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Clupeiform fishes are ecologically and economically important species contributing to industrial and artisanal fisheries worldwide. They represent key links in food webs, influencing the dynamic between trophic levels. The dietary interactions of these species are poorly studied in many regions, yet essential for fisheries management. To elucidate the role of these species in food webs of the Southern Brazilian Bight pelagic fisheries, we used metabarcoding analysis of fish stomach contents of Clupeiformes and possible predators. Onboard sampling from March to September 2016 allowed for processing of 87 stomach samples representing 31 species (including 12 samples representing three species of Clupeiformes). Links between trophic levels showed the predominance of Sardinella brasiliensis and Engraulis anchoita as important dietary items of a large range of fishes (28 species belonging to 18 families) and representing the majority of the total prey read abundance assigned to clupeiform fishes (~46% and ~32%, respectively). Opisthonema oglinum contributed to the diet of 16 species in 13 families and ~18% of total read abundance of clupeiform fishes as prey. The appearance of multiple clupeiform taxa in the diet of predators that are not commonly associated with pelagic prey indicates that ecosystem‐based fisheries management should not be separated between pelagic and demersal fisheries. The diet of Clupeiformes revealed an unexpectedly large diversity of fish species and a low proportion of invertebrates (<5% of clupeiform prey reads). This was likely due to a combination of both a limitation of the metabarcoding method (primer bias and low success of invertebrate taxonomic identification) as well as a contribution of early life stages (ichthyoplankton) to the diet of these fishes. The potential role of clupeiform fish populations as a constraint to the recruitment from the ichthyoplanktonic phase of other ecologically or commercially important fishes should be considered as an important direction for future studies. [ABSTRACT FROM AUTHOR]

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.

Three sardine species of Harengula and one of Opisthonema (Clupeiformes, Clupeidae) are known in the Western Atlantic, where the Amazon-Orinoco plume has been recognized as a major biogeographic barrier, albeit permeable to larger and generalist species. Here we used mitochondrial cox1 gene DNA sequences to check the lineage delimitation of both genera, testing the influence of the Amazon-Orinoco barrier (AOB) and marine provinces on their phylogeographic structure. Results indicate that the two genera are differently affected by the AOB, including cryptic speciation in Harengula and population structure in Opisthonema. Harengula show a broad distribution in the Brazilian Province (BRA) distinct from H. clupeola and H. jaguana from the Greater Caribbean Region (GCR). Divergence time between Harengula from the GCR vs. BRA was estimated as about 2.4 Mya, which coincides with the period of increasing sediment and freshwater discharge of the Amazon River in the Atlantic. Results also indicate the existence of a single species of Opisthonema, albeit with population structuring related to the marine provinces. Since species of both genera are relevant to artisanal fisheries and the maintenance of oceanic ecosystems, these results may help in fisheries management of these important marine resources. [ABSTRACT FROM AUTHOR]

The Suborder Clupeoidei Bleeker, 1859 comprises mostly marine fishes, which form large schools feeding on plankton. The fossil record of the suborder in the Late Paleogene reveals that clupeoids were abundant in the Western, Central, as well as Eastern Paratethys. Clupeoid descriptions from the Polish Outer Carpathians (SE Poland, Central Paratethys) remain incomplete due to usage of 'collective species', taxonomical inaccuracies, and lack of clear links between extinct and extant representatives. In this paper we present a new clupeoid, †Beksinskiella gen. nov., from the Oligocene of the Outer Carpathians, Poland. The new genus encompasses the nominal species †Maicopiella longimana (Heckel, 1850). †Beksinskiella gen. nov. has a unique combination of characters (skull roof with frontoparietal striae; smooth opercle; 6-7 branchiostegal rays; 42-48 vertebrae; dorsal and anal fins with 21-23 rays; the last two rays of the anal fin being elongated, and the presence of a complete series of abdominal scutes with the postpelvic ones poorly developed), supporting recognition of a new genus of the Suborder Clupeoidei. Similarities and differences between fossil and extant genera of Cluepoidei are discussed to shed light on their relationship. [ABSTRACT FROM AUTHOR]

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.

