Search Results (29)

Nursery habitats sustain fish populations by supporting early life stages and buffering environmental variability, yet their functioning under climate oscillations remains poorly understood in the Eastern Tropical Pacific. We analyzed ichthyoplankton assemblages in the Gulf of Tortugas, Colombia (2010–2020), to assess taxonomic composition, spatiotemporal variability, and environmental drivers. ENSO cycles and local oceanographic conditions were evaluated as determinants of nursery function and resilience using richness estimators, diversity indices, Caswell’s neutral model, and multivariate approaches (PERMANOVA, PERMDISP, CAP, BIOENV). Assemblages were dominated by Cetengraulis mysticetus, with recurrent contributions from Sciaenidae, Haemulidae, Gerreidae, and Carangidae—families of artisanal fisheries importance. ENSO phases explained interannual variability: El Niño years reduced diversity and weakened retention, whereas La Niña years supported more balanced assemblages. Spatial heterogeneity revealed central retention zones and peripheral diversity hotspots. Environmental gradients, particularly chlorophyll-a, zooplankton biomass, transparency, and pH, consistently structured larval distribution, reflecting the coupling of productivity, water quality, and circulation. These findings demonstrate that the Gulf of Tortugas functions as a dual nursery system and ecological node of resilience, underscoring the importance of protecting such habitats for ecosystem-based fisheries management and biodiversity conservation in a changing ocean. Full article

An association of Blue runner, Caranx crysos (Carangidae), with two species of rays, Common stingray Dasyatis pastinaca (Dasyatidae) and Bull ray Aetomylaeus bovinus (Myliobatidae), in which an individual C. crysos (the follower fish) follows a foraging ray (the nuclear species), is described, based on a sample of 61 video clips. Follower fish show three types of behaviour: swimming under the pectoral fin of the nuclear ray, swimming above the mid-dorsal line of the nuclear ray and very close to it, or swimming above the ray and darting from side to side. The first two of these behaviours seem to be species-specific as the first is only shown when the nuclear ray is A. bovinus and the second when the nuclear ray is D. pastinaca. Following fish do not allow conspecifics to approach the nuclear ray but are mostly indifferent to non-conspecifics doing so. The following fish benefit from the association by feeding on prey disturbed by the foraging activities of the nuclear ray but the nuclear ray is unreactive to the following fish, suggesting that this is a case of trophic commensalism. Full article

Coral reef ecosystems are increasingly threatened by climate change, pollution, and overfishing, causing major declines in marine megafauna and high-trophic-level fishes. Monitoring these species is vital for conservation, yet traditional survey methods are slow and resource intensive. This study presents a semi-automated monitoring pipeline that integrates deep learning (DL) with human-in-the-loop validation to streamline Baited Remote Underwater Video (BRUV) analyses in the Gita Nada Marine Protected Area (MPA), Indonesia. A total of 244 BRUV deployments from SORCE’s long-term monitoring program in the Gita Nada MPA, comprising 328 h of footage, collected 2023–2025 under Indonesian research oversight through Yayasan SORCE Konservasi Indonesia, were processed using a DL workflow. To address long-tailed species distributions, focal taxa were grouped into six Morphological Groups and detected using a YOLOv12x model trained via transfer learning from the Community Fish Detector. A custom temporal-tracking framework extracted ecological metrics including N, Time to First Visit ($T_{1^{st}}$), and Visit Duration ($T_{visit}$). The pipeline achieved moderate to high detection and tracking performance for several Morphological Groups, achieving object detection F1-scores of up to 0.873 and an overall tracker recall and precision of 0.80 and 0.76, respectively, although performance varied substantially among groups and was substantially limited for data-deficient taxa. As a proof-of-concept, we applied the framework to assess ecological shifts in Cheloniidae and Carangidae across coral-cover gradients. Overall, this semi-automated approach reduces BRUV processing effort and provides a scalable foundation for generating the large datasets needed to detect subtle ecological change. Full article

