Feeding protocol with live feed and inert diet to determine the ideal age/size for weaning mullet Mugil liza (Valenciennes, 1836).

The Lebranche mullet Mugil liza is a marine fish of great importance for artisanal and industrial fishing, as well as aquaculture. The use of live feeds during the larviculture phase of marine fish is a significant component of production costs. The present study evaluated the effects of the feeding transition on different larval stages of M. liza, from the combined supply of live feed (Brachionus rotundiformis + Artemia franciscana) and live + inert feed (Artemia franciscana + inert diet) until the weaning phase to only the inert diet. A total of 3240 M. liza larvae (weight 0.0133 ± 0.0062 g and length 0.793 ± 0.160 cm) were distributed among the 12 experimental units (n = 270), resulting in four groups with three replicates each. Treatment groups consisted of feed transition with A. franciscana (enriched metanauplii) to commercial inert feed starting weaning at four different larval ages: 28, 31, 34, and 37 days post hatching. Zootechnical performance indexes and intestinal histomorphometry were evaluated. Mortality, condition factor, and length variation coefficient did not show significant differences between treatments. Final weight, final length, weight gain, and length gain were significantly greater in larvae that started weaning at 31, 34, and 37 days post hatching. Weight coefficient of variation was significantly higher in larvae that started weaning at 28 days (67.51 ± 11.70) compared to 37 days (34.40 ± 7.30). In intestinal histology, villi height (180.3 ± 4.4) was significantly higher in larvae that started weaning at 37 days post hatching. Considering the evidence found in the present study, it is recommended to start weaning M. liza on the 31st day post-hatching, using a 2-day co-feeding protocol (31st and 32nd days). From the 33rd day after hatching, M. liza larvae can receive only commercial feed.

Do catadromous thinlip grey mullet benefit from shifting to freshwater? A perspective from fatty acid signature analysis.

To investigate the potential benefits of the catadromous thinlip grey mullet (Chelon ramada Risso, 1827) migration to freshwater, the total lipid content and fatty acid (FA) profile of female's muscle and gonads caught in both the estuary and river were analyzed. The freshwater contingent presented a higher body condition, greater muscle gross energy, and larger gonads with higher lipid reserves. These animals showed a muscle profile rich in C16:1n-7 and lower LC-PUFA that contrast with the higher relative amount of C18:1n-9, n-3 FA, and unsaturated LC-PUFA, such as C18 and C20 FA found in the estuarine contingent. The gonads of both contingents showed a constant and high relative amount of polyunsaturated FAs (PUFA, 37%). However, in terms of essential fatty acids (EFAs), the estuarine contingent had a higher relative amount of C18:2n-6, C20:4n-6, C20:5n-3, and C22:6n-3. On the other hand, the freshwater contingent showed a higher relative amount of n-3 FA precursors, namely C18:3n-3, and a still low relative amount of C22:6n-3. This suggests a mismatch between the metabolic omega-3 pathway and the physiological maturity stages, similar to a phenomenon of dormancy. In this sense, not all these individuals may reproduce annually, and the later stages of gonad development will require supplementary energy derived from feeding at the estuary. Thus, freshwater migration may promote a reproductive strategy enabling adults to take advantage of the warm and food-rich summer/autumn period, adjust spawning and juvenile appearance, and reduce the population's exposure to habitat changes and/or stochastic events.

Combined Dietary Administration of Chlorella fusca and Ethanol-Inactivated Vibrio proteolyticus Modulates Intestinal Microbiota and Gene Expression in Chelon labrosus.