Evolutionary radiation is a problematic concept whose definition and classification have recently changed. Radiations can be defined as the pattern of abrupt increase in diversity of a lineage. It is relevant to evaluate the presence and interaction of different types of radiation in extant and fossil organisms to adequately delimitate the radiation types and to know the diversity in the context of Earth's history. Here, we employed the superorder Clupeomorpha at the Early–Late Cretaceous boundary as a study case to investigate radiation types and their interactions, using both taxic and morphological approaches. Clupeomorpha is an extensively studied, diverse and ancient teleostean superorder with wide geographical and ecological distributions. We propose a model for calculating rates of origination in order to analyse the taxic diversification and employ geometric morphometrics to analyse the morphological diversification that occurred at the temporal boundary. The results suggest the absence of taxic radiation due to a constant increase in taxon origination. However, the expansion of the phylomorphospace occupation and the disparity increase suggest the presence of a 'climatic–geographical' or 'broad diversification‐like' disparity, according to current classifications. This illustrates the incompatibility of current radiation classifications with this case study. [ABSTRACT FROM AUTHOR]

The present paper is a review of the available literature on the significance of forage fish, the plethora of services they provide, and the threats faced by them. Forage fish are pelagic planktivorous species that operate as conduits of energy between the lower trophic level (plankton) and the upper trophic level (predators). A variety of ecosystem services are provided by them, from serving as prey for higher trophic levels to producing fish meal and oil. Forage fish have a consumption value for humans and cultural importance to many societies. Forage fish have faced constant natural and anthropogenic threats in the past, resulting in numerous fish collapses which subsequently impacted their predators. The economic benefit provided by forage fish has been estimated to be approximately $ 18.7 billion per annum. An introspection of the data on ecosystem services revealed lack of data on regulating and cultural services, eventually leading to a monetary underestimation and their commercial prioritization over the wider benefits they provide. [ABSTRACT FROM AUTHOR]

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.

The present study reports the occurrence of Gold spotted grenadier anchovy Coilia dussumieri Valenciennes, 1848 for the first time from the Andaman and Nicobar Islands, India based on three specimens (Standard length = 124.3 - 134.7 mm) collected from Junglighat fish landing Centre, Port Blair. Description of the species has been provided herewith along with the morphometric measurements and meristic characters. Only one species of the genus Coilia (Coilia ramcarati Hamilton 1820) was known from Andaman and Nicobar Islands earlier and the present report adds a new record to the ichthyofaunal list of Andaman and Nicobar Islands, India. [ABSTRACT FROM AUTHOR]

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., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Brittain R et al.)

The mitochondrial genome provides important information for phylogenetic analysis and an understanding of evolutionary origin. In this study, the mitochondrial genomes of Ilisha elongata and Setipinna tenuifilis were sequenced, which are typical circular vertebrate mitochondrial genomes composed of 16,770 and 16,805 bp, respectively. The mitogenomes of I. elongata and S. tenuifilis include 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA), two ribosomal RNA (rRNA) genes and one control region (CR). Both two species' genome compositions were highly A + T biased and exhibited positive AT-skews and negative GC-skews. The genetic distance and Ka / Ks ratio analyses indicated that 13 PCGs were affected by purifying selection and the selection pressures were different from certain deep-sea fishes, which were most likely due to the difference in their living environment. Results of phylogenetic analysis support close relationships among Chirocentridae, Denticipitidae, Clupeidae, Engraulidae and Pristigasteridae based on the nucleotide and amino acid sequences of 13 PCGs. Within Clupeoidei, I. elongata and S. tenuifilis were most closely related to the family Pristigasteridae and Engraulidae, respectively. These results will help to better understand the evolutionary position of Clupeiformes and provide a reference for further phylogenetic research on Clupeiformes species. [ABSTRACT FROM AUTHOR]

The Atlantic herring Clupea harengus is a small pelagic schooling fish belonging to the Clupeiformes. It constitutes a key species for fisheries and marine ecosystems of the Northern hemisphere. Due to its key importance for fishery several studies refer to the larval development of C. harengus and aim to further understand its reproductive biology. However, not much is known about the skeletal development of herring larvae. This study describes the axial skeleton development of Western Baltic herring. Cartilage and bone formation were traced by clearing and double staining herring larvae with a size spectrum of 6–35 mm. During the yolk-sac phase, the caudal fin starts to differentiate. Then, in the next phase the dorsal fin develops, followed by notochord flexion and anal fin formation. After a phase of pelvic fin development, the transition to the juvenile fish starts. The development of herring is compared to other clupeiforms, especially Alosa sapidissima , Engraulis japonicus and Sardinops melanostictus, for which information was available, and to previous research on herring larvae. [ABSTRACT FROM AUTHOR]

