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We present a genome assembly from an individual Sardina pilchardus (the sardine; Chordata; Actinopteri; Clupeiformes; Clupeidae). The genome sequence spans 869.40 megabases. Most of the assembly is scaffolded into 24 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 17.57 kilobases in length.

The River Mignone (Tarquinia, Viterbo, central Italy) is one of the best preserved watercourses in Lazio. Here, in April and May of the years 2020-2023, a conspicuous contingent of Alosa fallax (Lacépède 1803) was reported. The frenetic behaviour of the individuals observed, some of which showed swollen bellies and considerable size, suggested that this watercourse may represent a potential new breeding station for this threatened migratory euryhaline fish species. The correct recognition of the sex of A. fallax in the field, problematic during the breeding season, is crucial for understanding its population structure as indicators of possible reproduction. To this end, statistical analysis (Mann-Whitney U-test) of 20 morphometric measurements made on individuals captured and subsequently released revealed significant differences between the sexes for seven morphometric characters, confirming a sex ratio compatible with reproduction. However, the presence of a transverse dam with no fish ladder and the dispersion of biocides from farmland in the final stretch may represent a serious threat to effective reproduction.

Abstract Background The hydrogeological history of Lake Tanganyika paints a complex image of several colonization and adaptive radiation events. The initial basin was formed around 9–12 million years ago (MYA) from the predecessor of the Malagarasi–Congo River and only 5–6 MYA, its sub-basins fused to produce the clear, deep waters of today. Next to the well-known radiations of cichlid fishes, the lake also harbours a modest clade of only two clupeid species, Stolothrissa tanganicae and Limnothrissa miodon. They are members of Pellonulini, a tribe of clupeid fishes that mostly occur in freshwater and that colonized West and Central-Africa during a period of high sea levels during the Cenozoic. There is no consensus on the phylogenetic relationships between members of Pellonulini and the timing of the colonization of Lake Tanganyika by clupeids. Results We use short-read next generation sequencing of 10X Chromium libraries to sequence and assemble the full mitochondrial genomes of S. tanganicae and L. miodon. We then use Maximum likelihood and Bayesian inference to place them into the phylogeny of Pellonulini and other clupeiforms, taking advantage of all available full mitochondrial clupeiform genomes. We identify Potamothrissa obtusirostris as the closest living relative of the Tanganyika sardines and confirm paraphyly for Microthrissa. We estimate the divergence of the Tanganyika sardines around 3.64 MYA [95% CI: 0.99, 6.29], and from P. obtusirostris around 10.92 MYA [95% CI: 6.37–15.48]. Conclusions These estimates imply that the ancestor of the Tanganyika sardines diverged from a riverine ancestor and entered the proto-lake Tanganyika around the time of its formation from the Malagarasi–Congo River, and diverged into the two extant species at the onset of deep clearwater conditions. Our results prompt a more thorough examination of the relationships within Pellonulini, and the new mitochondrial genomes provide an important resource for the future study of this tribe, e.g. as a reference for species identification, genetic diversity, and macroevolutionary studies.

In this study, the complete mitochondrial genome of Ilisha striatula is presented, and we also discussed its mitochondrial characteristics. The full length of the mitochondrial genome was 16,847 bp, including 13 protein-coding genes (PCGs), 2 ribosomal RNAs, 22 transfer RNA genes, one non-coding control region (CR), and one origin of replication on the light-strand. The total nucleotide composition of the mitochondrial genome was 31.11% A, 24.62% T, 29.10% C, 15.16% G, and AT was 55.73%. The phylogenetic tree based on the ML method supported the placement of I. striatula in a close relationship with I. elongata. These data contribute to a better understanding of the systematics of the Pristigasteridae.

