Vanesa Lorencin’s scientific contributions

Every year, close to 8 million tons of waste crab, shrimp and lobster shells are produced globally, as well as 10 million tons of waste oyster, clam, scallop and mussel shells. The disposed shells are frequently dumped at sea or sent to landfill, where they modify soils, waters and marine ecosystems. Waste shells are a major by-product, which should become a new raw material to be used to the best of their potential. There are a number of applications for waste shells in many fields, such as agriculture, medicine, chemical production, construction, environmental protection, cosmetic industry, food and feed industry, and a plethora of other (often niche) applications, which are being developed by the day. This review provides a broad picture of crustacean and mollusc shell waste management and reutilization possibilities, reviewing well established, current, and potential strategies, particularly from the standpoint of sustainability challenges and energy demand.

In the shallow Northern Adriatic, marine mollusks are affected by bottom trawling and seafood disturbance. Seasonal oscillations of oceanographic factors additionally influence their physiology, stress responses and survival. Tissue responses to seasonal variations in green ormer (Haliotis tuberculata L.) and Mediterranean scallop (Pecten jacobaeus L.) in the Northern Adriatic have not been reported. Hence, their biochemical and antioxidant defense properties over seasons were studied and the microanatomical structure of their tissue was correlated with function. Histological analysis of gonads revealed two peaks of gonadal maturation and spawning during the spring/summer period and winter season for scallops, and one peak during the fall for ormers. The gonadal maturation of both species was correlated with their seasonal variations of metabolic demands and antioxidant capacity. The lipid vacuoles of tubuloacinar terminations in the digestive gland differed between the two species; in scallop they are several-fold larger in size and number. Low temperatures in winter contributed to a decline in enzymatic antioxidant defense in scallop tissues, having lower superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity, and higher concentrations of thiobarbituric acid reactive substances (TBARS) and total antioxidant status (TAS). In ormers, winter induced lower TAS, TBARS, SOD and GPx concentrations. The significant difference of winter TAS and TBARS levels between ormers and scallops was correlated with variations in their reproductive cycles, as well as in antioxidant defense systems. The most important factor for stress-related parameters for both species in this work was found to be the season-induced temperature change.

Due to the great economic importance of sea bass Dicentrarchus labrax (Linnaeus, 1758) in Mediterranean mariculture, the aim of this study was to explore the seasonal dynamics of the copepod parasite Lernanthropus kroyeri (van Beneden, 1851) on the gills of cultured sea bass. This is the first study of L. kroyeri on cultured sea bass from the Adriatic Sea. Sea bass (N = 457) samples were taken monthly from October 2012 to October 2014, from the same floating net cage. A significant positive correlation (r = 0.24; P < 0.0001), was found between the sea bass length and the total number of parasites, and between the fish length and egg string length of L. kroyeri (r = 0.647; P < 0.0001). Prevalence of L. kroyeri ranged from 94.4% to 100%. Female parasites dominated the population throughout the research period (72.6%), followed by males (25%) and immature parasites (2.4%). Gravid females were most dominant during the summer season, with their numbers significantly dropping in the winter. Observed seasonal dynamics of L. kroyeri reproductive patterns suggest that the winter season may be the best period for control and treatment of the infection. Furthermore, this new data may provide a basis for the development of epidemiological models with a focus on preventive measures in order to improve health management of mariculture in the Adriatic Sea, as well as in the whole Mediterranean area.

The present work is the first study of Mediterranean scallop (Pecten jacobaeus) biochemical properties, antioxidant defenses, and free radical scavengers during the yearly seasons in the Northern Adriatic, off Istria. Scallop nutrient reserves (glucose, triglyceride, and cholesterol) in four tissues under examination were positively correlated and were predominant in digestive gland and gonad. The muscle energy maxima were in correlation with the maximum fall gonosomatic index (GSI), when diatoms and coccolithophorids thrive. The decrease of GSI in summer might be related to the spawning or resorption of gametes. Summer also revealed elevated levels of glucose in gonad and digestive gland, while muscle glucose and cholesterol significantly varied in spring vs. winter samples. In relation to the diatom seasonal abundance, carotenoids, namely astaxanthin peaks were found in digestive gland, which, being stimulators of calcium transport over cell membranes, could have contributed to the high digestive gland levels of calcium in winter. In winter, total antioxidative status (TAS) of scallop tissues was 3-fold higher than in other seasons, particularly in digestive gland, having a significant correlation with magnesium, a regulatory tool in oxidative processes. The winter maxima of TAS and thiobarbituric acid reactive substances TBARS in relation to summer maxima of glutathione peroxidase and superoxide dismutase in digestive glands indicate to a decrease in antioxidant defense during cold months, and are related to the accumulation of lipid peroxidation products (such as malondialdehyde) in digestive gland of scallops. Although the increased susceptibility to oxidative stress could be attributed to winter temperature, other factors such as the gonad maturation, availability of food supply, and salinity might counteract that effect. The seawater alterations of salinity, temperature and water quality are in relation to the river Po influx, which is very likely to influence the physiological and biochemical responses of scallops in the Northern Adriatic.