Award: ANT-0741348

Pelagic fishes and invertebrates were sampled with 32 midwater trawls at nine sites along the Western Antarctic Peninsula (WAP) in the austral fall (March – April) of 2010. Study sites were located within four hydrographic regions running from north to south : a northern region near Joinville Island in Region I, near Anvers Island and Palmer Station in Region II, within Marguerite Bay and the Marguerite Trough in Region III, and a southern region near Charcot Island in Region IV. A total of 62 species were captured and cluster analysis identified distinct multispecies groups characteristic of each of the four regions. Unlike most coastal regions of the Antarctic, e.g. McMurdo Sound, the regional groups found along the Antarctic peninsula comprise a mix of open-ocean and Antarctic coastal species. In other areas of the Antarctic, the very cold coastal waters exclude oceanic fishes. The Antarctic silverfish, an important player in the Antarctic coastal system, was captured in the northernmost and southernmost regions of the peninsula but was completely absent near Palmer Station, a site where it was formerly abundant. It is believed that regional warming is ultimately responsible for the mid-peninsula population collapse and direct mechanisms of its cause are currently being examined. Last Modified: 03/25/2014 Submitted by: Joseph J Torres