Diplodus Puntazzo Research Articles

Early-Life Population Parameters and Hatch-Date Analysis of Sharpsnout Seabream (Diplodus puntazzo Walbaum, 1792) Juveniles in the Sea of Marmara, Türkiye

This research aims to determine early-life population parameters and hatch date of sharpsnout seabream (Diplodus puntazzo Walbaum, 1792) juveniles using microstructure analyses of sagittal otoliths collected from the Sea of Marmara, Türkiye. Specimens were collected using an experimental beach seine at 12 stations from November 2021 to March 2022. The mean catch per unit effort (CPUE) was 1.1 individuals per haul, with 44.4% of the total D. puntazzo specimens collected at the Erdek Station. A negative allometric growth was calculated from the length-weight relationship equation (W=0.0178L2.698). The daily age ranged between 39 days-1 and 141 days-1, with a mean of 78.9 ± 2.29 days-1. The daily growth rate and mortality ratio were calculated as 0.213 mm/day and 4.38%, respectively. The hatching mainly occurred in September and October.

A Review of Sperm Ultrastructural Characters in the Opecoelidae (Digenea) and Their Phylogenetic Implications, with New Data on Peracreadium characis, a Parasite of Diplodus puntazzo in Tunisia

The spermatozoon ultrastructure of Peracreadium characis (Stossich, 1886) (Digenea: Opecoelidae), an intestinal parasite of the sheephead bream Diplodus puntazzo (Walbaum, 1792) (Sparidae), is described by means of transmission electron microscopy (TEM). The mature spermatozoon possesses two axonemes of the 9+‘1’ trepaxonematan pattern, an anterior electron-dense material, two mitochondria, a nucleus and parallel cortical microtubules distributed in two bundles. The absence of external ornamentation of the plasma membrane and spine-like bodies are the noteworthy characters that distinguish the spermatozoon of P. characis from those of most opecoelids. In fact, only Helicometra fasciata lacks external ornamentation in the spermatozoon. A comparative study with the remaining opecoelids described so far reveals similarities in the ultrastructural organization of their sperm cells. In addition, the current data on sperm ultrastructure in species of the recognized opecoelid subfamilies are compared, namely the Hamacreadiinae, Helicometrinae, Opecoelinae, Opistholebetinae and Plagioporinae.

Relationships between Opercular Girth, Maximum Girth and Total Length of Six Sparid Fishes from Saros Bay (Northern Aegean Sea, Turkey): An Assessment for Ecosystem-based Fisheries Management

This study was conducted so as to unearth the relationships between opercular girth (Gope), maximum girth (Gmax), and total length (TL) for six sparid fishes (Boops boops, Diplodus annularis, Diplodus puntazzo, Diplodus vulgaris, Lithognathus mormyrus, Oblada melanura) belonging to family Sparidae sampled between April 2015 and July 2016 in Saros Bay (Northern Aegean Sea, Turkey). Gope and Gmax were found to increase linearly with total length for all the species. All r2 values were statistically significant (> 0.82, P < 0.001). This study reports the first information about length-girth relationships (LGRs) of Diplodus puntazzo for the Aegean sea. However, no LGRs estimates existed for Oblada melanura worldwide. These values are important for the selectivity of fishing gear so as to prevent the capture of younger, undersized, and immature individuals, it will assist the development of the ecosystem-based fisheries management.

Morphometric Characters of Sharpsnout Seabream (Diplodus puntazzo) Population in the Black Sea

Morphometric Characters of Sharpsnout Seabream (Diplodus puntazzo) Population in the Black Sea

Age, Growth, Reproduction and Fecundity of the Sharpsnout Seabream (Diplodus puntazzo Walbaum, 1792) in the Black Sea Region

