Effect of capture method on the physiology and nucleotide breakdown products in the Norway lobster (nephrops norvegicus)

The effects of capture method (creel and trawl) and trawling time (15, 60 and 150 min) were assessed in Norway lobsters by measuring stress-related metabolites together with nucleotide breakdown products. Furthermore, mechanical damage was scored in the animals captured by trawl. Capture method had a clear impact on the nucleotide profile in the Norway lobster muscle. In rested and creel-caught animals the main nucleotide was ATP, while in trawled animals the main nucleotide was AMP. According to these results the Adenylate Energy Charge (AEC) was lower in trawled animals compared with creel-caught animals, while trawling time did not affect AEC levels significantly. Stress-related and anaerobic metabolites together with muscle pH indicated that trawled animals, even at the shortest time tested, were using anaerobic metabolism. In the haemolymph, l-lactate increased with a delay compared with muscle, suggesting that the concentration of l-lactate in the muscle provides a more immediate measure of capture-stress in this species. Although physiological measures were similar for short and long tows, physical damage increased in long trawls. Further studies should elucidate whether the different physiological stresses and the physical damage that occur during capture could compromise the live transport of trawled animals, and if quality measures could thus be affected.