The use of functional feeds in aquaculture is currently increasing. This study aimed to assess the combined impact of dietary green microalgae Chlorella fusca and ethanol-inactivated Vibrio proteolyticus DCF12.2 (CVP diet) on thick-lipped grey mullet (Chelon labrosus) juvenile fish. The effects on intestinal microbiota and the transcription of genes related to metabolism, stress, and the immune system were investigated after 90 days of feeding. Additionally, the fish were challenged with Aeromonas hydrophila and polyinosinic-polycytidylic acid (poly I:C) to evaluate the immune response. Microbiota analysis revealed no significant differences in alpha and beta diversity between the anterior and posterior intestinal sections of fish fed the control (CT) and CVP diets. The dominant genera varied between the groups; Pseudomonas and Brevinema were most abundant in the CVP group, whereas Brevinema, Cetobacterium, and Pseudomonas were predominant in the CT group. However, microbial functionality remained unaltered. Gene expression analysis indicated notable changes in hif3α, mhcII, abcb1, mx, and tnfα genes in different fish organs on the CVP diet. In the head kidney, gene expression variations were observed following challenges with A. hydrophila or poly I:C, with higher peak values seen in fish injected with poly I:C. Moreover, c3 mRNA levels were significantly up-regulated in the CVP group 72 h post-A. hydrophila challenge. To conclude, incorporating C. fusca with V. proteolyticus in C. labrosus diet affected the microbial species composition in the intestine while preserving its functionality. In terms of gene expression, the combined diet effectively regulated the transcription of stress and immune-related genes, suggesting potential enhancement of fish resistance against stress and infections.

Otolith shape and elemental signatures provide insights into the connectivity of euryhaline Chelon labrosus inhabiting two close estuaries with different burdens of xenoestrogens in the Southern Bay of Biscay.

Intersex gonads have been observed in thicklip grey mullet Chelon labrosus, inhabiting estuaries with high burdens of xenoestrogens in the Southeast Bay of Biscay, but knowledge of population connectivity among estuaries is lacking for this euryhaline fish species. This study investigates the population structure of C. labrosus using otolith shape and elemental signatures of 60 adults (overall length âˆ¼ 38 cm) from two estuaries 21 nautic miles apart, one with a high incidence of intersex condition (Gernika), and the other one pristine (Plentzia). Otolith shape analyses were performed using elliptical Fourier descriptors, while elemental signatures of whole sagittae were obtained by inductively coupled plasma mass spectrophotometry. Univariate and multivariate statistics were applied to determine if otolith signatures show patterns of homogeneity between estuaries. The data indicated significant differences in the otolith shape and elemental composition between mullets of Gernika and Plentzia. Elemental differences were mainly driven by Sr, Li (both higher in Plentzia) and Ba (higher in Gernika). The 98% re-classification success rate obtained from stepwise linear discriminant function analysis suggests that Gernika and Plentzia individuals form separated population units. The limited connectivity between these two close estuaries would indicate a different life history of exposure to chemicals, which might explain the high prevalence of intersex condition in Gernika and its absence in Plenztia.

The asymmetry in the sagitta of four mugilid species obtained from Köycegiz Lagoon, Aegean Sea, Turkey.

Otolith features such as size and weight were analysed in 656 fish specimens of Chelon auratus, Chelon labrosus, Chelon saliens and Mugil cephalus collected from the Köycegiz Lagoon System, Aegean Sea, southwest Turkey. The aim was to calculate the asymmetry value of the otolith length (OL), otolith width (OW) and otolith weight (OWe). The asymmetry value of OL was greater than that of OW and OWe. The asymmetry value of the three otolith parameters increased with an increase in the fish's length. The probable cause of asymmetry in the otolith parameters investigated has been determined relative to the variability in growth prompted by ecological impact linked with the disparity in water temperature, salinity, depth and contaminants existing in the Köycegiz Lagoon System.

Monorchiids (Digenea, Trematoda) of fishes in the Yucatán Peninsula, Mexico, with the description of three new species based on morphological and molecular data.

Adult specimens of monorchiids (Digenea) were collected from the intestines of the white grunt, Haemulon plumierii Lacepède (Haemulidae), and the white mullet, Mugil curema Valenciennes (Mugilidae) from five localities off the Yucatán Peninsula and one locality in the Gulf of Mexico. Some specimens were photographed and sequenced for two molecular markers, the large subunit (LSU) of nuclear rDNA and the cytochrome c oxidase subunit 1 (cox1) of mitochondrial DNA. Other specimens were processed for morphological analyses. Newly generated sequences were aligned with other sequences available in GenBank. Bayesian inference and maximum likelihood analyses were implemented using the data sets of LSU and cox1 independently. Reciprocal monophyly evidenced through phylogenetic analyses, sequence divergence values for both molecular markers, and detailed morphological analyses, including scanning electron microscopy photomicrographs, revealed three new genetic lineages, i.e., species, as parasites of M. curema. The three new species are Sinistroporomonorchis mexicanus n. sp., Sinistroporomonorchis yucatanensis n. sp., and Sinistroporomonorchis minutus n. sp. Two additional species of monorchiids were sampled, characterised molecularly, and re-described, namely Sinistroporomonorchis glebulentus (Overstreet, 1971) from the white mullet, and Alloinfundiburictus haemuli (Overstreet, 1969), from the white grunt.