Unlike their marine counterparts, tropical freshwater clupeids receive little scientific attention. However, they sustain important fisheries that may be of (inter)national commercial interest. Africa harbours over 20 freshwater clupeid species within Pellonulini. Recent research suggests their most abundant parasites are gill-infecting monogenean flatworms within Kapentagyrus. After inspecting specimens of 12 freshwater clupeids from West and Central Africa, mainly sourced in biodiversity collections, we propose 11 new species of Kapentagyrus, which we describe using their haptoral and genital morphology. Because of their high morphological similarity, species delineation relies mostly on the morphometrics of anchors and hooks. Specifically, earlier, molecular taxonomic work indicated that the proportion between the length of the anchor roots, and between the hook and anchor length, is diagnostic. On average, about one species of Kapentagyrus exists per pellonuline species, although Pellonula leonensis harbours four species and Microthrissa congica two, while Microthrissa moeruensis and Potamothrissa acutirostris share a gill monogenean species. This study more than quadruples the number of known species of Kapentagyrus, also almost quadrupling the number of pellonuline species of which monogeneans are known. Since members of Kapentagyrus are informative about their hosts’ ecology, evolutionary history, and introduction routes, this enables a parasitological perspective on several data-poor African fisheries.

Stock assessment is necessary to understand the status of fishery stocks. However, for the data-poor fishery, it is very challenging to assess the stock status. The length-based Bayesian biomass (LBB) technique is one of the most powerful methods to assess the data-poor fisheries resources that need simple length frequency (LF) data. Addressing the present gap, this study aimed to assess the stock status of three sardines (Sardinella fimbriata, Dussumieria acuta, and D. elopsoides) in the Bay of Bengal (BoB), Bangladesh using the LBB method. The estimated relative biomass for S. fimbriata was B/B0 < BMSY/B0, indicating the overfished biomass, while the assessed B/B0 > BMSY/B0 for D. acuta and D. elopsoides indicates healthy biomass. Additionally, for S. fimbriata, the length at first landing was smaller than the optimum length at first landing (Lc < Lc_opt), indicating an overfishing status, but a safe fishing status was assessed for D. acuta and D. elopsoides (Lc > Lc_opt). Therefore, increasing the mesh size of fishing gears may help to ensure the long-term viability of sardine populations in the BoB, Bangladesh.

Abstract We evaluated the reproductive dynamics of two fish species, Lycengraulis grossidens and Platanichthys platana, in a subtropical freshwater coastal lagoon (Peri Lagoon) in Brazil. Samples were collected from nine sites every two months from June 2008 to April 2012. Different fishing methods were used to capture larvae, juveniles, and adults. Limnological variables were obtained using multiparameter probe. More females than males were collected of both fish species and the chi-square test (χ2) was used to confirm that the sex ratio was female-biased. Large numbers of maturing and mature fishes were observed in almost every sampling month. The gonadosomatic index (GSI) of L. grossidens was the highest in August, October, and December for females and in October for males, and no significant difference was found across years. The GSI of P. platana showed no significant difference across months for either sex; however, significant differences were recorded in year three (June 2010-April 2011) and year four (June 2011-April 2012) for females and in year three (June 2010-April 2011) for males. For both species, GSI was negatively correlated with temperature and water level. L. grossidens larvae were more abundant in October 2010, showing a positive correlation with water transparency, whereas P. platana larvae were more abundant in June 2011, showing a positive correlation with water transparency and negative correlation with temperature and precipitation. Both species were represented by different stages, including larvae, which confirm that these species reproduce in Peri Lagoon. Reproduction was more pronounced in autumn and winter; however, reproductive activity was evident throughout the sampling period. In conclusion, our results show that abiotic factors strongly influence the temporal pattern of reproductive activity and larval assemblages of both L. grossidens and P. platana in Peri Lagoon, Brazil.

