Diplodus Vulgaris Research Articles

Assessment of the effects of sex and harvesting season on lipid and fatty acid composition of Sparidae species.

In the present study, the lipid amount and fatty acid profile of different Sparidae species, including gilthead seabream, juvenile gilthead seabream, annular seabream, white seabream, common two-banded seabream were evaluated. Fish were seasonally collected from Köyceğiz Lagoon (Muğla, South Western Turkey) from June 2018 to June 2019 and after collection, the sex of each specimen was recorded. According to the results of the study, the highest lipid amount was found in female annular seabream individuals as 8.09 ± 0.78% in November and the lowest lipid amount was found in male juvenile gilthead seabream as 0.98 ± 0.12% in March. Palmitic acid and oleic acid were determined as the most abundant SFA and MUFA for all species, respectively. The highest value of DHA, which was the predominant PUFA was assessed as 15.33 ± 0.26% in female white seabream in November whereas the lowest value (3.83 ± 0.36%) was found in gilthead seabream in December. The n-6/n-3 ratio was determined between 0.27 ± 0.00 (for male common two-banded seabream in July)-1.20 ± 0.03 (for male gilthead seabream in December) and it followed within the range of healthy values for all species. As a conclusion, it was found that values of lipid and fatty acid profiles among the examined Sparidae species vary among the season of collection. The results of the study gave the seasonal nutritional values of four economically-important Sparidae species that being rich in healthy polyunsaturated fatty acids such as DHA, have beneficial in human nutrition.

The neglected role of omnivore fish in the overgrazing of Mediterranean rocky reefs

Sea urchins are considered the most important grazers in Mediterranean shallow sublittoral rocky reef ecosystems, but fish can also have an important role in overgrazing and the reduction of habitat complexity. In this study, the trophic behavior of fish was recorded when provided access to experimental surfaces with increased macroalgal biomass and associated benthic fauna, created by herbivore exclusion cages. After a sufficient period for substantial algal growth, the cages were removed and the activity of fish on these surfaces was recorded for 3 h by an automated photographic camera system. Control surfaces with no restriction on grazers were defined on similar substrates for comparison. To quantify the effects of fish feeding activity on macroalgal coverage, photographic samples were taken immediately after the opening of the cages and after each 3 h recording. The response of fish when the cages were removed was immediate and intense. Feeding activity by 13 different fish species was recorded in total, of which the most frequent were the omnivores Diplodus vulgaris, Coris julis and Thalassoma pavo, and to a lesser extent the herbivore Sarpa salpa. The coverage of erect algae was substantially decreased on the experimental surfaces due to fish feeding activity. The algae were either directly consumed by the fish or cut off when the fish were feeding on macroinvertebrates. We conclude that in addition to grazing by herbivores, fish of higher trophic levels can also significantly affect macroalgal assemblages and restrict the recovery of erect algae in overgrazed reefs where prey is scarce.

Paraketa balıkçılığında kullanılan farklı yemlerin avcılık performansı ve olta iğnesinde kalma oranı

