A randomised sampling design used in the longline fishery for Dissostichus eleginoides in the Southern Indian Ocean

A randomised cluster design was used successfully to sample otoliths from targetted individuals taken by individual longlines in the fishery for Dissostichus eleginoides. The line was divided into constituent baskets of line; we used the line as the sampling frame, and baskets as the primary sampling units. The design allows representative samples to be taken while a line is being hauled; it offers the potential of little disruption to commercial activities and reductions in observer effort needed to achieve known levels of confidence.