Leonidas Papaharisis

Bio: Leonidas Papaharisis is an academic researcher. The author has contributed to research in topics: Sea bass & Aquaculture. The author has an hindex of 1, co-authored 1 publications receiving 5 citations.

Stress assessment, quality indicators and shelf life of three aquaculture important marine fish, in relation to harvest practices, water temperature and slaughter method

Abstract: The objective of this study was to evaluate the effect of harvest practices and slaughter method on stress, quality and shelf life of whole fish (gilthead sea bream, European sea bass and red sea bream) towards the development of a humane slaughter practice. The use of hook and line resulted in significantly lower plasma cortisol and glucose in European sea bass and gilthead sea bream. Water temperature at harvest affected significantly the concentrations of stress indicators (plasma cortisol and glucose), mainly in European sea bass and gilthead sea bream. No significant differences were observed between the harvesting methods, regarding fish appearance, microbial spoilage and sensory scoring and subsequently shelf life. However, significantly lower hardness was recorded in fish harvested using the electric stunner, compared to the fish killed with slurry ice of the same harvesting period. Shelf life ranged between 13–18 days for gilthead seabream, 10–16 days for European sea bass and 10–14 days for red sea bream, depending on harvesting period.

Revising the Impact and Prospects of Activity and Ventilation Rate Bio-Loggers for Tracking Welfare and Fish-Environment Interactions in Salmonids and Mediterranean Farmed Fish

Abstract: Behavioral parameters are reliable and useful operational welfare indicators that yield information on fish health and welfare status in aquaculture. However, aquatic environment is still constraining for some solutions based on underwater cameras or echo sounder transmitters. Thus, the use of bio-loggers internally or externally attached to sentinel fish emerges as a solution for fish welfare monitoring in tanks- and sea cages-rearing systems. This review is focused on the recently developed AEFishBIT, a small and light data storage tag designed to be externally attached to fish operculum for individual and simultaneous monitoring of swimming activity and ventilation rates under steady and unsteady swimming conditions for short-term periods. AEFishBIT is a tri-axial accelerometer with a frequency sampling of 50–100 Hz that is able to provide proxy measurements of physical and metabolic activities validated by video recording, exercise tests in swim tunnel respirometers, and differential operculum and body tail movements across fish species with differences in swimming capabilities. Tagging procedures based on tag piercing and surgery procedures are adapted to species anatomical head and operculum features, which allowed trained operators to quickly complete the tagging procedure with a fast post-tagging recovery of just 2.5–7 h in both salmonid (rainbow trout, Atlantic salmon) and non-salmonid (gilthead sea bream, European sea bass) farmed fish. Dual recorded data are processed by on-board algorithms, providing valuable information on adaptive behavior through the productive cycle with the changing environment and genetics. Such biosensing approach also provides valuable information on social behavior in terms of adaptive capacities or changes in daily or seasonal activity, linking respiratory rates with changes in metabolic rates and energy partitioning between growth and physical activity. At short-term, upcoming improvements in device design and accompanying software are envisaged, including energy-harvesting techniques aimed to prolong the battery life and the addition of a gyroscope for the estimation of the spatial distribution of fish movements. Altogether, the measured features of AEFishBIT will assist researchers, fish farmers and breeders to establish stricter welfare criteria, suitable feeding strategies, and to produce more robust and efficient fish in a changing environment, helping to improve fish management and aquaculture profitability.

The effect of fishing season and storage conditions on the quality of European plaice (Pleuronectes platessa)

Abstract: The combined effect of fishing season (September/April) and storage conditions on the quality of European plaice ( Pleuronectes platessa ) was investigated. Investigated storage conditions were; fillets packaged in vacuum or a modified atmosphere (MA; 70% CO 2 , 20% N 2 , 10% O 2 ) and stored at 4 °C. As a control, whole fish on ice (0 °C) was used, representing the commercial standard. Plaice showed in general lower quality in April than September, demonstrated by a faster microbial evolution, higher content of biogenic amines, and higher rate of ATP degradation representing by K- and H-values. MA-fillets and whole fish on ice showed lower K- and H-values and biogenic amines content than fillets packaged in vacuum. VP-fillets had the lowest microbial quality as demonstrated by the shortest lag-phase of psychrotrophic aerobic plate count and aerobic bacteria, and the highest maximum specific growth rate of H 2 S-producing bacteria. MA packaging significantly reduced microbial growth; however, MA-fillets showed the lowest water content and the highest drip loss and water holding capacity. No differences between groups were observed in colour intensity or hue angle at the storage end. Despite the significant seasonal variations, MA packaging stands out as the best solution to maintain the freshness of convenient retail plaice products. • The effect of season and storage conditions on the quality of plaice was investigated. • Quality of plaice was significantly lower in April than September. • The storage conditions affected the microbial and physicochemical quality. • MAP (4 °C) is a best solution to produce satisfactory quality, retail plaice products.