In this study, the catch performance and remaining ratio on fishing hooks of natural alive mud shrimp (Upogebia pusilla) (CCK), siliconized mud shrimp (SCK) and siliconized pellet (SP) were investigated in a longline. The trials were carried out monthly between May 2016 and April 2017 in Zeytinlikuyu district of Kıyıkislacik Village – Milas-Mugla province. The main body diameter has 0.70 mm, leader and snoods have 0.40 mm. The snood length and distance is 1.5 m and 4.0 m, respectively. 14 no straight hooks were used. Totally 150 hooks, 50 for each bait were used and each bait was replaced in 25 hooks. The individuals caught during the samplings were separated as CCK, SCK and SP, and each individual was measured as the precision of mm the total length (TL) and weighted of 0.01 g. Totally 191 individuals from seven families with 18 different species were caught. Gilthead sea bream (Sparus aurata) was the abundant species with 48.7% in all bait type, and the followed by common pandora (Pagellus erythrinus) with 10.5%, common two-banded sea bream (Diplodus vulgaris) with 9.4% and annular sea bream (Diplodus annularis) with 8.9%. Of the 191 individuals, 55% (105 individuals) were caught with CCK, 33.5% (64 individuals) with SCK and 11.5% (22 individuals) with SP. The results of the trial with 3 different bait types were shoved that that there are significant differences between the catch rates of gilthead sea bream, annular and common two-banded sea bream (χ2, P<0.05). In paired tests between bait groups (CCK-SCK, CCK-SP and SCK-SP), there were no clear differences between the sizes of the individuals (ANOVA, P>0.05). Catch per unit effort (CPUE) values of CCK, SCK and SP were calculated as 0.05 n/h, 0.03 n/h and 0.01 n/h, respectively. In the same order, yield per unit effort (YPUE) values were determined as 7.28 g/h, 4.35 g/h and 2.99 g/h. When the remaining rate of baits on the hooks were evaluated, CCK gave the lowest rate with 6.32%2.01. It is thought that SCK should be used as an alternative particularly when natural mud shrimp cannot be utilized as alive or unable to be supplied due to the cold weather conditions and time restrictions. On the other hand, it is thought that performing such studies with bait made with natural binders such as gelatine instead of silicone will be extremely important in terms of less harm to both fish and nature.

Longline métiers and associated economic profiles in eastern Mediterranean fisheries: The case study of Kalymnos Island (South Aegean Sea)

The small-scale fishery has a high socio-economic importance in the Mediterranean Sea. This is especially relevant for specific areas that harbor, proportionally, very large part of the fleet, and thus, represent hot spots. Among such areas, Kalymnos Island merits special attention as it harbors the largest and most active small-scale fleet in the eastern Mediterranean. Therefore, the present study analyzes the small-scale longline fishery in Kalymnos, using the métiers approach, to assess its dynamics and evaluate associated economic profiles. A multivariate analysis was used to identify the relevant métiers, by inputting the main resources and fishing gear data that were recorded during landings. Six main practices were observed using set longlines, drifting longlines, handlines and squid jig-lines as fishing gears, and targeting the species Pagrus pagrus, Diplodus vulgaris, Pagellus erythrinus, Sparus aurata, Xiphias gladius, Octopus vulgaris and Loligo vulgaris; the above métiers earned a profit margin. The study revealed the multi-species nature of longline fishery in Kalymnos, and provided baseline information for their associated economic profiles, towards the development and implementation of sustainable management plans.

Extending full protection inside existing marine protected areas, or reducing fishing effort outside, can reconcile conservation and fisheries goals

Abstract Most fish stocks world‐wide are fished at maximum sustainable yield (MSY) or overfished, as many fisheries management strategies have failed to achieve sustainable fishing. Identifying effective fisheries management strategies has now become urgent. Here, we developed a spatially explicit metapopulation model accounting for population connectivity in the north‐western Mediterranean Sea, and parameterized it for three ecologically and economically important coastal fish species: the white seabream Diplodus sargus, the two‐banded seabream Diplodus vulgaris and the dusky grouper Epinephelus marginatus. We used the model to assess how stock biomass and catches respond to changes in fishing mortality rate (F) and in the size of fully protected areas within the existing system of multiple‐use marine protected areas (MPAs). For each species, we estimated MSY and the corresponding values of stock biomass (BMSY) and fishing mortality rate (FMSY), providing crucial reference points for the assessment of fisheries management. Diplodus sargus is currently in low overfishing, while D. vulgaris and E. marginatus are in high overfishing. Stock recovery to BMSY for the last two species requires a reduction of current F around 50%. This would guarantee an increase in both stock biomass (around 50% and 75% for D. vulgaris and E. marginatus respectively) and catch (around 15% and 30%) after a transient time of ~15–30 years. Alternatively, doubling the size of fully protected areas over fishable areas within the existing network of MPAs would lead to positive conservation effects for all three species without substantially affecting the overall productivity of the fishery and the total economic value of the catch. Synthesis and applications. We provide the first assessment of stock status for three coastal species in the north‐western Mediterranean and evaluate the ecological and fisheries outcomes of different management strategies. Extending full protection inside existing multiple‐use marine protected areas or reducing fishing effort outside can deliver both conservation and fisheries benefits.

