Peruvian coastal waters can be roughly divided into
three sections: 1) the northernmost part north of 4° S,
which is steadily influenced by tropical waters, 2) a
narrow transitional section (approx. 4-6° S) between
tropical and temperate waters, and 3) a large zone
south of 6° S, which is dominated by the temperate
Peru current (Humboldt current). The latter area
shows frequent cold water upwellings in normal
years, but also periodical El Niño events with warm
northern waters, poor in nutrients and oxygen,
expanding towards the south (Arntz & Fahrbach
1996). According to these current regimes, the marine
coastal fauna of northernmost Peru is largely Panamanian,
while the region from approx. 6° S (Peru) to
41° S (southern Chile) hosts a fauna that is adapted
to temperate conditions, and was considered as