Search Results (44)

Madagascar harbors a rich marine biodiversity, yet detailed knowledge of its fish species remains limited. Of the 1689 species listed in 2018, only 22% had accessible cytochrome oxidase I (COI) sequences in public databases. In response to growing pressure on fishery resources, this study aims to strengthen biodiversity monitoring tools. Its objectives were to enrich the COI database for Malagasy marine fishes, create the first 12S reference library, and evaluate the taxonomic resolution of different 12S metabarcodes for eDNA analysis, namely MiFish, Teleo1, AcMDB, Ac12S, and 12SF1/R1. An integrated approach combining morphological, molecular, and phylogenetic analyses was applied for specimen identification of fish captured using various types of fishing gear in Toliara and Ranobe Bays from 2018 to 2023. The Malagasy COI database now includes 2146 sequences grouped into 502 Barcode Index Numbers (BINs) from 82 families, with 14 BINs newly added to BOLD (The Barcode of Life Data Systems), and 133 cryptic species. The 12S library comprises 524 sequences representing 446 species from 78 families. Together, the genetic datasets cover 514 species from 84 families, with the most diverse being Labridae, Apogonidae, Gobiidae, Pomacentridae, and Carangidae. However, the two markers show variable taxonomic resolution: 67 species belonging to 35 families were represented solely in the COI dataset, while 10 species from nine families were identified exclusively in the 12S dataset. For 319 species with complete 12S gene sequences associated with COI BINs (Barcode Index Numbers), 12S primer sets were used to evaluate the taxonomic resolution of five 12S metabarcodes. The MiFish marker proved to be the most effective, with an optimal similarity threshold of 98.5%. This study represents a major step forward in documenting and monitoring Madagascar’s marine biodiversity and provides a valuable genetic reference for future environmental DNA (eDNA) applications. Full article

To investigate the species composition, reproductive dynamics, and hydrological drivers of fish resources in the early stage in the Guiping section of the Xunjiang River, we conducted a two-year survey (2022–2023) downstream of the Datengxia Dam. A total of 22,464 fish eggs and larvae were collected, representing 6 orders, 17 families, and 67 species, with Cyprinidae (58.2%) as the dominant family. Dominant species included Squaliobarbus curriculus, Gobiidae, Hemiculter leucisculus, and Culter, exhibiting significant interannual variation in abundance. The breeding season peaked from May to September, accounting for 94.6% of annual recruitment. Hydrological conditions strongly influenced reproductive output: the multiple flood pulse periods in 2022 (peak discharge: 29,000 m³/s) yielded 34.997 billion eggs and larvae, whereas reduced flows in 2023 (peak discharge: 12,200 m³/s) led to a 75.4% decline (8.620 billion). Redundancy analysis (RDA) revealed that discharge, water temperature, natural hydrological data, and dissolved oxygen were the primary environmental drivers, explaining 46.11% of variability in larval abundance (p < 0.001). Notably, the proportion of important economic fish, “four major Chinese carps”, plummeted from 4.9% (2022) to less than 0.1% (2023), indicating spawning ground function degradation. Our results demonstrate that flood pulses are essential for sustaining fish recruitment, particularly for pelagic spawning riverine fish like the four major Chinese carps. Their proportion plummeted to less than 0.1% in 2023, highlighting the urgent need for eco-hydrological management in the Xunjiang River. Full article

Parental care increases offspring survival but is typically costly to the parent providing it. Understanding diversity in parental care across animals is a timely topic in evolutionary ecology. Fishes are particularly well suited for studies aimed at understanding the diversity of parental care because parental care in fishes is highly variable across species. In most fish species, no care is provided. When parental care is provided, it is often paternal, although biparental and maternal care occur in some fish species as well. Parental care in fishes ranges from simple guarding of eggs in a territory to prolonged care of young after hatching. Within fishes, gobies are thought to exhibit diverse parental care. In the current manuscript, we begin to synthesize our knowledge of patterns of parental care in gobies by providing a review of the parental care strategies that are exhibited by gobiid species. Our review reveals that parental care in gobies most often includes guarding, fanning, and cleaning, although some species engage in other types of care such as larval release, the production of antimicrobial substances, and the construction of post-mating mounds. Care in gobies is most often paternal, but maternal and biparental care have been documented in some species. Full article