Title: Monorchiidae (Digenea, Trematoda) de poissons de la péninsule du Yucatán, Mexique, avec description de trois nouvelles espèces sur la base de données morphologiques et moléculaires. Abstract: Des spécimens adultes de Monorchiidae (Digenea) ont été collectés dans les intestins de la gorette blanche, Haemulon plumierii Lacepède (Haemulidae), et du mulet blanc, Mugil curema Valenciennes (Mugilidae) de cinq localités au large de la péninsule du Yucatán et d'une localité dans le Golfe du Mexique. Certains spécimens ont été photographiés et séquencés pour deux marqueurs moléculaires, la grande sous-unité (LSU) de l'ADNr nucléaire et la sous-unité 1 de la cytochrome c oxydase (cox1) de l'ADN mitochondrial. D'autres spécimens ont été traités pour des analyses morphologiques. Les séquences nouvellement générées ont été alignées avec d'autres séquences disponibles dans GenBank. L'inférence bayésienne et les analyses de vraisemblance maximale ont été mises en œuvre en utilisant les ensembles de données de LSU et cox1 indépendamment. La monophylie réciproque mise en évidence par des analyses phylogénétiques, des valeurs de divergence de séquence pour les deux marqueurs moléculaires et des analyses morphologiques détaillées, y compris des photomicrographies au microscope électronique à balayage, a révélé trois nouvelles lignées génétiques, c'est-à-dire des espèces, qui sont parasites de M. curema. Les trois nouvelles espèces sont Sinistroporomonorchis mexicanus n. sp., Sinistroporomonorchis yucatanensis n. sp. et Sinistroporomonorchis minutus n. sp. (Monorchiidae). Deux espèces supplémentaires de Monorchiidae ont été échantillonnées, caractérisées moléculairement et redécrites, à savoir Sinistroporomonorchis glebulentus (Overstreet, 1971) du mulet blanc et Alloinfundiburictus haemuli (Overstreet, 1969) de la gorette blanche.

Effects of Different Co-Feeding Protocols on the Early Weaning of Flathead Grey Mullet (Mugil cephalus) Larvae.

The sustainable expansion of aquaculture relies on a sufficient supply of eggs and larvae, which are the first step of life cycle management. However, marine fish larval rearing generally depends on live feed production, which needs additional facilities and labor. The flathead grey mullet (Mugil cephalus), a promising species for aquaculture diversification, has a precocious digestive system development, supporting the feasibility of early weaning strategies. For these reasons, this study evaluated survival, growth, proximate and fatty acid composition, and gene expression of Mugil cephalus larvae reared under three different weaning protocols. Three co-feeding treatments, two with different Artemia sp. concentrations (A100 and A50, 2 and 1 Artemia sp. mL-1 day-1, respectively) and one with only rotifers administered as live feed along the feeding trial (A0), were assessed from 22 to 36 days post-hatching (dph). The A0 treatment performed better in survival (64.79 ± 7.40%) than the A100 protocol (32.46 ± 12.82%). In contrast, the larvae of the A100 treatment presented significantly higher final length (15.51 ± 0.86 mm) than those of the A0 treatment (12.19 ± 1.45 mm) and higher final weight (41.28 ± 1.48 mg) than those of the A50 and A0 treatments (31.23 ± 3.65 mg and 24.03 ± 7.99 mg, respectively). On the other hand, the expression of digestive enzyme- and somatotropic factor-related genes did not show differences between treatments. The present results support the convenience of treatment A0 in maximizing survival, as rotifers should be maintained until 30-32 dph (until a total larval length of at least 10 mm). However, to improve growth and minimize size dispersion, Artemia sp. addition is recommended from day 26 to day 29 post-hatching (total larval length of 8 to 9 mm).

Evaluation of the Combined Administration of Chlorella fusca and Vibrio proteolyticus in Diets for Chelon labrosus: Effects on Growth, Metabolism, and Digestive Functionality.