The Atlantic anchoveta, Cetengraulis edentulus (Cuvier, 1829) is one of the most commercially important fish species in the littoral of Brazil. The present study evaluates the parasitic fauna of this engraulid fish from the southeastern Brazilian coast. Between October 2019 and March 2020, a total of 100 specimens of C. edentulus from the Sepetiba Bay, Rio de Janeiro, Brazil (22°57'44"S; 43°52'28"W), were examined. Eighty-five specimens of C. edentulus were parasitized by at least one species of metazoan, with a mean of 4.32 ± 6.12 parasites/fish. Eleven species of parasites were collected: five digeneans, two monogeneans, two copepods, one isopod and one nematode. The nematode Hysterothylacium sp. was the most abundant and dominant species, representing 51.85% of the metazoan parasites collected, showing positive correlation with the host's total length and parasite abundance and prevalence. The mean abundance and prevalence of Hysterothylacium sp. was significantly higher in female hosts. One pair of larval endoparasites showed positive covariation. Centengraulis edentulus represents a new host record for nine species of parasites. A dominance of endoparasitic larval stages is documented in the parasite community of C. edentulus. This may be a function of the feeding habits of engraulid fish, which feed mainly on zooplanktonic organisms. It may also have to do with to the fact that C. edentulus is the intermediate and/or paratenic host of fish parasites, birds, and marine mammals. [ABSTRACT FROM AUTHOR]

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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.

Despite being one of the richest Neogene deposits of marine fossil vertebrates along the Pacific coast of South America, no detailed study of bony fishes from the Bahía Inglesa Formation has been carried out. Through the revision of historical collections of the Caldera Paleontological Museum, we describe 27 fossil remains of bony fishes. Fossils described here are distributed in 13 taxa. Among these, Sardinops sp. cf. S. sagax (Clupeidae) represents the first fossil record of the genus for Chile, Labrodon sp. (Labridae) and Stelliferinae (Sciaenidae) are the first respective records for the southeast Pacific Ocean, Sarda sp. (Scombridae) represents the first fossil record for South America, Semicossyphus sp. (Labridae) and Anisotremus sp. (Haemulidae) are the first respective records for the Southern Hemisphere. Gymnosarda sp. (Scombridae) is described for the first time for the Neogene. We performed a paleobathymetric analysis of fossil fishes, including elasmobranchs, to understand the paleoenvironment followed by a similarity analysis that compares the faunal composition of the Bahía Inglesa Fm. with other fossil assemblages for the Pacific of South America. Our results show that the fish fauna from the Bahía Inglesa Fm. likely represents a depth range of 98 to 382 m with a mean depth range of 252 m in an uppermost bathyal environment. The assemblage from the Bahía Inglesa Fm. shows low taxonomic similarity levels with other Neogene geological units from the southeast Pacific Ocean. The study represents the first paleoecological and paleobiogeographic analysis of the fossil fish fauna from the Southeast Pacific. [ABSTRACT FROM AUTHOR]

Relationships between fish length and otolith length, width and mass were examined in the Australian anchovy Engraulis australis (White, 1790) recovered from the food of Gannet examined from colonies at islands of Horuhoru Rock and Mahuki Islands in the Hauraki Gulf, New Zealand. The relationships between otolith length-fish total length (TL), otolith-weight-TL, and otolith-width-TL were investigated by means of non-linear regression models (TL = 0.54 OL 16.86, TL = 4.39 OW 7.61 and TL = 26.19 OWe 2.2). This study characterizes the first reference available on the relationship of fish size and otolith size and weight for E. australis obtained from bird's food in the Pacific Ocean region. [ABSTRACT FROM AUTHOR]

