Fish welfare in capture fisheries: A review of injuries and mortality

Abstract

Concerns about the welfare of production animals have extended from farm animals to fish, but an overview of the impact of especially capture fisheries on fish welfare is lacking. This review provides a synthesis of 85 articles, which demonstrates that research interest in fish welfare in capture fisheries has increased over time and that research has focused more on trawls and hooks than on purse seines, gillnets, traps and seines. We found that various gear characteristics, fish characteristics and context variables affect external injuries and mortality. Although the influence of gear characteristics on injuries and mortality can by nature not be compared across gear types, synthesis of the articles reviewed shows that fish characteristics and context variables influence injuries and mortality across gear types. In terms of fish characteristics, decreasing fish length and certain fish species were associated with higher mortality. In terms of context variables, greater capture depth and a longer fishing duration were associated with more injuries and higher mortality, whereas a large change in water temperature, a longer duration of air exposure and a high density in the net were associated with higher mortality. These relations provide options to reduce injuries and mortality from commercial capture fisheries. Implementation of such options, however, would require analysis of potential trade-offs between welfare benefits, and ecological and economic consequences.