This study aimed to evaluate the combined effect of dietary Chlorella fusca and ethanol-inactivated Vibrio proteolyticus DCF12.2 (C + V diet) in Chelon labrosus juveniles, highlighting their nutritional, physiological, and morphological effects. The results showed that the combined dietary inclusion of C. fusca and V. proteolyticus significantly enhanced growth performance and feed utilization compared to the control group. The C + V diet increased the fish lipid quality index (FLQ), n-3 polyunsaturated fatty acids, and n-3/n-6 ratio, which might be beneficial in terms of human nutrition. The C + V diet considerably increased carbohydrate metabolic activity by statistically boosting plasma glucose. The dietary inclusion of C. fusca in conjunction with V. proteolyticus increased metabolic enzyme activity as well as intestinal absorption capacity compared to that found in the control group. In conclusion, the experimental diet was suitable for feeding C. labrosus, increasing their growth and the nutritional characteristics of the muscle and intestine, without causing tissue damage.

Population biology of Ellochelon vaigiensis (Quoy & Gaimard, 1825) in the Mekong Delta, Vietnam.

Ellochelon vaigiensis is widely distributed and plays a vital role in the fisheries in the Mekong Delta (MD), but data on its population biological traits have not been known. Consequently, this study was conducted to provide data on its population biology used for fishing status assessment and fish resources management. Fish specimens were collected using trawl nets in two regions of the Hau River mouth, including northern in Ben Tre and Tra Vinh (BTTV) and southern in Soc Trang and Bac Lieu (STBL). Fish population biological parameters were estimated using FiSAT II software based on the fish length-frequency data. The male and female length-frequency data in each ecoregion were pooled together. Data analysis of 1,383 individual fish showed the sex ratio of the species was 1.00:1.30 at BTTV (309 females and 402 males) and 1.00:1.25 STBL (299 females and 373 males). Most fish specimens were caught at 12-22 cm total length (914 individuals), accounting for 66.09% of the fish collection. The difference in salinity between these two regions could affect the population biological parameters of E. vaigiensis. There were five cohorts (e.g., five growth curves) in the BTTV and STBL. The von Bertalanffy curves of fish populations at BTTV and STBL were L = 33.6 (1 -e -0.46(t + 0.34)) L = 31.5 (1 -e -0.56(t + 0.29)), respectively. The growth index (Φ') of this species at STBL (2.74) was higher than that at BTTV (2.72), whereas its longevity at BTTV (6.52 yrs) was higher than at STBL (5.36 yrs). The biomass and relative yield parameters, including E 0.1, E 0.5 and E max were 0.358, 0.265 and 0.436 at BTTV; and 0.418, 0.293, and 0.513 at STBL, respectively. The fishing (F), natural (M), and total (Z) mortalities were 0.35/yr, 1.06/yr, and 1.41/yr at BTTV; and 0.55/yr, 1.24/yr, and 1.78/yr at STBL, respectively. The BTTV and STBL population was not overexploited because the exploitation rate (E BTTV = 0.25, E STBL = 0.31) was lower than E 0.1 (0.358 in BTTV and 0.418 in STBL).

Evaluation of the Effects of Two Different Feeding Frequencies on the Digestive Biochemistry of Two Mullet Species (Chelon labrosus and Liza aurata).

Mullets (Mugilidae) present significant potential for sustainable aquaculture diversification due to their eurythermal, euryhaline, and low-trophic nature. However, the physiological differences and optimal cultured conditions among the diverse mullet species are quite unknown. For these reasons, the present study aimed to address two main objectives: (1) to characterize the differences in digestive biochemistry, somatic indexes, and body composition between two mullet species (Liza aurata and Chelon labrosus); and (2) to evaluate the interactions of two different feeding frequencies (one against three meals per day) on the above-mentioned parameters, and also on the potential bioavailability of nutrients determined using in vitro assays. The results evidenced higher protease and amylase activities for Chelon labrosus than for Liza aurata, while the latter species presented a higher percentage of eviscerated weight and muscle lipids. Furthermore, the results from in vitro assays supported the higher enzyme activity of Chelon labrosus by an observed increase in the release of amino acids and reducing sugars measured for this species. Regarding feeding patterns, the results of the in vitro assays simulating enzyme: substrate (E:S) ratios corresponding to one or three meals per day point to a clear increase of nutrient bioavailability when the daily ration is split into several meals. The present results improve the physiological knowledge of mullet species and define criteria to develop better management protocols by producers.

