Ecological studies on fish fauna associated with Macrocystis pyrifera belts in the south of Fueguian Islands, Chile

Abstract

Fish fauna, habitat characteristics, and trophic relations within a Macrocystis pyrifera kelp community were studied in fjords and channels in the south of Tierra del Fuego, Chile between 1979 and 1980. The ichthyofauna is very similar to that described for the subantarctic islands, especially because of the predominance of nototheniid species. Greater species richness was found associated with rocky substrates. Experimental modifications of kelp canopy affected the abundance of only 3 out of 18 fish species. No fish were found to be herbivorous or to prey on sea urchins, but their diet was dominated by detritivores (amphipods and isopods) associated with the kelp. Comparison of these organizational features with those in kelp communities of the northern hemisphere illustrates notable contrasts. In spite of these differences, the trophic position of fish is similar wlthin a recycling food web. These Tierra del Fuego fish assemblages also appear to optimize microhabitat utilization in the rocky substrate, as has been documented in the North Pacific Ocean.