Best practices for the transport and live storage of flounder

Summary

Implementing plaice as a new species in capture-based aquaculture (CBA) can be straightforward in terms of logistics (coastal fishing) and access to storage locations in pens. However, several challenges need to be addressed. To ensure good fish welfare and quality, gentle fishing gear should be used. During fishing for live storage, knotless mesh in the seine net should be used to reduce fish injuries. Short towing times and moderate catch amounts provide better conditions for the fish. When delivering live fish, both the boat and the reception facility should be designed to avoid unnecessary stress, impacts, compression, or falls. This ensures the fish maintain good health and quality throughout the process from capture to delivery. It is recommended to keep the fish in water during boarding and sorting. Use water-filled canvas lifts in the codend and sort the fish gently on water-filled sorting tables/chutes. Only undamaged fish with good vitality should be transported alive to storage in pens. During transport, plaice need sufficient bottom area and plenty of oxygen-rich water. Fish density should be lower than 250 kg/m², and the stay in transport tanks should be under 2 days. It is recommended that the storage time in pens be shorter than 4 weeks, and trampoline bottoms should be used to prevent large accumulations of plaice in bottom depressions. A failing bottom can cause unnecessary stress on the fish, lack of oxygen, increased injury potential, and mortality. Plaice move little, but the fish can get abrasion injuries on fins and skin during storage in pens. Additionally, small catch injuries can develop into larger wounds during storage, especially the eyes and head are vulnerable, so regular inspection and care are necessary. Injured fish should be removed quickly. A raisable trampoline bottom can simplify care and reduce stress. During slaughter, plaice should be handled as gently as possible, but stunning is challenging due to the shape of the fish, so stunning/killing methods adapted to flatfish should be developed to better ensure animal welfare during slaughter.