Humboldt Current large marine ecosystem

Source: NOAA

Introduction

caption Location of the Humbolt Current Large Marine Ecosystem. (Source: NOAA)

The Humboldt Current Large Marine Ecosystem (LME) extends along the West Coast of South America from Northern Peru to the southern tip of Chile. It is one of the major upwelling systems of the world, responsible for extremely high levels of organic production. The Humboldt Current system contains cold, low salinity waters that flow in the direction of the Equator and can extend 1,000 kilometers offshore.

Productivity

The Humboldt Current LME is considered a Class I, highly productive (>300 gC/m2-yr), ecosystem. It is the most productive marine ecosystem in the world, as well as the largest upwelling system. The cold, nutrient-rich water brought to the surface by upwelling drives the system’s extraordinary productivity. The Humboldt’s high rates of primary and secondary productivity support the world’s largest fisheries. Upwelling occurs off Peru year-round but off Chile only during the spring and summer, because of the displacement of the subtropical center of high pressure during the summer. Periodically, upwelling is disrupted by El Niño Southern Oscillation (ENSO) events. Several projects have been undertaken to investigate the structure and function of upwelling areas in this LME. It is possible that changes in this LME could be caused by atmospheric forcing or shifts in circumpolar currents (see Loeb and Rojas, 1988). For a description of the circulation patters for this LME, see Robles et al., 1990, Wyrtki, 1967, Brockman et al., 1980, and Alheit and Bernal, 1993.

Fish and Fisheries

caption Catch by species in the Humboldt Current Large Marine Ecosystem. (Source: NOAA)

Approximately 18-20% of the world’s fish catch comes from the Humboldt Current Large Marine Ecosystem. The species are mostly pelagic: sardines, anchovies and jack mackerel. The LME’s high productivity supports other important fishery resources as well as marine mammals. Periodically, the upwelling that drives the system’s productivity is disrupted by El Niño Southern Oscillation (ENSO) events. When this occurs, fish abundance and distribution are significantly affected, often leading to stock crashes and cascading social and economic impacts. These events have led to sequential changes, where sardines and anchovies have replaced each other periodically as the dominant species in the ecosystem. These species changes can have negative consequences for the fishing industry and the economies of the countries that fish the system. Overfishing in the LME has caused a loss of biodiversity. It threatens and endangers sea otters, sea lions and some sea birds and whales. An ENSO episode combined with overfishing is able to deplete a fishery, as happened in 1972 when the anchovy fishery crashed (Alheit and Bernal, 1993). There are programs that assess and monitor fisheries in the region. One is the SELA-BID project for the assessment of sardine, mackerel and jack mackerel. A recent European Union-funded program called VECEP assesses and develops artisanal fisheries. There is a need, however, for a system-wide application of science to evaluate the long-term sustainability of the LME’s living marine resources. The University of British Columbia Fisheries Center has detailed fish catch statistics for this LME.

Pollution and Ecosystem Health

caption (Source: NOAA)

ENSO events occur regularly. The impact of these shifts, associated with climate variability, on the abundance and distribution of fish stocks results in difficulties in the area of fisheries management. There is increased anoxia in the LME’s bottom waters when primary and secondary producers, not consumed because fish stocks are over-fished, fall to the sea floor and decompose. Local forms of coastal pollution include sewage and industrial waste; the results of increasing development and urbanization. Petroleum exploitation also has negative impacts on human health, coastal tourism and coastal living marine resources. There is severe coastal habitat degradation near sources of pollution such as fish processing plants (nutrients), copper mining (heavy metals) and thermoelectric plants (heat pollution). There is a need to better understand the role of the LME as a source or a sink of CO2, and as a monitoring and early-warning site for global climate change. For more information on the Humboldt Current ecosystem health, see the GIWA web site. The overall objective of GIWA (Global International Waters Assessment) is to develop a comprehensive strategic assessment and to achieve significant environmental benefits at the national, regional and global levels.