In this study, the Sharpsnout Seabream (Diplodus puntazzo) population parameters (age, sex composition, length-weight relationship (LWR), age-length relationship, growth parameters, condition factor, gonadosomatic index, reproductive) of the sharpsnout seabream (Diplodus puntazzo) in the southern Black Sea Region have been investigated. In the study carried out between April 2018 and March 2019, 276 sharpsnout seabream were sampled and the average length and weight were calculated as 30.0 cm and 463.9 g, respectively. Male and female ratio was determined as 1:1.32 (P>0.05). Age of fish varied between 0-9 years. The von Bertalanffy growth parameters were L∞=48.1 cm, k=0.2656 year-1 and t0=-1.6587 year for all individuals. The LWR was found as W=0.0399 L2.7212 for all individuals. Total mortality rate (Z=0.560), natural mortality rate (M=0.501) and fishing mortality rate (F=0.059), growth performance index (φ'=2.73) and condition factor value (K=1.55) were calculated. The maximum GSI value was 6.83 in September. Mean relative fecundity was calculated as 14695.4 eggs / 1g. The mean egg diameter was calculated as 486.83µm. This study is very important in terms of being the first study on this species in the Black Sea and will provide a source for future studies.

The effect of different dietary protein levels on growth performance and nutrient utilization of snarpsnout sea bream ( Diplodus puntazzo )

This study evaluated the effects of different dietary protein levels on growth performance and nutrient utilization of snarpsnout sea bream (Diplodus puntazzo) juveniles. Five isoenergetic diets were formulated to contain a dietary protein level at 30% (P30), 35% (P35), 40% (P40), 45% (P45) and 50% (P50). Each diet was randomly assigned to triplicate groups of fish (IBW 2.80 g) and fed to apparent satiation for 100 days. The dietary protein to energy ratio significantly affected the feed intake with the lower ratios leading to a higher feed consumption. The growth performance of D. puntazzo was gradually increased as the dietary protein level increased up to 40% and then gradually reduced as the dietary protein increased further to 45% and 50%. The feed efficiency got improved as dietary protein levels increased up to 45% but slightly decreased at 50% protein level. A second-degree polynomial regression analysis estimated that a dietary protein level at 41.4% and 43.8% delivered the maximum weight gain and the higher feed efficiency, respectively. The increased dietary carbohydrate and lipid levels in fish fed a low protein diet (P30) resulted in a significant deterioration of feed conversion and growth rates showing also reduced nutrient retentions and causing severe mortalities.

First linkage maps and a pilot QTL analysis for early growth performance in common dentex (Dentex dentex) and sharpsnout seabream (Diplodus puntazzo)

Two potential candidate species for the Mediterranean aquaculture–the common dentex (Dentex dentex) and the sharpsnout seabream (Diplodus puntazzo)-are used in the present study in order to depict their genetic architecture for the first time. We have constructed the first linkage maps for both species using SNP markers derived from ddRAD sequencing. The quality of the maps produced was verified from comparative analysis with the most studied and phylogenetically related sparid species, the gilthead sea bream (Sparus aurata). A high genetic similarity was detected, based on the high number of alignments of the two new species against the reference genome of the gilthead seabream. Furthermore, a pilot study for QTL analysis per species was performed using phenotypic measurements at the juvenile stage (approximately 2 g) and revealed putative genomic areas which affect juvenile growth performance. One of those areas was located close to a candidate gene (ANGPTL6 gene) which affects growth performance. The present study improves our knowledge on the genetic architecture of those two species by presenting not only the first linkage maps, but also by providing some indications for growth performance QTL. The results can be used as a starting point to initiate further research for the genetic improvement of these two new species.

The complete mitochondrial genome of the white seabream Diplodus sargus (Perciformes: Sparidae) from the Tyrrhenian sea

The white seabream Diplodus sargus (Linnaeus, 1758) is a species of interest for commercial fisheries throughout its range of distribution and it is also reared using aquaculture techniques. Herein, we present the first complete sequence and annotation of the mitochondrial genome of this species. The D. sargus mitogenome is 16,515 base pairs in length and contains 13 protein-coding genes, 2 rRNA, 22 tRNA, and 2 non-coding regions (D-loop and L-origin). The overall nucleotide composition is: 27.3% A, 28.9% C, 26.8% T, and 17.0% G. Maximum likelihood analyses placed D. sargus as a sister species of Diplodus puntazzo. This study provides valuable information for further studying identification methods and evolutionary relationships of Sparidae species.

