91. The assessment of the conservation status of wide ranging species depends on 10 estimates of the magnitude of their population trends. The accuracy of global trend 11 estimates will depend on how many locations within a species range are sampled and 12 where in the range population size is sampled. 13 2. We ask how the spatial extent of sampling within a species range interacts with non-14 linear patterns in long-term trends to affect estimates of decline in standardised catch 15 of tiger sharks (Galeocerdo cuvier) in a shark control program on the east coast of 16Australia. We use Bayesian random effects models to estimate long-term population 17 trends. We compare estimates of trends where we use all data spanning 11.5 degrees 18 of latitude to estimates that used spatial subsets of the data. We also introduce a 19Pre-print. Contact chris.brown@griffith.edu.au method to that uses prior information on species life-history to inform on the expected 20 level of population variation. 21 3. As more regions were included in the model the trend estimates converged towards 22 an overall decline of 64% over three generations. Trends estimated from data only 23 from northern regions underestimated the regional decline, trends estimated from 24 data only from southern regions overestimated the regional decline. When a subset of 25 regions were modelled, rather than the full data-set, the estimated trend depended on 26 the choice of the Bayesian prior for population variation. The prior informed by life-27 history traits performed well, a prior incorrectly informed by life-history traits of a 28 much slower growing shark species performed poorly. 29Synthesis and applications The rate of decline in tiger sharks is consistent with a listing East 30Coast Australia tiger sharks as endangered under local legislation. Monitoring programs 31 that aim to estimate population trends should attempt to cover the extremes and mid-32 points of a population's range. Life-history information can be used to inform priors for 33 population variation and may give more accurate estimates of trends that can be justified 34 in debates about red listing of threatened species, particularly when sampling is limited. 35