Search

This study was conducted in the Gulf of Suez from 2021 to 2022 on the Haffara seabream (Rhabdosargus haffara), which belongs to the family Sparidae. The relative fecundity of R. haffara ranged from 345.1 to 631.2 oocytes/g, with an average of 391.7 oocytes/g. A unimodal winter peak was observed in advanced gametogenesis (stages IV and V) for both male and female R. haffara. A significant difference was recorded in the monthly average gonado-somatic index (GSI), which ranged from 0.5 to 4.0% for males and 0.8 to 10.0% for females. The monthly hepatosomatic index (HSI) for males ranged from 0.86 to 1.95% (mean: 1.23 ± 0.07%), while for females it ranged from 0.56 to 1.22% (mean: 0.99 ± 0.04%). Histological analyses were performed to determine the maturity of R. haffara, using samples from 100 individuals (50 males and 50 females) collected in 2021 and 2022. The histological analysis confirmed the biological observations of fish maturity discussed in earlier sections of this study. The length at 50% maturity was found to be 14.50cm. A total of 120 individuals of R. haffara were analyzed from eight populations. [ABSTRACT FROM AUTHOR]

Sponges play a significant role in many marine environments. In tropical regions, the relationship between Porifera and spongivorous organisms, including fish, has been extensively studied. In the Mediterranean Sea, the dominant predators of sponges are sea stars, sea urchins and nudibranches, while knowledge of fish feeding on sponges is limited to sporadic events. This study aimed to investigate sponges as part of the diet of the white seabream Diplodus sargus. The results revealed that sponges were abundantly present in seabream stomachs, reaching up to 79.7% of the total biomass ingested by a single individual. Five different species were found in fish stomachs. The presence and organization of the spicular component seemed to affect the biting strategy of fish. Sponges with a prevalent organic component, such as Chondrosia reniformis Nardo, 1847, and Chondrilla nucula Schmidt, 1862, were ingested as fragments, while specimens of the Tethya citrina Sarà & Melone, 1965, characterized by a globular body, were engulfed entirely. Data from this study represent the first effort to investigate the trophic relationship between fish and Porifera in the Mediterranean Sea.

Abstract Background While teleost fishes represent two thirds of marine vertebrates, the role of their external microbiota in relationship with their environment remains poorly studied, especially in wild populations. Hence, the interaction of their microbiota with ectoparasites is largely unknown. Microbiota can act as a protective barrier against pathogens, and/or be involved in host recognition by parasites. Thus, host-parasite associations should now be considered as a tripartite interplay where the microbiota shapes the host phenotype and its relation to parasites. Monogeneans (Platyhelminthes) are direct life cycle ectoparasites commonly found on teleost skin and gills. The role of bacterial communities within skin and gill mucus which either pre-exist monogeneans infestation or follow it remain unclear. This is investigated in this study using the association between Sparidae (Teleostei) and their specific monogenean ectoparasites of the Lamellodiscus genus. We are exploring specificity mechanisms through the characterization of the external mucus microbiota of two wild sparid species using 16s rRNA amplicon sequencing. We investigated how these bacterial communities are related to constrated Lamellodiscus monogeneans parasitic load. Results Our results revealed that the increase in Lamellodiscus load is linked to an increase in bacterial diversity in the skin mucus of D. annularis specimens. The date of capture of D. annularis individuals appears to influence the Lamellodiscus load. Correlations between the abundance of bacterial taxa and Lamellodiscus load were found in gill mucus of both species. Abundance of Flavobacteriaceae family was strongly correlated with the Lamellodiscus load in gill mucus of both species, as well as the potentially pathogenic bacterial genus Tenacibaculum in D. annularis gill mucus. Negative correlations were observed between Lamellodiscus load and the abundance in Vibrionaceae in gill mucus of D. annularis, and the abundance in Fusobacteria in gill mucus of P. acarne specimens, suggesting potential applications of these bacteria in mitigating parasitic infections in fish. Conclusions Our findings highlight the dynamic nature of fish microbiota, in particular in relation with monogeneans infestations in two wild sparid species. More generally, this study emphasizes the links between hosts, bacterial communities and parasites, spanning from the dynamics of co-infection to the potential protective role of the host’s microbiota.

A total of 933 samples of Pagellus bellottii were obtained from the coast of Ghana between January and December 2019, from commercial catches to determine the sex ratio, maturity stages, spawning period, and length at first maturity. The male to female ratio was 1.39:1. July and May were the main spawning peaks for female individuals of the assessed fish species. Two spawning periods were observed with a minor spawning period from November to January and major spawning from March to September. Female individuals matured slightly earlier than male individuals at 20 cm and 20.8 cm respectively. The results of this study could help to revise the existing minimum capture size of Red Pandora in Ghana.

Monogeneans are highly host‐specific parasites infecting marine and freshwater fish. However, little information is available about the parasitic taxa within Heteraxinidae. An integrative study was performed to understand the taxonomic status of an unconfirmed heteraxinid marine species parasitizing the gill region of Acanthopagrus bifasciatus (Sparidae) from the Arabian Gulf (Saudi Arabia). Based on the morphological study, this parasite has all the generic features of the genus Kannaphallus (Heteraxinidae, Mazocraeidea). Distinct criteria that discriminated this species from other taxa of the same genus are the presence of genital spines (26–29), a short sclerotized duct in the male copulatory organ, the number of testes (mean 40, range 30–50), and clamps in the haptoral structure (45–50 in a long row and 19–22 in a short row). DNA of parasite species reported in the present study was amplified and sequenced for the nuclear large subunit of the ribosomal RNA (28S rRNA) gene and the mitochondrial cytochrome c oxidase subunit I (COI) gene. Results indicate that sequences obtained from both genes are unique and different from related sequences from the genus Kannaphallus. Morphological as well as molecular data indicate that our specimens are from a new species, and the name Kannaphallus acanthopagrusi n. sp. is suggested. This is the first report of a heteraxinid parasitizing marine sparid fish from Saudi Arabia, with unique morphological and molecular features. [ABSTRACT FROM AUTHOR]

The age and growth of the common pandora (Pagellus erythrinus) were investigated along the El-Kala coastline (northeastern Algeria), marking the first study of its kind in this area. From March 2023 to February 2024, a total of 492 specimens were sampled, with total lengths (TL) ranging from 10.5 to 23.5 cm, total weights (TW) from 7.03 to 164.3g, and eviscerated weights (EW) from 6.1 to 157.3g. The ages of the specimens ranged from 0 to 6 years, determined using the direct method of scalimetry. The growth parameters based on the von Bertalanffy growth model, derived from the average age-length pairs, were as follows: L∞ = 23.72cm, K = 0.2 year-1, to = -0.901, and W∞ = 166.25g, with a performance index (φ') of 2.05 for both sexes combined. The relative growth equations for males, females, and all specimens were TW = 0.043TL².59, TW = 0.067TL².43 and TW = 0.052T².52, respectively, indicating negative allometry for all three categories. [ABSTRACT FROM AUTHOR]

