Nominal powerboat CPUE for the three outer islands of the Tristan da Cunha group of islands for the 1997-2008 period.

GLM analyses have been applied to the longline CPUE database for the three outer islands of the Tristan da Cunha group to produce a standardised CPUE series for use in population assessments (Johnston et al. 2010). Although longlines are used to harvest the bulk of the catches at these islands, powerboats are also used to harvest lobsters closer inshore. The powerboat CPUE database for the outer three islands (Inaccessible, Nightingale and Gough) contains information at a trip level.

It is proposed that a nominal CPUE trend be calculated from the powerboat data using the hours fished as the unit of effort.