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Peres fish (Osteochilus kappenii) is a native freshwater fish in Central Aceh, Indonesia. This study aimed to determine the morphology and histology development of the digestive tract of Peres larvae. Understanding the developmental stages is essential to support the success of larval rearing during ontogeny. The parameters observed include the total length (TL) of larvae, daily growth rate, larval morphology, and histology of the digestive tract. Furthermore, the total length of the larvae was measured from 1 to 25 day after hatching (DAH). The larvae sampling was conducted at 1, 2, 3, 4, 8, 10, 15, 20, and 25 DAH. Morphological and histological observations were carried out microscopically, and data were analyzed descriptively. The results showed that the TL of larvae growth at the beginning (1 DAH) and termination (25 DAH) of the study was 4.58 ± 0.24 mm and 9.62 ± 0.79 mm, respectively. Based on the structural development of the body and food sources, the development of percussion larvae was divided into four phases, namely the yolk sac (0-4 DAH), pre-flexion (5-15 DAH), flexion (16-20 DAH), and post-flexion (21-25 DAH). The yolk was completely absorbed 4 DAH, marking the end of the yolk sac phase, as the Peres fish larvae began to use external feed. At 25 DAH, the larval morphology was fully formed and pigmentation spread throughout the body. The digestive organs and glands are well-developed with differentiation of the midgut and hindgut, increased goblet cells in the intestine, and increased lipid vacuoles in the liver and zymogen in the pancreas to utilize feed optimally. [ABSTRACT FROM AUTHOR]

The size grading during fish farming benefits growth management and feed control, improving aquaculture efficiency. A guided live fish grading device was designed to solve the problem of high labor intensity and low efficiency in domestic live fish grading. The structural composition and working principle of the grading device were introduced, and the mechanical analysis and parameter design of the fish conveying mechanism were carried out. Based on the relationship between fish body mass and body shape parameters, the morphological data of experimental crucian carp were measured. Meanwhile, the power function fitting method was used to obtain the equation of the relationship between crucian body thickness and body weight, which serves as the basis for setting the distance between grading channels. When grading, the spacing between the guide plates on both sides of the grading channel is adjusted, and the grading channel is set to meet the fish specification requirements so that fish's body through the grading channel. Live fish grading performance experiment was carried out, with fish weight range of 0. 14-0. 33 kg and thickness range of 30-39 mm. Grading tests and effect analysis were conducted under three conditions of fish conveying speeds of 0. 15 m/ s, 0. 20 m/ s, and 0. 25 m/ s. The experimental results show that the grading accuracy can reach over 90% under normal conditions, and the appropriate grading speed and grading channel setting have higher efficiency. This guided grading device can quickly and accurately grade live fish, improving the efficiency of mechanized operations in the breeding process. [ABSTRACT FROM AUTHOR]

The decreased color intensity of Nemo is related to the amount of carotenoid concentration in the xanthophore of Nemo's skin. Therefore, efforts are needed to maintain stable carotenoid production. Tomato is one of the most abundant carotenoid producers. The utilization of carotenoids can maintain the morphological color of aquatic organisms. This study aimed to analyze the effect of carotenoid compounds on total carotenoid content, the size, and distribution of xanthophores on Nemo skin. A total of 60 Nemo with an average initial weight of 0.84±0.14 g and an average length of 2.95±0.08 cm. The research was conducted using a completely randomized design (CRD), consisting of four carotenoid concentrations in addition to fish pellet, 0%, 0.5%, 1%, and 1.5% with three replications. The results showed that the optimum dose of carotenoid compounds in increasing the total carotenoid content in nemo fish skin is 1.5%. Carotenoids added to the fish feed affected the distribution and maturity of xanthophore. However, it did not affect the size of the xanthophore. [ABSTRACT FROM AUTHOR]

Neomerintheignea (Scorpaenidae), a new species of scorpionfish from the western Pacific Ocean, previously confused with Neomerintheerostris (Alcock 1896), is described. The new species is characterized by the following combination of characteristics: body size less than about 90 mm standard length (SL); lateral lacrimal and second preopercular spines present; usually a distinct longitudinal ridge on lateral surface of maxilla; usually 18 pectoral-fin rays; 37–42 longitudinal series scale rows; pored lateral-line scales 23–25; scale rows above lateral line 4–6, below lateral line 9–11, between sixth dorsal-fin spine base and lateral line 5 or 6, and between last dorsal-fin spine base and lateral line 5–7; usually 6 upper gill rakers, 9–16 lower gill rakers (8–10 and 0–7 rakers on ceratohyal and hypobranchial, respectively); numerous cycloid scales on ventral body surface between isthmus and posterior to pelvic fin; 1st dorsal-fin ray length 14.7–19.1% of SL, 2nd dorsal-fin ray length 14.6–18.9% of SL, 3rd dorsal-fin ray length 15.6–18.9% of SL, 4th dorsal-fin ray length 15.2–19.1% of SL, and 5th dorsal-fin ray length 14.2–19.5% of SL; body bright orange to reddish-white when fresh; body and pectoral fins pale yellowish, with indistinct blotches on lateral body surface when preserved. A molecular genetic analysis based on the mitochondrial marker Cytochrome c oxidase subunit I showed that the new species formed a clade distinct from congeneric species. In addition, records of N.erostris, a species similar to N.ignea, are reviewed, and additional specimens from northern Australia noted. [ABSTRACT FROM AUTHOR]

A new species of deep-water snake eel, Ophichthus nigroventralis sp. nov. is described based on five specimens collected from deep-sea trawl landings at Kalamukku fish landing Centre, off Kochi, Arabian Sea, southwest coast of India. The new species is distinguished from its deep-water congeners by the following combination of characters viz., origin of dorsal fin slightly behind pectoral-fin tip; pectoral fin lanceolate, slightly shorter than upper jaw in length; head length 6.7–7.5 in TL; supraorbital (SO) pores 1 + 3; intermaxillary with a rosette of 10 pointed teeth; vomer with 6 anterior teeth in irregular biserial rows, 11 posterior teeth in a uniserial row; maxillary with 24–25 uniserial teeth; abdomen with numerous minute black pigmentation extends up to tail; pectoral fin whitish with brown base; vertebral count (pre-dorsal/pre-anal/total): 17–18/53–54/131–134. The genetic analysis reveals that the species Ophichthus urolophus is the closest congener for the new species with a genetic divergence of 4.2%. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, a new species of the genus Pseudocalotes is described from Yingjiang County, Dehong Dai, and Jingpo Autonomous Prefecture, Yunnan Province, China, based on four female specimens. Phylogenetic analyses based on NADH dehydrogenase subunit 2 (ND2) and NADH dehydrogenase subunit 4 (ND4) indicated that the new taxon is different from its congeners. Morphologically, the new species can be diagnosed from the other species by a combination of 18 characters. The recognition of this new species brings the number of described Pseudocalotes species to 22. In this study, a new species of the genus Pseudocalotes is described from Yingjiang County, Dehong Dai and Jingpo Autonomous Prefecture, Yunnan Province, China, based on four female specimens. It can be distinguished from its congeners by the following combination of characters: (1) interoculabials 3 or 4; (2) canthals 5–7; (3) cicrcumorbitals 8–11; (4) 1 scale between rostral and nasal; (5) interparietal 1; (6) superciliaries 4–6; (7) supralabials 6–7, the 1st in contact with the nasal; (8) infralabials 6–8; (9) transverse gular fold and antehumeral fold present; (10) 2–3 enlarged scales between eye and ear; (11) nuchal crest single, consists of 3–5 erected spines; (12) dorsal crest row single, discontinuous and low, located between two keeled, parallel and enlarged scale rows; (13) enlarged postrictals absent; (14) scales around midbody 53–62, dorsal body scales heterogenous in size and shape; (15) midventrals smaller than dorsals; (16) subdigital scales on the 4th finger 20–26, and on the 4th toe 24–29; (17) dorsal background coloration light taupe with four irregular brown patches along the middle of dorsal; (18) inner lips wathet, tongue aurantiacus, throat bluish black. The population from Yingjiang County was nested within a highly supported lineage, formed a sister taxon with P. kakhienensis (SH 97/UFB 100) and according to the p-distance, the new species differed from its congeners by 14.5% to 35.2% for NADH dehydrogenase subunit 2 (ND2) and 15.5% to 25.0% for NADH dehydrogenase subunit 4 (ND4). [ABSTRACT FROM AUTHOR]