Fish-borne parasites encompass diverse taxonomic groups, including nematodes of the genus Eustrongylides (family Dioctophymatidae), which infect fish, fish-eating birds, and, occasionally, humans. Eustrongylides spp. are globally distributed, with E. ignotus and E. tubifex prevalent in North America, while E. excisus is more frequent in Europe and the Middle East. This study investigates the presence of E. excisus in a fish community of the Po River (Turin, northwest Italy). Among 170 fish sampled from three sites along the Po River, only two Padogobius bonelli individuals from the Murazzi site were found to be infected, each hosting a single larva within the abdominal cavity. Molecular analysis (ITS rDNA sequencing) confirmed the parasite as E. excisus, showing 100% identity with known sequences. Although prevalence in this study was low (1.18%), the findings significantly expand the known host range of E. excisus, previously reported only in other gobiid species in Eastern Europe. The parasite is widely distributed in Italy, especially in commercial fish from large lakes, and its spread is facilitated by oligochaete intermediate hosts and piscivorous birds like cormorants. Given the benthic habits and diet of P. bonelli, increased monitoring is needed to better understand the parasite’s transmission dynamics and the potential risks to native biodiversity and human health. Full article

Filial cannibalism is the consumption of one’s own viable progeny. It occurs in a range of taxa but is particularly well-documented in fish species. Since parental care in fishes is typically male-biased, it is usually assumed that filial cannibalism is predominantly performed by the parental male while he is providing care to offspring. Filial cannibalism by females is less studied in fish. Video-recorded observations of ten pairs of adults housed in captivity revealed the first documentation of female filial cannibalism in the redhead goby (Elacatinus puncticulatus). Females were observed consuming both their own eggs and larvae. We discuss non-adaptive and adaptive explanations for female filial cannibalism in the redhead goby, including confinement due to captivity, nutritional or energetic need, and a possible lack of kin recognition. Understanding the evolutionary significance of filial cannibalism exhibited by females is an important biological inquiry. Since the redhead goby is a species used in the aquarium trade, understanding the conditions that influence female filial cannibalism in captivity may yield practical implications. Full article

Surf zones are important nursery grounds for fish larvae and juveniles. However, little is known about fish larvae and juveniles in the surf zone along the coast of Jiangsu Province. To describe the species composition of fish larvae and juveniles, monthly collections were conducted at eight stations during the spring tide from February 2024 to January 2025. The fish larvae and juveniles were sampled using a seine net (1m × 4m; 1 mm mesh aperture), with sampling repeated three times at each station per month. A total of 1435 fish larvae and juveniles were collected, belonging to 42 species and 37 genera in 21 families. Almost half of them were postflexion larvae. Gobiidae, with 14 species, was the most diverse family. Based on the index of relative importance (IRI) result, the dominant species was Amoya pflaumi, accounting for 35.33% of the total number of individuals collected. Common species were Mugil cephalus, Amblychaeturichthys hexanema, Tridentiger trigonocephalus, Acanthogobius ommaturus, Mugilogobius abei, Thryssa mystax, Periophthalmus modestus, Sillago sihama, and Mugilogobius myxodermus. All other species were classified as rare. No fish larvae or juveniles were collected in February 2024 and January 2025. The species number, catch per unit effort (CPUE), Margalef’s richness index, Pielou’s evenness index, and Shannon–Wiener diversity index showed similar trends, and significant differences could be found for each parameter among sampling months. The cluster analysis from the ten months (excluding February 2024 and January 2025) indicated a significant seasonal change in the community structure of fish larvae and juveniles. Fish larvae and juveniles were abundant and diverse at one station near an aquaculture tidal flat for seaweed. This study provides essential basic data to support the management and conservation of fishery resources in the surf zone along the coast of Jiangsu Province. Full article

In the late Cenozoic, the south-west of Eastern Europe was a region affected by extensive hydrological transformations that resulted in the retreat of the Eastern Paratethys and the emergence and further evolution of freshwater communities. In recent decades, a relatively rich fossil actinopterygian fauna has been described from this area. The present study was based on previous systematic studies and aimed to assess and trace the temporal dynamics of the diversity of fish assemblages that existed in the area from the Late Miocene until the end of the Pleistocene. Species diversity, taxonomic diversity, taxonomic complexity, and functional diversity were analysed. It was found that the diversity of the fish assemblages notably decreased during the Late Miocene, when representatives of the families Clariidae, Moronidae, Sciaenidae, and Gobiidae disappeared, and remained relatively low during the Pliocene. During the Pleistocene, however, functional diversity gradually increased, despite fluctuating species and taxonomic diversity and taxonomic richness and complexity, which suggests an increasing stability of the coenotic structure within the fish communities. The revealed temporal trends reflect the impact of the palaeoenvironmental and palaeoecological processes that characterised the region during the late Cenozoic, particularly orogenic and climatic changes, and the evolution of a typical limnophilous, lacustrine-riverine fish fauna. Full article