Genetic variation of Diplodus sargus and Diplodus vulgaris in four Mediterranean coastal regions of Egypt based on microsatellites

Genetic variation of Diplodus sargus and Diplodus vulgaris in four Mediterranean coastal regions of Egypt based on microsatellites

Maximum Length Record of Common Two-banded Seabream (Diplodus vulgaris Geoffroy Saint-Hilaire, 1817) for Aegean Sea with Turkish Waters

The maximum length, weight, and age information of living things in an ecosystem are necessary for population dynamics and stock assessment studies. Hence, the recording of such data may be beneficial for scientific databases for life history and fisheries science. The common two-banded seabream (Diplodus vulgaris Geoffroy Saint-Hilaire, 1817) is a widespread demersal marine fish, which belongs to the Sparidae family and inhabits down to 90 m depth. Because it is a demanded seafood, it has commercial importance and usually available in the fish market almost every month of the year in Turkey. A single specimen of common two-banded seabream with 31.9 cm in total length and 467.00 g in total weight, which was caught off İbrice Bight (Saroz Bay) with handline by a professional fisherman on 12 June 2015, was obtained from a fishmonger. This study aims to present the maximum size record of this species for the Aegean Sea with Turkish waters.

Charter fishing in the Aegean Sea (Turkey), Eastern Mediterranean: The missing point of fisheries management

This study attempts to improve the scientific knowledge of charter fishing on the Aegean coast of Turkey, where fishing activity and ecological indicators were investigated. Fishing and socio-economic data from both charter boat owners and charter fishers were collected using on-site questionnaires, and seasonal on-board surveys during 2017. No differences were observed between CPUE estimates from the questionnaire and the on-board surveys. The highest and lowest fishing activity were found in autumn and summer respectively. Charter owners reported conflicts with both private boat owners as well as commercial fishers. The annual activity was estimated to be 9246 charter trips hosting 138,690 charter fishers, who caught 277−305 tonnes. The total annual fisher and boat owner expenditure was estimated at €3.5 million and €0.6 million respectively. A total of 38 species were identified; most of the catch was represented by sparids, of which there were several species, such as Diplodus vulgaris, Sparus aurata, and Pagellus erythrinus, all of which were highly undersized. The results highlighted that the fishers and boat owners had limited knowledge of fishing policies. We conclude that managers should pay more attention to this activity and revise the existing regulations of charter fishing to improve fisheries management.

Population Structures of the Two Banded Seabream, Diplodus vulgaris and the White Seabream, Diplodus sargus Reveal New Records in Maximal Age

The common two-banded seabream Diplodus vulgaris and Diplodus sargus were sampled from
 non-commercial fishing catches around the Maltese Islands between July 2012 and December
 2017. A total of 1550 (D. vulgaris N=1204, D. sargus N=346) specimens were collected. In this
 study, age, growth, length-weight relationship (LWR), condition factor (K) and relative condition
 factor (Kn) were investigated. Ages ranged from 0 to 17 years for D. sargus and 0 to 16 years for
 D. vulgaris. A positive allometric growth was observed for D. sargus while growth in D. vulgaris
 was isometric. Average Kn was found to be 0.99 and 1.01 in D. vulgaris and 0.97 and 1.00 in D.
 sargus for males and females respectively. The growth parameters of the von Bertalanffy equation
 were: L∞=26.71 and 30.86 cm, K= 0.275 and 0.286 year-1
 and tₒ = -2.27 and -1.61 year for all
 individuals of D. vulgaris and D. sargus respectively. This study is the first reference on the LWR
 equation parameters, Kn, K and Age for these species around the Maltese Islands and establishes
 a new maximum age for D. vulgaris of 16 years.

