A branch of this stream deviates and moves to the south along the coast of Ecuador
and arrives to the north of Peru, where it is named El Niño Current. This stream of
warm waters flows up to Cabo Blanco (4°15
0 S–81°14
0 W) where it turns towards
the west to form part of the Equatorial Current. The area between Cabo Blanco and
Punta Illecas is recognized as a region of tropical water masses where waters
coming from the north mix with a branch of the Peruvian Current that maintains a
weak flow towards the north (Hooker 2010).
Beneath the mentioned surface currents, there are other subsurface current. The
Equatorial countercurrent (or Cromwell Current) flows from west to east towards
Ecuador. A branch deviates and flows to the southeast to near the Peruvian north
coast between 5° and 8°S. It flows under the Peruvian Current and in opposite
direction (from north to south). It is close to the coast between Paita and Punta
Falsa (5–6°S), flowing between 50 and 300 m in depth. It moves away from the
coast to be integrated into the Subsurface Peruvian Current and continues to the
south (Cromwell 1953). One of the most important characteristics of the current is
a high concentration of oxygen, higher than 1.0 ml
-1 at 100–200 m (Morón 2000)
permitting processes that will be discussed later on Pequeño (2000) discusses the
Intermediate Antarctic Water masses in deeper waters. In southern Chile they are
rather shallow, going deeper to the north, reaching a depth of 1,500 m at
approximately 35°S and even deeper to the north. He also mentions that off Chile,
at depths of 3,500–4,200 m, the relatively salty, but very cold, Deep Antarctic
Currents flows towards the north over the Pacific sea floor, crossing probably the
Chilean-Peruvian trench. This facilitates the displacement of ichthyofauna of
Antarctic origin towards less than 20°S, off the Peruvian coast. Pequeño (2000)
also mentions that some authors (like Petersen et al. 1972) described the presence
of a mass of intermediate water of the southeast Pacific sea or Intermediate
Antarctic waters (between 500 and 1,500 m deep) located off Chile, Peru and
Ecuador
8.1.3 General Ecological Characteristic
Peru is situated in a peculiar geographical area where temperate waters coming
from the south and tropical waters from the north meet, generating a diverse and
dynamic ecological system. Furthermore, the recurrent phenomenon called ‘El
Niño’ makes the ecological processes even more complex, altering the abundance
and distribution of marine organisms. The Peruvian sea is considered one of the
more productive of the world because an intense upwelling system in most of
the littoral develops a productivity that has made Peruvian fishing industry one of
the most important in the world. The upwelling system is closely related to the
Peru Current that flows continuously from south to north, pushed by the trade
winds. Upwelling transports waters from depths of 50–150 m towards the surface
in areas close to the coast, carrying nutrients accumulated over the bottom
of the continental platform. Upwelling waters are characterized by low
8 Echinoderms of Peru
281
and arrives to the north of Peru, where it is named El Niño Current. This stream of
warm waters flows up to Cabo Blanco (4°15
0 S–81°14
0 W) where it turns towards
the west to form part of the Equatorial Current. The area between Cabo Blanco and
Punta Illecas is recognized as a region of tropical water masses where waters
coming from the north mix with a branch of the Peruvian Current that maintains a
weak flow towards the north (Hooker 2010).
Beneath the mentioned surface currents, there are other subsurface current. The
Equatorial countercurrent (or Cromwell Current) flows from west to east towards
Ecuador. A branch deviates and flows to the southeast to near the Peruvian north
coast between 5° and 8°S. It flows under the Peruvian Current and in opposite
direction (from north to south). It is close to the coast between Paita and Punta
Falsa (5–6°S), flowing between 50 and 300 m in depth. It moves away from the
coast to be integrated into the Subsurface Peruvian Current and continues to the
south (Cromwell 1953). One of the most important characteristics of the current is
a high concentration of oxygen, higher than 1.0 ml
-1 at 100–200 m (Morón 2000)
permitting processes that will be discussed later on Pequeño (2000) discusses the
Intermediate Antarctic Water masses in deeper waters. In southern Chile they are
rather shallow, going deeper to the north, reaching a depth of 1,500 m at
approximately 35°S and even deeper to the north. He also mentions that off Chile,
at depths of 3,500–4,200 m, the relatively salty, but very cold, Deep Antarctic
Currents flows towards the north over the Pacific sea floor, crossing probably the
Chilean-Peruvian trench. This facilitates the displacement of ichthyofauna of
Antarctic origin towards less than 20°S, off the Peruvian coast. Pequeño (2000)
also mentions that some authors (like Petersen et al. 1972) described the presence
of a mass of intermediate water of the southeast Pacific sea or Intermediate
Antarctic waters (between 500 and 1,500 m deep) located off Chile, Peru and
Ecuador
8.1.3 General Ecological Characteristic
Peru is situated in a peculiar geographical area where temperate waters coming
from the south and tropical waters from the north meet, generating a diverse and
dynamic ecological system. Furthermore, the recurrent phenomenon called ‘El
Niño’ makes the ecological processes even more complex, altering the abundance
and distribution of marine organisms. The Peruvian sea is considered one of the
more productive of the world because an intense upwelling system in most of
the littoral develops a productivity that has made Peruvian fishing industry one of
the most important in the world. The upwelling system is closely related to the
Peru Current that flows continuously from south to north, pushed by the trade
winds. Upwelling transports waters from depths of 50–150 m towards the surface
in areas close to the coast, carrying nutrients accumulated over the bottom
of the continental platform. Upwelling waters are characterized by low
8 Echinoderms of Peru
281