The susceptibility of shi drum juveniles to betanodavirus increases with rearing densities in a process mediated by neuroactive ligand-receptor interaction.

Nervous necrosis virus (NNV) is one of the greatest threats to Mediterranean aquaculture, infecting more than 170 fish species and causing mortalities up to 100% in larvae and juveniles of susceptible species. Intensive aquaculture implies stressed conditions that affect the welfare of fish and their ability to fight against infections. In fact, a higher susceptibility to NNV has been related to poor welfare conditions. In order to analyze the physiological link between stressed conditions and increased susceptibility to NNV, as well as its possible role in the pathogenesis of this disease, we reared shi drum (Umbrina cirrosa) juveniles (30.7 ± 3.10 g body weight), which are expected to be asymptomatic upon NNV infection, at three stocking densities (2, 15, and 30 kg/m3) for 27 days and subsequently challenged them with NNV. We firstly characterized the stressed conditions of the specimens before and after infection and recorded the mortalities, demonstrating that stressed specimens reared at 30 kg/m3 suffered mortalities. However, the viral loads in different tissues were similar in all experimental groups, allowing horizontal and vertical transmission of the virus from asymptomatic specimens. All of these data suggest that shi drum tolerates wide ranges of culture densities, although high densities might be a setback for controlling NNV outbreaks in this species. In an attempt to understand the molecular pathways orchestrating this susceptibility change in stressed conditions, we performed a transcriptomic analysis of four tissues under mock- and NNV-infected conditions. In addition to the modification of the exceptive pathways such as cell adhesion, leukocyte migration, cytokine interaction, cell proliferation and survival, and autophagy, we also observed a heavy alteration of the neuroactive ligand-receptor pathway in three of the four tissues analyzed. Our data also point to some of the receptors of this pathway as potential candidates for future pharmacological treatment to avoid the exacerbated immune response that could trigger fish mortalities upon NNV infection.

Enzymatic, skeletal, and histological ontogeny of shi drum (Umbrina cirrosa) larvae under intensive culture conditions.

This study was conducted to investigate the structural and ontogenetic development of the skeletal system and digestive tract histologically and enzymatically in larvae of shi drum (U. cirrosa) under intensive rearing conditions until 40 days after hatching (DAH). Among digestive enzymes, amylase was detected at 0.89 ± 0.12 mU mg protein-1 on the first hatching day. The specific activities of trypsin and lipase were detected simultaneously with mouth opening on 3 DAH with 28.47 ± 3.52 and 2.8 ± 0.32 mU mg protein-1, respectively. In addition, pepsin was found for the first time at 0.88 ± 0.21 mU mg protein-1 on 15 DAH in association with stomach formation and increased sharply up to 40 DAH. In the structural development of the skeletal system, the development of the caudal fin in larvae was morphologically associated with the flexion of the notochord. It was observed that the shape of the fin and spine, which reached 40 DAH, became similar to the adult shape. Histologically, 3 DAH, the mouth and anus were opened. The formation of the primitive stomach was observed at the end of the seventh day-the pyloric sphincter formed between 13 and 18 days. A functional stomach was seen on the 15th DAH. Therefore, U. cirrosa is believed to have critical aquaculture potential that can be cultured under intensive conditions. The developmental profile of skeletal, enzymatic, and histological ontogeny observed in U. cirrosa is similar to that described for other sciaenid species.

Toxic metals and total lipids comparison between wild and farmed fish of South mediterranean.

A total of 151 wild and farmed fish samples of three species (S. aurata, D. labrax and U. cirrosa) from south Mediterranean were examined for cadmium, lead and mercury and total lipids detection to verify possible differences between wild and farmed fish. Mercury was detected only in S. aurata samples, with mean values of 0.056 ± 0.128 mg/kg and 0.031 ± 0.033 mg/kg for farmed and wild samples, respectively. The results verified no significant differences in Pb, Cd and Hg levels between wild and farmed fish samples (p < 0.05). The farmed fish samples showed higher total lipids contents than wild (p > 0.05). As far as we know, this work report first findings on the toxic metal presence in farmed Umbrina cirrosa, showing no detectable Hg, Cd and Pb values. The results of this work seems to confirm that the presence of toxic metals could be more related to the pollution the site than the type of production.