The seasonal and interannual temporal variation in the composition, richness, diversity, and similarity of fish larval assemblages associated with an Eastern Tropical Pacific (ETP) coral reef system was studied in March (cold water) and September (warm water) during the years 2017, 2018, and 2019. Throughout the study period, we collected 4779 fish larvae and identified 88 taxa, encompassing 46 families. This increased the total number of recorded fish taxa for the region to 146. Fish larvae were collected by daytime and nighttime surface trawls, using a bongo net 30 cm in diameter and 180 cm in length, equipped with mesh sizes of 300 and 500 μm. The species diversity and abundance of ichthyoplankton over this ETP coral reef changed by intra-annual variation of the hydrological conditions of the upper layer of the sea. Six significant assemblages were identified (SIMPROF, p < 0.05), each one associated with each sampling period (ANOSIM, R = 0.764); Cetengraulis mysticetus, Diaphus pacificus, Anchoa sp., Anisotremus sp., Bremaceros bathymaster, Oligoplites saurus, Caranx sp., Seriola sp., Gobiidae sp., Microgobius sp., and Synodus evermanni were the species that contributed to dissimilitude between groups. Canonical correspondence analysis revealed significant associations between specific larval fish taxa abundance and temperature, salinity, dissolved oxygen, and zooplankton biomass. Overall, the assemblage of ichthyoplankton in this ETP coral reef system is sensitive to seasonal changes in water column hydrographic conditions. Full article

A large sample of 65 individuals of the recently described goby Zebrus pallaoroi was collected in France. The species identity of these individuals was confirmed based on morphology. In addition, the species identity was validated through genetic analysis for one of the two specimens collected from the new depth records for the species. The diagnostic characters of Z. pallaoroi, originally based on a limited number of type specimens, were tested on this larger sample and critically analyzed. The diagnostic characters of Z. pallaoroi were revised, and recommendations were made for improving the study of diagnostic characters in gobiid species description, particularly when based on small sample sizes. The record of Z. pallaoroi in the western Mediterranean significantly expands its known geographic range, increases the maximum recorded depth of the species, and reveals syntopic co-occurrence with its phylogenetically closest relatives. Full article

To describe the species composition of fish larvae and juveniles in the Nanji Islands, monthly collection was conducted at 12 stations around the Nanji Islands from March 2023 to February 2024 by using horizontal tow at the surface layer. The fish larvae and juveniles were collected by a larva net (1.3 m mouth diameter, 0.5 mm mesh aperture). A total of 6446 fish larvae and juveniles were collected, belonging to 59 species and 54 genera in 11 families. Most of them were preflexion larvae (93.31%). Gobiidae, with eight species, was the most diverse family. Based on the index of relative importance (IRI) result, the dominant species was Sebastiscus marmoratus (Cuvier, 1829), accounting for 84.52% of the total number of samples collected. The common species were Stolephorus commersonii Lacepède, 1803; Omobranchus elegans (Steindachner, 1876); Nibea albiflora (Richardson, 1846); Parablennius yatabei (Jordan & Snyder, 1900); Lateolabrax maculatus (McClelland, 1844); and Odontamblyopus lacepediiand (Temminck & Schlegel, 1845). Other species were all rare species. The highest species number was in September (18 species), and the highest density was in December. Only one fish larva was collected in April. Pielou’s evenness index was highest in November, while Margalef’s richness index and Shannon–Wiener diversity were highest in September. The result of cluster analysis showed that the 11 months (except April) could be divided into four groups. The species number, density, and three diversity indexes showed no significant correlation with temperature and salinity. Full article

Telemetry techniques are important tools in freshwater fish ecology but are limited by the size of the fish in relation to the size of the electronic tags. The emergence of very small PIT tags (8 mm, mini PIT tags) opens the door to study the individual movement and behavior of small-sized fish species and life stages previously outside the scope of fish telemetry. Although high survival from mini PIT tags have been shown in some groups of fish, suitability assessments are lacking for many taxa, and potential behavioral effects have rarely been evaluated. Here, we evaluate the survival tagging effects in small-sized (35–76 mm) Padanian goby (Padogobius bonelli) implanted with mini PIT tags. PIT-tagging was associated with high survival and tag retention in the tagged fish. No effects of PIT-tagging on volitional swimming activity nor on maximum swimming speed were found. Similar results were obtained implanting larger tags (12 mm) in gobies down to 50 mm in length. Our results indicate that PIT telemetry—using mini PIT tags—is applicable for the study of behavior and movement in small-sized gobies. Full article