Rovers, rubyfishes, and bonnetmouths (Emmelichthyidae) comprise a small family of fishes that can be distinguished from other perch-like fishes by their generally red, fusiform bodies, highly protrusible mouths, and large rostral cartilage. Their highly protrusible upper jaws have led ichthyologists to group morphologically similar but distantly related taxa within the Emmelichthyidae and is one of the stunning examples of morphological convergence within perchlike fishes. In 2014, the first and only emmelichthyid from the Red Sea, Emmelichthys marisrubri, was described. This species is diagnosed by 80-83 lateral-line scales, 8 dorsal-fin rays, and 4-5 isolated dorsal spines that are separated from membrane-bound dorsal-fin elements, among other features. While examining the osteology of E. marisrubri, I discovered several differences in the oral jaws, suspensorium, neurocranium, and dorsal fin when compared to other species of rovers. Based on these differences and the results of a phylogenetic analysis, I transfer this taxon to the genus Dipterygonotus within the Lutjanidae and among the fusiliers (formerly Caesionidae), an Indo-Pacific group of fishes that also have highly protrusible upper jaws. [ABSTRACT FROM AUTHOR]

Hydrodynamic pressure sensors offer an auxiliary approach for ocean exploration by unmanned underwater vehicles (UUVs). However, existing hydrodynamic pressure sensors often lack the ability to monitor subtle hydrodynamic stimuli in deep-sea environments. In this study, we present the development of a deep-sea hydrodynamic pressure sensor (DSHPS) capable of operating over a wide range of water depths while maintaining exceptional hydrodynamic sensing performance. The DSHPS device was systematically optimized by considering factors such as piezoelectric polyvinylidene fluoride–trifluoroethylene/barium titanate [P(VDF-TrFE)/BTO] nanofibers, electrode configurations, sensing element dimensions, integrated circuits, and packaging strategies. The optimized DSHPS exhibited a remarkable pressure gradient response, achieving a minimum pressure difference detection capability of approximately 0.11 Pa. Additionally, the DSHPS demonstrated outstanding performance in the spatial positioning of dipole sources, which was elucidated through theoretical charge modeling and fluid–structure interaction (FSI) simulations. Furthermore, the integration of a high Young's modulus packaging strategy inspired by fish skull morphology ensured reliable sensing capabilities of the DSHPS even at depths of 1000 m in the deep sea. The DSHPS also exhibited consistent and reproducible positioning performance for subtle hydrodynamic stimulus sources across this wide range of water depths. We envision that the development of the DSHPS not only enhances our understanding of the evolutionary aspects of deep-sea canal lateral lines but also paves the way for the advancement of artificial hydrodynamic pressure sensors. [ABSTRACT FROM AUTHOR]

The two scorpionfish species Scorpaena maderensis and S. porcus are well camouflaged ambush predators that rapidly change body colouration to adjust to background colour in less than 1 min. We tested whether individuals of both species also adjust body pattern to that of the background. We placed fish on backgrounds of different pattern granularity and quantified the change in fish body pattern over 1 min. We used calibrated image analysis to analyse the patterns from the visual perspective of a prey fish species using a granularity (pattern energy) analysis and an image clustering approach. In our experiment, fish did not change their most contrasting pattern components as defined by the dominant marking size, but changed their average marking size. Moreover, fish responded with a change in pattern in contrast to the different experimental backgrounds, especially when compared to the acclimation phase. These results indicate that scorpionfish have one main pattern that can be adjusted by modulating its internal contrast. A reduction in pattern contrast could thereby improve background matching, while an increase could promote camouflage via disruptive colouration. [ABSTRACT FROM AUTHOR]

Simple Summary: While feeding, the larvae of pygmy moths (Nepticulidae) consume part of a leaf's photosynthetic tissue, thus causing damage to the host plant. Although these insects play a natural role in terrestrial ecosystems, they are perceived as pests in horticulture. This study investigates the identity of a potential Nepticulidae pest infesting plum trees in the Caucasus, initially presumed to be the widespread European Stigmella plagicolella (Stainton). Contrary to expectations, our detailed taxonomic analysis revealed a new species of pygmy moth with distinct male genitalia morphology and molecular differences from its European counterpart. This discovery challenges previous records and highlights the need for accurate pest identification. We hypothesize that the proximity of the Caucasus to Europe emphasizes the importance of monitoring and preventing unintentional pest spread, particularly given potential climate change impacts on the distribution and behavior of pests. Our findings contribute to both practical pest management and scientific understanding of evolutionary processes shaping the Caucasian and European biota. In instances of severe infestations, Nepticulidae larvae can inflict damage on cultivated plants. Previously, it was assumed that the Prunus-feeding Nepticulidae have continuous distribution from Europe to the neighboring Caucasus. During recent fieldwork in the Caucasus, leaf mines were found on plum trees that initially resembled those of Stigmella plagicolella (Stainton) in Europe. However, upon rearing the adults, significant differences emerged, leading to the hypothesis that a different Prunus-feeding species exists in the Caucasus; this challenges previous records in Western Asia. This paper presents the outcomes of our morphological, molecular, and statistical investigations, unveiling S. colchica sp. nov., a previously unknown potential plum-tree pest. Distinguished by male genitalia characteristics, the new species differs from S. plagicolella. The inter- and intraspecific divergences between S. colchica sp. nov. and S. plagicolella range from 3.5% to 6.02%. Moreover, the utilized delimitation algorithms reliably clustered two species separately, as does our mitotype network. A statistical analysis also shows a discernible trend between the leaf mines of S. colchica sp. nov. and S. plagicolella. This unexpected discovery not only documents a new potential pest, enhancing our understanding of the Caucasian fauna, but also contributes to the broader biological inventory. [ABSTRACT FROM AUTHOR]

