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.
10In the Mediterranean Sea Nephrops (Nephrops norvegicus) is predominantly caught with 11 bottom trawls, but it is also harvested with creels. While the size selection of Nephrops in 12 bottom trawls is well documented, there is no previous information on creel size selection for 13 this species. Therefore, sea trials were carried out to assess the selective properties of 14 commercial creels with 41 mm mesh size netting mounted as a square mesh netting as 15 prescribed by the legislation. Creel size selection was assessed for Nephrops and two main 16 crustacean bycatch species: mantis shrimp (Squilla mantis) and blue-leg swimming crab 17 (Liocarcinus depurator). The influence of the soak time on creel selectivity was also 18 investigated, and no significant difference was detected between one and two day soak times. 19The average carapace length of a crustacean with 50% probability of being retained (L50) was 20 31.69 mm for Nephrops, which is 59% larger than the minimum landing size (MLS) set by 21 the fishery regulation, therefore demonstrating a mismatch between MLS and gear selectivity 22 in this fishery. Comparison of creel selectivity obtained in our study with the historical results 23 obtained from commercial bottom trawl selectivity studies for Nephrops in the Mediterranean 24 *Manuscript including abstract Click here to view linked References Sea demonstrated that the creel L50 was significantly higher than in the trawl fishery, this 25 implies that creel fishery is targeting larger Nephrops than trawl fishery. 26 27
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.
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