Estimating Discard Mortality in Commercial Fisheries without Fish Dying: A 3R Challenge

Abstract

Globally, it is estimated that around 10% of the fish that are caught are discarded. This is considered to be a wasteful human marine activity since these fish are often dead or dying. To reduce the high discard rates of commercial fisheries, the European Union (E.U.) has enacted a landing obligation that includes the ability to exempt “species for which scientific evidence demonstrates high survival rates”. Therefore, discard survival studies (henceforth DSSs) have become one of the most politically prioritized fisheries research areas in European fisheries. International expert groups have produced guidance reports to promote best practices and to harmonize the methodologies. Nevertheless, there has not been any focus on how to implement animal welfare (AW) regulations experimentally. Discard survival studies are “frontrunners” in fisheries science research areas that are embedded by animal research welfare requirements and are expected to be more restrictive in the future because of an increased public focus on fish welfare. This paper focuses on AW regulations in relation to conducting DSSs, but the outreach is much broader. We investigate experimental procedures by bringing in relevant examples, using output results, and relating this information to relevant AW guidelines and regulations by focusing on implementing 3R principles.

Effects of Fish Discards as a Substitute for Fish Meal on the Growth Rates and Health Status of Oreochromis niloticus

“…Believes that discards are significant resource waste and negatively affect fisheries' financial sustainability, as well as the exploitation of marine biological resources and ecosystems (Madsen et al, 2022). Little information about how it affects the Nile tilapia's blood traits and immunity is available.…”