This study was attempted to reveal the changes in three hematological parameters such as blood hemoglobin, number of white blood cells (WBCs) and number of red blood cells (RBCs) and one biochemical (e.g., glucose) parameter along with the changes in histomorphological structures of gills and kidney of Nile tilapia fry reared in saline water. Two experimental set up were used for two different age groups-5 days-after-hatch (5DAH) and 15 days-after-hatch (15DAH) - to test a novel hypothesis: if a little difference in the age during the first exposure to saline water could produce any variation in the results. They were placed into 6 plastic drums having six different salinity levels: 0, 5, 10, 15, 20 and 25. After 60 days, at least 5 individuals were taken out from each drum to observe the above-hematological and histomorphological parameters. A two-way-ANOVA revealed that, except for hemoglobin, all the observed parameters have been affected the effect of age × salinity interaction (P<0.05). Between the two age groups, only the overall average glucose value and RBC count were significantly different. Among various salinity levels, only RBC and WBC counts differed significantly. Further, the mean glucose value, RBC counts and WBC count at different salinities differed significantly from the base mean value of each parameter. With regard to the histomorphological structure of the gills and kidney, various malformations were evident. Though hypertrophy, epithelial uplifting and epithelial necrosis were present as gill degenerations, hyperplasia was prevalent across almost all salinity levels. On the other hand, glomerular necrosis, pyknotic nucleus, hyaline droplets degeneration, shrinking of the glomeruli, etc. were observed in kidney structures. By assisting to understand the effects of salinity stress, all these data on tilapia fry will help to determine the prospects and scope of culturing the species in high-salinity water. [ABSTRACT FROM AUTHOR]

Although the primary function of the swim bladder is buoyancy, it is also involved in hearing, and it can be associated with sonic muscles for voluntary sound production. The use of the swim bladder and associated muscles in sound production could be an exaptation since this is not its first function. We however lack models showing that the same muscles can be used in both movement and sound production. In this study, we investigate the functions of the muscles associated with the swim bladder in different Pteroinae (lionfish) species. Our results indicate that Pterois volitans, P. radiata and Dendrochirus zebra are able to produce long low‐frequency hums when disturbed. The deliberate movements of the fin spines during sound production suggest that these sounds may serve as aposematic signals. In P. volitans and P. radiata, hums can be punctuated by intermittent louder pulses called knocks. Analysis of sonic features, morphology, electromyography and histology strongly suggest that these sounds are most likely produced by muscles closely associated with the swim bladder. These muscles originate from the neurocranium and insert on the posterior part of the swim bladder. Additionally, cineradiography supports the hypothesis that these same muscles are involved in altering the swim bladder's length and angle, thereby influencing the pitch of the fish body and participating in manoeuvring and locomotion movements. Fast contraction of the muscle should be related to sound production whereas sustained contractions allows modifications in swim bladder shape and body pitch. [ABSTRACT FROM AUTHOR]

Important morphological and ecological modifications occur during the transition between pelagic and demersal phases in marine fish. However, it is still unknown how fast these shape changes may occur. We studied the shape changes of a common cryptobenthic fish, the triplefin Helcogrammoides chilensis (Cancino, 1960) during the shift from pelagic larvae to recently settled individuals, along rocky shores in central Chile during the austral summers of 2020 and 2021. The working hypothesis was that larval stages would show more allometry and faster shape changes in the head and the paired fins insertion than benthic juveniles, in preparation for their new environment. Shape changes were analyzed utilizing landmark-based geometric morphometrics, while age was estimated using sagittal otolith microstructure analysis. There was an important overlap in the size (length and weight) between older larvae and recently settled individuals (between 20 and 25 mm SL, and 0.08–0.17 g), nonetheless, the head shape and paired fins were clearly different between stages. Pelagic larvae (46–88 days post hatch) had a shorter pectoral fin base, a frontal mouth opening, and eyes located at the level of the tip of the upper jaw. Meanwhile, recently settled individuals (80–112 days post hatch) had wider, vertically positioned pectoral fins, mouths displaced to a vertical position, and eyes located upper and forward the head. Larvae experienced faster growth rates than settlers (0.24 vs. 0.02 mm day−1, respectively), and the pattern of ontogenetic shape changes decreased two orders of magnitude after settlement. It is plausible that after the pelagic–demersal shift most of the fish's energy was used in body structure rearrangement and incrementing body pigmentation, as an adaptation of cryptobenthic juvenile to the rocky reef. [ABSTRACT FROM AUTHOR]

Simple Summary: In this paper, a new Pareas species of the P. hamptoni complex is described from southern Yunnan Province, China, based on morphological and molecular evidence. Genetically, the new species is most closely related to P. hamptoni sensu stricto, for which we confirm the distribution in China. Morphologically, the new species can be distinguished from P. hamptoni sensu stricto and all other congeners by a combination of morphological characteristics. The discovery of the new species brings the total number of recognized species of the genus Pareas to 31, of which 25 occur in China. We describe a new species of the genus Pareas, based on three specimens collected from Guanyinshan Provincial Nature Reserve in Yuanyang County, Honghe Prefecture, Yunnan Province, China. The new species is distinguished from its congeners by one preocular, one postocular or postocular fused with subocular, loreal not bordering the orbit, one row enlarged vertebral scales, five rows keeled mid-dorsal scales at the middle of the body, 189–192 ventral scales and 72–89 subcaudal scales. The dorsal surfaces of the head and body are yellowish red or yellowish brown, and the belly and ventral surfaces of the head and tail are pinkish yellow or yellow with more or less small black spots. Phylogenetic analyses of mitochondrial DNA recovered the new species being the sister taxon to P. hamptoni sensu stricto. The genetic divergences between the new species and P. hamptoni sensu stricto were 4.2% in the Cyt b sequences and 5.0% in the ND4 sequences. In addition, based on specimens collected from Honghe and Wenshan prefectures, we confirmed that P. hamptoni sensu stricto is distributed in China. [ABSTRACT FROM AUTHOR]

