Estimating Unreported Recreational Landings of Lobster and Stock Assessment Impacts

Attention on including recreational fishing in stock assessments has increased in recent years. However, obtaining reliable estimates of total mortality in recreational fisheries still face several challenges. In Norway, recreational landings represent a major share of removals in several valuable coastal groundfish and shellfish fisheries, exceeding commercial landings of high-value species such as the red-listed European lobster (Homarus gammarus). A mandatory registration for the recreational lobster fishery, implemented in 2017, showed that more than 30,000 recreational lobster fishers participate in the fishery yearly. By using this license frame we compared diary and recall survey designs to estimate effort and catches. The diary survey requires substantial effort to secure high response rates but provides high-resolution data. Online recall surveys are less resource-demanding but likely more prone to recall biases. Our results show that the two survey methods perform overall equally well in reproducing catch-per-unit-effort indices and, thus, total landing estimates. Furthermore, we present estimates of the reconstructed total catch in the Norwegian lobster fishery and their effect on stock perception and reference points. The results of this case study contribute novel insights into the application of a low-cost approach for assessing recreational catches, as well as the importance of including recreational catches into stock assessments.