The Mediterranean Sea is a biodiversity and climate change hotspot. The increase in seawater temperature affects marine ecosystems causing marine species to change their distribution and abundance. Such changes lead to alterations in community composition, often characterized by an increase in warm-affinity species over time, known as tropicalization of temperate seas. Monitoring programmes are useful for understanding the consequences of the ongoing transformations driven by ocean warming. In this study, underwater visual censuses (UVC) were conducted for fish and benthic communities at 24 stations of the Balearic Archipelago in 2022 and 2025. The comparison between both periods revealed an increase in the frequency of warm-affinity species, including the fishes Sparisoma cretense (Teleostea, Scaridae) and Caranx crysos (Teleostea, Carangidae); the invertebrates Telmatactis cricoides (Cnidaria, Actiniaria) and Hermodice carunculata (Annelida, Polychaeta, Amphinomidae) and the algae Penicillus capitatus (Chlorophyta, Ulvophyceae). Our findings highlight the importance of monitoring programmes to identify evidence of processes such as tropicalization and to provide timely information to respond to shifting marine ecosystems. Full article

The greater amberjack (Seriola dumerili) is a globally important aquaculture fish species belonging to the family Carangidae. However, current research on the ovarian development and regulation of the greater amberjack is limited, particularly with regard to early ovarian development in artificially bred individuals. Therefore, this study aims to analyze the ovarian transcriptomes at the primary growth stage in one-year-old fish at the chromatin nucleolar stage and two-year-old fish at the perinucleolar stage to suggest how early ovarian development takes place in artificially bred greater amberjacks. To do this, the study constructed ovarian mRNA expression profiles of different stages of artificially bred fish and identified differentially expressed genes (DEGs), Gene Ontology terms, and Kyoto Encyclopedia of Genes and Genomes pathways important for various physiological processes. A functional analysis revealed that the DEGs closely related to ovarian development were involved in cell growth and death (e.g., ccnd1, cdk1, cdc6, cdc25b, fbxo43, cdkn1a and cdkn1d), the TGF-beta signaling pathway (e.g., gdf6, bmpr1b, gsdf, amh, tgfb3, and smad6), steroid hormone biosynthesis (e.g., hsd3b1, hsd11b2, hsd17b12 and hsd20b2), and the endocrine system (e.g., mapk8a, mapk11, mapk12a, mapk13 and adcy9). These findings suggest that ovarian development is the result of the coordinated regulation of various genes responsible for various functions. This study provides a theoretical basis for exploring the underlying molecular mechanisms of early ovarian development in artificially bred greater amberjacks. Full article

C-type maneuvers (abbreviated as C-turns), a crucial escape response from for carangiform fish, are investigated to elucidate their yaw control mechanism. High-speed photography coupled with image processing was used to quantify the time-varying midline curvature during C-turns of adult zebrafish (Danio rerio). Self-propelled simulations replicated the motion, resolving the evolving vorticity field and pressure gradients. Statistical analyses revealed a pronounced linear correlation between body deformation and total turning angle for yaw angles exceeding 60°. Notably, large-angle turns (>140°) exhibited both higher initial speed and sustained greater mean speed throughout the maneuver, indicating that achieving substantial yaw not only relies on enhanced body deformation, but also, critically, on inertial dominance persisting throughout the unsteady hydrodynamic interaction. The vortex dynamics and pressure distributions obtained form simulations corroborate the inferred control strategy rooted in this inertial dominance. Full article

The marine fish genus Trachinotus (Carangidae: Trachinotinae) comprises species of considerable economic and ecological importance; however, a significant gap in genomic data has limited the understanding of its evolutionary history and systematics. To address this gap, we determined the complete mitochondrial genomes of two key species, Trachinotus goodei (Palometa) and Trachinotus mookalee (Indian Pompano). The mitogenome of T. goodei was sequenced from genomic DNA and assembled de novo, whereas the T. mookalee mitogenome was assembled by mining publicly available RNA-Seq data, demonstrating a cost-effective approach for expanding genomic resources. The resulting mitogenomes were 16,547 bp and 16,545 bp long, respectively, and both presented conserved gene content (13 protein-coding genes, 22 tRNAs, 2 rRNAs) and organization typical of teleost fishes. Phylogenetic analysis incorporating these new genomes with those of four other Trachinotus species was performed via a concatenated dataset of 13 protein-coding genes. Maximum likelihood and Bayesian inference recovered Trachinotus as a strongly supported monophyletic group. The phylogeny revealed a fundamental and deeply divergent split between three major clades, two comprising species from the western Atlantic and the other containing species from the eastern Atlantic/Mediterranean/Indo-Pacific. This robust biogeographic partition provides compelling evidence that allopatric speciation is a primary driver of diversification within the genus. Full article