The nuchal glands are organs of chemical defense embedded under the skin of several species of Rhabdophis and contain toxins sequestered from consumed prey. Rhabdophis subminiatus possesses nuchal glands, but not much information is available on its toxin source and prey preference, particularly based on its chemosensory response. We hypothesized that the response of R. subminiatus toward toads would be higher than other potential prey because the snake needs to sequester toxins contained in toad skin. We also examined the snake preference toward several bufonid species to test a hypothesis that the preference toward Duttaphrynus melanostictus is higher than other toad species due to its high availability in the habitat of the snake. To test the hypotheses, we conducted chemical response tests and compared the tongue-flick attack score (TFAS) of the snake toward prey chemical stimuli. The first experiment used only one toad species (D. melanostictus) and various potential prey animals for the source of chemical stimuli. The second experiment used chemical stimuli from several species of frogs and toads. In the first experiment, snakes showed the highest response toward D. melanostictus. However, in the second experiment, snakes showed the highest response toward a toad, Ingerophrynus biporcatus, followed by D. melanostictus, and a lower response toward another toad, Phrynoidis asper. These results indicate that the snake has a high preference toward toads, but its preference varies among toad species. Taken together, this study suggests that R. subminiatus discriminates different potential prey chemical cues and probably consumes toads to sequester their toxins. [ABSTRACT FROM AUTHOR]

This work is aimed to study the effect of turbidity on the swordtail’s body shape during its early developmental stages. For this purpose, two treatments were designed as turbid and clear water, each with three replicates for 60 days. The body shape data was extracted by digitizing 16 landmark points on 2D pictures to analysis using the geometric morphometric technique. The results showed a significant difference between the two treatments in terms of body shape. Fish under turbid conditions had shorter eye diameters, lower and shorter heads, more dorsal position snout, and deeper caudal peduncles. The priorities in the new environment i.e. turbid water needs to be changed to decrease the adverse effect of the resulting pressures of this environment and increase the survival rate leading to increasing the ability of the developing fish to occupy a wider range of habitats. [ABSTRACT FROM AUTHOR]

Optimizing utilization of nutrients and improving protein digestibility, particularly in the early stages of cultivable species, is a challenging task for the sustainable development of aquaculture. The use of protein-digesting enzymes as a feed supplement is an eco-friendly approach to improve protein digestibility. Exogenous enzymes, particularly proteases, have been shown to improve fish growth, nutrient digestibility, immunological parameters, intestinal topography, and most importantly, water quality. Although there is a clear understanding of the role of proteases and their mechanism of action, their role as a feed supplement in aquaculture remains controversial. In this review, we present updated information on the impact of proteases in improving various development indicators and fish health in general. Based on the information gathered from the current state of knowledge, it is clear that extensive research has to be made to broaden the application of proteases overcoming the drawbacks that could hinder its application in the field. [ABSTRACT FROM AUTHOR]

Based on morphological features, genetic distances, and phylogenetic relationships, we report the discovery of two new species of Enyalioides from the montane forest of Cordillera de Colán in northern Peru. The first new species can be distinguished from its congeners by the combination of the following characters: scales immediately posterior to superciliaries on lateral edge of skull conical, slightly higher than adjacent scales; gular scales heterogeneous in size; scales on neck mostly large and conical; dorsal scales between dorsolateral crests covered by large, keeled, mucronate scales; scales on flanks tiny, tuberculate or granular, with scattered enlarged conical or tuberculate scales; ventral scales keeled or feebly keeled; caudal scales heterogeneous, increasing in size posteriorly on each segment; and marked sexual dichromatism. Among other features, the second new species differs from other Enyalioides in having a distinctively low vertebral crest; scales immediately posterior to superciliaries on lateral edge of skull barely projected and similar in height to adjacent scales; 56-71 vertebral scales from occiput to base of tail; dorsal scales feebly keeled and heterogeneous in size; ventral scales keeled; and caudal scales heterogeneous, increasing in size posteriorly on each segment. In addition, we present an updated identification key for species of Hoplocercinae. [ABSTRACT FROM AUTHOR]

– We describe a new species of the progenetic gobiid fish genus Schindleria from Rapa Nui (Easter Island, Chile). Schindleria squirei n. sp. belongs to the long dorsal-fin type (LDF) of Schindleria. The new species is characterized by an in vivo translucent, elongate and slender body; a dorsal fin longer than the anal fin (predorsal-fin length 60.2% in SL vs. preanal-fin length 70.4% in SL); a short tail (29.8% in SL); a short (10.9% in SL) and massive head (48.7% width in head length) with a convex dorsal profile; a long and relative narrow pectoral-radial plate (52.4% width of pectoral-radial plate length); 20-21 dorsal-fin rays; 12 anal-fin rays; first anal-fin ray situated opposite the dorsal-fin ray 9-10; teeth on both jaws tiny, conical, densely set; a straight, thin, rod-like maxilla, posteriorly flattened, and with a plate-like expansion; a lower jaw which forms a wide arch with a truncated, at the symphysis somewhat dented, margin and only slightly exceeding the upper jaw; black eyes; a dorsally pigmented swim-bladder; and no other external pigmentation on its body, in preserved specimens. [ABSTRACT FROM AUTHOR]

Simple Summary: This is the first study to investigate the spatial distribution and population structure of the tub gurnard (Chelidonichthys lucerna) in different regions of the northeast Atlantic. To analyze fish body shape, a morphometry-based method, which helps identify variations in fish body shape that may exist due to genetic factors or environmental adaptability, was used. This study relied on C. lucerna individuals captured in the following three fishing areas: Conwy Bay (United Kingdom), Biscay Bay (Spain) and Matosinhos (Portugal). The findings indicate the existence of significant regional differences in fish bodies, thus highlighting the existence of distinct fish populations in the three regions. Results also suggest that the Spanish and British populations may inhabit similar habitats, as some similarities in body shape were found. To confirm these findings, we recommend future research using a holistic approach with alternative and complimentary stock assessment tools. The study of geometric morphometrics among stocks has proven to be a valuable tool in delineating fish spatial distributions and discriminating distinct population units. Variations in fish body morphology can be linked to genetic factors or to phenotypic adaptability in response to environmental variables. The tub gurnard (Chelidonichthys lucerna) is a demersal species that usually lives in the bottom of the continental shelf, being widely distributed along the northeast Atlantic, Mediterranean and Black seas. Worldwide interest in the species has increased since 2006, when ICES recognized its potential for commercial exploitation. However, despite its broad geographic occurrence, to date, research on C. lucerna population structure at large spatial scales is still lacking. In this paper, body geometric morphometrics, using a landmark-based truss network, was applied in order to discriminate C. lucerna populations caught in three different fishery grounds areas along the northeast Atlantic: Conwy Bay (United Kingdom), Biscay Bay (Spain) and Matosinhos (Portugal). The results obtained in this study revealed a high overall relocation success (95%) of samples to their original locations, thus demonstrating the existence of significant regional differences and indicating that we are dealing with different fish population units. Moreover, the data revealed a partial overlap between individuals from Spain and United Kingdom, suggesting that in geographically distant areas these populations may inhabit similar environments. However, to corroborate these findings, future works using a holistic approach with alternative and complimentary stock assessment tools (e.g., genetic and phenotypic natural tags) are highly recommended. [ABSTRACT FROM AUTHOR]