Measurement of Fish Morphological Features through Image Processing and Deep Learning Techniques

Noninvasive morphological feature monitoring is essential in fish culture, since these features are currently measured manually with a high cost. These morphological parameters can concern the size or mass of the fish, or its health as indicated, for example, by the color of the eyes or the gills. Several approaches have been proposed, based either on image processing or machine learning techniques. In this paper, both of these approaches have been combined in a unified environment with novel techniques (e.g., edge or corner detection and pattern stretching) to estimate the fish’s relative length, height and the area it occupies in the image. The method can be extended to estimate the absolute dimensions if a pair of cameras is used for obscured or slanted fish. Moreover, important fish parts such as the caudal, spiny and soft dorsal, pelvic and anal fins are located. Four species popular in fish cultures have been studied: Dicentrarchus labrax (sea bass), Diplodus puntazzo, Merluccius merluccius (cod fish) and Sparus aurata (sea bream). Taking into consideration that there are no large public datasets for the specific species, the training and testing of the developed methods has been performed using 25 photographs per species. The fish length estimation error ranges between 1.9% and 13.2%, which is comparable to the referenced approaches that are trained with much larger datasets and do not offer the full functionality of the proposed method.

Otolith Fingerprints and Tissue Stable Isotope Information Enable Allocation of Juvenile Fishes to Different Nursery Areas

Integrated otolith chemistry and muscle tissue stable isotope analyses were performed to allocate juvenile Diplodus puntazzo and Diplodus vulgaris to nurseries in the Adriatic Sea. Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) was used to quantify the concentrations of chemical elements in the otoliths. Fish muscle samples were analysed for δ13C and δ15N. In general, Ba/Ca and Sr/Ca ratios and isotopes varied between sites and species. Values of δ13C and δ15N were significantly different between species and sites. Multivariate analysis detected a significant difference in the element signature between species while there was no evidence for a significant interaction for sites. A clear pattern across the four groups of interest, D. puntazzo_Estuary > D. vulgaris_Estuary > D. puntazzo_Coastal > D. vulgaris_Coastal, following decreases in δ13C, and increases in δ15N were found. It seems that these species are feeding on the same local food web within more productive estuarine site while at costal site, feeding segregation among investigated species is evident. Both species were re-allocated correctly to the estuarine waters based on the otolith chemistry and stable isotopes information and higher value of δ15N. Combining otolith chemistry with tissue isotope ratios of juvenile fish provided complementary information on nursery habitat use at different spatial scales and elucidated ecological and environmental linkages.

Aerobic growth index (AGI): An index to understand the impacts of ocean warming and deoxygenation on global marine fisheries resources

Ocean warming and deoxygenation are affecting the physiological performance of marine species by increasing their oxygen demand while reducing oxygen supply. Impacts on organisms (e.g., growth and reproduction) can eventually affect entire populations, altering macroecological dynamics and shifting species’ distribution ranges. To quantify the effect of warming and deoxygenation on marine organisms, Penn et al. (2018) and Deutsch et al. (2020) developed two metabolic indices that integrate physiological, biogeographic and climatic data. Here, we develop an alternative index, referred to as Aerobic Growth Index (AGI) based on an approach that integrates the von Bertalanffy growth and metabolic theory. We compare the results derived from the application of AGI with those of the two previously published metabolic indices for six species: Atlantic blue crab (Callinectes sapidus), sharpsnout seabream (Diplodus puntazzo), Atlantic cod (Gadus morhua), Australian spiny lobster (Panulirus cygnus), red drum (Sciaenops ocellatus) and common cuttlefish (Sepia officinalis). The baseline (1971–2000) habitat suitability values of AGI are significantly and positively correlated with both metabolic indices (R2 ≥ 0.92). All three indices also show similar spatial patterns and magnitudes of viable habitat loss by the end of the 21st century (2071–2100) relative to baseline conditions under a high greenhouse gas trajectory (Representative Concentration Pathway 8.5). Our results support the applicability and use of AGI to better understand the impacts of warming and deoxygenation on global marine fishery resources. Given the uncertainties surrounding mechanisms linking temperature, oxygen and biogeography, there is a need for different indicators to account for these uncertainties in climate change projections.