Arachidonic acid (AA) is an essential fatty acid that has vital influences on early development in marine fish larvae. In this regard, a 30-day research was run to examine the effects of live food enrichment with graded levels of AA on some physiological responses of Acanthopagrus latus larvae. Four experimental emulsions containing four levels of AA were used to enrich live foods (rotifer and Artemia), including very low (6%, N), low (12%, L), medium (24%, M), and high (37.8%, H) AA levels. Newly hatched larvae were distributed into twelve 250-L cylindrical tanks with initial density 15,000 larvae in each tank supplied with seawater (23 ± 1 °C; 40.0 ± 1.0 g L−1). Nannochloropsis oculata was used in a green water system and live foods were offered to larvae two times daily. Larvae in the H group had lower total length (7.24 ± 0.6 mm) than those in other treatments. The highest survival rate after air exposure and osmotic stress challenges was in the H group. The level of n-6 polyunsaturated fatty acids, mainly AA, was enhanced in the larval whole body with increasing AA level in the emulsion. The highest and lowest alkaline phosphatase activities were in the H and N groups, respectively. The aminopeptidase N and leucine-alanine peptidase activities in the N group were lower than those in the other treatments. The trypsin activity gradually increased with the increment of AA in the emulsions. The highest and lowest chymotrypsin, amylase, and pepsin activities were in H and N groups, respectively. The highest and lowest phospholipase A2 activity was in the M and N groups, respectively. The activity of catalase in the whole body of the M group was greater than that in the rest of the treatments. The highest and lowest superoxide dismutase activities were in M and N groups, respectively. The activity of glutathione reductase in the L and M groups was higher than that in the rest. Total antioxidant capacity in the whole body of larvae in the N group was lower than that in the other treatments and the H group showed the highest value. The whole body malondialdehyde level in the L group was lower than that in N and H groups and M showed intermediate value. Based on the findings of the present study, moderate levels of AA suggested for the enrichment of live foods in A. latus by considering n-3 long-chain polyunsaturated fatty acid content in the enrichment solution. [ABSTRACT FROM AUTHOR]

Background: While teleost fishes represent two thirds of marine vertebrates, the role of their external microbiota in relationship with their environment remains poorly studied, especially in wild populations. Hence, the interaction of their microbiota with ectoparasites is largely unknown. Microbiota can act as a protective barrier against pathogens, and/or be involved in host recognition by parasites. Thus, host-parasite associations should now be considered as a tripartite interplay where the microbiota shapes the host phenotype and its relation to parasites. Monogeneans (Platyhelminthes) are direct life cycle ectoparasites commonly found on teleost skin and gills. The role of bacterial communities within skin and gill mucus which either pre-exist monogeneans infestation or follow it remain unclear. This is investigated in this study using the association between Sparidae (Teleostei) and their specific monogenean ectoparasites of the Lamellodiscus genus. We are exploring specificity mechanisms through the characterization of the external mucus microbiota of two wild sparid species using 16s rRNA amplicon sequencing. We investigated how these bacterial communities are related to constrated Lamellodiscus monogeneans parasitic load. Results: Our results revealed that the increase in Lamellodiscus load is linked to an increase in bacterial diversity in the skin mucus of D. annularis specimens. The date of capture of D. annularis individuals appears to influence the Lamellodiscus load. Correlations between the abundance of bacterial taxa and Lamellodiscus load were found in gill mucus of both species. Abundance of Flavobacteriaceae family was strongly correlated with the Lamellodiscus load in gill mucus of both species, as well as the potentially pathogenic bacterial genus Tenacibaculum in D. annularis gill mucus. Negative correlations were observed between Lamellodiscus load and the abundance in Vibrionaceae in gill mucus of D. annularis, and the abundance in Fusobacteria in gill mucus of P. acarne specimens, suggesting potential applications of these bacteria in mitigating parasitic infections in fish. Conclusions: Our findings highlight the dynamic nature of fish microbiota, in particular in relation with monogeneans infestations in two wild sparid species. More generally, this study emphasizes the links between hosts, bacterial communities and parasites, spanning from the dynamics of co-infection to the potential protective role of the host's microbiota. [ABSTRACT FROM AUTHOR]

The present study presents length-weight, length-length, length-girth relationships, and biometry of male and female specimens of saddled seabream, Oblada melanurus(Linnaeus, 1758), in the Turkish Aegean Sea. The length-length and length-weight relationships were calculated by measuring 516 individuals. The total length values of all male and female O. melanurus specimens were in the range of 17.2-30.7 and 18.5-30.0 cm, respectively, and the mean values were 21.84±2.04 and 22.44±2.12 cm, respectively. The length-weight relationships were W=0.0110TL3.057 for males, W=0.0114TL3.043 for females, and W=0.0089TL3.122 for all the specimens. The results denoted a high correlation (r²=0.966; p<0.001) in the length-length relationships. Furthermore, 287 individuals (105 females and 182 males) were examined for length-girth relationships and biometric analyses. Ten morphometric characters were analyzed to analyze biometry. In conclusion, no statistically significant differences were determined in morphology between the sexes (p<0.05). [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Sultan Qaboos University Journal for Science is the property of Sultan Qaboos University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study of the polyopisthocotylan parasites of marine fishes in the western Mediterranean is carried on using an integrative approach combining morphology and DNA barcodes. Ktarius patrickbrueli n. gen. n. sp (Polyopisthocotyla, Microcotylidae), from the gills of the pink dentex Dentex gibbosus (Teleostei, Sparidae) from the western Mediterranean Sea off Tunisia, is described. Anatomical and morphological features of the new genus are described, and the molecular barcodes for nuclear and mitochondrial markers (28S rRNA and cox1) are generated. The new genus is closely related to Microcotyle by sharing a symmetrical haptor, inverted question mark-shaped ovary and unarmed vagina. However, Ktarius n. gen. can be distinguished from Microcotyle and other Microcotylinae taxa by an unarmed male copulatory organ, formed by a long muscular cirrus, a basal layer of concentric muscles, and an elongated thick-walled ejaculatory bulb. A partial 28S rDNA sequence of K. patrickbrueli n. gen. n. sp. was obtained and found to be distinct from all known microcotylid sequences, with a p-distance of 5–13%. A phylogenetic tree constructed from available microcotylid sequences revealed that K. patrickbrueli n. gen. n. sp. clustered in a strongly supported clade of Microcotylinae, containing species of Omanicotyle, Bivagina, and Microcotyle confirming its belonging to the Microcotylinae subfamily. The cox1 sequences of K. patrickbrueli n. gen. n. sp. were highly divergent from the closely related genus Pauciconfibula and confirmed its distinction. This new genus is the third polyopisthocotylan genus to be described from sparids of Dentex.