Neuromast morphology and distribution are characterized during early ontogeny of anchoveta (Engraulis ringens) and common sardine (Strangomera bentincki). Although both species share morphological features, they show several differences during their early ontogeny, such as size at hatching and yolk absorption. Larvae were obtained from incubation of planktonic eggs (at 12°C), collected during the spawning season 2001 (August-September) at Coliumo Bay. The neuromasts were observed from hatching to 25 days, and the pattern of neuromast appearance, in newly hatched larva, until yolk absorption, was determined using Janus Green staining and scanning electronic microscope. Results showed a similar pattern of neuromast development in both species. At hatching, two pairs of neuromasts were observed in the cephalic area and 8-9 in the rest of the body, which increased to 19 pairs and to 30-39 pairs at a larval size of 11 mm, respectively. On the average, 12 hair cells per neuromast were counted, with little variation among neuromasts. The polarity of these hair cells was closest to multiple polarity. Neuromast positioning for both species, anchoveta and common sardine larvae, are similar to those of Engraulis mordax and Clupea harengus, respectively. The similar development pattern of these species seems to be related to similar functional constraints and close taxonomic affinity.

The aim of this study is to provide information on the proximate composition and caloric value of the Clupeiformes fishes Chirocentrodon bleekerianus, Pellona harroweri, and Lycengraulis grossidens. The specimens were collected between 2007 and 2010 in Northern Rio de Janeiro. The bromatological analysis (protein, lipid, and mineral matter) was performed on composite samples; carbohydrate content and gross energy were calculated from relationships between variables. The fish species were significantly different in size (total length and weight), proximate composition, and gross energy; only the carbohydrate content was similar. The species L. grossidens was represented by larger individuals with higher lipid content, as C. bleekerianus and P. harroweri had the highest percentages of protein and mineral matter, as well as the highest gross energy values. The percentage of protein was directly proportional to the amount of gross energy, as the percentage of lipid showed an inverse relationship with these two variables. This study provides a basis for understanding the food selectivity of marine carnivores in coastal regions and elaborating bioenergetics models.

O objetivo deste trabalho é fornecer informações sobre a composição centesimal e o valor calórico dos peixes Clupeiformes Chirocentrodon bleekerianus, Pellona harroweri e Lycengraulis grossidens. Os espécimes foram coletados entre 2007 e 2010 na costa norte do estado do Rio de Janeiro. Análises bromatológicas (proteína, lipídio e matéria mineral) foram realizadas em amostras compostas, e o teor de carboidrato e a energia bruta foram calculados a partir de relações entre as variáveis. As espécies de peixes foram significativamente distintas em relação ao porte (comprimento total e peso), composição centesimal e energia bruta, e apenas o teor de carboidrato foi similar. A espécie L. grossidens foi representada por indivíduos maiores e com teor de lipídio superior, enquanto C. bleekerianus e P. harroweri apresentaram os maiores percentuais de proteína e matéria mineral, além de valores de energia bruta mais elevados. O percentual de proteína foi diretamente proporcional ao valor de energia bruta, enquanto o percentual de lipídio apresentou relação inversa com essas duas variáveis. O presente estudo servirá de base para o entendimento de a seletividade alimentar de carnívoros marinhos em regiões costeiras e para a elaboração de modelos de bioenergética.