A NEW SPECIES OF PROSOGONOTREMA (SCLERODISTOMIDAE: PROSOGONOTREMATINAE) FROM THE FLATHEAD GREY MULLET, MUGIL CEPHALUS LINNAEUS (MUGILIFORMES: MUGILIDAE), FROM THE ARABIAN GULF OFF IRAQ.

Prosogonotrema iraqiense n. sp. (Sclerodistomidae: Prosogonotrematinae) is described in the flathead grey mullet, Mugil cephalus Linnaeus (Mugiliformes: Mugilidae), collected from the Arabian Gulf off Iraq during June and October 2019. Currently there are 11 species of ProsogonotremaVigueras, 1940 commonly accepted: Prosogonotrema arabicaYadav, 1980; Prosogonotrema bilabiatumVigueras, 1940 (type species); Prosogonotrema caesionisGu and Shen, 1979; Prosogonotrema diacanthiBilqees and Durrani, 1980; Prosogonotrema karachienseBilqees and Durrani, 1980; Prosogonotrema pavasiLokhande, 1990; Prosogonotrema piscicola (Srivastava, 1949) Gibson, 2002 (Syn. Bhaleraoia piscicolaSrivastava, 1949); Prosogonotrema plataxumGu and Shen, 1979; Prosogonotrema posterouterinaYadav, 1980; and Prosogonotrema symmetricumOshmarin, 1965 originally described from marine fishes, and Prosogonotrema nickoliBilqees and Khan, 1992 described from a freshwater cyprinid. Six additional species that have been considered synonyms of P. bilabiatum are also considered. Prosogonotrema diacanthi is considered a junior synonym of P. piscicola and Prosogonotrema carangiHussain and Rao, 1980nec Velasquez, 1961 is determined to be a species distinct from P. bilabiatum and is reassigned herein as Prosogonotrema aluteri nomen novum per the ICZN. Prosogonotrema iraqiense differs from all currently recognized species in the genus by having the width of the ventral sucker approach or exceed the width of the body and from all except P. pavasi (body length/width ratio 1:1.4-1:1.5) by having a distinctive narrower, more elongate body profile with a larger body length/width ratio (1:5.8-1:6.1 vs. 1: 2.0-1:4.1). A key to the 18 species we recognize in Prosogonotrema is included.

Spawning induction and larval rearing in the thinlip gray mullet (Chelon ramada): The use of the slow release gonadotropin releasing hormone analog (GnRHa) preparation, leuprorelin acetate.

The thinlip gray mullet (Chelon ramada) belongs to the Mugilidae family, it is a low-trophic, euryhaline species adapted to a wide range of environmental conditions. As such, it represent a candidate to diversify aquaculture production toward more sustainable species. Nonetheless, several bottlenecks have to be overcome before production is undertaken at commercial scale. Indeed, C. ramada mature females do not spawn without hormonal treatments in captivity. This report describes the use of the gonadotropin releasing hormone analog (GnRHa), leuprorelin acetate as an effective single-dose inducer of spawning in this species. Wild mature females (n = 10; 29 ± 1 cm total length, TL and 199 ± 20 g body weight, BW) exhibiting protruded papilla and bulging abdomen, presenting vitellogenic oocytes (diameters higher than 657 µm) and fluent males (n = 21; 28 ± 1 cm TL and 181 ± 80 g BW) were treated with a single injection of leuprorelin acetate. Breeders spawned more than 500,000 eggs with a mean fertilization and hatching rate of 92 ± 3 and 91.4 ± 0.4 %, respectively. Larvae grew according to the equation y = 2.6841e0.044x, mean survival rate at 19 dph was 13.8 ± 1.5 %. Mean SGR% day-1 slightly decreased concomitantly with tail flexion, probably for a greater investment on ontogenic development rather than growth. Present results suggest that mature C. ramada presents easily recognizable reproductive traits, adapts without difficulty to captive conditions, and can be easily induced to spawn administrating a single dose of leuprorelin acetate. The protocol used in our study resulted in high fertilization and hatching rates, as well as promising larval survival minimizing broodstock stress.

Nickel and cadmium tissue bioaccumulation and blood parameters in Chelon auratus and Mugil cephalus from Anzali free zone in the south Caspian Sea (Iran) and Faro Lake (Italy): A comparative analysis.

