Validation of a vigour index for trawl-caught Norway lobsters ( Nephrops norvegicus ) destined for the live market: Underlying links to both physiological condition and survivability

Abstract

Recent improved practices in the trawl fishery for Norway lobsters (Nephrops norvegicus) have made it possible to increase the proportion of trawl-caught lobsters that can be transported alive successfully. A major contributor to this has been the introduction of on-board seawater tanks, which allow for the recovery of animals immediately after they have been landed from the net.In this study, we have validated a vigour index that could be used both by fisheries scientists and by the industry dealing with live-traded Nephrops, allowing identification of the proportion of trawl-caught lobsters that fail to recover following capture and are not in a condition to survive live transportation. Results indicate that the process of visual selection into one of four possible vigour categories reflects with good accuracy the underlying physiological state of the animals, as assessed by the level of adenylate 5' -triphosphate in the tail muscles, by the proportions of other nucleotides as expressed in the Adenylate Energy Charge, and by the amount of intra-muscular L-lactate present. The vigour index also correlates well with their subsequent survival potential in a semi-dry transport system.

Welfare in Farmed Decapod Crustaceans, With Particular Reference to Penaeus vannamei

“…A condition/welfare index based on both physical appearance and behaviour (e.g. 'vigour') as developed by Albalat et al (2017) for trawl-caught langoustines N. norvegicus, combined with one or more haemolymph measures, would represent a major step forward.…”

Meta‐analytic assessment of physiological markers for decapod crustacean welfare

“…There are various established operational welfare indicators for finfish, such as rapid opercular movements, physical damage inspections (e.g., eyes, fins, scales), gulping air at the water surface and condition of the gills (e.g., colour, mucous; Calduch‐Giner et al., 2022). Likewise, condition indices have been used by crustacean graders as proxies for welfare, vitality and survivability, for example, reflex action mortality predictors (RAMP) developed for crabs (e.g., snow crabs, Chionoecetes spp., Oregoniidae, blue crabs, Callinectes sapidus , Portunidae); Stoner, 2012; Yochum et al., 2015; Walters et al., 2022), or a vigour index for langoustine ( Nephrops norvegicus (Nephropidae); Albalat et al., 2017). These are relatively simple to use and can provide near real time assessment of mortality based on physical trauma and aberrations.…”

“…Likewise, condition indices have been used by crustacean graders as proxies for welfare, vitality and survivability, for example, reflex action mortality predictors (RAMP) developed for crabs (e.g., snow crabs, Chionoecetes spp., Oregoniidae, blue crabs, Callinectes sapidus, Portunidae); Stoner, 2012;Yochum et al, 2015;Walters et al, 2022), or a vigour index for langoustine (Nephrops norvegicus (Nephropidae); Albalat et al, 2017). These are relatively simple to use and can provide near real time assessment of mortality based on physical trauma and aberrations.…”