Understanding the effects of uncertainty on catch series over data-limited stock assessment and harvest strategies of Brazilian southern red snapper (Lutjanus purpureus) fishery

Catch time series are still the only historical information to assess many global fisheries, and the low quality of catch data is one of the major issues in quantifying the condition of stocks and sustainable exploitation levels for most Brazilian fisheries. Data-limited methods for stock assessment and management strategy evaluation were applied to the southern red snapper (SRS; Lutjanus purpureus) fishery in Brazil, enabling the assessment of the effects of uncertainty on historical catch series over stock status estimations and management strategy performance. We estimated biomass trends and reference points through catch-only stock assessment with four combinations of the available catch time series. Using management strategy evaluation methods, we also evaluated the capacity of different strategies to avoid overfishing, maintain population sustainability, and achieve yield optimization and stability. The differences in catch series affect the assessed variables: stock status results range from 0.28 to 0.43 of virgin biomass, current fishing mortality varies from 28 to 53% above sustainable levels, and sustainable yield results range from 5,320 to 7,580 t. Early uncertainty in the SRS catch series has the greatest impact on absolute estimations and sustainable yield. Still, recent misreporting strongly influences current fishing mortality and catch limit estimations. Under this uncertainty, static management strategies based on effort control and constant catch tend to be more sensitive and riskier, resulting in the poorest performance on sustainability criteria, especially in pessimistic scenarios. Dynamic procedures based on regular biomass estimations tend to be more conservative and robust, with better performance in avoiding overfishing and achieving yield stability.