Sagittal otoliths of five wrasse species, Coris julis, Symphodus tinca, Symphodus cinereus, Symphodus ocellatus and Symphodus rostratus from the eastern Adriatic were compared using descriptive morphological characters (types of anterior and posterior otolith regions and otolith margins) and shape indices (formfactor, roundness, circularity, rectangularity and elipticity). All shape indices except the formfactor were used to build the discriminant function, with circularity and roundness being the main variables that explain the interspecific variability. The overall classification score of the discriminant analysis was 62.8%, with the lowest score obtained for S. ocellatus (44.3%) and the highest for C. julis (83.3%). Otolith morphometric parameters (length, width, thickness and weight) were used in predictive linear regression equations to estimate fish size. For all investigated wrasses, except for S. rostratus, otolith length showed the strongest and otolith thickness the weakest relationship to both fish length and weight. Multiple linear regression equations based on log transformed variants explained higher proportion of variation in fish size than simple linear regressions, although these differences in R 2 were relatively low, amounting to 1.3-12.1% when compared to the best simple regressions for different species.

Relative growth and reproductive biology of Munida rutllanti were investigated for the first time in the Adriatic Sea. A total of 938 individuals were analysed. Sex-ratio differed statistically from the expected 1:1. Six individuals exhibited secondary sex characteristics of both males and females. Carapace length of males ranged from 10.5 to 21.5 mm, while in females it ranged from 11.2 to 19.4 mm. Sexual dimorphism was observed in seven morphometric characters. Ovigerous females were first observed in summer and later in autumn with higher frequency. Realized fecundity showed wide variation (273-3250 eggs) and positive correlation between the brood and female size. An epicaridean isopod Pleurocrypta sp., parasitizing the gill chamber of both sexes was isolated and its effect on the oogenesis was studied by histological examination of host reproductive system. Growth inhibition, modification of secondary sex characteristics, as well as retardation of oogenesis and failure of oviposition, are repercussions of bopyrid infestation. Given the small prevalence (7.85%) of the bopyrid in the M. rutllanti Adriatic population, we assume that for the moment there is no severe effect on the host population dynamic.

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Floating fish farms attract a great number of wild fish species, changing their behaviour and physiology. The saddled bream, Oblada melanura, sampled from populations aggregated around the Adriatic fish farm and from natural/control populations, were analysed for differences in eleven blood biochemistry parameters and liver histomorphology. The levels of lactate dehydrogenase (LDH), alkaline phosphatase (ALKP) and urea (URE) in cage-associated saddled bream (428.00±SD 321.56 U/L, 86.13±SD 39.87 U/L and 0.05±SD 0.16 mmol/L, respectively) were significantly lower than those observed in the control specimens (1047.06±SD 505.56 U/L, 125.75±SD 34.70 U/L and 1.99±SD 0.73 mmol/L, respectively). In contrast to that, concentrations of aspartate aminotransferase (AST) in cage-associated fish (87.63±SD 132.34 U/L) were higher than values noted for the control population (6.55±SD 5.90 U/L). URE and AST presented the main variables contributing to the discrimination between two analysed populations. One-way ANOSIM based on the blood parameters showed significant difference between saddled bream that fed around cages and those from the remote waters (R=0.697; P < 0.01). Hepatocytes of cage-associated fish contained large cytoplasmatic clear spaces indicating excessive accumulation of fat in the hepatocyte cytoplasm. All observed differences can be attributed to contrasting feeding behaviour of sampled populations but basic nutritional differences between them should be quantified in the future. Moreover, further research is necessary to detect their impact on the health status of the fish.

Sagittae otoliths of eight juvenile species: Boops boops, Diplodus vulgaris, Diplodus puntazzo, Sarpa salpa (family Sparidae), Liza ramada, Liza aurata (family Mugilidae), Atherina boyeri, Atherina hepsetus (family Atherinidae) were analysed and compared using descriptive morphological characters and morphometric indices. The noticeable differences among the otoliths of the investigated species are in their overall shape, margins (i.e. irregular, sinuate or crenate) and anterior region. Otolith shape varied from elliptic to pentagonal in sparids, elliptic to rectangular in mugilids and elliptic in two atherinids. Aspect ratio (OW/OL), ratio of the sulcus length occupied by the cauda length (CL/SL) and ratio of the sulcus length occupied by the ostium length (OSL/SL) were calculated for all species. The otolith contour was described using wavelets. The Canonical Analysis of Principal Coordinates (CAP) gave an overview of the otolith shape differentiation between eight juveniles. Using the Wavelet coefficients, the first principal component (CAP1) explained 58.1% of the variation among species and the second principal component (CAP2) 25.2%.