A new maximum size record of the shi drum (Umbrina cirrosa Linnaeus, 1758) for Aegean Sea / Um novo registro de tamanho máximo do corvina (Umbrina cirrosa Linnaeus, 1758) para o Mar Egeu

The present study has been conducted to find out new findings on maximum length and weight values of Umbrina cirrosa in the Bay of Saros (Northern Aegean Sea, Turkey). On September, 11, 2016, a single specimen of Umbrina cirrosa with 68.8 cm total length and 2600.00 g total weight was caught by handline at a depth of 20 m. The provable size is the second largest length ever reported in the all seas of the world.

O presente estudo foi realizado para descobrir novas descobertas sobre os valores máximos de comprimento e peso de Umbrina cirrosa na Baía de Saros (Mar Egeu do Norte, Turquia). Em 11 de setembro de 2016, um único espécime de Umbrina cirrosa com 68.8 cm de comprimento total e 2600.00 g de peso total foi capturado por linha de mão a uma profundidade de 20 m. O tamanho provável é o segundo maior comprimento já registrado em todos os mares do mundo.

Skeletal ontogeny of the vertebral column and of the fins in shi drum Umbrina cirrosa (Teleostei: Perciformes: Sciaenidae), a new candidate species for aquaculture.

The osteological development of the vertebral column and fins in shi drum Umbrina cirrosa was studied in order to improve knowledge for its introduction in Mediterranean aquaculture. The osteological development was studied in 171 individuals, of total length (LT ) from 2·7 to 30·2 mm that were reared under the mesocosm technique. Vertebral ontogeny starts at 3·4 and 4·0 mm LT , with the formation of the first cartilaginous neural and haemal arches, and spines, respectively, and is completed with the full attainment of epicentrals (12·5 mm LT ). The formation of vertebral centra occurs between 4·1 and 7·4 mm LT . Pectoral supports are the first fin elements to develop (3·0 mm LT ), followed by those of the caudal fin (3·8 mm LT ), pelvic fin (3·9 mm LT ) and finally by those of the dorsal and anal fins (4·5 mm LT ). The caudal fin is the first to develop fin rays and attain the full count of principal fin rays (4·5-6·8 mm LT ), but the last to be fully completed with the formation of procurrent fin rays (6·9-17·5 mm LT ). The next fins starting to present rays are the dorsal (5·3 mm LT ) and the pectoral fins (5·6 mm LT ), while the anal and pelvic fins are the last (5·7 mm LT ). Following the caudal principal fin rays (6·8 mm LT ), the dorsal, anal (6·9 mm LT ), pelvic (7·4 mm LT ) and pectoral fins (9·8 mm LT ) are the next with fully completed ray counts. Aggregation of qualitative changes, such as the appearance of cartilages, the beginning and the complement of the ossification process and the full complement of elements in U. cirrosa were measured as cumulative frequency counts. These measurements reveal three ontogenetic intervals: one very developmentally active period during early life stages (from 3 to 5·9 mm LT ), a second slower developmental period (from 6·0 to 8·9 mm LT ) and finally a period of ontogeny more focused on structure refinement up to metamorphosis and settlement (>9·0 mm LT ).

A New Maximum Size Record of the Shi Drum (Umbrina cirrosa Linnaeus, 1758) for Aegean Sea

Abstract The present study has been conducted to find out new findings on maximum length and weight values of Umbrina cirrosa in the Bay of Saros (Northern Aegean Sea, Turkey). On September, 11, 2016, a single specimen of Umbrina cirrosa with 68.8 cm total length and 2600.00 g total weight was caught by handline at a depth of 20 m. The provable size is the second largest length ever reported in the all seas of the world

Resumo O presente estudo foi realizado para descobrir novas descobertas sobre os valores máximos de comprimento e peso de Umbrina cirrosa na Baía de Saros (Mar Egeu do Norte, Turquia). Em 11 de setembro de 2016, um único espécime de Umbrina cirrosa com 68.8 cm de comprimento total e 2600.00 g de peso total foi capturado por linha de mão a uma profundidade de 20 m. O tamanho provável é o segundo maior comprimento já registrado em todos os mares do mundo.