Abstract

The inland Sea of Chiloé is a semi-enclosed sea of northern Patagonia characterized by freshwater inputs from a fjord in the north, and high influence of offshore waters in the southern sub-basin. The zone has been referred as an important fish nursery ground. In order to assess its relevance as a spawning ground and the strategies for temporal coexistence of fish larvae from diverse origins in these inshore waters, we investigated the horizontal and vertical distributions, and the feeding habits of early fish stages during a period of high productivity. Ichthyoplankton richness and abundances were higher in the northern sub-basin affected by nutrient discharges, dominated by the offshore midwater species Maurolicus parvipinnis and the shelf-break and demersal hake Merluccius gayi. The larvae of the coastal rockfish Sebastes oculatus and the clupeid Strangomera bentincki were more abundant at the surface, while the larvae of the hakes, Merluccius gayi and M. australis, and the midwater fish M. parvipinnis, reached deeper waters. The co-occurring inshore larvae of M. parvipinnis, M. gayi and S. oculatus fed actively at day and nighttimes and preyed on a wide spectrum of sizes, being the small calanoid copepods, the most frequently consumed food items in the largest larvae of M. parvipinnis and M. gayi. Nauplii were frequent food items for smaller larvae of M. parvipinnis, S. oculatus, and S. bentincki. The high spring productivity and the large abundances of potential zooplanktonic prey, along with larval spatial segregation, are visualized as the main factors enabling that fish larvae with different origins co-inhabit and grow inshore.