Abstract Background Biogeography has been linked to differences in gut microbiota in several animals. However, the existence of such a relationship in fish is not clear yet. So far, it seems to depend on the fish species studied. However, most studies of fish gut microbiotas are based on single populations. In this study, we investigated the gut microbiota of fish from three wild populations of the two-banded sea bream Diplodus vulgaris (Geoffroy Saint-Hilaire, 1817) to determine whether its diversity, structure and potential functionality reflect the geographic origin of the fish, at large and small geographical scale. Additionally, we explored the host- and environmental-related factors explaining this relationship. Results We showed that the taxonomy and potential functionality of the mucosa-associated gut microbiota of Diplodus vulgaris differ to varying degrees depending on the spatial scale considered. At large scale, we observed that both the taxonomical structure and the potential functionality of the fish microbiota differed significantly between populations. In contrast, the taxonomical diversity of the microbial community displayed a significant relationship with factors other than the geographic origin of the fish (i.e. sampling date). On the other hand, at small scale, the different composition and diversity of the microbiota differ according to the characteristics of the habitat occupied by the fish. Specifically, we identified the presence of Posidonia oceanica in the benthic habitat as predictor of both the microbiota composition and diversity. Lastly, we reported the enrichment of functions related to the metabolism of xenobiotics (i.e. drugs and 4-aminobenzoate) in a population and we indicated it as a potential target of future monitoring. Conclusions With this study, we confirmed the importance of investigating the gut microbiota of wild fish species using multiple populations, taking into account the different habitats occupied by the individuals. Furthermore, we underscored the use of the biodegradation potential of the gut microbiota as an alternative means of monitoring emerging contaminants in Mediterranean fish.

The saddle seabream, Oblada melanura, is an important species in Mediterranean coastal fisheries. The artisanal gillnet fishery on Tunisia's northern coast was sampled on a monthly basis between April 2015 and March 2016. The sex ratio varied by month throughout the year, with females dominating from November to December and equal sex ratios during the rest of the year. For both sexes, gonad maturity and gonadosomatic index (IG) indicated that spawning occurs from May to September. In terms of energy investment, fish feed throughout the year. During the spawning period (May to September), gonadal production (IG) appears to be supported by liver reserves (IH). These reserves came from external sources (i.e. food) in the period before spawning. During the spawning period, it was necessary for the fish to continue feeding in order to support their body development. Estimated lengths at 50% maturity were similar for females (L50 = 17.14 cm) and males (L50 = 17.01 cm). [ABSTRACT FROM AUTHOR]

The Pacific Porgy (Calamus brachysomus) is a commercially important fish in Baja California Sur, Mexico, where it reproduces year-round. The feeding habits of fishes can change during reproductive stages in response to changes in energetic demand. The objective of this study was to characterize the trophic habits of the Pacific Porgy and how these varied by sex, reproductive stage, and season. Monthly samples were obtained from July 2015 to July 2016 in the central Gulf of California. The stomach contents of 235 specimens (108 males and 127 females) were analyzed. The trophic spectrum comprised 90 prey items, including 58 mollusks, 14 echinoderms, 13 arthropods, 2 chordates, 1 annelid, 1 poriferan, and algal remains. According to the prey-specific index of relative importance (%PSIRI), the most important prey items were the bivalves Transennella spp. (7.24%), Argopecten spp. (6.94%), Anadara spp. (6.25%), Septifer zeteki (6.19%), and Tivela spp. (6.1%). The trophic spectrum varied significantly by season but not by sex or reproductive stage. There were no significant interactions between sex and season or sex and reproductive stage. According to the Levin index, C. brachysomus exhibited a narrow trophic niche (Bi = 0.31). Costello graphs indicated the dominance of a few species, with shifts in the relative abundance of prey species. Based on the trophic analysis, C. brachysomus was classified as a tertiary consumer (3.18). Therefore, C. brachysomus represents an important link between upper and lower trophic levels. Based on these results, we inferred that the Pacific Porgy is an opportunistic predator that feeds actively during all reproductive stages. Thus, the energetic requirements needed for reproduction appear to be covered by the prey that comprise the trophic spectrum of C. brachysomus without this species needing to switch to more energy-rich prey. [ABSTRACT FROM AUTHOR]

A formerly unexploited stock of red porgy that was intensely fished along southern Brazil in the 1970s collapsed in less than a decade. Subsequently, population dynamics or stock status has not been reported, so we updated growth parameters by analysis of otolith annual‐increments and micro‐increments. Growth did not change after the stock collapsed, which suggested no density‐dependent effect. Given the lack of growth changes and data‐limitation, we used an age‐structured assessment model set until 1984 to forecast relative spawning biomass and assess recovery possibilities. Projections showed that a 19 years moratorium would have been necessary for the stock to rebuild. The model suggested an annual catch of at least 170 t in the post‐collapse period because the stock did not recover, and a small‐scale hand‐line fishery with unreported landings continued fishing. Our results reinforced the need for more curated and up‐to‐date data collection to properly assess and manage this formerly abundant stock. [ABSTRACT FROM AUTHOR]

Bluespotted seabream Pagrus caeruleostictus, a member of the family Sparidae, is one of the high‐priced seabream species in Ghana. Although the fish has been exploited in the Gulf of Guinea for over hundreds of years, there is scanty information on the state of the fish stock. Hence, we sought to investigate the exploitation status and aspects of the reproductive biology of the species by collecting monthly length and weight data for 18 months (February 2016 to July 2017). These data were fitted to growth and mortality models. The sexual maturity, fecundity and spawning seasons were also determined within the same period. The growth model of the fish revealed that the asymptotic length (L∞) and growth coefficient (K) values determined were 52.7 cm (total length) and 0.52 year−1, respectively. The mortality models also showed that the fishing mortality (F) of the fish was 2.20 year−1, whereas its natural mortality (M) was 0.83 year−1, with F/M > 0.5 indicating that the fish is over‐exploited. The lengths at first sexual maturity (Lm) of the males and females were 36.2 and 28.0 cm, respectively. Pagrus caeruleostictus, which was found to be highly fecund, had two spawning periods in a year, occurring in September and March, both with unimodal ova diameter frequency distributions. Based on these findings, we recommend that catch limits and other appropriate management measures (e.g. temporal and spatial closures) should be prescribed for the seabream fishery in the Gulf of Guinea to ensure the sustainability of the fishery. [ABSTRACT FROM AUTHOR]