Age, Growth and Reproductive Biology of the Common Two-Banded Seabream (Diplodus vulgaris Geoffroy Saint-Hilaire, 1817) from the Northern Aegean Sea, Turkey

The present study aims to describe population dynamics (age, growth, mortality and fecundity) of common two-banded seabream. Sampled individuals were obtained monthly between November 2017 and October 2018 directly from commercial fisherman in the Northern Aegean Sea. Ages were estimated from 327 otolith readings; the minimum and maximum ages observed were 1 and 8 years, respectively, corresponding to 13 and 29 cm total length (TL). The length-weight relationship was W = 0.0156*L2.97 (R2 = 0.92) for the whole population and isometric growth was detected. The growth parameters of Von Bertalanffy fitted to back-calculated size for age data were: L∞ = 30.69 cm, K = 0.20 and t0 = −2.64 per year. The instantaneous rates of total mortality (Z) and natural mortality (M) were 0.86 and 0.47 per year, respectively. Rates of fishing mortality F and exploitation E were 0.39 and 0.35 per year, respectively. The spawning season extended from September to March and peaked in December. Total lengths at 50% maturity were 18.32 cm for males and 20.37 cm for females. Mean absolute fecundity (F) was 73,154 ± 10,271 oocytes, ranging from 10,727 to 316,730.

A multidisciplinary analytical framework to delineate spawning areas and quantify larval dispersal in coastal fish

Assessing larval dispersal is essential to understand the structure and dynamics of marine populations. However, knowledge about early-life dispersal is sparse, and so is our understanding of the spawning process, perhaps the most obscure component of biphasic life cycles. Indeed, poorly known species-specific spawning modality and species-specific early-life traits, as well as the high spatio-temporal variability of the oceanic circulation experienced during larval drift, hamper our ability to appraise the realized connectivity of coastal fishes. Here, we propose an analytical framework which combines Lagrangian modelling, network theory, otolith analyses and biogeographical information to pinpoint and characterize larval sources which are then grouped into discrete spawning areas. Such well-delineated larval sources allow improving the quantitative evaluations of both dispersal scales and connectivity patterns. To illustrate its added value, our approach is applied to two case-studies focusing on Diplodus sargus and Diplodus vulgaris in the Adriatic sea. We evidence robust correlations between otolith geochemistry and modelled spawning areas to assess their relative importance for the larval replenishment of the Apulian coast. Our results show that, contrary to D. sargus, D. vulgaris larvae originate from both eastern and western Adriatic shorelines. Our findings also suggest that dispersal distances and dispersal surfaces scale differently with the pelagic larval duration. Furthermore, 30.8% of D. sargus larvae and 23.6% of D. vulgaris larvae of the Apulian populations originate from Marine protected area (MPA), exemplifying larval export from MPAs to surrounding unprotected areas. This flexible multidisciplinary framework, which can be adjusted to any coastal fish and oceanic system, exploits the explanatory power of a dispersal model, fine-tuned and backed-up by observations, to provide more reliable scientific basis for the management and conservation of marine ecosystems.

Modelling long-term fisheries data to resolve the attraction versus production dilemma of artificial reefs