BACKGROUND: Analysis of heavy metal concentrations in fish blood is a valuable tool in environmental pollution monitoring. Among different type of fish, detritivorous fish are a very good indicator for monitoring pollution and environmental stress, along with hematological studies, which are an important indicator in eco-toxicological and biological studies. AIM: The aim of this study was to evaluate the influence of environment on bioaccumulation of Ni and Cd and on blood parameters in Chelon auratus and Mugil cephalus (a detritivorous fish which is widely distributed in the world) captured in Caspian Sea and Faro Lake. METHODS: For the research blood and tissues samples were collected from 40 mullets (20 Mugil cephalus from Italy and 20 Chelon auratus from Iran) in 2019. The hematological (white blood cell, WBC; red blood cell, RBC; thrombocyte count, TC; hematocrit, Hct; hemoglobin concentration, Hb; mean corpuscular volume, MCV; mean corpuscular hemoglobin, MCH and mean corpuscular hemoglobin concentration, MCHC) and biochemical parameters (aspartate aminotransferase, AST; alanine aminotransferase, ALT; alkaline phosphatase, ALP; lactate dehydrogenase, LDH and creatine phosphokinase, CPK were assessed. RESULTS: Although the concentration of Ni and Cd in the muscle of fish have no significant health risks and were low in both regions, the most elevated concentration was found in the liver of Caspian Sea mullet. In all cases, the results obtained for all biochemical and most hematological parameters of individual Faro Lake, were considerably lower than the Caspian Sea, demonstrating that habitats and environmental conditions affect the blood metabolites. CONCLUSIONS: The results of this study show that these measurements can be used as criteria for the quantitative evaluation of fish /health and provide information on the extent of potential poisoning and the risks posed to the populations and fisheries.

Spermatological characteristics and effects of cryopreservation in Lebranche mullet spermatozoa (Mugil liza Valenciennes, 1836): First report of ultra-rapid freezing.

The present study investigated the spermatological characteristics of raw semen of Lebranche mullet (Mugil liza), namely pH, and sperm density, and motility; and subsequently evaluated the effects of different times of exposure to cryoprotectants, and the application of an ultra-rapid freezing protocol, on sperm motility and plasma membrane integrity. Semen samples were analyzed undiluted (control) and diluted 1:50 v/v in CF-HBSS + 10% Dimethyl sulfoxide + 30% Ethylene glycol + 94.58 gL-1 Trehalose dehydrate (n = 15). Two treatments - diluted semen samples in cryoprotective medium without ultra-rapid freezing (T1), and diluted semen in cryoprotective medium with ultra-rapid freezing (T2) - were evaluated at 0, 2, 4, 6 and 8 min. The frozen samples were thawed at 37ºC for 60 s. The spermatological characteristics recorded for the semen were: pH: 7.57 ± 0.21; sperm density: 30.4 ± 2.9 × 109 sperm mL-1; motility: 82 ± 4.9%. Sperm motility presented differences after 2 min exposure to cryoprotectants (70.0 ± 2.7%) and ultra-rapid freezing (66.5 ± 5.8%) compared to the control group (98.5 ± 1.9% and 98.5 ± 2.1%, respectively; p < 0.05). On the other hand, the plasma membrane integrity of the spermatozoa after 2 min exposure to cryoprotectants (64.0 ± 8.6%) and ultra-rapid freezing (62.5 ± 5.2%) presented no differences compared to the control group (69.5 ± 3.9% and 70.0 ± 3.5%, respectively p > 0.05); however, differences were observed in the parameters evaluated after longer exposure and cryopreservation times. This is the first report evaluating the effects of different times of exposure to cryoprotectants and direct ultra-rapid freezing in liquid nitrogen on Mugil liza sperm. Our results demonstrated the protocol of sperm ultra-freezing is safe within a time´s window of 2 min of exposure to cryoprotectants, after which a toxicity effect on sperm can be observed.

Molecular evidence supports the validity of three Parabrachiella species infecting mugilids.