The main goal of the current work was to describe and analyse the Digenean community structure in Sarpa salpa. A total of 114 specimens of S. salpa were collected from the Central Coast of Algeria at six localities. The fish were immediately transported to the laboratory to be examined for digeneans. From 107 of the 114 S. salpa examined, a total of 8,722 specimens of seven species belonging to three families were recovered. Among them, Robphildollfusium fractum and Mesometra orbicularis were the most prevalent and abundant species. Moreover, Lepocreadium album was found for the first time in S. salpa from the coast of Algeria, and Centroderma spinosissima and Wardula capitellata represent new parasites to the Algerian digenean fauna that infect teleost fish. The component community of these Digeneans is characterised by R. fractum as its dominant species representing 62% of the total number of collected Digeneans, as well by a Shannon diversity index (H′) and Dominance Simpson index (D) of 1.03 and 2.23, respectively. According to Spearman's correlation test, Mesometra brachycoelia and W. capitellata were negatively correlated to the host biological factors. On the other hand, R. fractum showed a positive correlation between its mean abundance and the total length of the fish. With these findings, we provided the component structure of the Digenean fauna of S. salpa and highlighted their diversity, contributing to the biodiversity of the parasitic Platyhelminthes in Algeria. [ABSTRACT FROM AUTHOR]

The Pacific Porgy (Calamus brachysomus) is a commercially important fish in Baja California Sur, Mexico, where it reproduces year-round. The feeding habits of fishes can change during reproductive stages in response to changes in energetic demand. The objective of this study was to characterize the trophic habits of the Pacific Porgy and how these varied by sex, reproductive stage, and season. Monthly samples were obtained from July 2015 to July 2016 in the central Gulf of California. The stomach contents of 235 specimens (108 males and 127 females) were analyzed. The trophic spectrum comprised 90 prey items, including 58 mollusks, 14 echinoderms, 13 arthropods, 2 chordates, 1 annelid, 1 poriferan, and algal remains. According to the prey-specific index of relative importance (%PSIRI), the most important prey items were the bivalves Transennella spp. (7.24%), Argopecten spp. (6.94%), Anadara spp. (6.25%), Septifer zeteki (6.19%), and Tivela spp. (6.1%). The trophic spectrum varied significantly by season but not by sex or reproductive stage. There were no significant interactions between sex and season or sex and reproductive stage. According to the Levin index, C. brachysomus exhibited a narrow trophic niche (Bi = 0.31). Costello graphs indicated the dominance of a few species, with shifts in the relative abundance of prey species. Based on the trophic analysis, C. brachysomus was classified as a tertiary consumer (3.18). Therefore, C. brachysomus represents an important link between upper and lower trophic levels. Based on these results, we inferred that the Pacific Porgy is an opportunistic predator that feeds actively during all reproductive stages. Thus, the energetic requirements needed for reproduction appear to be covered by the prey that comprise the trophic spectrum of C. brachysomus without this species needing to switch to more energy-rich prey.

Anisakid nematodes have been found in a variety of marine fishes worldwide and they are known to cause anisakiasis and allergic symptoms in human. One-hundred and five fish specimens of different sizes of red porgy (Pagrus pagrus) were collected randomly from Sharkia fish markets originating from the Gulf of Suez, Red Sea, Egypt and examined for the presence of ascaridoid nematodes. The overall prevalence of ascaridoids was 36.19% (38/105). Four morphotypes belonging to two genera of anisakid nematodes (Anisakis type I and Terranova type II larvae) as well as one genus of raphidascarid; Hysterothylacium (larvae and adult) were reported during this study. Hysterothylacium larvae were the most predominant species (23.81%) and abundance value =1.68. Interestingly, Pagrus pagrus was found as new host and locality records for larvae of Terranova type II. The results revealed a significant statistical correlation between fish length and number of the recovered ascaridoid nematodes (rs= 0.244, P < 0.05). There was a positive correlation between the host length and presence of Anisakis type I L3 (rs=0.276, P < 0.001). Significant differences were observed between the occurrence of Terranova type II L3 and Hysterothylacium L3 occurrence (rs= 0.388, P < 0.001) and adult (rs= 0.442, P < 0.001). In addition, a highly significant relationship was observed between the presence of Hysterothylacium L3 and adult (rs= 0.428, P < 0.001). Furthermore, the obtained results were lower than the recommended Egyptian standards (-100 parasites/fish), demonstrating that human health risk through consumption of fish flesh is not possible. [ABSTRACT FROM AUTHOR]

Background: The microbiota in fish external mucus is mainly known for having a role in homeostasis and protection against pathogens, but recent evidence suggests it is also involved in the host-specificity of some ectoparasites. In this study, we investigated the influence of seasonality and environmental factors on both fish external microbiota and monogenean gill ectoparasites abundance and diversity and assessed the level of covariations between monogenean and bacterial communities across seasons. To do so, we assessed skin and gill microbiota of two sparid species, Oblada melanura and Diplodus annularis, over a year and collected their specific monogenean ectoparasites belonging to the Lamellodiscus genus. Results: Our results revealed that diversity and structure of skin and gill mucus microbiota were strongly affected by seasonality, mainly by the variations of temperature, with specific fish-associated bacterial taxa for each season. The diversity and abundance of parasites were also influenced by seasonality, with the abundance of some Lamellodiscus species significantly correlated to temperature. Numerous positive and negative correlations between the abundance of given bacterial genera and Lamellodiscus species were observed throughout the year, suggesting their differential interaction across seasons. Conclusions: The present study is one of the first to demonstrate the influence of seasonality and related abiotic factors on fish external microbiota over a year. We further identified potential interactions between gill microbiota and parasite occurrence in wild fish populations, improving current knowledge and understanding of the establishment of host-specificity. [ABSTRACT FROM AUTHOR]

Dentex gibbosus (Pink dentex) is a fish species of increasing economic interest in the Mediterranean Sea that is consumed both whole and processed. The growing value of this sparid in European markets is responsible for its substitution with fraudulent species. The distinctive morphologic feature of D. gibbosus is the conspicuous hump on the forehead in the older and larger specimens. However, the head is regularly convex in young individuals, requiring high skills and competencies for correct identification. Authentication becomes even more challenging in the case of prepared and processed products. Therefore, the molecular characterization of Pink dentex plays a crucial role in preventing commercial fraud with species substitution. This paper proposes a comparative mitogenome analysis between 19 sparid species of commercial interest as a tool to accurately design species-specific primers targeting a fragment of the NAD2 gene for the identification of D. gibbosus. We successfully detected Pink dentex DNA both using endpoint and real-time PCR. The findings showed the high specificity of the designed primers, demonstrating this a suitable, fast, and cost-effective method that could be used for the unambiguous identification of Pink dentex. This innovative approach for sparid authentication is expected to contribute to seafood traceability, public health assurance, integrity, and the credibility of the seafood industry. [ABSTRACT FROM AUTHOR]

In this study, the complete mitochondrial genome of the Taiwan tai Argyrops bleekeri was determined for the first time by next-generation sequencing. The circular mtDNA molecule was 16,646 bp in size and the overall base composition was A (27.77%), C (28.95%), G (16.60%), and T (26.68%), with a slight bias toward A + T. The complete mitogenome encoded 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a control region. Phylogenetic analysis based on the 13 PCGs of the Sparidae family revealed that Argyrops appears to be most closely related to Pagrus and Parargyrops, but further research is needed. [ABSTRACT FROM AUTHOR]

