Larval Dungeness (Metacarcinus magister) crab arrival, count, and size along the coast of British Columbia

This data package contains datasets obtained from counting and measuring larval Dungeness crab (Metacarcinus magister) caught with light traps at various locations across the Salish Sea in British Columbia, Canada. This work is an ongoing collaborative project between the Hakai Institute and numerous community and institutional partners within the Sentinels of Change project led by Hakai Institute. The purpose of this project is to investigate the magnitude and timing of Dungeness larval delivery in the Salish Sea.

This project began in 2022 with 20 light traps deployed across locations in the Canadian portion of the Salish Sea. The project expanded to 30 sites in 2023, going beyond the Salish Sea to other parts of the BC Coast. In 2024 there were 29 light trap sites. Light traps are deployed from April 15th to September 1st (although some started slightly later in the spring in some years). The traps operate on a timer which turns the light on during dark hours and is adjusted through the season. The traps are checked approximately every two days and Dungeness megalopae (final larval stage) are counted each time. The carapace widths of Dungeness megalopae are also measured each week. Initially, measurements were taken by hand using calipers, however this technique was switched starting July 15th 2022 to a photo technique which allows measurements to be taken later using software (ImageJ).