Selection of marine fish for integrated multi-trophic aquaponic production in the Mediterranean area using DEXi multi-criteria analysis

Producing food according to the sustainability and “circular economy” principles is considered a strategic goal by several world Institutions. Integrated Multi-Trophic Aquaculture (IMTA) responds to these criteria and stemming from it, the “Self-sufficient Integrated Multitrophic AquaPonic” (SIMTAP) aims to drastically reduce production inputs and waste outputs while maximizing the total food production. In order to succeed, proper selection of the most suitable fish, intermediate organisms and plant species to be grown in the system plays a fundamental role. To validate the SIMTAP concept and experimental prototype, the biological characteristics of fish and other species should be assessed taking into account their complementarity and adaptability to the physical and technical traits of the considered system.This study aimed to identify the most suitable marine organisms for food production within the SIMTAP system and to create a decision model via the DEXi decision support system. Hence, in the present work a brief description of the SIMTAP concept, as well as the biological, zootechnical and commercial characteristics of several candidate fish species, are discussed. The criteria considered to address the species selection were: natural geo-distribution, domestication degree, environmental requirements, feeding regime, growth performances, and market value. The candidate species were: Sparus aurata, Dicentrarchus labrax, Mugil cephalus, Diplodus puntazzo, Seriola dumerili, Umbrina cirrosa, Argyrosomus regius, Psetta maxima, Acipenser spp., Solea spp., Octopus vulgaris. Finally, it seems that the DEXi approach increased the objectivity of the species selection process. Gilthead Sea Bream, European Sea Bass and Flathead Grey Mullet resulted to be the most suitable species for SIMTAP production.

An initial survey on the occurrence of staphylococcal infections in Turkish marine aquaculture (2013–1014)

A tentative survey on selected marine fish farms was undertaken to delineate the extent to which infections with Staphylococcus species occur in Turkish aquaculture systems. To determine the presence and the distribution of fish pathogenic staphylococci, representative farm types such as marine cages as well as inland pond farms working with saline-ground water and a large hatchery were selected. Field sampling was performed in a total of 13 commercial fish farms that are located in the most-popular aquaculture sites of Turkey. Samples were taken between October 2013 and August 2014. Almost all size classes of the most commonly marine cultured fish species in Turkey were investigated, including Dicentrarchus labrax, Sparus aurata, Argyrosomus regius, Diplodus puntazzo, Dentex dentex, Onchorhynchus mykiss and Salmo labrax. After a visual check, specimens with various clinical signs were sampled for bacteriological and histopathological investigations. Mixed infections of staphylococci along with Vibrio and Aeromonas representatives were detected in Dicentrarchus labrax, Sparus aurata and Diplodus puntazzo samples obtained from 7 farms. The following pathogens were identified: Staphylococcus. epidermidis, S. aureus, S. capitis subsp. capitis, S. lentus, S. hominis subsp. hominis and S. sciuri subsp. sciuri. Main clinical and histopathological effects of the infections in fishes were revealed. The pathogenicity of some isolates was confirmed with in vivo pathogenicity assay and SDS-PAGE analysis.

Experimental infection model with the bivalvulid Enteromyxum leei (Myxidiidae) in the sharpsnout seabream, Diplodus puntazzo (Sparidae), and evaluation of the antiparasitic efficacy of a functional diet.

An infection model for sharpsnout seabream Diplodus puntazzo (Walbaum) challenged with the myxosporean Enteromyxum leei (Diamant, Lom et Dyková, 1994), resembling the natural infection conditions, was used to evaluate the antiparasitic efficacy of a functional diet. Fish of an average weight of 12.5 ± 1.2 g were delivered either a functional (included as feed supplement at 0.3% levels) or a control extruded diet. After four weeks of administration of the experimental diets, fish were challenged with the parasites (cohabitation with infected donors; donor: recipient ratio 1 : 1). The experiment was terminated four weeks after the start of the challenge. At the end of the experiment, growth and feeding (specific growth rate and feed efficiency), as well as immunological parameters (respiratory burst activity, antibacterial activities, hemoglobin concentration, anti-protease activity and ceruloplasmin activity) were measured along with cumulative mortality and total parasitic count in the gut. No significant difference was evident with regard to growth and feeding performance, mortality, gut parasitic load or immunological parameters as the parasitical challenge significantly affected both the performance of the control and functional diet fed fish. However, there was a less prominent impact on antibacterial, anti-protease and ceruloplasmin activity in fish fed with the functional diet. Overall, the present study validated the experimental cohabitation infection model and evaluated the efficacy of a functional ingredient as an antiparasitic agent, showing some potential effects on the fish immune response.