The cephalic portions of the latero-sensory canal system in Denticeps clupeoides are described and analyzed. The species, a small herring-like fish from relictual West African streams, is the most primitive living clupeomorph and sole Recent representative of suborder Denticipitoidei. As sister group to over 360 species in Clupeoidei, Denticeps is a key taxon in understanding clupeomorph and lower teleostean relationships. Observations on recently-collected specimens of Denticeps clupeoides revealed comparatively-important and previously-unrecorded details of the cephalic latero-sensory canals which are relevant for understanding relationships at different levels in clupeomorph phylogeny. The infraorbital, supraorbital, preopercular, extrascapular and post-temporal canals of Denticeps have unbranched tubules in soft tissue, as in the hypothesized plesiomorphic condition for lower teleosts. Contrastingly, the presence of a complex network formed by a high order of branching of cephalic canals is hypothesized as a synapomorphy of the Clupeoidei. Denticeps and the Clupeoidei share an exclusive sensory branch that originates at the junction between the extrascapular bone and the recessus lateralis, here hypothesized as an additional synapomorphy of Clupeiformes. A supratemporal system is newly recorded in Denticeps, and the character is proposed as a synapomorphy of Clupeiformes, and not of Clupeoidei as previously thought. The hypothesis that the supratemporal system is homologous to the supraorbital cavern is refuted, and the latter is corroborated as an autapomorphy of Denticeps. Another autapomorphy of Denticeps (or Denticipitoidei) is the presence of the postorbital bulla, a hitherto unrecorded specialization of the infraorbital canal associated with infraorbitals 4 and 5. Homologies of other tubules of the cephalic sensory canals in Denticeps are also discussed, with emphasis on their bearing on the recognition of homologies of infraorbital bones in Denticeps and other lower teleosts. In general, data from the cephalic latero-sensory system corroborate Denticeps as the sister group to all other Recent clupeomorphs, and provide additional support for the monophyly of Clupeoidei and Clupeiformes.As porções cefálicas do sistema de canais látero-sensoriais em Denticeps clupeoides são descritas e analisadas. A espécie, uma pequena sardinha com distribuição restrita a poucos riachos relictuais na África Ocidental, é o mais primitivo Clupeomorpha vivente, e único representante Recente da subordem Denticipitoidei. Como grupo irmão das mais de 360 espécies incluídas em Clupeoidei, Denticeps é um táxon-chave no entendimento das relações filogenéticas em Clupeomorpha e outros Teleostei inferiores. Observações com base em espécimes recentemente coletados de Denticeps clupeoides revelaram detalhes inéditos e comparativamente importantes dos canais látero-sensoriais cefálicos, relevantes para o entendimento de relações em diferentes níveis da filogenia de Clupeomorpha. Os canais infraorbital, supraorbital, preopercular, extrascapular e pós-temporal de Denticeps possuem túbulos simples nos tecidos moles, como na situação considerada plesiomórfica para teleósteos inferiores. Em contraste, a presença de uma rede complexa formada por ramificações múltiplas dos canais cefálicos é considerada uma sinapomorfia de Clupeoidei. Denticeps e Clupeoidei compartilham um ramo sensorial exclusivo que se origina na junção entre o osso extrascapular e o recessus lateralis, aqui proposto como uma sinapomorfia adicional de Clupeiformes. O sistema supratemporal é registrado pela primeira vez em Denticeps, e o caráter é consequentemente proposto como sinapomorfia de Clupeiformes, e não de Clupeoidei como se acreditava previamente. A hipótese de que o sistema supratemporal seria homólogo à caverna supraorbital é refutada, e a última é considerada autapomórfica para Denticeps. Uma outra autapomorfia de Denticeps (ou Denticipitoidei) é a presença da bula pós-orbital, uma especialização previamente desconhecida do canal infraorbital associada com os infraorbitais 4 e 5. As homologias de outros túbulos dos canais sensoriais cefálicos em Denticeps também são discutidas, com ênfase no reconhecimento de homologias dos ossos infraorbitais em Denticeps e em outros Teleostei inferiores. Em geral, os dados do sistema látero-sensorial cefálico corroboram a hipótese de Denticeps como grupo irmão de todos os outros clupeomorfos Recentes, e fornecem evidência adicional para o monofiletismo de Clupeoidei e Clupeiformes.

Foram estudados as hábitos alimentares dos peixes engraulídeos Anchoa januaria e Cetengraulis edentulus na Baía de Sepetiba, Rio de Janeiro, de julho de 1983 a julho de 1985. Os itens alimentares e as estruturas morfológicas relacionadas à alimentação indicaram que a área superficial dos rastros branquiais de A. januaria e C. edentulus é mais eficiente para a filtração dos alimentos, do que as distâncias entre os mesmos. Estas estruturas morfológicas possibilitam uma seletividade no tamanho dos itens alimentares, resultando em formas distintata de obtenção do alimento, entre as duas espécies. A. januaria seleciona o zooplâncton, por captura dos itens alimentares, enquanto C. edentuluss é um fitoplanctófago filtrador. Anchoa januaria tem hábitos alimentares diurnos e explgra diferentes estratos da coluna d'água durante os períodos frio e quente.Feeding habits of the engraulidid flsh - Anchoa januaria and Cetengraulis edentullus were studied in the Baía de Sepetiba, Rio de Janeiro, from July 1983 to July 1985. Dietary items and morphological structures "blted to feeding indicate that the surface structures of branchial rays of A. januaria and C. edentulus are more useful for food filtration than the distance between them. Those morphological structures provide a separation of the size of dietary items, thw resoltins in different forms of feeding behaviors between two species. A. januaria is a selective zooplanktivore, picking up food items, whereas C. edentulus is a filtering phytaplanktivore. Anchoa januaria is a diurnal feeder and exploits different layers in the water column during the warm and cold seasons.