Fish is an important resource in Malawi as a source of food for the majority as it provides affordable source of dietary animal protein as well as income. A number of fish species in the Malawi water bodies have their population dwindling. One of the species under serious threat of extinction is the Opsaridium microlepis - a potamodromous fish species that migrate to the rivers during its spawning period and its management seems a nightmare. A number of studies reveal contrasting results on genetic makeup and morphological aspect of this fish species. With changes in the ecosystems of the rivers connecting Lake Malawi, coupled with absence of strong management measures in the major rivers adjoining the lake, problems have arisen in the conservation of potamodromous fish species. This necessitated the present study to investigate if the morphological features of stocks of O. microlepis are the same or not and if they have changed to adapt to changes in the ecosystems. One hundred and eleven O. microlepis fish samples were collected from Linthipe River (48), Bua River (59) and North Rumphi River (4) monthly from March to August 2020 using trawled and static gillnets. Twenty-four morphometric characteristics were measured to determine if any morphological differences existed among the fish samples from the three rivers. Principal component analysis (PCA) was used to compare morphology of the fish. Results of the study showed no significant morphological differences among stocks from the three rivers, implying that O. microlepis in these rivers belong to same stock morphologically. The study reveals that the species do not differ morphologically even though they migrate to different rivers for breeding. The study further notes that numerous activities taking place along the tributary rivers (as observed during the study) such as modification of fishing gears as well as fishing methods and the deterioration of the spawning grounds due to siltation from soil erosion caused by deforestation and agriculture, are putting the potamodromous fish species such as O. microlepis under serious threat. The study recommends that the populations of O. microlepis from the rivers can be managed equally since they are morphologically similar. Adopting uniform catchment management and sustainable exploitation of O. microlepis (such as regulations on mesh sizes and fishing methods, closing the rivers from fishing activities during spawning period, river bank and catchment management and restoration) with the aim of conserving the stocks from further overexploitation in these rivers is recommended so that the communities and the people at large continue to utilize the resource sustainably and at the same time, sustaining their livelihood. [ABSTRACT FROM AUTHOR]

Otolith is important for studying fish populations and life histories. In this study, the dominant species of Schizothorax grahami in the source section of the Chishui River was taken to understand the relationships between otolith morphology and total length (TL). Results showed a large difference between the four TL groups (A/B/C/D), except group B is similar to group C. The combined discrimination success rate of linear discriminant analysis was 62.2%. Group A and D's success rate is the highest, at around 75%. Meanwhile, the success rate for Group B and Group C is below 65%. The one-way ANOVA of the Shape Index and the Canonical analysis of Principal Coordinates with two coefficients (Fourier coefficients and Wavelet coefficients) showed that Group B is similar to Group C, with a large difference from the other two groups. When TL was greater than 100 mm (the pearl organs appearing), the otolith growth was lower changing. Otolith morphology still changes with growth after sexual maturity in fish, so the larger fish is more useful for conducting otolith morphology studies for accurate evaluation and management of local fishery resources. [ABSTRACT FROM AUTHOR]

To explore the morphological and phenotypic characteristics and differences among different populations of Larimichthys crocea, traditional morphological measurements were carried out on three wild populations from Zhoushan, Xiamen and Zhanjiang and two farmed populations from Ningde and Wenzhou. Seven morphological parameters of five L. crocea populations were compared and analyzed. The results of one-way ANOVA showed significant differences in trunk and caudal stalk among the five populations. The contribution rates of the first five principal components to the total difference among different populations were 29.984%, 18.462%, 17.234%, 12.167%, and 9.904%, respectively, and the cumulative contribution rates were 87.751%. Trunk can be used to distinguish different geographic populations best. The cluster analysis results showed that the distance between wild populations was the closest, while the distance between farmed populations was far. The step discriminant method established the classification discriminant function of 5 populations. The discriminant accuracy P1 was 78.3%-92.7%, the discriminant accuracy P2 was 76.4%-96.5%, and the comprehensive recognition rate was 99.3%. The discriminant accuracy of this method was high, and it could provide a reference for the differentiation of different populations of L. crocea. This study provided basic morphological data for identifying a large yellow croaker population, protecting germplasm resources, and breeding improved varieties. [ABSTRACT FROM AUTHOR]

A central question in biology is the molecular origins of phenotypic diversity. While genetic changes are key to the genotype–phenotype relationship, alterations to chromatin structure and the physical packaging of histone proteins may also be important drivers of vertebrate divergence. We investigate the impact of such an epigenetic mechanism, histone acetylation, within a textbook example of an adaptive radiation. Cichlids of Lake Malawi have adapted diverse craniofacial structures, and here we investigate how histone acetylation influences morphological variation in these fishes. Specifically, we assessed the effect of inhibiting histone deacetylation using the drug trichostatin A (TSA) on developing facial structures. We examined this during three critical developmental windows in two cichlid species with alternate adult morphologies. Exposure to TSA during neural crest cell (NCC) migration and as postmigratory NCCs proliferate in the pharyngeal arches resulted in significant changes in lateral and ventral shape in Maylandia, but not in Tropheops. This included an overall shortening of the head, widening of the lower jaw, and steeper craniofacial profile, all of which are paedomorphic morphologies. In contrast, treatment with TSA during early chondrogenesis did not result in significant morphological changes in either species. Together, these data suggest a sensitivity to epigenetic alterations that are both time‐ and species‐dependent. We find that morphologies are due to nonautonomous or potentially indirect effects on NCC development, including in part a global developmental delay. Our research bolsters the understanding that proper histone acetylation is essential for early craniofacial development and identifies a species‐specific robustness to developmental change. Overall, this study demonstrates how epigenetic regulation may play an important role in both generating and buffering morphological variation. [ABSTRACT FROM AUTHOR]

Turcinoemacheilus ekmekciae, new species, from upper Euphrates and Tigris drainages is distinguished from other species of Turcinoemacheilus in Western Asia by having a dark stripe broader than the eye diameter along the lateral line, rarely possessing roundish blotches, 5–6 mandibular pores in mandibular canal, a comperatvely smaller head, a deeper body, and a greater pre‐pelvic distance. Our specimens collected from the upper Great Zab, near the type locality of Turcinoemacheilus kosswigi, showed notable genetic divergence (a minimum K2P of 3.3%) from sequences reported as T. kosswigi in previous studies. Despite morphological similarities, this molecular difference suggests that the populations analysed in previous studies may represent a potential new species of Turcinoemacheilus, which we tentatively named as Turcinoemacheius cf. kosswigi. Molecular data also suggest that T. ekmekciae is characterized by a minimum K2P distance of 3.5% from Turcinoemacheilus minimus and T. cf. kosswigi. The three methods for species delimitation (assemble species by automatic partitioning [ASAP], Poisson tree processes [PTP], and multi‐rate PTP [mPTP]) that were utilized for testing species assignments consistently identified our test group as a distinct species. [ABSTRACT FROM AUTHOR]

