Overview

• Researchers led by Professor Robert Britton compared scale cortisol levels in domesticated carp from five recreational fisheries with those of wild carp from five natural populations.
• Most wild carp showed cortisol concentrations several times higher than farmed fish, with some individuals exceeding tenfold differences.
• Authors attribute the lower chronic stress in hatchery-reared carp to selective breeding for resilience and abundant food from angling baits.
• The study confirms that while catch-and-release induces acute stress, it does not raise long-term cortisol in domesticated carp.
• Fishery managers are advised to maintain comprehensive welfare monitoring, including disease checks and water-quality assessments during warm weather.