This study presents, for the first time, the occurrence and community structure of wild fish inside marine aquaculture cages of gilthead seabream (Sparus aurata), European sea bass (Dicentrarchus labrax), greater amberjack (Seriola dumerili), meagre (Argyrosomus regius), and common dentex (Dentex dentex). Coexistence of farmed and wild fish was observed only in cages of gilthead seabream and European sea bass, with wild fish constituting 0.08% of the total sampled fish biomass. Twelve wild fish species from five families were recorded: Carangidae, Clupeidae, Mugilidae, Moronidae, and Sparidae. Bogue (Boops boops) and jack mackerel (Trachurus sp.) were the most abundant. Multivariate analysis indicated that location significantly influenced the wild fish community composition, while reared species and farming duration, along with their interaction, had no significant effect. Descriptive comparisons suggested potential differences in biometric traits of bogue and jack mackerel between reared species and farming duration. The findings highlight the need for further research on wild fish in cages to better understand the potential health and biosecurity risks they may pose. Full article

Estuaries are vital coastal ecosystems that support fish during key life stages such as spawning, feeding, and early development. This study investigates ichthyoplankton composition and abundance in the Sanquianga Tapaje estuarine system, located in the southern Eastern Tropical Pacific (ETP) of Colombia. Zooplankton samples were collected using bongo nets at 11 stations across four river mouths (Tapaje, Amárales, Sanquianga, and Guascama), alongside measurements of oceanographic parameters at 1 and 10 m depths. A total of 357 fish larvae were identified, representing 23 species and 11 families, with Engraulidae, Gobiidae, and Carangidae dominating the assemblage. Water column conditions reflected typical tropical estuarine dynamics, influenced by tidal action and freshwater input. Spearman’s rank correlation revealed strong positive associations between larval abundance and surface salinity (r_s = 0.81, p = 0.003), as well as dissolved oxygen saturation and concentration (r_s > 0.68, p < 0.021). Diversity indices (Shannon, Pielou, Whittaker) indicated high species turnover in transitional zones, and larval hotspots were associated with outer estuarine zones. Salinity and dissolved oxygen emerged as key drivers of ichthyoplankton distribution. These findings underscore the ecological complexity and nursery function of tropical estuaries, offering baseline data to inform biodiversity conservation, ecosystem monitoring, and adaptive management in Colombia’s Pacific region and across the ETP. Full article

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

This study offers an in-depth analysis of the mitochondrial genome of Selene dorsalis (Gill 1863), a species native to the Eastern Atlantic Ocean. The circular mitochondrial DNA molecule measures 16,541 base pairs and comprises 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA genes, and a control region (CR). The nucleotide composition exhibits a notable adenine-thymine (AT) bias, accounting for 53.13%, which aligns with other species in the Carangidae family. Most PCGs initiate with the ATG codon, with the exception of Cytochrome C oxidase subunit I, which starts with GTG. Analysis of relative synonymous codon usage reveals that leucine and serine are the most prevalent amino acids in the mitochondrial genome of S. dorsalis and its congeners (S. vomer and S. setapinnis). All tRNAs display the typical cloverleaf structure, though tRNA Serine (S1) lacks a dihydrouracil arm. Pairwise comparisons of synonymous and nonsynonymous substitutions for all PCGs yielded values below ‘1’, indicating strong purifying selection. The CR spans 847 bp, representing 5.12% of the mitochondrial genome, and is characterized by high AT content (62.81%). It is situated between tRNA-Pro (TGG) and tRNA-Phe (GAA). The CR contains conserved sequence blocks, with CSB-1 being the longest at 22 bp and CSB-D the shortest at 18 bp. Phylogenetic analysis, using Bayesian and Maximum-likelihood trees constructed from concatenated PCGs across 72 species, successfully differentiates S. dorsalis from other carangids. This study also explores how ocean currents and gyres might influence lineage diversification and parapatric speciation of Selene species between the Atlantic and Pacific Oceans. These results highlight the importance of the mitochondrial genome in elucidating the structural organization and evolutionary dynamics of S. dorsalis and its relatives within marine ecosystems. 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