Predaceous fish-eating species of the order Clupeiformes have a large mouth with well-developed teeth, and reach the greatest sizes within their families (up to 90 cm). We found that the pristigasterid Chirocentrodon bleekerianus, a small clupeiform (about 10 cm) from the tropical SW Atlantic, is able to prey on proportionally large clupeoid fishes and caridean shrimps. Fish preys are folded in the stomach of this herring, their heads and tails pointing toward the predator's head. This distinctive orientation of fish prey is also recorded for some small to medium-sized, fish-eating species of the tropical freshwater order Characiformes with canine-like teeth similar to those found in C. bleekerianus.

The aim of the present study provides the first results on the reproductive biology of the anchovy, Anchoa marinii, in a nearby-coastal area of Mar Chiquita coastal lagoon, 37º32'00"S 57º19'00"W, Argentina. To perform this, we employed mainly female gonads, at both microscopic and macroscopic levels. The oocyte diameter distribution and the microscopy analysis of oocytes, showed different batches of growing oocytes, suggesting that the anchovy is a multiple spawner, with constant oocytes recruitment all over the reproductive season. The batch fecundity ranged between 749 and 3,207 oocytes for females, and the relative fecundity ranged from 127 to 422 yolked oocytes per female gram (ovary free). The fecundity estimation has been made with yolked oocytes. No correlation between the fecundity estimation and female size and total weight (without ovary) has been found. The estimated L50 values were 74.13 and 73.76 mm TL for females and males, respectively. Shoals of females in advanced maturity phase were recorded, between December to April in the study area. During this period a significant increase of species abundance was correlated with water temperature increase (above 16°C). This fact, together with the detection of post-ovulatory follicles, indicated the existence of reproductive events in the nearby-coastal area of Mar Chiquita coastal lagoon.

ABSTRACT This publication is the second in a series that will together constitute an Atlas of Teleostei Otoliths for the Southeastern-Southern Brazilian area. Here we present results of morphologic and morphometric analyses of 12 Clupeiform species (3 Clupeidae, 7 Engraulidae and 2 Pristigasteridae) by means of the most commonly used features, measurements and indices. Three otoliths of each species have been illustrated and photographed whenever possible. The frequency of occurrence has been calculated for each characteristic by total length class (TL), and the ontogenetic differences have been analyzed (multiple χ² test; significance 0.05).

ABSTRACT Reproductive biology of the Brazilian menhaden, Brevoortia aurea (Clupeiformes), was studied in Mar Chiquita Coastal Lagoon. Its abundance was analysed in relation to environmental variables, and the main biological-reproductive parameters were estimated: size at first maturity, batch and relative fecundity, frequency distribution of oocyte diameters and gonadosomatic index (GSI). Moreover, its reproductive cycle was analysed histologically. Samples were collected from May 2012 to April 2013. Once the spawning period was detected, extra samples were added (October and November 2013). The specimens were caught with gillnets, at a distance of 2,300 meters from the mouth of the lagoon. The highest abundances were observed in the months of October and November. Both macroscopic and microscopic analysis allowed to confirm that in these months the saraca spawn in the mixo-eurihaline area of the lagoon. Females were recorded in the five phases of ovarian development. Histological and frequency distribution of oocyte diameters characterized this species as a batch spawner with undetermined fecundity. The fecundity varied between 19,900 and 178,508 oocytes/female. Relative fecundity ranged between 41 and 381 oocytes/g female ovary free. The size at first maturity was estimated on 277 and 265 mm total length for females and males, respectively.