Hyperiid amphipods in the eastern part of the South Pacific gyre

Studies were made of Amphipoda Hyperiidea collected in 1987 with a pelagic trawl in the South Pacific anticyclonic gyre in the vicinity of the Nazca and Sala y Gómez ridges (17°35 to 26°01S, 80°10 to 100°50W), at depths ranging from 50 to 300 or 600 m. Forty-three hauls contained 7 198 specimens, comprised of 119 species within 43 genera. Two of the species appeared to be new for science; two others were found in the Pacific Ocean for the first time. A comparison with hyperiid collections from other tropical Pacific regions revealed great stability of oceanic faunal composion. However, the collections differed considerably in their dominant species. Furthermore, comparison of Hyperiidea from various parts within the investigated area of the South Pacific gyre also reflected differences in dominant species. The degree of these mesoscale spatial differences was comparable to that among the central regions of the northern and southern anticyclonic gyres.