Two new species of luminous roughies, Aulotrachichthys spiralis and Aulotrachichthys titan (Beryciformes: Trachichthyidae), are described, based on 32 specimens from three main islands of Japan (from Honshu, Shikoku, and southern Kyushu) and a single specimen from the Kyushu-Palau Ridge (northwestern Pacific Ocean), respectively. The holotype of A. titan was previously reported as Aulotrachichthys sajademalensis (Kotlyar 1979), a species restricted to the Western Indian Ocean, including off Somalia and the Saya de Malha Bank. Compared with congeners, the two new species are characterized by dorsal- and anal-fin spine and body scale numbers, shapes of the fin spines and interorbital ridges, relative lengths of the striated muscle band on the caudal peduncle, and several body proportions. These diagnostic characters in species of Aulotrachichthys are reviewed. [ABSTRACT FROM AUTHOR]

This article reports on a rare case of abnormal hyperpigmentation in a freshwater sardine species, Triportheus auritus, from the Amazon basin in Brazil. Hyperpigmentation, characterized by excessive pigmentation in the skin or other tissues, has been observed in various fish species. However, this is the first documented case of hypermelanosis in Amazonian freshwater fishes. The specimen was collected from the Tefé River and showed hyperpigmentation on the scales and skin of the head. The rarity of this abnormality suggests that it may be an individual abnormality rather than a common occurrence in the population. The article provides detailed morphometric data and histological analysis of the specimen. The authors speculate that the survival of the hypermelanic individual may be facilitated by the aquatic lighting conditions of the black water in the Tefé River. [Extracted from the article]

The article informs about the diversity of sea mammals, encompassing 137 living species worldwide, classified into at least seven distinct evolutionary lineages that returned to the sea. Topic include the majority are cetaceans, divided into toothed whales and baleen whales, while other groups include pinnipeds, sirenians, a polar bear, sea and marine otters, and extinct species like desmostylians, aquatic sloths, and the oyster bear Kolponomos.

Microplastic ingestion was reported for common bottlenose dolphins (Tursiops truncatus) inhabiting Sarasota Bay, FL, USA, a community that also has prevalent exposure to plasticizers (i.e., phthalates) at concentrations higher than human reference populations. Exposure sources are currently unknown, but plastic-contaminated prey could be a vector. To explore the potential for trophic exposure, prey fish muscle and gastrointestinal tract (GIT) tissues and contents were screened for suspected microplastics, and particle properties (e.g., color, shape, surface texture) were compared with those observed in gastric samples from free-ranging dolphins. Twenty-nine fish across four species (hardhead catfish, Ariopsis felis; pigfish, Orthopristis chrysoptera; pinfish, Lagodon rhomboides; and Gulf toadfish, Opsanus beta) were collected from Sarasota Bay during September 2022. Overall, 97% of fish (n = 28) had suspected microplastics, and GIT abundance was higher than muscle. Fish and dolphin samples contained fibers and films; however, foams were common in dolphin samples and not observed in fish. Suspected tire wear particles (TWPs) were not in dolphin samples, but 23.1% and 32.0% of fish muscle and GIT samples, respectively, contained at least one suspected TWP. While some similarities in particles were shared between dolphins and fish, small sample sizes and incongruent findings for foams and TWPs suggest further investigation is warranted to understand trophic transfer potential. [ABSTRACT FROM AUTHOR]

Geometric morphometry has evolved as a powerful tool to unravel species delimitations within the genus Aristolochia. A survey conducted on the variation of Aristolochia trilabiata flowers and leaves revealed an overlooked entity in its affinity, which is newly described herein as Aristolochia franzii. The new species differs from its relative A. trilabiata by various floral characters, notably the presence of papillae on both the upper and lower limb zones, the presence of a well defined medial upper limb zone, the number of veins on the lateral upper limb zone, a considerably shorter tube, and the relative position of upper and lower limb zones. Furthermore, the leaf shape of A. franzii is cordiform-elongate to hastate, compared to the consistently more compact and shorter cordiform leaves of A. trilabiata. So far, A. franzii has been recorded from Northern Brazil (Amazonas) and French Guiana. An illustration of the diagnostic characters and comparison with A. trilabiata is provided, as well as the geographic distribution and a preliminary assessment of the conservation status. [ABSTRACT FROM AUTHOR]

We characterized a natural sea louse epizootic of Caligus clemensi and the effects of parasitism on Pacific herring Clupea pallasii in Port Angeles Harbor, WA, USA. Infestation prevalence on newly metamorphosed age 0 Pacific herring reached 100% prevalence by mid-August. At this time, the mean louse intensity was 4.6 lice/fish, and a positive correlation occurred between louse intensity and herring body length. The epizootic then waned, with infestation prevalence decreasing to less than 25% and the mean parasite intensity falling below 1 louse. While skin injuries were not detected, motile lice preferentially aggregated around head and anterior dorsal areas. However, louse tropism became evenly distributed over the body as the parasite intensity increased. Louse-induced mortality in herring was negligible in controlled experiments. These results indicate that Caligus clemensi epizootics reach high prevalence, but also fade from mid-summer to early fall. Due to the predominant presence of motile copepod stages, we suggest that the epizootic fades because lice complete their life cycle and dislodge from the host; however, multiple explanations for epidemic fading are possible. [ABSTRACT FROM AUTHOR]

A time-calibrated phylogeny, based on nuclear ultraconserved elements and including representatives of all major alestid lineages, strongly supports two distantly related clades within the currently accepted concept of Brycinus. The first, which includes the type species of the genus, B. macrolepidotus (herein Brycinus), and a second, composed of taxa previously referred to as the B. nurse group (herein Brachyalestes), are both resolved as monophyletic. These results provide strong evidence for the restriction of the genus Brycinus to nine species, and for the revalidation of the genus Brachyalestes to accommodate 20 valid species. Within Brachyalestes, a new species from the Lulua River basin, initially misidentified as Brycinus kingsleyae, is described and resolved as sister to the widespread, central Congolese lowland species, Brachyalestes bimaculatus. Within Brachyalestes, a subclade mostly restricted to the Central Congo basin is estimated to have undergone diversification within the last 10 million years, suggesting that Late Neogene riverine reorganization likely influenced their allopatric speciation. The split of the new species, endemic to high elevation tributaries of the Lulua River, from its lowland sister species, Brachyalestes bimaculatus, suggests a Late Miocene/Early Pliocene colonization into the upland river ecosystems of the Katanga plateau in the southwestern Democratic Republic of Congo. [ABSTRACT FROM AUTHOR]

We here present the first study on the consumed prey by an epigean population of the Italian cave salamander (Speleomantes italicus) from the Republic of San Marino. Using the harmless technique of stomach flushing, we aimed to provide the first data on the diet and on the degree of individual specialization that characterizes the studied population. We performed two-night surveys (one in autumn 2022 and one in spring 2023) in which we opportunistically searched for salamanders in forested areas and dry walls. Captured salamanders were sexed, weighed, photographed, measured and stomach flushed. Overall, we inspected the stomach contents of 67 individuals, recognizing 1,018 prey items belonging to 28 different prey categories. The examined population was mainly composed by generalist individuals, and no differences in number and diversity of prey consumed were observed among salamanders. Contrarily to what has been observed in other Speleomantes species, flying prey provided a minor contribution to the diet of the investigated population. Our study produced the first information on the diet of Speleomantes italicus from the Republic of San Marino, representing the starting point for future assessments on the dietary habits of this specific population. [ABSTRACT FROM AUTHOR]

