bottom gear type to the total catch ranges between 13.5 and 30%.

Fishing effort:

The total effective effort increased steadily from around 60 million kW in the 1960s to its peak at 200 million kW in the mid-2000s.

Primary Production Required:

The primary production required (PPR) to sustain the reported landings reached 10% of the observed primary production in 1996 and fluctuated between 5 to 9% 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 low (2). According to the Global Orchestration scenario, this increased to moderate in 2030 and remained moderate in 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 relatively low 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 low values are due to the relative remoteness of this LME from significant sources of plastic. The abundance of floating plastic in this category is estimated to be on average over 40 times lower that those LMEs with the highest values. There is evidence from sea-based direct observations and towed nets to support this conclusion.

Ecosystem Health

Mangrove and coral cover:

0.52% of this LME is covered by mangroves (US Geological Survey, 2011) and 0.01% by coral reefs(), the lowest coral cover of any LME.

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 255. 32% of coral reefs cover is under very high threat, and 26% under high threat (of the 5 possible threat categories, from low to critical). When combined with past thermal stress (between 1998 and 2007), these remain constant. By year 2030, 59% 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 63% by 2050.

Marine Protected Area change:

The Gulf of California LME experienced an increase in MPA coverage from 0 km² prior to 1983 to 14,369 km² by 2014. This represents an increase of 50,000%, within the highest category of MPA change.

Cumulative Human Impact:

The Gulf of California LME experiences an average overall cumulative human impact (score 3.23; maximum LME score 5.22), but which is still well above the LME with the least cumulative impact. It falls in risk category 2 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: sea surface temperature (1.37; maximum in other LMEs was 2.16), ocean acidification (0.88; maximum in other LMEs was 1.20), UV radiation (0.39; maximum in other LMEs was 0.76), and sea level rise (0.12; maximum in other LMEs was 0.71). Other key stressors include ocean based pollution, demersal destructive commercial fishing, and demersal non-destructive low-bycatch commercial fishing.

Ocean Health Index:

The Gulf of California LME scores average on the Ocean Health Index compared to other LMEs (score 71 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 increased 1 point compared to the previous year, due in large part to changes in the scores for food provision, coastal livelihoods and economies, and clean waters. This LME scores lowest on food provision, coastal protection, carbon storage, coastal livelihoods, and iconic species goals and highest on artisanal fishing opportunities, natural products, coastal economies, and lasting special places 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 the Gulf of California 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, 225,547 km² wide, includes the eastern coast of Baja California and the northwest shoreline of Mexico. Its population is moderately large (medium risk) 30% of which lives in rural areas. Population size is projected to decrease by a million in 2100, a density of 27 persons per km² in 2010 decreasing to 22 persons per km² in 2100.

Coastal poor:

The indigent population makes up 49% of the LME’s coastal dwellers. This LME places in the highest-risk category based on percentage of poor and among those with medium risk category using absolute number of poor at nearly 3 million (present day estimate).

Revenues and Spatial Wealth Distribution:

Fishing and tourism depend on ecosystem services provided by LMEs. The Gulf of California LME ranks in the low revenue category in fishing revenues based on yearly average total ex-vessel price of US 2013 $206 million for the period 2001-2010. Fish protein accounts for 8% of the total animal protein consumption of the coastal population. Its yearly average tourism revenue for 2004-2013 of US 2013 $12.9 billion places it in the low revenue category. On average, LME-based tourism income contributes 14% 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 Gulf of California LME falls in the category with medium risk.

Human Development Index:

Using the Human Development Index (HDI) that integrates measures of health, education and income, the present-day Gulf of California LME HDI belongs to the average HDI and medium risk category. Based on present-day HDI of 0.750, this LME has an HDI Gap of 0.250, the difference between contemporary 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 Gulf of California LME is projected to increase its HDI to the very high category with the lowest risk in 2100 under a sustainable development pathway or scenario. Under a fragmented world scenario, this LME is projected to slip to the highest risk category (very low HDI) because of reduced income level and bigger 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 Gulf of California LME is in the high risk 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 threat index for sea level rise in 2100 is in the lowest risk category, and which increases to medium risk under a fragmented world development pathway.