The parasitic copepod genus Parabrachiella is composed of 70 species, 14 of which are found in South America. The finding of new specimens of Parabrachiella mugilis from Turkey allowed us to compare the nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene of this species with those of the South American Parabrachiella exilis and Parabrachiella platensis; all these species are parasites of mugilids. In addition, specimens of Parabrachiella fasciata, Parabrachiella oralis and Parabrachiella dispar from Chile, and Parabrachiella chevreuxi from Argentina were included in the comparison. Our results confirmed that the three Parabrachiella species parasitizing mugilids, which had been identified by morphology, are valid entities. However, P. exilis was recently synonymized with P. mugilis. The latter species showed a great genetic distance from P. exilis (16%) and was closer to Parabrachiella fasciata (13%) and to species with long posterior processes. Parabrachiella exilis and P. platensis (parasite on Mugil cephalus and Mugil liza, respectively) had a low genetic distance (9%) and Parabrachiella kabatai (parasite of Isacia conceptionis) had a low genetic distance (12-13%) from P. fasciata, P. platensis and P. exilis. In addition, the three parasitic copepods from South America have short and round posterior processes compared to other species, which have long posterior processes. Most species with long posterior processes are clustered together in a Pacific Ocean clade (P. hugu from the North Pacific Ocean), with the exception of P. chevreuxi, which has been found in the South Atlantic Ocean. This study adds seven new sequences, making a total of nine sequenced South American species of Parabrachiella.

Morphological and molecular characterization of Neoechinorhynchus (N.) cephali n. sp. (Acanthocephala: Neoechinorhynchidae) Stiles and Hassall 1905 infecting the flathead grey mullet Mugil cephalus (Linnaeus, 1758) from the southwest coast of India.

The present paper describes Neoechinorhynchus (Neoechinorhynchus) cephali n. sp., an acanthocephalan parasite infecting the intestine of the flathead grey mullet Mugil cephalus from the southwest coast of India. The parasite exhibited a prevalence of 7.40%, mean intensity of 18.5 and abundance of 18-19 worms/infected host. Morphologically, N. (N.) cephali n. sp. is sexually dimorphic, small, cylindrical, slightly curved and creamy white in colour. Females are larger than males, measured 8.87 × 0.88 mm and 5.65 × 0.66 mm, respectively. Proboscis is armed with three circles of six hooks each, which progressively decreases in size posteriorly. Hooks are backwardly curved and robust and tapering with a sharp, pointed tip, striations on the surface and a manubrium at its base. The body is aspinose, trunk surface with micropores and pits and proboscis surface with papilliform structures. The body wall is with five dorsal and two ventral hypodermal nuclei, along with lacunar canals connected by circular anastomoses. Lemnisci are subequal, small lemnisci are uninucleated, and large ones are binucleated. The cement gland is oval, with four giant nuclei; bursa is with many sensory cells. Eggs are elliptical, with concentric shells, and polar prolongation is absent. In the molecular and phylogenetic analyses based on the 18S ribosomal DNA region, the present species stands out with a high bootstrap value and is positioned as a sister branch of N. (N.) dimorphospinus. Based on the differences in morphology, morphometry and molecular and phylogenetic analyses, the present species of acanthocephalan infecting M. cephalus is considered as new, and the name Neoechinorhynchus (Neoechinorhynchus) cephali n. sp. is proposed.

Phylogenetic affinities of Forticulcitinae (Haploporidae) parasites of mullet from the Americas, with the description of three new species and notes on the genera and key species.

Members of Forticulcitinae Blasco-Costa, Balbuena, Kostadinova & Olson, 2009 include endoparasites of mullet fishes distributed worldwide. Adult specimens were collected from the intestines of white mullet (Mugil curema) and flathead grey mullet (Mugil cephalus) from five localities in the Gulf of Mexico and a single locality in Venezuela. Photogenophores were sequenced for two nuclear molecular markers, the large subunit (LSU) and second internal transcribed spacer (ITS2) of nuclear rDNA. The new sequences were aligned with other sequences downloaded from GenBank. The maximum likelihood and Bayesian inferences were deduced using the combined dataset (LSU + ITS2). The phylogenetic analyses revealed four new lineages belonging to Forticulcitinae. Three new species are described in the present study. Ekuarhuni mexicanus n. sp. can be differentiated from its congeneric species by presenting a longer hermaphroditic sac length (136-180 µm) and a wider testis (91-123 µm). Forticulcita macropharyngis n. sp. and Forticulcita venezuelensis n. sp. are the 8th and 9th species described in Forticulcita. Both species belong to the diminutive morphotype of Forticulcita. Forticulcita macropharyngis n. sp. can be morphologically distinguished from the other congeneric species by the presence of a massive and muscular pharynx (46-110 µm long, 74-106 µm wide). Forticulcita venezuelensis n. sp. is the second species of the studied genus recorded in South America and can be differentiated from congeneric species by possessing the largest testis (138-201 µm long, 83-100 µm wide). Finally, the fourth lineage corresponds to Overstreetoides Andrade-Gómez & García-Varela, 2021; however, few specimens of this lineage were collected, precluding any description of the species. In addition, a key is proposed for differentiating the genera and species of Forticulcitinae.