Red porgy (Pagrus pagrus) is a reef-associated, economically-important, winter-spawning, protogynous Sparidae species that appears to have declined in abundance in recent years along the southeast United States Atlantic coast. We used spatially-explicit generalized additive models built with fishery-independent chevron trap (1990–2021) and video data (2011–2021) to quantify the ways in which red porgy relative abundance and mean size varied across temporal, spatial, environmental, and habitat variables. Mean red porgy relative abundance from traps declined by 77% between 1992 and 2021, and declines were similarly large (69%) on video between 2011 and 2021. The largest two-year decline in relative abundance occurred early in the COVID-19 pandemic (2019–2021)– 32% in traps and 45% on video–despite already low abundance. Highest red porgy relative abundance from traps and video occurred in deep areas (i.e., 60–100 m) between southern North Carolina and north Georgia, and red porgy preferred low relief but continuous hardbottom habitats (i.e., pavement). We confirmed recent low recruitment of red porgy in the region based on the large increase in mean length (29%) and severe (~99%) declines of juvenile red porgy caught over the 32-year trap survey. Evidence suggests that recruitment failure is partially or mostly responsible for red porgy abundance declines, and, moreover, the regulation of harvest is unlikely to achieve sustainable management goals until recruitment increases. [ABSTRACT FROM AUTHOR]

A biometric analysis was performed on a sample of 420 specimens of the blackspot seabream, Pagellus bogaraveo (Brunnich, 1769), from the eastern Adriatic Sea. The total length of all specimens ranged from 9.2 to 47.8 cm (23.70 ± 7.63 cm). Eighteen morphometric and eight meristic characteristics were determined. There were no statistically significant differences between the sexes in the morphometric and meristic characteristics of the blackspot seabream in the Adriatic Sea. Regarding meristic characteristics, there are no significant morphological differences between the blackspot seabream population in the Adriatic Sea and that in other areas of the Mediterranean Sea and the eastern Atlantic Ocean. Relative growth was studied by comparing changes in morphological characteristics with growth in total length and head length. The results indicate the presence of a single population of P. bogaraveo in the Adriatic Sea. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Pagellus acarne is found in coastal waters worldwide and it includes important species of commercial and recreational fisheries. In this study, 16 morphometric variables of the sagittal otolith, including six morphometric characters, six shape indices, and four ecomorphological indexes, were investigated for the first time among P. acarne stocks collected from the Aegean and Marmara Seas coasts of Turkey. Statistically significant differences were found between the right and left otolith variables of P. acarne individuals in both stocks (p < 0.05). Similarly, significant differences were observed on the same side between stocks (p < 0.05). The right otoliths exhibited higher discrimination power than the left within the two stocks. The PCA showed that only five (31.25%) (otolith area, otolith perimeter, form factor, roundness, and edge complexity index) out of the sixteen variables were quite important characters in the differentiation between stocks. These otolith characters demonstrated a very high rate of accurate discrimination (99.0%) between stocks. The results indicated otolith morphometric characters, shape indices, and ecomorphological indexes can be used as suitable tools to discriminate P. acarne stocks. This is the first study to include all otolith characters such as morphometrics, shape, and ecomorphological indices that discriminate between P. acarne stocks from these localities. [ABSTRACT FROM AUTHOR]

Naricolax stocki (Roubal, 1981) is redescribed based on specimens of both sexes, recovered from the blackhead seabream Acanthopagrus schlegelii (Bleeker, 1854) (Perciformes, Sparidae) in Japan. Both sexes of its copepodid V are described for the first time. [ABSTRACT FROM AUTHOR]

Morphological asymmetry was analysed in two marine fish species Acanthopagrus arabicus and Planiliza klunzingeri, in brackish and freshwater habitats in southern Iraq. For both species, specimens from the Shatt al-Arab River and Shatt al-Basrah Canal exhibited greater asymmetry values for snout length. In both locations examined, the levels of asymmetry of the physical traits increased as the fish grew. The high levels of asymmetry in the two fish species may be linked to heavy metal pollutants in the two aquatic environments studied. [ABSTRACT FROM AUTHOR]

The red porgy (Pagrus pagrus) and the common dentex (Dentex dentex) are Sparidae species of high commercial value, traded in the Greek market. In some cases, fish species identification from Greek fisheries is difficult for the consumer due to the strong morphological similarities with their imported counterparts or closely related species such as Pagrus major, Pagrus caeroleustictus, Dentex gibbosus and Pagellus erythrinus, especially when specimens are frozen, filleted or cooked. Techniques based on DNA sequencing, such as COI barcoding, accurately identify species substitution incidents; however, they are time consuming and expensive. In this study, regions of mtDNA were analyzed with RFLPs, multiplex PCR and HRM in order to develop a rapid method for species identification within the Sparidae family. HRM analysis of a 113 bp region of cytb and/or a 156 bp region of 16s could discriminate raw or cooked samples of P. pagrus and D. dentex from the aforementioned closely related species and P. pagrus specimens sampled in the Mediterranean Sea when compared to those fished in the eastern Atlantic. HRM analysis exhibited high accuracy and repeatability, revealing incidents of mislabeling. Multiple samples can be analyzed within three hours, rendering this method a useful tool in fish fraud monitoring. [ABSTRACT FROM AUTHOR]

Marine plastic litter, originating from land-based sources, enters the marine environment by passing through coastal ecosystems such as lagoons and estuaries. As early life history stages (ELHS) of many commercially important fish species rely on these transitional areas as nursery grounds, we hypothesized that they encounter a spatial gradient of habitat quality and pollution from inner to outer parts of their vital environment. With sizes < 5 mm, anthropogenic particles (AP), among them microplastic (MP) fibers and fragments, entail a high bioavailability for ELHS of fish, potentially facilitating AP uptake at early developmental stages which may have implications for their survival and growth. This study provides a contextualization baseline between feeding preferences and uptake of AP by the white seabream Diplodus sargus (Linnaeus, 1758) in an estuarine nursery ground on the southern coast of Portugal. Juvenile fish showed a generalized, omnivorous feeding mode with differences in trophic resource utilization between individuals collected at distinct seagrass meadows in the lagoon. A total of 23.13% of the fish (n = 147) were detected with AP in the gastrointestinal tract, and the mean number of AP per AP-feeding individual was 1.64 ± 1.04, with anthropogenic fibers (n = 47) occurring more frequently than fragments (n = 9). Knowledge of the underlying factors for MP ingestion will be greatly enhanced by considering environmental conditions along with species-stage and life-stage specific feeding modes and prey preferences which shape the uptake probability of anthropogenic fibers and fragments. [ABSTRACT FROM AUTHOR]

