Revista Chilena de Historia Natural 81 (2): 205-219, 2008
RESEARCH ARTICLE
Environmental effects on the spatial variability of the ichthyoplankton from southern Chile
during November 2005
The distribution and abundance of ichthyoplankton from southern Chile (41-45°S) during
November 2005 were analyzed, in relation to the oceanographic features of the water column (temperature, salinity, stratification).
During the sampling period, 44.606 fish eggs and 2.016 fish larvae were collected, belonging to 28 taxa. Early life stages of small
pelagic fishes dominated the plankton samples, with mean densities of ~ 14,000 eggs 10 m<sup>-2</sup> of anchovy
(Engraulis ringens) and > 100 larvae 10 m<sup>-2</sup> of clupleids. Multivariate analysis showed the
conformation of two groups of stations, one associated to deeper fjord areas, with strong vertical gradients of temperature and salinity,
and higher stratification. The other group was associated to the shallow and well-mixed eastern border of Chiloé Island. In areas with
strong stratification (i.e., higher Brunt-Väisäla frequency, N<sup>2</sup>), significant higher densities of pelagic and
mesopelagic fish eggs and larvae were collected (i.e., Strangomera bentincki, Maurolicus parvipinnis).
Comparing these results with an oceanographic cruise carried out 10 years before in the same area (October 1995), changes in the
ichthyoplankton composition were detected; this may be caused by potential differences in the marine fish species which utilize fjords
and channels of southern Chile as spawning and early nursery zone.
Key words:
inland sea, fjords, fish
larvae, Brunt-Väisäla frequency, environmental factors
