Analysis of dietary overlap between young stages of Notothenia rossii and Trematomus newnesi (Pisces, Notothenidae) at Potter Cove, South Shetland islands.

MOREIRA, E.; BARRERA ORO, E. R.

Capital Federal

Conferencia; SCAR XXXI & OPEN SCIENCE CONFERENCE.; 2010

SCAR e Instituto Antártico Argentino.

We estimated dietary overlap and potential competition between early juveniles stages of two notothenids, Notothenia rossii (N=140, 8.5?21 cm TL) and Trematomus newnesi (N= 324, 4?15.4 cm TL), collected at Potter Cove, King George/25 de Mayo Island, South Shetland Islands. The data of diet (in W%) were taken from ecological studies on the same species in the same area, carried out in the frame of the Ichthyology Project of the Instituto Antártico Argentino and published in 2007 and 2008. The comparative dietary analysis to the lowest possible taxonomic level between the two fish species, using the ?S? index of Linton et al. (1981), showed low food overlap (~50%). Although young stages of Notothenia rossii and Trematomus newnesi are demersal and prey mainly on gammaridean amphipods (Gondogeneia antarctica, Gondogeneia sp., Oradarea sp.) of the benthic community associated with macroalgae beds, food competition seems to be avoided by resource partitioning in a depth gradient or by different prey species.