Restoring endangered Northern Abalone (Haliotis kamtschatkana) populations in British Columbia, Canada, using hatchery-raised individuals

摘要

This study investigated the effectiveness of using hatchery-raised northern abalone (Haliotis kamtschatkana) to supplement wild populations in Barkley Sound, BC. Densities of abalone were assessed at sites outplanted by the Bamfield Huu-ay-aht Community Abalone Project, and all fell at or below the suspected Allee threshold. The potential for improving outplanting success was then examined by releasing both larval and juvenile hatchery-reared individuals at different treatment densities and tracking their survival over time using cohort analyses and mark-recapture methods, respectively. Predators represented the major source of mortality for outplanted abalone and congregated at outplant sites. Tagging, handling, and temperature stress did not result directly in mortality. Juvenile abalone were particularly vulnerable in the first 24 hours after outplanting, experiencing 64 % mortality during that period. The behaviours of hatchery-raised abalone differed from those of wild individuals. I recommend outplanting 50,000 larvae/m2 or groups of 100 juveniles in predator exclosure cages.