The main role of artificial reefs (ARs) is to enhance the productivity and sustainability of coastal fisheries by creating new fish biomass. From a modelling point of view, the creation of new fish biomass would be realized by a shift to a state of higher carrying capacity of the environment (K) for aquatic populations and communities. However, it has not been possible to demonstrate unequivocally rising K as a result of AR deployment because of the difficulty in disentangling enhancements due to simple distributional changes (the attraction hypothesis) versus total abundance rise (the production hypothesis). Here we develop a modelling framework based on simple, inexpensive fisheries data to quantify the impact of ARs, disentangling attraction from production by assessing the rise in regional K. The rationale is that if attraction to ARs from the wider region was the main driver of increased abundance in the ARs then regional K would have remained constant before, during and after deployment of the ARs. Therefore an increase in regional K disproves the hypothesis of attraction. The study case is the fishery for the two-banded seabream Diplodus vulgaris in southern Portugal. Monthly time series of 27 years of landings, 20 years of fishing effort, were available from three small-scale fleets: one was the artisanal fleet operating on the ARs and the other two were semi-industrial fleets operating on the wider continental shelf. The model that we developed and applied incorporated the data from all fleets so it evaluated the change in regional K. We show that regional K for D. vulgaris increased by 35% after final deployment of the ARs and it did so in linear fashion during four years. From a fisheries perspective the result was more nuanced because although the deployment succeeded in raising regional K, stock biomass and thereby enhancing the artisanal fishery, it also led to a substantial rise in total fishing mortality and exploitation rate because the semi-industrial fleets operating offshore increased their harvest rate nearly 3-fold. Our modelling framework has wide applicability in other regions due to the elementary nature of the necessary fishing monitoring data.

Parasitological, morphometric and genetic characterization of two Sparidae species: Diplodus sargus and Diplodus vulgaris along Tunisian coasts

Parasitological, morphometric and genetic characterization of two Sparidae species: Diplodus sargus and Diplodus vulgaris along Tunisian coasts

The occurrence of two xanthochromic fish, Epiniphelus marginatus (Serranidae) and Diplodus vulgaris (Sparidae) (Osteichthyes) in the eastern Mediterranean

Xanthism in fishes has a genetic basis that causes abnormal skin colouration of yellow to orange-gold. Xanthochromic specimens are rare in nature. We report two cases of adult xanthochromic specimens from the Mediterranean Sea: Epinephelus marginatus from Israel and Diplodus vulgaris from Greece and discuss the reason for the paucity of reports of xanthochromic fish from the Mediterranean.

Fish nursery value of algae habitats in temperate coastal reefs.

The nursery function of coastal habitats is one of the most frequently mentioned and recognized ecosystem services in the valuation of coastal ecosystems. Despite its importance our understanding of the precise habitat parameters and mechanisms that make a habitat important as a nursery area is still limited for many species. The study aimed to establish the importance of different algae morphotypes in providing shelter and food for juvenile coastal fish during the main settlement peaks, in early spring and late summer, in littoral rocky reef systems in the Northwestern Mediterranean. The results of our study showed strong seasonal differences in algae cover, composition and height between the two sampling periods. Overall, during spring the algae were well developed, while in late summer, both density and height, of most algae decreased considerably. Equally, prey biomass, in form of suitable sized invertebrate fauna associated to the algae, decreased. Accordingly, the shelter and food for the fish settling in this habitat during late summer were less abundant, indicating a mismatch between the observed presence of juvenile fish and optimal habitat conditions. Differences in prey densities were detected between algae morphotypes, with structurally more complex algae, such as Cystoseira spp. and Halopteris spp. consistently containing more prey, independent of season, compared to simpler structured morphotypes such as Dictoytales. The study furthermore related juvenile fish density to habitats dominated by different algae morphotypes. Out of the three-study species (Diplodus vulgaris, Symphodus ocellatus, Coris julis) only S. ocellatus showed a significant association with an algae habitat. S. ocellatus related positively to habitats dominated by Dictoytales which provided the highest cover during late summer but had the lowest prey densities. A strong association of this species with Cystoseira, as reported by other studies, could not be confirmed. Cystoseira was abundant within the study area but in a state of dieback, showing loss and reduced height of foliage, typical for the time of year within the study area. It is therefore likely that algae-fish associations are context-dependent and that several algae species may fulfil similar functions. We also discovered that prey biomass did not appear to have an important effect on juvenile abundances. Nevertheless, the availability of prey may influence juvenile fish condition, growth performance and ultimately long-term survival. We therefore suggest that future studies on habitat quality should also include, besides abundance, indicators related to the condition and growth of juveniles.