To meet the requirements of amphibious exploration, ocean exploration, and military reconnaissance tasks, a pneumatic amphibious soft bionic robot was developed by taking advantage of the structural characteristics, motion forms, and propulsion mechanisms of the sea lion fore-flippers, inchworms, Carangidae tails, and dolphin tails. Using silicone rubber as the main material of the robot, combined with the driving mechanism of the pneumatic soft bionic actuator, and based on the theory of mechanism design, a systematic structural design of the pneumatic amphibious soft bionic robot was carried out from the aspects of flippers, tail, head–neck, and trunk. Then, a numerical simulation algorithm was used to analyze the main executing mechanisms and their coordinated motion performance of the soft bionic robot and to verify the rationality and feasibility of the robot structure design and motion forms. With the use of rapid prototyping technology to complete the construction of the robot prototype body, based on the motion amplitude, frequency, and phase of the bionic prototype, the main execution mechanisms of the robot were controlled through a pneumatic system to carry out experimental testing. The results show that the performance of the robot is consistent with the original design and numerical simulation predictions, and it can achieve certain maneuverability, flexibility, and environmental adaptability. The significance of this work is the development of a pneumatic soft bionic robot suitable for amphibious environments, which provides a new idea for the bionic design and application of pneumatic soft robots. Full article

The distribution of fish eggs and larvae (ichthyoplankton) reflects spawning and nursery areas as well as dispersal routes. This study’s goal is to demonstrate how the identification of ichthyoplankton species and stages and their spatial distribution among natural reefs (NRs) and artificial reefs (ARs) may serve as decision-making tools in conservation and fishery management. Natural reefs exhibited an eight-times higher abundance of eggs, as well as the highest abundance of larvae in the yolk-sac and preflexion phases. In contrast, ARs had the highest abundance of larvae in the flexion and postflexion phases. Natural reefs may serve as breeding grounds for Scaridae, Labridae, and Mugilidae; whereas, ARs may serve as breeding sites for Lutjanidae, Synodontidae, Carangidae, Fistularidae, and Haemulidae. Our study revealed differences between ARs and NRs, which demonstrate the potential of artificial reefs to expand the supply and settlement options of reef fishes and consequently can lead to increased fish production with potential benefits to adjacent fishing areas through connectivity. Thus, ARs as no-take sites can be effective tools for both fishery management and biodiversity conservation. The findings highlight the potential use of ichthyoplankton tools and the importance of considering both types of reefs in marine conservation and management efforts. Full article

This study provides the first socio-ecological overview of the Seriola dumerili fishery occurring in the Balearic Islands. This pelagic top-predator is among the five most valued fish resources of the Balearic community. Despite its ecological importance and potential vulnerability to aggregation fishing, few studies address the ecology of this large Carangidae species. Shining a light on its ecology is vital to ensure adequate species conservation and the sustainable and effective management of the fishery. Historical catches from 1950–1999, alongside detailed landing data for the last 21 years, were analysed to identify potential patterns in ecological and socio-economic factors. Significant inter-annual variability among the years was found in historical catches of greater amberjack, while catches and mean prices of the different size categories revealed significant results between seasons and months, respectively. Additionally, the purse seine fleet accounted for the highest percentage of S. dumerili catches. CPUE did not appear to change greatly between months and years after the annual 8-month fishing ban imposed in 2011 and therefore a re-evaluation of the closure was intended. Overall, this study suggests seasonality influences the S. dumerili fishery in the Balearic Islands, within which ecological influences show a higher regulating power than socio-economic factors. Full article