How much is enough? analysis of the net sampling effort in the Elephant Island area necessary to adequately assess and describe krill and zooplankton assemblages during summer

Data from 1995-1997 US Antarctic Marine Living Resources (AMLR) Program surveys in the Elephant Island area are examined to determine the level of sampling effort required to adequately assess the (1) abundance and demographic structure of Antarctic krill and (2) relative abundance and interspecific relations of krill, salps and other macrozooplankton taxa in the Elephant Island area during summer months. Both parametric and nonparametric techniques are used. Between-survey and between-year comparisons are made to examine possible changes in sampling adequacy resulting from ecological changes operating on seasonal and interannual time scales. The results of these analyses indicate that minimal efforts such as 8 station transects are generally unreliable. Results from most analyses indicate that the data from at least 55 stations are required to adequately estimate krill, salp, and other zooplankton abundance, describe krill length-frequency and maturity stage composition, and assess the abundance relations of krill, salps, and other zooplankton taxa in the Elephant Island area.