No abstract

Age, growth and mortality were analysed for brown comber, Serranus hepatus, collected in the eastern Adriatic from May 2002 to June 2003. Fish aged 2-7 years were present in the samples. Growth in length including both sexes was expressed using the von Bertalanffy equation, L ¥ ¼ 14.82, K ¼ 0.217 and t 0 ¼ )1.672. Age class 2, ranging in length from 5.8 to 9.0 cm TL, dominated the sample (29.3%). Total and natural mortality were Z ¼ 1.73 year )1 and M ¼ 0.63 year )1 , respectively. The exploitation rate, E ¼ 0.64, revealed a high fishing pressure on the stock in the studied area.

The age and growth of the blackspot seabream, Pagellus bogaraveo, were determined by examining sagittal otoliths from fish sampled in the eastern Adriatic Sea. A total of 674 specimens (181 males, 90 hermaphrodites, 108 females, and 295 immatures) ranging from 8.80 to 47.27 cm (21.93 ± 9.00 cm) in total length were analyzed. The maximum observed age for the whole sample was 13 years. The sample was dominated by 1-year-old specimens as a consequence of an abundance of juvenile specimens collected by beach seines. Growth was described by the von Bertalanffy growth curve (L∞ = 52.3 cm, K = 0.15 year−1, t0 = 0.49 year, R2 = 0.97), and the growth performance index (Φ’) was 2.61. The length, width, thickness, and mass of the otoliths were compared with the total length and age of P. bogaraveo from the eastern Adriatic. The analysis showed that the measures were adequate predictors of age. These results can be of value for more effective management measures aimed at the conservation of this species.

Biometric properties and diet composition were examined in 120 specimens of the common pandora caught in the eastern Adriatic Sea. Biometric analysis of the morphometric and meristic characteristics indicate a homogenous morphology stock of P. erythrinus in the eastern Adriatic Sea. Changes in some of the morphometric characteristics obtained in conjunction with an increase in body length showed that smaller specimens have a longer dorsal fin, standard length, eye diameter and postorbital distances than larger specimens. The meristic characteristics of the common pandora from Italian waters and the Black Sea are mostly in agreement with data in our study. The prey species identified in the stomachs belong to five groups: Decapoda, Bivalvia, Polychaeta, Teleostei and Euphausiacea. Decapods were the most important ingested prey group while bivalves were second in importance. Various prey groups and species found in the stomach indicate that the common pandora could be an opportunistic predator

Immunofluorescence and immunohistochemical techniques were used to define the distribution of cytoskeletal (cytokeratin 8, vimentin) and extracellular matrix components (collagen type I, collagen type II, hyaluronic acid, and aggrecan) and bone morphogenetic proteins 4 and 7 (BMP4 and BMP7) in the notochord of the lesser spotted dogfish Scyliorhinus canicula L. Immunolocalization of hyaluronic acid was observed in the notochord, vertebral centrum, and neural and hemal arches, while positive labeling to aggrecan was observed in the ossified centrum, notochord, and the perichondrium of the hyaline cartilage. Type I collagen was observed in the mineralized cartilage of the vertebral bodies, the notochord, the fibrocartilage of intervertebral disc, and the perichondrium. A positive labeling to type II collagen was observed in the inner part of the cartilaginous vertebral centrum and the notochord, as well as in the neural arch and muscle tissue, but there was no appreciable labeling of the hyaline cartilage. The presence of both BMP4 and BMP7 was seen in the mineralized vertebral centrum, notochordal cells, and neural arch. The notochordal cells expressed both cytokeratin 8 and vimentin, but predominantly vimentin. Hyaluronic acid, collagen type I, and collagen type II expression confirmed the presence of a mixture of notochordal and fibrocartilaginous tissue in the intervertebral disc, while BMPs confirmed the presence of an ossification in the cartilaginous skeleton of the spotted dogfish.