Tenualosa ilisha is a popular anadromous and significant trans-boundary fish. For sustainable management and conservation of this fish, drawing an appropriate picture reflecting population status of this species is very essential based on their all-strategic habitats in Bangladesh. In this study, 139 samples from 18 sites were collected and cross-species gene enrichment method was applied. Like most of the Clupeiforms, nucleotide diversity of this shad was very low (0.001245–0.006612). Population differences between most of the locations were low and not significant (P > 0.05). However, P values of a few locations were significant (P < 0.05) but their pairwise FST values were very poor (0.0042–0.0993), which is inadequate to recognize any local populations. Our study revealed that the presence of a single population in the Bangladesh waters with some admixtured individuals, which may contain partial genes from other populations. Most of the individuals were admixed without showing any precise grouping in the ML IQtree and Network, which might due to their highly migratory nature. Fishes from haors and small coastal rivers were not unique and no genetic differences between migratory cohorts. The hilsa shad fishery should be managed considering it as a single panmictic population in Bangladesh with low genetic diversity. [ABSTRACT FROM AUTHOR]

Fishery statistics are mainly made by recording the popular fish names, which is later translated into scientific identification. However, these names often either refer to a species group and/or vary along their distribution, increasing identification uncertainty. Species that have cultural value for traditional communities are known as culturally important species (CIS). Herein, we assessed Fishers' Ecological Knowledge to investigate small-silvery herrings (ginga) used as part of a traditional dish "ginga com tapioca", that is recognized as a cultural heritage in the Brazilian northeastern. Through 103 interviews conducted in six communities in three states, we determined that ginga, although a name known elsewhere, is only traded as such in the metropolitan area of Natal. In this region, ginga is caught with drift net and deemed profitable by fishers. We identified both over- and under-differentiation, with ginga recognized by fishers as five, and sold as three main species, namely Opisthonema oglinum, Harengula sp., and Lile piquiting. The larger specimens of two of those species (O. oglinum and Harengula sp.) were also traded as sardines. We found that most individuals sold as ginga were juveniles, which might impact the recruitment of some fish species. Due to its unique cultural relevance to the local community of Natal, ginga could be considered a CIS, which could aid future management or conservation measures. [ABSTRACT FROM AUTHOR]

Mangaluru coast, Southwest coast of India has vast aquatic bio-resources and offers considerable scope for marine fisheries development. The present investigation was carried out to assess the ichthyofaunal diversity off Mangaluru coast, Karnataka, India (Lat.12°50'54" N; Long. 74°50'11" E). The data for the study was collected from 160 multiday trawlers operating from Mangaluru fishing harbour during September, 2012 to April, 2013. A total of 97 species belonging to 72 genera, 50 families and 15 orders were recorded. Order Perciformes was the most diversified group having 56 fish species (57.7 %) followed by Clupeiformes 14 fish species (14.4 %), and Tetraodontiformes and Pleuronectiformes with 4 fish species each (4.1 %). The family Carangidae contributed 13.4 per cent of total number of species, followed by Clupeidae (6.2 %) and Engraulidae (5.2 %). Trichiurus lepturus contributed 15.42 per cent of total landing followed by Sardinella longiceps (12.1 %), Nemipterus japonicus (10.7 %), Decapterus russelli (9.9 %), Rastrelliger kanagurta (9.6 %) and Nemipterus randalli (8.4 %). The overall cluster analysis of the Bray-Curtis similarity (hierarchical clustering) shown that maximum similarity (89.7 %) was between March-2013 and April-2013. The study showed that the samples from adjacent months were having more similarity in species composition and abundance. The stress value, which overlying on the MDS plot (0.06), showed greater extent of ordination in the collected samples. [ABSTRACT FROM AUTHOR]

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.

Wolf herrings (Chirocentridae; Clupeoidei) are commonly found in local fish markets throughout the Indo‐West Pacific region where they constitute an auxiliary source of food and income for local communities. The validity of the two species of wolf herrings, Chirocentrus dorab Forsskål, 1775 and C. nudus Swainon, 1839, is only supported by slight morphological differences. The identification of either species is challenging, especially for juveniles, and precludes accurate assessments of these natural resources at a species level. As a step towards gaining better knowledge of the genetic structure of these fishes, we examined genetic differentiation between these two species by reconstructing their entire mitogenomic sequences using high‐throughput sequencing technology. We found that the mitogenome of each species shared the same gene content and order that were the same for those found in most other teleost fishes. Despite their high morphological similarity, these two species of Chirocentrus were genetically well differentiated (p‐distance = 16.3% at their cytochrome oxidase I). A mitogenomic time‐calibrated phylogenetic analysis showed that wolf herrings originated about 35 million years ago, and they represent a case of morphological stasis. Furthermore, comparison of published and newly determined mitochondrial COI barcode region sequences from 22 individuals revealed species‐level cryptic genetic diversity within C. dorab. Altogether, these mitochondrial data are effective in discriminating species within this genus and informing population genetic relationships within species of wolf herrings. [ABSTRACT FROM AUTHOR]