A comprehensive updated review of published literature on xanthochromic malpigmentation in wild marine fishes is provided for the first time, with 68 species reported, including seven elasmobranchs and 61 teleosts. The revision highlights the difficulty in separating similar natural colourings from abnormal ones, the presence of some probably misidentified species and the higher occurrence of this phenomenon in some taxonomic groups. The capture of a specimen of the sharpsnout seabream Diplodus puntazzo with abnormal skin coloration is reported. The specimen was caught in northern Spain (Galician waters, North-eastern Atlantic) in 2022 with gillnets. The general yellow-orange pigmentation, lead us to consider the specimen as xanthochromic. This is the first case of xanthism in Diplodus puntazzo and the third record of this colour aberration in the family Sparidae. The identification of the specimen was made based on morphological characters and confirmed by DNA barcoding. A description of the anomalous compared to normal colouration was also carried out. [ABSTRACT FROM AUTHOR]

Bycatch is a significant issue in global fisheries and understanding the length–weight relationships (LWR) of fish species can provide valuable insights for stock assessment and management efforts. In this study, we estimated the LWR of 74 fish species in trawl fleet discards from the Gulf of Cadiz, including 24 species for which LWR data had not been previously reported in this region. LWR was calculated from the formula W = aLb where parameter a is the intercept of the equation, related to body shape, and parameter b is the slope, which indicates the type of growth of the species. A total of 20,007 individuals from 40 families were measured and weighed. The most abundant species were Engraulis encrasicolus, Trachurus trachurus, Serranus hepatus, Sardina pilchardus, Capros aper, and Diplodus bellottii, and the Sparidae family was the most represented with ten species. The parameter b, which represents the type of growth, ranged from 2.1607 to 3.7040. A positive allometric growth trend was observed in 64% of the species. The inclusion of individuals with a low sample size proved useful, particularly for first reports in a new study area. However, caution should be taken when using these data, as the estimates of the length–weight relationship for these species may be less precise. Further studies with larger sample sizes are needed to confirm the results and improve the accuracy of the estimates. Overall, our findings contribute to the understanding of the LWR of fish species in the Gulf of Cadiz, informing future research and management efforts in the region. [ABSTRACT FROM AUTHOR]

Triceracolax chrysophryenus (Roubal, Armitage & Rohde, 1983) is redescribed based on specimens of both sexes, recovered from the nasal cavity of the red sea bream, Pagrus major (Temminck & Schlegel, 1843) (Perciformes, Sparidae) in Japan. Leg 1 exopod of the female of the species is recognized to be 2-segmented. [ABSTRACT FROM AUTHOR]

A tag-recapture study was undertaken on Polysteganus praeorbitalis in the Pondoland Marine Protected Area (PMPA) on the east coast of South Africa. A total of 1 042 fish were tagged over a period of 16 years and 255 individuals (24.5%) were recaptured, some of them on multiple occasions. Data analysis showed that 84.7% of recaptured fish remained in relatively small home ranges (-750 m linear distance), while 13.3% abandoned their home ranges and undertook unidirectional movements (of 21-1 211 km) along the KwaZulu-Natal coast in a north-easterly direction, most likely to spawn. While the no-take area of the PMPA provides effective protection for resident fish, the export of adult P. praearbitalis provides strong evidence of the benefits that no-take MPAs can offer to adjacent fisheries. Based on the tag-recapture length data, the growth rate was found to be relatively slow, averaging 46 mm y-1. This growth rate was similar to that determined by a study of ageing using sectioned otoliths. Reliable tag-recapture data can thus be used to provide a valuable means of validating growth rates determined by other methods. [ABSTRACT FROM AUTHOR]

Length-weight relationships for 32 coastal fish species from the Mediterranean Marchica coastal lagoon, Nador (north-eastern Morocco) are presented in this study. Field studies were conducted during the period 2015-2016. The sampling gear used was a large seine net, targeting pelagic and demersal fish species. The most abundant families were Gobiidae, Labridae, Engraulidae, Atherinidae, Clupeidae and Sparidae. The fit of the equations (W=a Lb) with a and b parameters estimated from regular and functional regression (of log-transformed weight and length data) were determined. The exponent b varied between 2.1317 for Sparus aurata and 3.4897 for Pagellus acarne, whereas all the remaining values of b were higher than 2.91. [ABSTRACT FROM AUTHOR]

Common snook, Centropomus undecimalis (Bloch, 1792), with barnacle patch above gill plate caught by Captain Brook Wallace and photographed by Pete Mersch, 83.8 cm (33 in) long. Further, we have found similar photos of acorn barnacles on "red drum", I Sciaenops ocellatus i (Linnaeus, 1766) (fig. 2); a "gag grouper", I Mycteroperca microlepis i Goode & Bean, 1879 (figs. Sheepsheads eat acorn barnacles, to the extent that these barnacles are used as bait for this fish. Wild-caught sheepshead, Archosargus probatocephalus (Walbaum, 1792), with acorn barnacles attached (Ace Fishing, 2018). [Extracted from the article]

In the present study, intraspecific morphometric distribution of Spicara flexuosum was investigated along the five locations on the Turkish coast based on eight morphological characters. A total of 116 samples were obtained along the Turkish coasts (Istanbul, Yalova [Armutlu], Izmir, Mersin and Antalya) by using trawlers and the handline fishing method within the period in 2014–2015. Principal component analysis and the dendrogram-based Euclidean distance method were used to evaluate different morphometric traits among five locations. The most important ratios of the morphometric loading characters were the head length to interorbital distance, head length to eye diameter, maximum body height two to head height, and head height to head length. The classification matrix based on the discriminant function analysis showed that 94.7% of original grouped were correctly classified. Principal component and cluster analysis showed the existence of two morphologically differentiated groups of S. flexuosum. First one composed of Istanbul and Yalova and the second one consisted of Izmir, Mersin and Antalya. This study is the first description of the intraspecific distribution of morphometric characters for S. flexuosum along the Turkish coast as well as the Mediterranean region for fisheries management purposes. [ABSTRACT FROM AUTHOR]

This review explores the similarities and differences in the life-history styles of eight morphologically similar sparid species that occupy the nearshore coastal waters around South Africa. All eight species spawn at sea with two taxa, Acanthopagrus vagus and Rhabdosargus holubi, being dependent on estuaries as primary nursery areas. Two of the species, Rhabdosargus globiceps and Rhabdosargus sarba, have a high proportion of their juveniles in estuaries but are not completely dependent on these systems as nurseries. The remaining four species, Rhabdosargus thorpei, Diplodus capensis, Diplodus hottentotus and Sarpa salpa, have a major proportion of their juveniles on the coastal shelf, with only a small percentage in estuaries. Four of the species (D. capensis, D. hottentotus, R. holubi and S. salpa) occur in all four biogeographic regions, three (A. vagus, R. sarba and R. thorpei) are primarily found in the tropical and subtropical waters and one species (R. globiceps) primarily in temperate areas. All eight species have relatively fast growth rates and a small size at reproductive maturity when compared to other larger sparids, which occupy offshore reef systems and are not found in South African estuaries at any stage of their life cycle. By adopting different life-history styles, the fishes belonging to the family Sparidae have successfully colonised all South African estuaries and the adjacent coastal shelf waters in all four marine biogeographic provinces and are ranked as a dominant marine fish family in terms of both number and biomass in estuaries on the subcontinent. [ABSTRACT FROM AUTHOR]