Non-coding RNA Expression Patterns of Two Different Teleost Gonad Maturation Stages.

Non-coding RNAs (ncRNAs) are involved in several different regulatory pathways including reproduction. In teleost fish, efficacious reproduction is heavily dependent on the completion of the reproductive cycle. The presence of ncRNA, however, and their expression dynamics and putative regulatory role in mature and immature gonads have not yet been extensively explored. Therefore, the abundance of ncRNAs in mature and immature female sharpsnout seabream (Diplodus puntazzo) was investigated. The sharpsnout seabream is a rudimentary hermaphrodite which, in captivity, displays dysfunctions in the gonad maturation process. Our analyses revealed a gonad specific read length distribution with two main peaks representing miRNAs (21-26nt) and PIWI RNA (27-34nt). Besides, distinct expression patterns for several ncRNA biotypes including microRNAs (miRNAs), PIWI RNAs (piRNAs), and ribosomal RNAs (rRNAs) were detected. Identified miRNA accounted to 938, corresponding to ~ 13% of obtained transcripts. Among the differential expressed ncRNAs, 10 (~ 7%) were annotated as miRNA, out of which 2 were found in higher abundance in immature gonads (miR-125c and miR-24) and 8 (miR-451, miR-7a, miR-122-1, miR190a, miR129, ENSGACT00000029608, ENSGACT00000029489, and ENSGACT00000029667) were found to be higher expressed in mature gonads. Putative miRNA targets, including long non-coding RNAs (lncRNAs) and genes, are proposed. Target genes are involved in several processes of fish oocyte development, such as steroidogenesis, proteolysis, and apoptosis, and may explain hormone regulation. This study demonstrates a gonad maturation biased ncRNA profile which in turn may support the role of ncRNAs in ovarian physiology and reproductive performance of fish, stressing the specific function of each RNA biotype in oocyte development.

The complete mitochondrial genome of the sharpsnout seabream Diplodus puntazzo (Perciformes: Sparidae)

The sharpsnout seabream Diplodus puntazzo Walbaum, 1792 is a target species of small-scale fishery activities and is cage-cultured for human consumption. Nonetheless, genetic information on this species is limited. We here first sequence its complete mitochondrial genome. The sequence is composed of 16,638 base pairs, accounting for 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 2 non-coding regions (D-loop and L-origin). The overall nucleotide composition is: 27.4% A, 28.9% C, 26.9% T, and 16.8% G. Maximum likelihood analyses placed D. puntazzo close to Acanthopagrus and some Pagellus species.

Helping decision making for reliable and cost-effective 2b-RAD sequencing and genotyping analyses in non-model species.

High-throughput sequencing has revolutionized population and conservation genetics. RAD sequencing methods, such as 2b-RAD, can be used on species lacking a reference genome. However, transferring protocols across taxa can potentially lead to poor results. We tested two different IIB enzymes (AlfI and CspCI) on two species with different genome sizes (the loggerhead turtle Caretta caretta and the sharpsnout seabream Diplodus puntazzo) to build a set of guidelines to improve 2b-RAD protocols on non-model organisms while optimising costs. Good results were obtained even with degraded samples, showing the value of 2b-RAD in studies with poor DNA quality. However, library quality was found to be a critical parameter on the number of reads and loci obtained for genotyping. Resampling analyses with different number of reads per individual showed a trade-off between number of loci and number of reads per sample. The resulting accumulation curves can be used as a tool to calculate the number of sequences per individual needed to reach a mean depth ≥20 reads to acquire good genotyping results. Finally, we demonstrated that selective-base ligation does not affect genomic differentiation between individuals, indicating that this technique can be used in species with large genome sizes to adjust the number of loci to the study scope, to reduce sequencing costs and to maintain suitable sequencing depth for a reliable genotyping without compromising the results. Here, we provide a set of guidelines to improve 2b-RAD protocols on non-model organisms with different genome sizes, helping decision-making for a reliable and cost-effective genotyping.