Coastal environments, such as bays, are essential to the development of fishery resources due to their economic and ecological importance. This paper presents an updated checklist of coastal marine fishes as part of a long-term monitoring program in Aratu Bay (2014–2024), Bahia state, eastern Brazil. A total of 109 species belonging to 58 families and 24 orders were cataloged. Five endemic species and ten species listed as at risk according to the IUCN criteria (from Vulnerable onwards) were identified. The Carangidae was the most representative family in terms of species number, followed by Gobiidae and Sciaenidae. The ichthyofauna was dominated by mobile invertebrate feeders and macrocarnivores. Two non-native species were observed in the region: the Muzzled blenny, Omobranchus sewalli and the mud sleeper Butis koilomatodon. Aratu Bay supports a diverse ichthyofauna with diverse trophic guilds and habitats, rendering it an important area for the feeding and development of economically valuable species, including those facing threats. Full article

Estuaries are crucial fish nursery habitats owing to their high productivity and the presence of various microhabitats for the early development of aquatic organisms. This study investigated the temporal and spatial patterns of the species composition and abundance of larval fish assemblages in the Nakdong River estuary, South Korea, through bi-monthly sampling in the inner and outer estuaries. Fifty-five larval taxa were collected, and the larval fish assemblages were dominated by a few species. Engraulis japonicus (28.8%) was the most abundant, followed by Gobiidae sp.1 (22.6%), Clupea pallasii (13.9%), and Omobranchus sp. (6.1%). The species richness, abundance, and diversity tended to be higher during the warm season in the inner estuary. Multivariate analyses revealed that the structures of larval fish assemblages were significantly influenced by the season and site. Spatial and seasonal changes in larval fish assemblages resulted from the different occurrence patterns of common fish larvae in relation to water temperature and salinity. Among the predominant fish larvae, E. japonicus was captured more frequently in more saline outer estuaries during the warm season, whereas Gobiidae sp.1 and C. pallasii were more abundant in less saline inner estuaries during the warm and cold seasons, respectively. The results of this study improve our understanding of larval biodiversity in estuarine habitats in relation to environmental modification and contribute to the evaluation of nursery functions in the Nakdong River estuary. Full article

The Yellow River Estuary and its adjacent waters serve as crucial spawning, foraging, and nursery areas for marine organisms, possessing abundant biological resources. Monitoring fish communities provides a baseline for implementing the sustainable utilization of marine resources. In this study, data were collected from 15 spring surface and bottom sites and 17 summer surface sites using eDNA and trawl surveys. The results showed that 37, 40, and 35 fish species were detected using eDNA in the spring (surface and bottom) and summer (surface), respectively, with 38 fish species caught during summer trawling. The dominant species mainly belonged to Engraulidae of Clupeiformes in the spring and Gobiidae of Perciformes in the summer, characterized by smaller-sized, short-lived, and pelagic fish species. The summer surface communities exhibited higher diversity than the spring surface and bottom communities. NMDS analysis revealed a degree of seasonal differences in fish communities and that there may be a lack of vertical stratification in the spring communities. The pH and DO were identified as the key environmental factors affecting the fish community. Additionally, the combination of eDNA and trawl surveys was regarded as a superior survey method. Our study provides valuable information for understanding seasonal fish communities in the Yellow River Estuary and its adjacent waters, contributing to fishery resource management and conservation in the region. Full article

We sequenced and analyzed the complete mitochondrial genome of Lentipes ikeae and explored the phylogenetic relationships among Sicydiinae based on mitochondrial genome sequences. The complete mitochondrial genome sequence of L. ikeae was determined using the Illumina HiSeq X Ten sequencing platform, and the gene structural characteristics and base composition were analyzed. Based on the mitochondrial genome sequences of 28 Sicydiinae species published in GenBank and mitochondrial protein-coding genes (PCGs), Acanthogobius flavimanus (Gobionellinae) was selected as an outgroup to construct phylogenetic trees of Sicydiinae using the maximum likelihood and Bayesian inference methods. The mitochondrial genome of L. ikeae (GenBank number: OP764680) has a total length of 16,498 bp and encodes 13 PCGs, 22 transfer RNA genes, two ribosomal RNA genes, and a D-loop (control) region. Gene rearrangement is not observed. The mitochondrial genome of L. ikeae exhibits an AT preference, with AT skew > 0 and GC skew < 0 across the entire genome. The phylogenetic relationships of Sicydiinae based on 13 mitochondrial PCG sequences are Sicydium + (Stiphodon + (Sicyopus + Lentipes)) + Sicyopterus, indicating that Sicydium, Sicyopterus, Lentipes, and Stiphodon are all monophyletic groups. Full article