Socio-economic Conditions

Both Chile and Peru rely on their fisheries resources. Coastal tourism is increasingly important to the economies of both countries. There is increasing development and urbanization along the coast. Other economic activities include aquaculture, copper mining and petroleum exploitation. A UNIDO and Global Environment Facility (GEF) supported project (PDF-B) for this LME involves the sustainable management of coastal and marine resources for improved food security, water quality and environmental security, and is to contribute to the eradication of poverty and hunger in the region. It is meant to prevent further degradation of the coastal and marine environment and arrest the overexploitation of the living resources.

Governance

caption (Source: NOAA)

Peru and Chile, the countries bordering this LME, have established regional cooperation for management of this LME. A regional workshop for the joint stock evaluation of sardine and anchovy for Southern Peru and Northern Chile was organized by IFOP and IMARPE in November 1999. IFOP is Chile’s Fisheries Research and Development Institute. IMARPE is Peru’s Marine Research Institute. The workshop was attended by senior scientists and by industry and resource managers from both countries. Increasingly, the two nations have become aware of some of the threats and issues associated with the management of the LME. There is a need to better understand the biophysical, social, economic and political factors impacting this LME, to develop institutional capacity and to harmonize policies and legislation. The key players and relevant departments are the two governments, commercial and artisanal fisheries, mining, petroleum and other industries affecting the coastal zone, the principal port authorities, tourism interests and donor agencies. Cooperation is facilitated by the fact that both countries utilize the same language and adhere to some of the same international conventions. The UNIDO/GEF PDF Block B funded project seeks to develop effective governance measures for this LME based on sound scientific outcomes and on a consensus developed between stakeholders at all societal levels.

References

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  • Alheit, J. 1987. Egg cannibalism versus egg predation: Their significance in anchovies. S. Afr. J. Mar. Sci. 5:467-470.
  • Alheit, Jurgen, and Bernal, Patricio. 1993. Effects of Physical and Biological Changes on the Biomass Yield of the Humboldt Current Ecosystem. in Kenneth Sherman, Lewis M. Alexander, and Barry D. Gold (eds.) 1993. Large Marine Ecosystems, Stress, Mitigation, and Sustainability. American Association for the Advancement of Science. Washington, D.C. ISNB:08716806X.
  • Bernal, P.A., Robles, F.L., and Rojas, O. 1983. Variabilidad fiscia y biologica en la region meridional del sistema de corrientes Chile-Peru. FAO Fish. Rep. 291:683-711.
  • Brockman, C. Fahrbach, E., Huyer, H., and Smith, R.L. 1980. The poleward undercurrent along the Peru coast: 5-15. Deep-Sea Res. 27A:847-856.
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  • Loeb, V.J., and Rojas, O. 1988. Interannual variation of icthyoplankton composition adn abundance relations off northern Chile, 1964-83. Fish Bull. U.S. 86:1-24.
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  • Pauly, D., and Palomares, J.L. 1989. New estimates of monthly biomass, recruitment, and related statistics of anchoveta (Engraulis ringens) off Peru (4-14 degrees S), 1953-1985. In: The Peruvian upwelling ecosystem: Dynamics and interactions. pp. 189-206. Ed. by D. Pauly, P. Muck, J. Mendo, and I. Tsukayama. ICLARM Conference Proceedings 18.
  • Robles, F.L., Alarcon, E., and Ulloa, A. 1980. Water masses in the northern Chilean zone and their variations in the cold period (1967) and warm periods (1969, 1971-73). In: Proceedings of the workshop on the phenomenon known as "El Nino." pp. 83-174. UNESCO. ISBN: 9231015095.
  • Santander, H., Alheit, J., and Smith, P.E. 1984. Estimacion de la biomasa de la poblacion desovante de anchoveta peruana, Engraulis ringens, en 1981 por aplicacion del "Metodo de Produccion de Huevos." Bol. Inst. Mar Peru, Callao 8:208-250.
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  • Valdes, E.S., Shelton, P.A., Armstrong, J.J., and Field, J.G. 1987. Cannibalism in South African anchovy: Egg mortality and egg consumption rates. S. Afr. J. Mar. Sci. 5:613-622.
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Citation

(2008). Humboldt Current large marine ecosystem. Retrieved from http://www.eoearth.org/view/article/51cbee0b7896bb431f695b88

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