Variability of Otolith Morphology and Morphometry in Eight Juvenile Fish Species in the Coastal Eastern Adriatic

AbstractSagittae otoliths of eight juvenile species:Boops boops,Diplodus vulgaris,Diplodus puntazzo,Sarpa salpa(family Sparidae),Liza ramada,Liza aurata(family Mugilidae),Atherina boyeri,Atherina hepsetus(family Atherinidae) were analysed and compared using descriptive morphological characters and morphometric indices. The noticeable differences among the otoliths of the investigated species are in their overall shape, margins (i.e. irregular, sinuate or crenate) and anterior region. Otolith shape varied from elliptic to pentagonal in sparids, elliptic to rectangular in mugilids and elliptic in two atherinids. Aspect ratio (OW/OL), ratio of the sulcus length occupied by the cauda length (CL/SL) and ratio of the sulcus length occupied by the ostium length (OSL/SL) were calculated for all species. The otolith contour was described using wavelets. The Canonical Analysis of Principal Coordinates (CAP) gave an overview of the otolith shape differentiation between eight juveniles. Using the Wavelet coefficients, the first principal component (CAP1) explained 58.1% of the variation among species and the second principal component (CAP2) 25.2%.

Evaluation of Dietary Protein Level in Practical Feed for Twoband Bream Diplodus vulgaris

AbstractThe effects of different dietary protein levels on growth performance and health status of TwobandBream Diplodus vulgaris juveniles were investigated. Three test diets that had increasing protein levels (30, 36, and 42%) and used fish meal as the protein source were formulated. Each of the test diets was fed in triplicate groups of 28 juvenile fish (initial weight, 23.65 ± 0.34 [mean ± SD]) to satiety for a period of 80 d. Growth performance and feed utilization were best in the group fed the diet with a protein level of 36%. Ammonia nitrogen excretion showed an increasing trend as dietary protein levels increased, and retention rates of ammonia nitrogen per intake were highest in fish fed the 42% protein diet. Whole‐body proximate composition and hematological variables were not significantly affected by protein level in the diets. However, serum glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) values were significantly affected by dietary protein level and showed an increasing trend as the dietary protein level in the diets increased. As a result, an improved health status of Twoband Bream was observed in the fish fed a 36% protein level.

FISH PREDATION ON A MEDITERRANEAN ECHINOID: IDENTIFICATION AND PRESERVATION POTENTIAL

Abstract: Wound morphologies on the Recent Mediterranean echinoid Sphaerechinus granularis (Lamarck) from the Italian island of Giglio allow the reconstruction of predation events by sparid fish. These lethal attacks leave characteristic bite marks and other features including scratch marks of teeth, bitten off spines, and fragmented jaw supports. The bite marks consist of semicircular indentation on the edge of a gaping wound showing intraplate fragmentation. The attack is initiated on the upper side of the echinoid test. Comparison of predation traces to jaw and tooth morphologies allows the sparid fish Diplodus vulgaris (Geoffroy Saint-Hillaire) and Diplodus sargus (L.) to be identified as the most likely predators. This type of fish predation is compared to other known predatory attacks on echinoid taxa in the Mediterranean Sea. The fossilization potential of this type of predation is discussed with respect to test preservation, based on the degree of fragmentation, abrasion and encrustation of the i...

Occurrence of microplastics in commercial fish from a natural estuarine environment

Microplastic ingestion has been reported for several marine species, but the level of contamination in transitional systems and associated biota is less known. The aim of this study was to assess the occurrence of microplastic ingestion in three commercial fish species: the sea bass (Dicentrarchus labrax), the seabream (Diplodus vulgaris) and the flounder (Platichthys flesus) from the Mondego estuary (Portugal). Microplastics were extracted from the gastrointestinal tract of 120 individuals by visual inspection and digestion solution. A total of 157 particles were extracted from 38% of total fish (96% fibers), with 1.67 ± 0.27 (SD) microplastics per fish. Significantly higher amount of ingested microplastics was recorded for D. vulgaris (73%). The dominant polymers identified by μ-FTIR were polyester, polypropylene and rayon (semi-synthetic fiber). It is reported for the first time the presence of this pollutant in fish populations from the Mondego estuary raising concerns on their potential negative effects.