The interpretation of δ13C values in trophic ecology requires standardization of the lipid content of organisms estimated through their C:N ratio. To avoid time-consuming lipid extractions, the use of mathematical corrections has been developed for many years, and the conclusions generally point in the direction of species-specific adjustment of the models. This study aimed at defining the maximum taxonomic level required to obtain the best corrected δ13C values in small pelagic fish of the order Clupeiformes. δ13C values of six species were analyzed bulk and lipid-free, and were used to fit and validate linear and mass-balance models at different taxonomic levels. Despite a species effect combined with the C:N ratio effect, the corrected δ13C values produced by a global model for the Clupeiformes were as good as or better when compared to lipid-free samples than those produced by species-specific models, paving the way for possible generalization to other species in this order. At the order level, the linear model outperformed the mass-balance model. • Changes in δ13C values following lipid removal depend on bulk C:N ratio and species. • Corrected δ13C values from linear and mass balance models were similar. • Linear lipid correction model can be applied at the Clupeiforme order level. • Clupeiforme order has an average lipid-free C:N ratio of 3.1 [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Shads of the genus Alosa are essential to commercial fisheries across North America and Europe, but in some areas their species boundaries remain controversial. Traditional morphology‐based taxonomy of Alosa spp. has relied heavily on the number of gill rakers and body proportions, but these can be highly variable. We use mitochondrial (mt)DNA (coI and cytb) and genome‐wide single nucleotide polymorphisms (SNP) along with morphological characters to assess differentiation among endemic Ponto‐Caspian shads in the Sea of Azov. Morphological species assignments based on gill‐raker number were not congruent with genetic lineages shown by mtDNA and SNPs. Iterative analysis revealed that genetic lineages were associated with sampling location and several other morphometric traits (caudal peduncle depth, pre‐anal length and head length). Phylogenetic analysis of the genus placed Ponto‐Caspian Alosa spp. in the same evolutionary lineage as endangered Alosa spp. endemic to Greece, highlighting the importance of these findings to conservation management. We conclude that gill‐raker number is not reliable for delimiting species of Alosa. This taxonomic uncertainty should be addressed by examining type material to provide a robust integrative classification for these commercially important fishes. [ABSTRACT FROM AUTHOR]

This study records the occurrence of a hermaphrodite individual of the apapá Pellona flavipinnis captured in a floodplain area of the Amazon River. Histology of the left gonad revealed the presence of testicular germ cells (spermatocytes and spermatozoa) in the cranial portion and mature ovarian cells (primary and vitellogenic oocytes) in the caudal portion, separated by connective tissue. This is the first record of a hermaphrodite fish of the family Pristigasteridae, order Clupeiformes. [ABSTRACT FROM AUTHOR]

Migration is a widespread phenomenon among animals and has a profound influence on the evolution of species traits. Diadromous fishes provide an extreme example of migration, moving between marine and freshwaters, often travelling thousands of kilometres for feeding and reproduction. Diadromy has been linked to changes in feeding ecology, body size and various life-history attributes. However, most studies have focused on intraspecific variation and associated mechanisms. In this study, we use phylogenetic comparative methods to analyse body size and trophic position across Clupeiformes (anchovies, herring, shad and allies), a large clade of fishes that includes both diadromous and non-diadromous species. We found that diadromous species are larger than non-diadromous species, but there is no difference in trophic position, and that these patterns are not attributable to common ancestry. Diadromous species show a decoupling of body size and trophic position, whereas non-diadromous clupeiforms have a positive relationship between body size and trophic position. Using a model-fitting approach, we detected a signal of strong selection driving diadromous fishes to different adaptive peaks from non-diadromous fishes for body size, but a single adaptive peak for trophic position. We suggest that diadromous fishes have evolved larger body size than obligate marine and freshwater species as an adaptation to maximize energy expenditure during long-distance migration. [ABSTRACT FROM AUTHOR]

