The dominant shallow water fish is Notothenia coriiceps (Gon and Heemstra 1990). N. coriiceps feeds primarily along the bottom as an ambush predator and includes macroalgae, amphipods, and gastropods as

important components of its diet (Casaux et al. 1990, Gon and Heemstra MI-503 price 1990, Iken et al. 1997, Zamzow et al. 2011 and references therein). We also occasionally observe the much smaller Harpagifer antarcticus within the macroalgal canopy, although it is reportedly more common under rocks than among macroalgae (Daniels 1983). Harpagifer antarcticus from shallow waters are reported to feed on amphipods as well as other invertebrates including gastropods (Casaux 1998). Seals are the most obvious top predators, which would constitute a fourth trophic level in this community even though the Antarctic Dabrafenib purchase Shag (Phalacrocorax bransfieldensis) is

known to consume H. antarcticus in deeper water (Casaux 1998) and larger fish consume smaller ones (Daniels 1982, Zamzow et al. 2011). Fish are commonly reported as major prey items of several of the common seal species including Arctocephalus gazelle, Leptonychotes weddellii, and Hydrurga leptonyx (e.g., Casaux et al. 2003, 2006, 2009). Both N. coriiceps and H. antarcticus have cryptic lifestyles, moving very little and remaining under the larger algae (or rocks

in H. antarcticus) most of the time, which we hypothesize is adaptive in reducing predation by seals. However, this cryptic lifestyle coupled with whatever predation by seals does occur could reduce the effectiveness of the fish in controlling amphipod densities and thereby help enable the high densities of macroalgal-associated amphipods that are observed in the community. As in lower latitude communities, mesograzers appear to benefit larger macroalgae by removing smaller, epiphytic algae. Peters (2003) noted that filamentous, epiphytic algae are very uncommon in the Antarctic subtidal and he hypothesized that this is because of the very high click here densities of amphipods that are observed within the macroalgal canopy. Only two taxa of free-living, epiphytic, filamentous algae are routinely observed in the subtidal (Wiencke and Clayton 2002, Peters 2003, authors’ personal observations). Geminocarpus spp. bloom early in the growing season, primarily on senescing, second year Desmarestia antarctica Moe & Silva. Elachista antarctica Skottsberg can be found throughout the growing season on Palmaria decipiens (Reinsch) RW Ricker, which is primarily restricted to the intertidal and shallow subtidal and which supports very low densities of amphipods (Huang et al. 2007, Aumack et al. 2011a).