The complete mitochondrial genome of Moolgarda perusii (Teleostei: Mugilidae).

We determined the complete mitochondrial genome of Moolgarda perusii, which is 16,781 bp in length, and contains 13 protein-coding genes (PCGs), two rRNAs, 22 tRNAs, and a complete control region. The total base composition of the mitogenome is 28.7% T, 27.0% C, 28.5% A, and 15.9% G. Of the 13 PCGs, 11 PCGs start with an ATG codon. Eight PCGs use TAA/TAG/AGA as the termination codon, whereas five PCGs have incomplete stop codon TA/T. This study would be useful for further studying population genetics and understanding the phylogenetic relationship of the family Mugilidae.

White mullet Mugil curema population structure from Mexico and Brazil revealed by otolith chemistry.

The white mullet Mugil curema supports several fisheries in the neotropical region; nevertheless, the population structure is still elusive. The aim of this study was to assess the presence of adult management units and nursery areas from five sampling sites throughout the Gulf of Mexico and northern Brazil using otolith microchemistry. The Li/Ca, Na/Ca, Mn/Ca, Sr/Ca, Ba/Ca and Pb/Ca ratios were measured in otolith core (juvenile stage) and edge (adult stage) (N = 131) using laser ablation-inductively coupled plasma-mass spectrometry. Several ratios were significantly different between sampling sites for core and edge (P < 0.05). For otolith edge, permutational multivariate analysis of variance showed significant differences (P < 0.05) between all sampling sites from Mexico (except between Mecoacán and Tamiahua, P > 0.05) and between Mexico (pooled samples) and Brazil. Quadratic discriminant analyses showed jackknifed classification higher in the edge (66.6% and 99.5% for Mexico and Brazil plus Mexico, respectively) than in the core (46.3% and 76.5% Mexico and Brazil plus Mexico, respectively). The two cluster analyses based on the core microchemistry (Mexico and Brazil plus Mexico) produced three main clusters, which did not coincide with catchment areas. These results support the segregation of the M. curema adult life stages among several sampling sites from Mexico and Brazil; moreover, core analysis suggested that the nursery areas did not correspond to the capture sites or adults stocks.

A New Species of Synbranchiella (Cestoda: Proteocephalidae) from the Mountain Mullet ( Dajaus monticola) in Costa Rica.

A new species of the recently erected genus of proteocephalid cestodes, Synbranchiella Arredondo, Alves and Gil de Pertierra, 2017 , is described based on specimens found in the mountain mullet, Dajaus monticola (Bancroft, 1834), from Costa Rica. The new species is placed in Synbranchiella because of the cortical position of the genital organs (typical of the former subfamily Monticelliinae); a robust scolex (lacking a metascolex) having a dome-shaped apex and biloculate suckers (lacking free posterior margins); vitelline follicles in 2 narrow lateral bands; a vagina always anterior to the cirrus-sac; and a genital pore that is markedly pre-equatorial, i.e., close to the anterior margin of proglottids. The new species, Synbranchiella megacirrus, differs from the type and only other species of the genus, Synbranchiella mabelae Arredondo, Alves and Gil de Pertierra, 2017 , that infects the marbled swamp eel, Synbranchus marmoratus Bloch, 1795, in Argentina by the absence of preporal vitelline follicles (present in S. mabelae); a well-developed, large, elongate vaginal sphincter (small and ring-like in S. mabelae); and a large cirrus-sac relative to the proglottid size (cirrus-sac length is on average 48% of the proglottid width in S. megacirrus vs. 31% in the latter species). This is the first adult tapeworm reported from mountain mullet and the first record of the genus outside of South America, thereby greatly extending the range of distribution of species of Synbranchiella.