El nino – Southern Oscillation

History

• Captain Camillo in 1892• In tweentieth century thoughth of as a local

phenomenar• Year 1998 appr. 16 % of the worlds coral rifts

were destroyed (which brougth the phenominar to worldwide attention

• El Nino happens when weakening trade winds (which sometimes even reverse direction) allow the warmer water from the western Pacific to flow toward the east. This flattens out the sea level, builds up warm surface water off the coast of South America, and increases the temperature of the water in the eastern Pacific.

• An El Nino condition results from weakened trade winds in the western Pacific Ocean near Indonesia, allowing piled-up warm water to flow toward South America.

• The deeper, warmer water in the east limits the amount of nutrient-rich deep water normally surfaced by the upwelling process.

Effect of biological production

• Low primary production bottom up effect• Fish species decrease but horse mackerel

increase• Fish species migration, moves to suitable

habitat

How do we predict it?• The first signs of an El Niño are:• Rise in air pressure over the Indian Ocean, Indonesia,

and Australia• Fall in air pressure over Tahiti and the rest of the

central and eastern Pacific Ocean• Trade winds in the south Pacific weaken or head east• Warm air rises near Peru, causing rain in the northern

Peruvian deserts• Warm water spreads from the west Pacific and the

Indian Ocean to the east Pacific. It takes the rain with it, causing extensive drought in the western Pacific and rainfall in the normally dry eastern Pacific.

Implication for local communities

• Loss of primary source of income in coastal areas

• Regional changes in climate– Warmer, drier, colder, weather

• Go for less dependence on a single source of income

Implication for management

• Catch quota must be adjusted according to predicted production.

• El Nino leads to change/drop in fish production. Quotas must take this into account.

• Need for prediction tools

Developments of prediction tools

• Development of meteorological models• Development of models for the community

structure – Primary production– Fish production

• Goal: Sustainable fisheries

Political involvement

• Setting quotas• Education of the local population (Jackson

2007)• Development of coastal communities – Alternative source of income– Less dependence of the climate