How much do icefish (Notothenioidei, Channichthyidae) eat in the southern Scotia Arc and the Antarctic Peninsula region?

Ration and daily food consumption in 3 low-Antarctic (Champsocephalus gunnari, Chaenocephalus aceratus, and Pseudochaenichthys georgianus), and 3 high-Antarctic (Chionodraco rastrospinosus, Cryodraco antarcticus, and Chaenodraco wilsoni) ice fish species were estimated around islands of the southern Scotia Arc in 1996, 1999, 2001, 2002, 2003, 2007 and 2009, and in 2006 off the north western part of the Antarctic Peninsula. Variability of food consumption was comparatively low between years in the krill – feeding C. gunnari and C. wilsoni, both within an area and between areas. Food intake was more variable in C. aceratus and C. antarcticus which, as larger fish, rely heavily on fish as their primary dietary component. Their food intake varied by a factor of 2 or 3 between years. Most estimates of daily food intake of demersal Antarctic fish both available in the scientific literature and from our study range from 0.5 – 2.5% body per day. These values may be exceeded locally and temporarily in summer when krill is abundant and likely forms dense aggregations in frontal zones such as the Weddell – Scotia Confluence. It is still unknown how long digestion time of various food items takes and if fish empty their stomachs completely before taking in new food. If we assume that digestion of krill takes about 48 hours while the digestion of fish prey takes likely in excess of 96 hours, our data are well in line with those from previous more limited studies.