Asiatic short-tailed shrews (Blarinella and Parablarinella) are small insectivorous mammals distributed mainly in central and southwestern China, and adjacent Myanmar and Vietnam, currently comprising three species. In 2021, we collected five specimens of Asiatic short-tailed shrews in the Dabie Mountains, eastern China, which is geographically distant from the known distribution of the taxa. Herein, we integrated molecular and morphometric approaches to assess the taxonomy, phylogeny, and divergence of Asiatic short-tailed shrews. Our results indicate that the specimens collected from Dabie Mountains represent a new species, formally described here. The new species is morphologically distinguishable from other Asiatic short-tailed shrews by the combination of a triangular upper P4, lighter feet color, relatively broader skull, and more curved outline of tooth row of P4–M3. Phylogenetic analyses indicate the new species is sister to P. griselda , and the p -distance of Cyt b between the two species is 8.3%. The divergence between the new species and P. griselda occurred ca. 3.08 million years ago and may have been affected by East Asia's topographic and climate changes in the late Pliocene. [ABSTRACT FROM AUTHOR]

Floronia huishuiensis Zhou & Xu, sp. nov. (♂♀) is the first species in the genus Floronia to be described from Baiyan Cave in Guizhou Province, China. The new species is similar to F. zhejiangensis Zhu, Chen & Sha, 1987 but differs in structural details of the genital organs, primarily by the presence of a well-developed retrolateral tibial apophysis, a hook-shaped distal end of the radix in the male palp, and the rectangular posterior median plate in the epigyne. The illustration of copulatory organs of F. bucculenta (Clerck, 1757) and F. zhejiangensis Zhu, Chen & Sha, 1987 were reproduced here for comparison. A detailed description, photographs of the habitus and copulatory organs of the new species and a distribution map is provided. [ABSTRACT FROM AUTHOR]

Phylum Tardigrada is represented by microscopic eight-legged panarthropods that inhabit terrestrial and marine environments. Although tardigrades are emerging model animals for areas of research including physiology, evolutionary biology, and astrobiology, knowledge of their external morphology remains insufficient. For instance, homologies between marine and terrestrial relatives largely remain unexplored. In the present study we provide detailed pictures of the head sensory organs in a new tardigrade, Ramazzottius groenlandensis sp. nov. Specimens were collected from a mixed moss and lichen sample on Ella Island, East Greenland. The new species differs from congeneric species in the presence of polygonal sculpturing on the dorsal cuticle, which is accentuated in the posterior region of the body, a lateral papilla on leg IV, and distinctive egg morphology. A Bayesian phylogenetic analysis (18S rRNA + 28S rRNA + COI) places the new species within the genus Ramazzottius with high confidence. Interestingly, the new species shows a full set of well-developed cephalic organs, which correspond to all sensory fields found in eutardigrades. Details on the full set of head organs were present only for heterotardigrades. The surface of these organs is covered with small pores, which presumably play a sensory role. This discovery suggests the homology of head sensory structures between heterotardigrades and eutardigrades, implying that the distinctive arrangement and positioning of sensory organs on the head is a plesiomorphic feature of tardigrades. Moreover, we find that the Ramazzottius oberhaeuseri morphotype forms a morphogroup, not a monophyletic species complex. [ABSTRACT FROM AUTHOR]

Fish morphology is incredibly plastic and local/resident morphology can be influenced by factors including habitat, predation, resource availability, and water velocity. Through analysis of body shape using geometric morphometrics, we describe the degree of phenotypic plasticity within a generalist fish species resident to low‐order tributaries of Green Bay and Lake Michigan. We predicted that isolated populations of creek chub (Semotilus atromaculatus) would display plastic responses in body shape due to differences in selective pressures imposed by stream environments. We show that body shape of creek chub was significantly different between streams which are considered to be isolated populations, and while we expected body shape variation to remain constant between study years, we found that shape was not fixed and changed over time in the same manner among focal streams. The diversity of creek chub diet and degree of agricultural land use in the watershed were significant predictors of body morphology. The effect of resource availability and land use within the watershed demonstrates how selective pressures influence phenotypes at the population level. Our study provides insight into morphological changes of stream fish populations, which may be important in the context of changing ecosystems and novel conditions. [ABSTRACT FROM AUTHOR]

The increasing microplastic pollution in the marine environment has raised global concern. The main risk of microplastics in aquatic ecosystem is their bioaccumulation in aquatic organisms. A few studies have reported microplastic pollution in the digestive system of Caspian Sea fish species, but there is no research on sturgeon species, nor on fish gills. We investigated the occurrence of microplastics in the gastrointestinal tract (GIT) and gills of 62 specimens belonging to four species including three teleosts (Cyprinus carpio, Rutilus kutum, and Chelon aurata) and one sturgeon (Acipenser persicus, a valuable endangered species) from the Caspian Sea between January and March 2022. Fish tissues were removed, exposed for 24 h to 10% KOH, and then dried on filter paper. Particles were observed under a stereomicroscope and analyzed by Raman microspectrometry, scanning electron microscopy, and energy‐dispersive spectroscopy. A total of 91 microplastics were detected in the GIT (average of 1.46 ± 1.17 items/individual) and 63 microplastics in the gills (average of 1.01 ± 0.62 items/individual). A significant correlation was not found between the number of microplastics found in both tissues and fish body length, body weight, GIT weight, and gill weight (p > 0.05), except between microplastics isolated from gills and gill weight in C. carpio (rs = 0.707, p = 0.022). The abundance of microplastics in fish followed the order of A. persicus > C. aurata > R. kutum > C. carpio. The microplastics were in the size range of 45 to 5000 µm, with particles of 300 to 1000 µm being the most prevalent; 74.68% of the particles were shaped like fibers, 30.53% were red, and 70.6% were composed of nylon polymer. Environ Toxicol Chem 2023;42:2453–2465. © 2023 SETAC [ABSTRACT FROM AUTHOR]