Incomplete original descriptions, the unavailability or poor conditions of specimens and the lack of detailed redescriptions have caused the validity of several species of the genus Encotyllabe Diesing, 1850 to be questioned. To date, seven of the recognized species were described upon one or two specimens, hindering study of intraspecific variations. This was made worse by considering few morphoanatomical differences sufficient to erect new species. Among Encotyllabe spp. occurring in Mediterranean waters, E. vallei was first described from the gilt-head bream Sparus aurata (Sparidae) off Italy. Although beautifully illustrated for a paper from that century, morphometric data for E. vallei from the type-host S. aurata remain unavailable. Previous records of E. vallei provided either morphometrical or molecular data, and its validity was questioned. We provide a redescription of E. vallei based on newly collected specimens from the S. aurata from the southwestern Mediterranean (off Algeria) using integrative taxonomy. Analysis of cox 1 sequences of E. vallei from S. aurata , compared to sequences from other sparid hosts, mainly Pagellus bogaraveo , revealed a divergence not exceeding 2%, suggesting a stenoxenic specificity for this monogenean. Given that P. bogaraveo is the type-host for Encotyllabe pagelli , we were tempted to suggest a synonymy between E. vallei and E. pagelli. We refrained from doing so because E. pagelli was first described from the Atlantic coast off Brest, France. Morphological data for Encotyllabe from P. bogaraveo are warranted assessing the host specificity of E. vallei and whether there might be a species complex within individual sparid fish species. [ABSTRACT FROM AUTHOR]

Marine noise is an emerging pollutant inducing a variety of negative impacts on many animal taxa, including fish. Fish population persistence and dynamics rely on the supply of early life stages, which are often very sensitive to disturbance. Impacts of marine noise pollution (MNP) on juvenile fish have rarely been investigated in temperate regions. This is particularly true for the Mediterranean Sea, which is considered as an MNP hotspot due to intensive maritime traffic. In this study, we investigate the relationship between MNP related to boat traffic and (i) assemblage structure and (ii) the density of juvenile fishes (post-settlers at different stages) belonging to the Sparidae family. We quantified MNP produced by boating at four coastal locations in the French Riviera (NW Mediterranean Sea) by linearly combining five variables into a 'noise index' (NI): (i) boat visitation, (ii) number of boat passages/hour, (iii) the instantaneous underwater noise levels of passing boats, (iv) continuous boat underwater noise levels and (v) duration of exposure to boat noise. Then, using the NI, we identified an MNP gradient. By using juvenile fish visual censuses (running a total of 1488 counts), we found that (i) the assemblage structure and (ii) the density patterns of three fish species (i.e., Diplodus sargus, D. puntazzo, D. vulgaris) changed along the MNP gradient. Specifically, the density of early D. sargus post-settlers was negatively related to MNP, while late post-settler densities of D. puntazzo and, less evidently, D. vulgaris tended to decrease more rapidly with decreasing MNP. Our findings suggest the following potential impacts of MNP on juvenile sparids related to coastal boat traffic: (i) idiosyncratic effects on density depending on the species and the developmental stage (early vs. late post-settlers); (ii) negative effects on recruitment, due to possible alteration of late post-settlement movement patterns. [ABSTRACT FROM AUTHOR]

The gill monogenean Sparicotyle chrysophrii (Van Beneden & Hesse, 1863) Mamaev, 1984 is a specific and common parasite of wild and cultured gilthead sea bream Sparus aurata Linnaeus, 1758, able to cause disease and mortality in aquaculture systems. Few molecular studies have been carried out on this monogenean, and its population structure and genetic diversity are barely known. This study provides the first contribution to the population genetic variation of S. chrysophrii, based on two molecular markers - the structural ribosomal RNA (rRNA) for the large subunit (28S) and the cytochrome c oxidase subunit I (COI) gene. Samples were collected from the gills of farmed and wild S. aurata from Italy and the Spanish Mediterranean. The analysis included previously published sequences. The 28S rDNA analysis was consistent with previous studies of specimens isolated from S. aurata and confirmed the presence of only one species on the gills of this host in the Mediterranean Sea. The COI sequences analysis suggested that the samples isolated in a previous study from a different host species, wild Boops boops (Linnaeus, 1758) in the Adriatic Sea, may represent a new undescribed sister species of S. chrysophrii. The low nucleotide diversity of S. chrysophrii isolated only from S. aurata versus the high haplotype diversity revealed small differences between haplotypes. The haplotypes shared between wild and farmed hosts from Spain provided the first molecular evidence of the possible transfer of S. chrysophrii between wild and farmed populations of S. aurata. The mtDNA COI analysis did not show a clear genetic structure, probably the result of several factors including coevolution, wild and farmed host interactions, and host population structure in space and time. [ABSTRACT FROM AUTHOR]

Myxosporeans are widespread cnidarian parasites that usually parasitize fish as part of their complex life cycle, thus constituting a potential threat for the aquaculture industry. White seabream Diplodus sargus (L.) is a commercially valuable sparid fish reared in Southern European aquacultures. Nonetheless, knowledge on myxosporean infections potentially harming the sustainable production of this fish is extremely limited. In this study, a myxosporean survey was conducted on D. sargus specimens reared in two Southern Portuguese fish farms. Two coelozoic myxosporeans were detected infecting the gall bladder, and are herein reported based on microscopic and molecular procedures: Ceratomyxa sargus n. sp. and Zschokkella auratis Rocha et al., 2013, previously described from reared stocks of gilthead seabream Sparus aurata in the same geographic locality. Ceratomyxa sargus n. sp. is the 12th species of the genus to be reported from Southern European sparids, reinforcing a substantial radiation of Ceratomyxa within this fish family and geographic region. SSU rRNA-based Bayesian inference and maximum likelihood analyses revealed C. sargus n. sp. positioned separately from other sparid-infecting Ceratomyxa spp. reported from Southern European countries, demonstrating that this species does not share a more immediate common ancestor with its closest relatives based on host affinity and geography. The recognition of a novel sparid-infecting lineage within the Ceratomyxa clade strengthens the contention that this genus entered sparid fish multiple times, namely in the Southern European region. The identification of Zschokkella auratis infections in D. sargus demonstrates that host shift has occurred among sparids reared in the Southern Portuguese coast. This agrees with the broad host specificity that is usually attributed to this genus, and that may be suggested to be the outcome of the capacity of the Zschokkella morphotype to undergo host shift/switch based on our findings and the limited molecular data available for this genus. Thus, a better understanding of Zschokkella host-associated diversification and dispersal mechanisms requires the increasing availability of molecular data from infections of the same species occurring in multiple hosts and geographical locations. [ABSTRACT FROM AUTHOR]

