Download FAR 2017/12 Recalculation of historial landings of porbeagle shark

Historical conversion factors (CFs) applied to shark fin processed weights to determine landed whole weights have sometimes been inappropriate, leading to biased estimates of fishing mortality. A new time series of New Zealand annual porbeagle shark mortality was derived using appropriate CFs and an allowance for mortality of discards and released live sharks. The revised time series resulted in 6% more mortality by weight overall for 1998−2016, with annual values varying by –22% to +42%.