Background. The poorly known anchovy Stolephorus nelsoni Wongratana, 1987 (Engraulidae), previously known only from the type specimens from Australia, is redescribed and its validity confirmed, on the basis of the holotype, paratype, and 15 additional specimens from Indonesia and Australia. Similar to Stolephorus brachycephalus Wongratana, 1983 in sharing the maxilla reaching more or less to the posterior border of opercle, a predorsal-fin scute absent and the preopercle rounded, the specific distinctiveness of S. nelsoni and differences between the two species have remained unclear. This study sought to confirm the validities of the two species and the distributional range of S. nelsoni. Materials and methods. Seventeen and 9 specimens of S. nelsoni and S. brachycephalus, respectively, including the holotype of each, were examined morphologically, counts and proportional measurements following Hata and Motomura (2017). Results. Comparisons of S. nelsoni with S. brachycephalus revealed the former to have 12-14 (mode 13) branchiostegal rays [vs. 10-11 (11)], 15-17 branched anal fin rays [vs. 20-22 (20)] and relatively fewer gill rakers [37-43 (39, 40) on the first gill arch vs. 35-37 (35)]. Stolephorus nelsoni also differed from S. brachycephalus in body depth [21.7%-23.7% (mean 22.6%) of standard length vs. 18.2%-20.3% (19.1%)], anal-fin base length [16.1%-19.3% (17.6%) vs. 21.6%-24.4% (23.2%)], caudal-peduncle length [15.7%-21.7% (18.8%) vs. 12.6%-15.2% (14.1%)] and snout length [4.5%-5.5% (5.1%) vs. 3.6%-4.3% (4.0%)]. Conclusion. The validities of both species were confirmed, Indonesian examples of S. nelsoni being the first known records of the species outside Australian waters. [ABSTRACT FROM AUTHOR]

The anchoveta (Engraulis ringens) and sardine (Strangomera bentincki) are coastal pelagic species with important spawning areas off the coast of Chile. The discharge of secondary-treated effluents from a kraft pulp plant near one of these spawning areas has raised environmental concerns. Therefore, effluent effects on the development of anchoveta and sardine eggs were assessed by in vitro exposure. Eggs were sampled between 2007 and 2010 off Talcahuano, Chile. Subsequent toxicity tests (96 h duration, 12 °C) were performed using increasing effluent concentrations, a filtered seawater control, and two potassium dichromate concentrations (to verify consistent embryonic sensitivity). Egg mortality and hatching success were evaluated. For anchoveta, mortality (9.9 ± 7.1%) did not significantly differ among groups in five toxicity tests except the final toxicity test that showed significant differences in mortality (5.6% control vs 27.8% in 100% effluent). For sardines, no differences in mortality existed between the effluent dilutions (2.6 ± 3.6%) and control (6.3 ± 3.9%). Notably, anchoveta egg survival and hatching success rates were inconsistent, i.e., the highest rates of hatching failure occurred on the same sampling date with the highest rates of survival for the 100% effluent group (72%). In conclusion, the obtained results indicate that (i) anchoveta egg mortality and hatching failure increase only under 100% effluent exposure, coinciding with decreased egg quality near the end of spawning season and (ii) high effluent dilutions not significantly increase sardine and anchoveta egg mortalities. Nevertheless, the recorded adverse effects to the hatching process should be studied in greater detail, particularly considering interspecific variability and the complexity of reproductive processes, especially during early development. [ABSTRACT FROM AUTHOR]

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Stolephorus continentalis sp. nov. is described from 36 specimens from Hong Kong and northern Vietnam. The new species is closely related to the endemic Chinese anchovy S. chinensis (Günther 1880), which is redescribed with a lectotype designated, with both species having a long upper jaw with the posterior tip just reaching to the posterior border of the preopercle; no predorsal scute; the posterior preopercular border rounded, convex; the posterior tip of the depressed pelvic fin not reaching to vertical through dorsal-fin origin; a pair of dark patches behind the occiput without a following pair of dark lines; and no black spots below the eye and lower-jaw tip. However, the new species is distinguished from S. chinensis in having higher total gill-raker counts on the first, second, third, and fourth gill arches (43-48, 33-40, 23-26, and 18-21, respectively vs. 35-41, 29-34, 19-24, and 16-19), and longer pectoral (16.5-19.2 % SL vs. 15.8-16.4 %) and pelvic fins (9.1-11.6 % SL vs. 8.2-8.3 %). Examination of the specimens previously considered as S. chinensis from Southeast Asia revealed that they differed from true S. chinensis and S. continentalis in having eight transverse scales (vs. 10 in the latter two species). The applicable scientific name for the Southeast Asian species is suggested here as Stolephorus oceanicus Hardenberg 1933. [ABSTRACT FROM AUTHOR]

