The algal polysaccharide agar has long been used as a food binder due to its structure, rheological behaviour, stability and interactions^properties that help to generate ¢rm, round, disk-shaped pellets that may be used in recirculating sea urchin-rearing systems. Three algae-based diets (Ulva lactuca, Gracilaria gracilis, Cystoseira sp.) containing 3% and 6% agar were tested on the sea urchin Paracentrotus lividus in order to examine the e¡ect of varying percentages of agar on pellet stability in water and sea urchin gonad growth. The kinetics of water absorption and solute leaching of pellets were measured by immersing quadruplicate samples of the pellets in water for1, 2,3, 4,5 and 6 days. Our results show that the pellets had good water stability, were readily consumed by sea urchins and the presence of agar did not hamper sea urchin gonad growth. Animals fed Ulva-containing pellets reached a more advanced gametogenic stage with respect to animals fed Cystoseira-and Gracilaria-containing pellets. Moreover, the presence of agarase activity in the digestive system indicated that agar may be an energy source. Pellets are relatively low cost and easy to prepare and store. They may represent a useful resource for rearing sea urchins under intensive conditions.

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The Mar Piccolo of Taranto (Ionian Sea, Southern Italy) is a semi-enclosed and strongly polluted basin. For decades, it has been subjected to different anthropogenic impacts. These stressors caused severe sediments contamination with high concentration of different pollutants (PAHs, PCB, heavy metals). In order to assess the current status of sediments contamination, an ecotoxicological investigation combined with chemical analysis (heavy metals, PAH, and PCB) has been performed. In order to derive ecologically relevant conclusions, a multiorganisms and multiend-points approach has been applied, exposing organisms from different trophic levels to elutriate and whole sediment. The battery of bioassays consists of a microalgal growth inhibition test (Dunaliella tertiolecta), acute and sublethal assays (end-points: mortality, immobilization and swimming speed alteration) on crustaceans larvae and juveniles, and rotifers (Amphibalanus amphitrite, Artemia salina, Corophium insidiosum and Brachionus plicatilis), and embryotoxicity test on echinoderms (Paracentrotus lividus). Considering the high levels of sediment contamination highlighted from chemical analysis, an unexpected very low toxic effect was observed, even considering the sublethal end-point (larval swimming speed alteration). The results of this study suggest a very complex contaminants dynamic in the Mar Piccolo sediments that, despite a strong level of contamination, seems to not affect in a proportional manner the biological compartment.

Understanding the role of ocean currents in the recruitment of commercially and ecologically important fish is an important step toward developing sustainable resource management guidelines. To this end, we attempt to elucidate the role of surface ocean transport in supplying recruits of European sardine (Sardina pilchardus) to the Gulf of Manfredonia, a known recruitment area in the Adriatic Sea. Sardine early life history stages (ELHSs) were collected during two cruises to provide observational estimates of their age-size relationship and their passive pelagic larval duration (PPLD). We combine these PPLDs with observations of surface ocean currents to test two hypotheses: (1) ELHSs are transported from remote spawning areas (SAs) by ocean currents to the Gulf of Manfredonia; (2) sardines spawn locally and ELHSs are retained by eddies. A historical surface drifter database is used to test hypothesis 1. Hypothesis 2 is tested by estimating residence times in the Gulf of Manfredonia using surface drifters and virtual particles trajectories that were computed from high-resolution observations of surface currents measured by a high-frequency (HF) radar net-work. Transport to the Gulf of Manfredonia from remote SAs seems more likely than local spawning and retention given a mismatch between observed PPLDs of 30-50 days and relatively short ( < 10-day) average residence times. The number and strength of connections between the gulf and remote SAs exhibit a strong dependence on PPLD. For PPLDs of 20 days or less, the gulf is connected to SAs on the western Adriatic coast through transport in the Western Adriatic Current (WAC). SAs on the east coast are more important at longer PPLDs. SAs in the northern and central Adriatic exhibit weak connections at all PPLD ranges considered. These results agree with otolith microstructure analysis, suggesting that the arrival of larvae in the gulf is characterized by repeated pulses from remote SAs. This is the first attempt to describe the processes related to Lagrangian connection to, and retention in, the Gulf of Manfredonia that will be complemented in the future using validated numerical ocean models and biophysical models.