Recreational shellfish harvesting on a sandy beach in the Algarve coast (southern Portugal): First appraisal of the annual catch of wedge clams (Donax trunculus)

This study aimed to characterise the recreational harvesting of wedge clams ( Donax trunculus ) in the Algarve coast (southern Portugal) and estimate its annual catches by recreational harvesters (RHs). For this purpose, 50 harvesting surveys were performed along the sandy intertidal during one-year (May 2022 - April 2023), roughly on a weekly basis during suitable tidal ranges (≤ 1.0 m). Overall, RHs were gender-balanced and older harvesters (≥ 65 years-old) prevailed. RHs were clearly more numerous from late spring to summer, especially in August, with most RHs collecting wedge clams with foot / hand and only a minority (≈20 %) also using a shrimp-net. RHs catches comprised mostly D. trunculus below the minimum conservation reference size (MCRS = 25 mm in shell length) legally stipulated for this species. The estimation of RHs annual catches of D. trunculus was based on standardised catches per harvester (number and weight hour −1 ), extrapolated using the total number of RHs and suitable tides for wedge clams recreational harvesting during the one-year study period. Collecting and processing geolocated data on RHs activity allowed mapping the spatial-temporal distribution of the recreational harvesting effort targeting wedge clams, further confirming the importance of spatial data as a support tool for management and decision-making processes. This study further confirmed the need to raise awareness and inform RHs about the best harvesting practices, aiming ultimately to improve the assessment and promote the long-term sustainable management of this recreational activity and shellfish resource. • Experimental recreational harvesting (RH exp ) replicated recreational harvesters (RH). • RH exp was a representative proxy of RHs typical activity and wedge clams’ catches. • RHs catches comprised mostly individuals below the MCRS for Donax trunculus. • RHs geolocated data is a key useful tool for mapping harvesting activity and effort. • RHs awareness and best harvesting practices needed to promote sustainable management.