Assemblages of micronektonic fishes and invertebrates in a gradient of regional warming along the Western Antarctic Peninsula

摘要: Abstract Micronektonic fishes and invertebrates were sampled with 32 midwater trawls at nine sites along the Western Antarctic Peninsula (WAP) in austral fall (March–April) of 2010. Study located within four hypothesized hydrographic regions: near Joinville Island Region I, Croker Passage, Anvers Island, Renaud II, Marguerite Bay Trough III, Charcot IV. A total 62 taxa representing 12 taxonomic groups pelagic 9 families fish captured, but assemblages dominated by only a few species. The most numerically abundant euphausiids, Thysanoessa macrura, Euphausia superba, E. crystallorophias, combining to contribute nearly 79% catch. Biomass dominants included which contributed more than 44% catch, notothenioid Pleuragramma antarctica, salp, Salpa thompsoni. comparison catches among revealed that largest volumetric abundances biomasses captured site. Cluster analysis abundance data identified distinct multispecies Passage fifth assemblage samples from III. Assemblages both superba S. thompsoni, conditions favored neritic assemblage, underscored substantial numbers P. antarctica. was oceanic nature major inputs myctophid, Electrona antarctica hyperiid amphipod, Themisto gaudichaudii. well-mixed strong representation fauna. mid-peninsula character, being overwhelmingly macrura T. five sites: Bay, two Island. They completely absent Trough. One Passage. majority larger 150 mm standard length (SL), very smaller size present. If resident populations reproduce recruit locally rather sustained larval advection, those will be highly susceptible local disappearance. This may causative factor behind absence region. Continued warming subsequent sea ice reductions not cause population collapses regions, also change character faunal WAP an system.