No abstract

Two microplastic sets, polystyrene (PS) and polymethyl methacrylate (PMMA), were tested for adverse effects on early life stages of Sphaerechinus granularis sea urchins.Microparticulate PS (10, 80 and 230 µm diameter) and PMMA (10 and 50 µm diameter) were tested on developing S. granularis embryos from 10 min post-fertilisation (p-f) to the pluteus larval stage (72 h p-f), at concentrations ranging from 0.1 to 5 mg L -1 . Both PS and PMMA exposures resulted in significant concentration-related increase of developmental defects and of microplastic uptake in plutei. Moreover, embryo exposures to PS and PMMA (5 and 50 mg L -1 ) from 10 min to 5 h p-f resulted in a significant increase of cytogenetic abnormalities, expressed as significantly increased mitotic aberrations, while mitotoxicity (as % embryos lacking active mitoses) was observed in embryos exposed to PS, though not to PMMA. When S. granularis sperm suspensions were exposed for 10 min to PS or to PMMA (0.1 to 5 mg L -1 ), a significant decrease of fertilisation success was observed following sperm exposure to 0.1 mg L -1 PS, though not to higher PS concentrations nor to PMMA. Sperm pretreatment, however, resulted in significant offspring damage, as excess developmental defects in plutei, both following sperm exposure to PS and PMMA, thus suggesting transmissible damage from sperm pronuclei to the offspring. The overall results point to relevant developmental, cytogenetic and genotoxic effects of PS and PMMA microplastics to S. granularis early life stages, warranting further investigations of other microplastics and other target biota.

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The ability of mussels to cope with environmental conditions depends on the species’ capacity to acclimate or adapt within its morphometric and physiological parameters. In the present study,we investigated the effect of aquaculture site and translocation on different stocks of Mediterranean mussel, Mytilus galloprovincialis Lamarck, 1819. We used shell morphological ratios (width/length, height/length and height/width) and allometric relationships (volume-length and shell weight-length) in addition to condition index (wet meat weight/total weight) and mortality to compare cultivated and translocated mussels from the northern Adriatic Sea, Croatia. Mussels were collected from five cultivation areas (Lim, Pomer, Raša, Vabriga and Budava), and then moved for three months to experimental station at marine protected area in Lim Bay. Differences between cultivated mussels suggested morphological plasticity, although translocation weakly affected allometric relationships. Decrease in condition index was pronounced in translocated mussels, indicating adaptation to different local environmental conditions. High post translocation mortality was observed in mussels transferred to the experimental area. Our study shows plastic response of M. galloprovincialis, which can provide a useful information of mussel stocks selection in aquaculture.

Total arsenic concentration in the edible part of mussels Mytilus galloprovincialis was evaluated seasonally in the coastal area of Rijeka Bay (North Adriatic Sea, Croatia). Sampling stations were located close to the City of Bakar with no industrial facilities (site 1), in the vicinity of the oil refinery and oil thermoelectric power plant (Urinj, site 2), and 4 miles away from the Plomin coal thermoelectric power plant (Brseč village, site 3). Additionally, the concentration of arsenic in the tail muscle of the lobster Nephrops norvegicus, collected in Rijeka Bay, was studied. During winter at sites 2 and 3, the total arsenic in the edible part of the mussels was 16.4 mg As/kg FW (FW=fresh weight) and 4.38 mg As/ kg FW, respectively, and increased during springtime at site 2 (6.5 mg As/kg FW) compared to the rest of the year, when individual total arsenic concentration at all sites ranged from 1.7 to 3.7 mg As/kg FW. In the winter (sites 2 and 3) and springtime (site 2) there was no correlation between the length of the mussel shell and the arsenic concentration in the edible part of the mussels. In the other seasons, at sites 1, 2 and 3, there was a correlation between arsenic in the edible part of mussels and shell length in most cases (correlation coefficients r varied from 0.64 to 0.85; P <0.05 to P <0.01). Correlation between shell length (in the narrow range of shell lengths from 3.4 to 5.0 cm) and arsenic in the edible part of the mussels shows linearity with a high regression coefficient ( r =0.914; P <0.001). The increase of arsenic in the mussels during winter and spring was suggested at least partially as a result of a low nutritional status, i.e. reduced weight of the mussels' edible part during winter. In addition, a linear relationship was found between body length and arsenic concentration in the tail muscle (mean 17.11€4.48 mg As/kg FW) of the Norway lobster.