Latin american journal of aquatic research
versión On-line ISSN 0718-560X
LANDAETA, Mauricio F et al. Ichthyoplankton distribution in South Patagonia, Chile: potential effects of ice melting from the Southern Ice Field. Lat. Am. J. Aquat. Res. [online]. 2011, vol.39, n.2, pp.236-249. ISSN 0718-560X. http://dx.doi.org/10.4067/S0718-560X2011000200005.
In October-November 2009, an oceanographic survey was carried out between 50 and 53°S off southern Chile, near the Southern Ice Field. The stations near the glacier showed low temperatures (1-3°C) and salinity (< 25), and high stability (Brunt-Väisälä frequency N > 0.1 cycles s-1). Main ichthyoplankton taxa were eggs and larvae of southern sprat Sprattus fuegensis, lightfish Maurolicus parvipinnis, Macrouridae, and southern hake Merluccius australis. The main spawning area of S. fuegensis (~8000 eggs 10 m-2) occurred in mixed zones of the adjacent continental shelf, whereas the spawning of M. parvipinnis occurred in intermediate channels associated with medium stability values (N~0.06 cycles s-1). Fish egg and larval abundances were null or scarce near the glacier, and the abundance of M. parvipinnis eggs was positively related to the temperature and salinity of the water column, and negatively related to water column stability. Moreover, a negative relationship was observed between seawater density and the diameter of S. fuegensis eggs. The relation between ice melting and ichthyoplankton may have consequences for advective transport and mass mortality of fish eggs and larvae, as well as pelagic-benthic coupling in the Chilean South Patagonia. Global climate change has increased glacier ice melting at high latitudes, and the increased entry of colder, less saline waters in coastal areas may have consequences for the ichthyoplankton in the Chilean Patagonia.
Palabras clave : stratification; distribution; ichthyoplankton; Southern Ice Field; southern Chile.