The impact of harvesting location on the physiological indicators of the American lobster (Homarus americanus H. Milne Edwards, 1837) (Decapoda: Nephropidae) during live storage

Abstract

Shore-based live holding is a required step for post-harvest economic success in the American lobster (Homarus americanus H.Milne Edwards, 1837) fishery. This study evaluated and quantified nutritional condition and gene expression of hepatopancreas during live storage of American lobsters harvested from inshore and offshore locations in Nova Scotia, Canada in early winter. Crude-fat percentage of lobster hepatopancreas and plasma biochemical indicators in haemolymph were used to evaluate the nutritional status of lobsters during live storage. Hepatopancreas crude-fat levels were significantly higher in lobsters from inshore in contrast to offshore locations. Similarly, inshore lobsters were easily distinguished from offshore lobsters because of higher haemolymph Brix and plasma triglyceride, cholesterol, and total protein concentrations. Elevated plasma aspartate aminotransferase activity in inshore lobsters when compared to offshore lobsters suggests that handling practices in the inshore fishery have more impact on harvested lobsters than offshore fishing practices. Inshore lobsters were nevertheless able to recover by four weeks in storage with no obvious mid- and long-term effects. Microarray analysis of hepatopancreas tissue resulted in gene expression profiles that routinely separated inshore from offshore lobsters at all storage time points. The biochemistry of haemolymph and the crude-fat and molecular gene expression analysis of hepatopancreas proved to be useful tools for differentiating lobster harvesting locations. Lobsters harvested inshore in January and stored at the wharf for one month in contrast to lobsters harvested fresh in February had similar gene expression and biochemical profiles; indicating that there is no disadvantage to the live-storage of lobsters caught early in the winter, compared to fresh caught lobsters a month later.