Sources of otolith morphology variation at the intra-population of two species of sparidae (Pagellus erythrinus and Diplodus vulgaris) collected from the island of Kerkennah (Tunisia)

Event Abstract Back to Event Sources of otolith morphology variation at the intra-population of two species of sparidae (Pagellus erythrinus and Diplodus vulgaris) collected from the island of Kerkennah (Tunisia) Marwa Mejri1*, Imen Jmil1, Jean-Pierre QUIGNARD1 and Monia Trabelsi1 1 Faculté des Sciences Mathématiques, Physiques et Naturelles de Tunis, Marine Biology, Tunisia The sea breams, belongs to the Sparidae family, and represents in general ones of main target species of the commercially important fish for Mediterranean shelf fisheries (Fiorentini et al. 1997). In another hand, saccular otolith (Sagitta) have long been recognized as one of the most useful fish anatomic structures because of their accretionary growth, therefore it can be used as powerful tools in fish ageing (Do et al., 2006), identification of fish species and populations (Jawad, 2007), ecomorphological studies (Volpedo and Echeverria, 2003) and determination of fish prey identity in feeding studies (Tarkan et al., 2007). The aim of this research is to investigate and compare by using otolith shape, the stock structure of two species of Sparidae fish (Pagellus erythrinus and Diplodus vulgaris) and in order to see the response of asymmetry for each populations. Here, we analyzed 120 (60 individuals of Pagellus erythrinus, 60 individuals of Diplodus vulgaris, specimens originating from one location in Tunisian (island of kerkennah)). Otolith shape was determined by using Fourier analysis. The mathematical analysis of the otolith shape was achieved by the Discriminant Factor analysis (D.F.A). The basis of this method is the detection of the phenotypic polymorphism between two different populations of fish, between pairs of otoliths from each population and between the pairs of otoliths between the two species. For the Pagellus erythrinus population, the P-value (left-right) is statistically significant (p < 0.05) (asymmetry).However, the p values for the distances of Diplodus vulgaris population were significant (P <0.05) (asymmetry), but the shape asymmetry remains more important for Diplodus vulgaris than in the population of Pagellus erythrinus. In this study the asymmetry (Left-Right) of otoliths detected in both populations is probably due to the physico-chemical and genetic stress. Keywords: otolith, shape, stock, Pagellus erythrinus, Diplodus vulgaris, Symmetry, asymmetry Conference: IMMR'18 | International Meeting on Marine Research 2018, Peniche, Portugal, 5 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Fisheries and Management Citation: Mejri M, Jmil I, QUIGNARD J and Trabelsi M (2019). Sources of otolith morphology variation at the intra-population of two species of sparidae (Pagellus erythrinus and Diplodus vulgaris) collected from the island of Kerkennah (Tunisia). Front. Mar. Sci. Conference Abstract: IMMR'18 | International Meeting on Marine Research 2018. doi: 10.3389/conf.FMARS.2018.06.00119 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 17 Apr 2018; Published Online: 07 Jan 2019. * Correspondence: Miss. Marwa Mejri, Faculté des Sciences Mathématiques, Physiques et Naturelles de Tunis, Marine Biology, Tunis El Manar, Tunisia, mejrimarwa991@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Marwa Mejri Imen Jmil Jean-Pierre QUIGNARD Monia Trabelsi Google Marwa Mejri Imen Jmil Jean-Pierre QUIGNARD Monia Trabelsi Google Scholar Marwa Mejri Imen Jmil Jean-Pierre QUIGNARD Monia Trabelsi PubMed Marwa Mejri Imen Jmil Jean-Pierre QUIGNARD Monia Trabelsi Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.