Aberrant otoliths in four marine fishes from the Aegean Sea, Black Sea, and Sea of Marmara (Turkey)

Saccular otoliths are hearing and balance structures in teleosts and normally consist of aragonite, but in some cases may become aberrant vaterite. Environmental factors, nutritional problems, pollution, stress, and changes in water parameters, as well as a combination of these, may cause abnormal saccular otoliths. The aberrant otoliths may cause several problems such as discriminating hyaline and opaque rings, validating and tracing otolith rings, and measuring radii in the fisheries studies. In the present study, the aberrant and normal saccular otoliths morphologies were examined and described in Pagellus acarne, Trachurus mediterraneus, Diplodus puntazzo, and Merlangius merlangus from the Aegean Sea, Black Sea, and Sea of Marmara. The saccular otolith morphologies of the four fish species were classified from normal to completely crystalline as ”Type 0”, ”Type 1”, ”Type 2”, ”Type 4”, and ”Type 5”. ”Type 3” was not detected in the current study. The current study presents for the first time anomalous otolith morphology on the saccular otoliths in the D puntazzo, P. acarne, and T. mediterraneus. The data obtained from this study provide a comparison between populations and habitats for the researchers working in this field. The present study revealed that different fish species represented distinctive and similar morphological otolith characteristics in terms of abnormal otolith morphology.

First Report of Predation on Egg Capsules of Invasive Rapa Whelk by Sharpsnout Seabream (Diplodus puntazzo) in the Black Sea

The presence of the egg capsules of Rapa whelk, Rapana venosa, in the stomachs of sharpsnout seabream was observed for the first time. Samples were collected on August, 2017 in the Artvin, Hopa region (Black sea of Turkey). Rapa whelk is one of the successful invasive species in the world. Due to high predation pressure on native mussels by invasive whelk in the Black Sea, their populations decreased. Female rapa whelks lay high amount of egg capsules on hard substratum (stones, mussels, whelks etc) during summer. The sharpsnout seabream seems to be an important predator on egg capsules of Rapa whelk due to both species shared same habitat in summer months.

Characterization of a Highly Virulent Edwardsiella anguillarum Strain Isolated From Greek Aquaculture, and a Spontaneously Induced Prophage Therein.

Edwardsiella-associated outbreaks are increasingly reported on both marine and freshwater aquaculture setups, accounting for severe financial and biomass losses. E. tarda, E. ictaluri, and E. hoshinae have been the traditional causative agents of edwardsiellosis in aquaculture, however, intensive studies due to the significance of the disease have just recently revealed two more species, E. piscicida and E. anguillarum. Whole genome sequencing that was conducted on the strain EA011113, isolated from farmed Diplodus puntazzo after an edwardsiellosis outbreak in Greece, confirmed it as a new clinical strain of E. anguillarum. Extensive phylogenetic analysis showed that this Greek strain is closely related to an Israeli E. piscicida-like clinical strain, isolated from diseased groupers, Epinephelus aeneus and E. marginatus in Red Sea. Bioinformatic analyses of E. anguillarum strain EA011113 unveiled a wide repertoire of potential virulence factors, the effect of which was corroborated by the mortalities that the strain induced in adult zebrafish, Danio rerio, under different levels of infection intensity (LD50 after 48 h: 1.85 × 104 cfu/fish). This strain was non-motile and according to electron microscopy lacked flagella, a fact that is not typical for E. anguillarum. Comparative genomic analysis revealed a deletion of 36 nt found in the flagellar biosynthetic gene (FlhB) that could explain that trait. Further in silico analysis revealed an intact prophage that was integrated in the bacterial genome. Following spontaneous induction, the phage was isolated, purified, characterized and independently sequenced, confirming its viability as a free, inducible virion as well. Separate genomic analysis of the prophage implies a plausible case of lysogenic conversion. Focusing on edwardsiellosis as a rapidly emerging aquaculture disease on a global scale, this work offers some insight into the virulence, fitness, and potential lysogenic conversion of a of a newly described, yet highly pathogenic, strain of E. anguillarum.