Abstract Background Animal-associated microbial communities appear to be key factors in host physiology, ecology, evolution and its interactions with the surrounding environment. Teleost fish have received relatively little attention in the study of surface-associated microbiota. Besides the important role of microbiota in homeostasis and infection prevention, a few recent studies have shown that fish mucus microbiota may interact with and attract some specific parasitic species. However, our understanding of external microbial assemblages, in particular regarding the factors that determine their composition and potential interactions with parasites, is still limited. This is the objective of the present study that focuses on a well-known fish-parasite interaction, involving the Sparidae (Teleostei), and their specific monogenean ectoparasites of the Lamellodiscus genus. We characterized the skin and gill mucus bacterial communities using a 16S rRNA amplicon sequencing, tested how fish ecological traits and host evolutionary history are related to external microbiota, and assessed if some microbial taxa are related to some Lamellodiscus species. Results Our results revealed significant differences between skin and gill microbiota in terms of diversity and structure, and that sparids establish and maintain tissue and species-specific bacterial communities despite continuous exposure to water. No phylosymbiosis pattern was detected for either gill or skin microbiota, suggesting that other host-related and environmental factors are a better regulator of host-microbiota interactions. Diversity and structure of external microbiota were explained by host traits: host species, diet and body part. Numerous correlations between the abundance of given bacterial genera and the abundance of given Lamellodiscus species have been found in gill mucus, including species-specific associations. We also found that the external microbiota of the only unparasitized sparid species in this study, Boops boops, harbored significantly more Fusobacteria and three genera, Shewenella, Cetobacterium and Vibrio, compared to the other sparid species, suggesting their potential involvement in preventing monogenean infection. Conclusions This study is the first to explore the diversity and structure of skin and gill microbiota from a wild fish family and present novel evidence on the links between gill microbiota and monogenean species in diversity and abundance, paving the way for further studies on understanding host-microbiota-parasite interactions.

Successful captive seed production of the recently identified sparid, Sparidentex jamalensis , is a significant achievement for its farming and conservation. In each breeding attempt, a male with oozing milt was paired with a female freshly implanted with an LHRH-a pellet (100 μg LHRH Kg−1 of fish). Oocyte diameter of the selected female was ranging from 420 to 470 μm. The pair was maintained in a rectangular fibre reinforced plastic (FRP) tank (3000 L) adequately aerated from a single point aeration. Over three consecutive days, the fish spawned in batches, commencing from 42 h after pellet implantation. The daily spawning fraction of this multiple spawner ranged from 0.179 to 1.123 million per female. Among 18 attempts, successful spawnings were observed in 12 (66.7%) instances. Fertilisation rates ranged between 82 and 88%, with hatching percentages varying from 76 to 84%. The embryonic developmental phase spanned 17 to 22 h. At the pre-flexion stage [13 days post hatch (dph)], larvae measured up to 4.2 ± 0.18 mm, with notochord flexion initiating on 15 dph (8.45 ± 1.2 mm), accompanied by marked development in dorsal, anal, and caudal fins. Completion of fin ray formation and initiation of scale and lateral line development commenced on 30 dph (21.1 ± 0.3 mm) indicating the metamorphosis of larvae to juveniles. By 40 dph (28.46 ± 3.8 mm), the advance juvenile displayed fully formed fins, silvery scales and a distinct lateral line. Rapid developments in total length, body girth, mouth opening, and eye diameter were particularly noticeable as flexion development neared completion (15 dph). During larval rearing, three critical phases were observed: the period from mouth opening to first feeding (3 to 5 dph), the weaning period (25 to 30 dph), and the metamorphosis phase (35 to 40 dph), each exhibiting distinct mortality patterns. Initial swim bladder inflation was observed before 13 dph (4.2 ± 0.18 mm). Co-feeding copepod nauplii and rotifer (3 numbers mL−1 each) emerged as the ideal feeding strategy during the initial phase, significantly enhancing survival rates. The final larval survival at the end of metamorphosis on 40 dph ranged between 3.8 and 6.2%. Notably, natural light exposure, with a diurnal variation from 1000 to 4000 lx near the water surface, played a pivotal role in improving the initial larval survival. • First report on seed production of the newly described seabream Sparidentex jamalensis. • Mouth opening, weaning and metamorphosis as critical phases with distinct mortality. • Co-feeding of copepod nauplii with rotifer as the ideal initial larval feeding strategy. • Natural light with a diurnal variation from 1000 to 4000 lx ideal for initial larval survival. [ABSTRACT FROM AUTHOR]

A total of 243 Pagellus erythrinus saccular otoliths' shape and size, including length, width, area, and perimeter, were examined among individuals of the Chebba, Sfax, Gabes, and Zarzis stations located in the Gulf of Gabes, Tunisia. The objective was to assess the geographic variation in the otoliths' shape and size and the effect of potential fluctuating asymmetry in otolith size on the stock structure of P. erythrinus individuals from these stations. Analysis of the otolith shape showed a statistically significant difference (Wilks' λ = 0.1661, p < 0.0001), i.e., asymmetry, in the left and right otoliths shape among individuals of the four stations, as well as among those within the Chebba and Gabes stations. Besides, a significant shape difference was observed in the left-left and right-right otoliths among individuals of both Chebba and Gabes, Chebba and Zarzis, Gabes and Sfax, Gabes and Zarzis, and Sfax and Zarzis stations. Moreover, a significant fluctuating asymmetry was detected in width between the left and right otoliths only among individuals of the Sfax and Gabes stations. Discriminant function analysis of the otoliths' contour shape confirmed the presence of three separate main stocks, one corresponding to the Chebba and Sfax stations, the second representing Gabes, and the third characterizing Zarzis, which should be managed separately. [ABSTRACT FROM AUTHOR]

The study of fishery biology and population dynamics was conducted for Boops boops collected from the commercial catches of gillnets operated in the Egyptian Mediterranean waters off Alexandria. A total of 880 specimens were sampled from the area between Sidi Kirayr to El-Montazah during the period 2018-2020. The length range varied between 11.0 and 20.0 cm TL with a mean of 13.98±1.19 cm and the total weight varied from 14 to 88 g with a mean total weight of 28.51±6.67 g. The length-weight relationship was computed as W= 0.0119 L2.9453 by using total weights and W= 0.0112 L2.9335 by using gutted weights. The mean condition factor (k) was 0.953±0.029 and the overall sex ratio (M: F) was 1.00:0.49. The von Bertalanffy growth parameters were estimated to be K= 0.38 yr-1, L∞= 27.85 cm and tο= -0.443 yr. The growth performance index (Фˋ) was 2.47. The values of natural (M), fishing (F) and total mortality (Z) were calculated as 0.865, 3.845 and 4.710 yr-1, respectively. The current exploitation ratio (Ecur= 0.816) is high reflecting the high exploitation of this species. The yield per recruit and the relative yield per recruit were also studied and the results confirmed that the stock of B. boops is highly exploited and the management of the pelagic gillnets is required. [ABSTRACT FROM AUTHOR]