Anchoviella hernanni sp. nov. is described from the upper Amazon River basin, in tributaries of the Marañon, Ucayali and Madre de Dios river drainages that drain the Peruvian Andes. The new taxon can be distinguished from all congeners except Anchoviella jamesi, Anchoviella manamensis and Anchoviella perezi, by having 12–15 gill rakers in the lower branch of the first gill arch (v·16–35) and from those species by the distance between verticals through the posterior margin of the orbit to the posterior margin of the upper jaw 9·5–14·8% head length; LH (v. up to 6·0% LH). An updated identification key of all freshwater species of Anchoviella and morphological comparisons between all species of the genus occurring in Peru are provided. [ABSTRACT FROM AUTHOR]

The anchovy, Engraulis ringens, is an economically valuable fish, and the most heavily exploited resource in the Humboldt Current System. To analyze its genetic structure and diversity, microsatellite markers were developed using 454 pyrosequencing. A total of 27,352 reads containing di-, tri-, tetra-, penta-, and hexanucleotide microsatellite repeat units were identified from 136,537 reads. Among 80 loci containing more than six repeat motifs, 32 primer sets (40%) produced reproducible PCR products, and all of these loci were polymorphic. Some loci showed deviations from HWE and possible null allele's presence, results of an excess of homozygotes. In an analysis of 45 individuals from one E. ringens population, the number of alleles per locus ranged from 2 to 33, observed heterozygosity ranged from 0.171 to 0.976, and the probability of identity values ranged from 0.006 to 0.513. These microsatellites will be useful for numerous ecological studies focused on this important pelagic fish; including the examination of population genetic structure, estimating effective population size and providing information for fisheries management. [ABSTRACT FROM AUTHOR]

The Coilia nasus is an important fish species, which is of commercial values in China. In order to manage the fisheries resources and the development of sustainable fishing strategies to protect this species, 11 microsatellite loci polymorphisms and mtDNA COI sequences were used to examine the genetic diversity of C. nasus in Japan and China. In total, the 40 COI haplotypes and 93 microsatellite alleles were detected. The mtDNA phylogeny did not support population grouping, but the distribution patterns of mtDNA haplotypes and the results of STRUCTURE analysis based on microsatellite indicated a degree of genetic isolation in this species. Our study suggested that the lack of a population genetic structure might result in its amphidromous life cycle, and the geographical distance and habitat fragments might cause isolated populations. Thus, the sampling populations of C. nasus in Japan and China could be divided as four geographical/ecological populations. [ABSTRACT FROM AUTHOR]

Otolith microchemistry allows reconstructing the life histories and understanding the habitat uses of fishes. In this study, the relationship of Sr:Ca ratios and salinity from various environments, i.e. freshwater of the Min River, brackish water of the estuary and seawater of the coastal marine (Fujian Province, China), were built, revealing a significant positive correlation (p < 0.05). A total of 29 adult Chinese gizzard shad Clupanodon thrissa were collected in 2017–2020 for otolith (sagitta) microchemistry. The specimens were only collected from the Min River and the estuary, with none from the coastal marine regions despite same efforts input. The results confirmed that all 29 individuals hatched in either freshwater or brackish water. Four contingents were recognized based on various life histories, including three migratory contingents (Types A-C, N = 26) and one freshwater residential contingent (Type D, N = 3). The three migratory contingents were the freshwater-brackish migratory contingent (Type A, N = 12), the brackish-freshwater migratory contingent (Type B, N = 10) and the brackish-variable migratory contingent (Type C, N = 4). Only a small proportion of C. thrissa individuals (N = 4) migrated to seawater habitat during the first few months of lifetime, and most individuals preferred freshwater habitat during the first year. There were no significant differences between life history pattern and sex (p = 1.00), and between the number of fish migratory times crossing different habitats and age (p = 0.84). The lower reaches of the Min River and the estuary are confirmed to be important spawning grounds for C. thrissa , based on otolith microchemistry of this study and gonad histology of a previous examination. The findings have significant implications for the Min River and the estuary protection and fishery stock management. [ABSTRACT FROM AUTHOR]

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.