Variabilidad espacio-temporal de los eufáusidos frente a la costa de Concepción, Chile

Abstract

Spatial and temporal distribution of euphausiids collected in four seasonal cruises of Concepción in 1991 was analyzed. Eight species of euphausiids were identified, Euphausia mucronata, E. vallentini, Nyctiphanes simplex, Nematoscelis megalops, Nematobrachion flexipes, Stylocheiron longicorne, S. affine and S. suhmii. Most species have been previously recorded in the Southeastern Pacific Ocean, with exception of 5. suhmii, that is commonly distributed in the Central Pacific Ocean. The presence of S. suhmii constitutes the first record for the Humboldt Current System. The most abundant and frequent species were E. mucronata (76%) and N. simplex (23%). The euphausiids were collected in different seasons of the year, even though they show seasonal and spatial fluctuations associated to the oceanographic conditions. The seasonal maximum was determinate in autumn and the minimum in winter. Significant differences between the different oceanographic sections were found. Besides, an inverse relationship between the abundance of E. mucronata and the dissolved oxygen concentration was found, associated to coastal upwelling events.