Multiple indicators have been used to assess the degree of exposure of fish to anthropogenic chemicals in their stream habitats. We hypothesized that brook stickleback (Culaea inconstans) in a headwater stream receiving urban and agricultural runoff (South Fork Whitewater River, SFWR) would exhibit poorer condition, reduced reproductive fitness, and a greater left side to right side morphological asymmetry (i.e., fluctuating asymmetry or FA) than fish from a nearby headwater stream with a forested drainage basin (Garvin Brook). Male and female fish were collected from both streams just prior to spawning in 2013–2015. In 2013 and 2014, fish were assessed for overall condition (Fulton's K), internal measures of condition (hepatosomatic index, HSI) and reproductive fitness (gonadosomatic index [GSI], total oocyte count, and oocyte mass). In 2015, measurements of head length, jaw length, eye diameter, pectoral fin length, and pelvic fin length were made on both sides of each fish for assessing degree of FA. We observed declining condition with fish size, increased liver size, and reduced oocyte counts and oocyte size in female brook stickleback in SFWR relative to those from Garvin Brook. SFWR females had significantly higher FA than Garvin females for all structures assessed, except pelvic fin length. FA also was slightly higher for all structures in SFWR males compared to Garvin males, but differences were not significant. A composite FA index combining all measurements from an individual fish into a single value displayed highly significant differences for female fish (SFWR FA >> Garvin FA), but not for male fish (SFWR FA = Garvin FA). Exposure of brook stickleback to reduced water quality in SFWR during early development appears to increase morphological asymmetry in female (but not male) fish, and continuing exposure to compromised water quality throughout life impacts both general condition and reproductive fitness of stickleback, especially older female fish, in SFWR. [ABSTRACT FROM AUTHOR]

H.G. Moser was not particularly well known regarding the Elopomorpha, but he began his seminal 1981 fish larvae morphology review by describing the mysteries of European eels and their leptocephali, and he eventually described some California Current leptocephali. Descriptions of all types of leptocephali and then microscope photographs have revealed complex pigmentation patterns and diverse body shapes that parallel the features of the other teleost fish larvae that his review showed so clearly, some of which appear to mimic gelatinous zooplankton (GZ). Most recently, underwater photographs and video of leptocephali indicate that predator avoidance through transparency, shape-change-mediated mimicry, or morphological features have evolved in response to natural selection from predation in ways generally similar to other fish larvae. Several families of leptocephali perform remarkable curling into round or flattened shapes or use expandable chromatophores when threatened, which appears to mimic GZ for predation reduction. Like a number of other teleost fish larvae, some leptocephali have body extensions or telescopic eyes, and at least one has a long caudal filament with pigmented swellings that is similar to the remarkable GZ mimicry appendages of some fish larvae. The morphology and use of mimicry of leptocephali in comparison to other fish larvae is reviewed as a tribute to H.G. Moser's remarkable career. [ABSTRACT FROM AUTHOR]

Previous studies have shown that Nannochloropsis gaditana can partially replace fishmeal in the diet of gilthead seabream, Sparus aurata. However, its effect on muscle growth is hardly known. This experiment was carried out with gilthead seabream adults that were fed with N. gaditana at two inclusion levels (2.5 or 5%) either raw (R2.5 and R5 groups) or cellulose-hydrolyzed (H2.5 and H5 groups) for 45 days in the final fattening phase. The body length and body weight were measured in all fish at the beginning and end of the experiment. Also, the white muscle transverse area (WM), size, number and fibrillar density of the white fibers were measured in 9 fish group−1. After 45 days, the body parameters and the WM did not show significant differences among the groups. However, muscle cellularity did show significant differences, such that the hypertrophy values were higher in the H2.5 and H5 than in the R2.5 and R5 groups. On the contrary, R2.5 and R5 showed the highest fibrillar density and hyperplasia values, which are often positively correlated with the fillet firmness and therefore could improve the final quality of the fish. No significant differences attributable to the inclusion levels of N. gaditana were observed. [ABSTRACT FROM AUTHOR]

Obliquogobius trifasciatus sp. nov. (Teleostei: Gobiidae) is described on the basis of three specimens (29.5–30.5 mm in standard length) collected in the East China Sea, northwest of the Ryukyu Islands, southern Japan, in a depth of 115–124 m. The new species is characterized by the following combination of characters: 2nd dorsal and anal fins each with I, 9 rays; head moderate in size, its length 32.8–34.1% of standard length; lateral surface of nape scaled; postorbital pore G of cephalic sensory canal present; gill opening moderate in size, extending anteriorly to level with posterior margin of eye; pelvic fins united medially, with a well-developed connecting membrane (between innermost rays) and frenum (between spines); caudal fin dorsoventrally asymmetrical, lacking a distinct obliquely pointed tip, and with three lowermost branched rays much shorter than other branched rays; three broad black (dark brown in preserved specimens) bands, superposed by yellow chromatophores, on lateral surface of body, anteriormost band located under 1st dorsal-fin base, middle band just behind a vertical line through posterior end of 2nd dorsal-fin base, and posteriormost band on caudal-fin base; a small faint, yellow-tinged dusky blotch on center of caudal peduncle (between middle and posteriormost bands on body); a large black blotch, covering almost entirety of 1st dorsal fin; 2nd dorsal and caudal fins generally pale yellow, without a barred pattern. [ABSTRACT FROM AUTHOR]

Background: The starry puffer fish (Arothron stellatus, Anonymous, 1798) is a poisonous tetradontidae fish inhabiting the Red sea. The skin constitutes an important defense against any external effects. The study aims to characterize the dorso-ventral skin of the juvenile and the adult starry puffer fish using light and scanning electron microscopies. Twenty specimens of juvenile and adult fresh fishes were used. Results: The scanning electron microarchitecture of the skin of the juvenile and adult fish showed delicate irregular-shaped protrusions, and well-defined bricks-like elevations on the dorsal side and interrupted folds as well as irregular-shaped protrusions on the ventral side. In adult fish, the patterned microridges of the superficial and deep epithelial cells (keratinocytes) were larger and well-defined in the dorsal skin than in the ventral side, the contrary was seen in the juvenile fish. The microridges were arranged in a fingerprint or honeycomb patterns. The openings of the mucous cells were more numerous in the dorsal skin in both age stages but more noticeable in adult. Furthermore, the sensory cells were more dominant in the juveniles than the adults. The odontic spines were only seen in adult. Histologically, few taste buds were observed in the epidermis of the dorsal skin surface of the adult fish. Both mucous and club cells were embedded in the epidermis of the juvenile and adult fish with different shapes and sizes. Melanophores were observed at the dorsal skin of both juvenile and adult fishes while fewer numbers were noticed at the ventral surfaces. Several dermal bony plates with different shapes and sizes were demonstrated in the skin of both adult and juvenile fishes. Conclusion: The structural variations of skin of the juvenile and adult fishes may reflect the various environmental difficulties that they confront. [ABSTRACT FROM AUTHOR]

Simple Summary: The millipede assassin bugs are well known for their prey specialization. In this study, we examined the fine structures of the antennae, mouthparts, and legs of four genera and species of ectrichodiines using a scanning electronic microscope and compared them with those in Tribelocephalinae, a lineage closely related to Ectrichodiinae. We found that ectrichodiines possess distinctly more slightly transverse ridges on the mandibles, which probably facilitate stabilizing mandibular stylets in prey tissues. The small papillae on the legs are considered to adapt to immobilize millipedes. Overall, our study illustrates, at a microstructural level, the remarkable morphological adaption of prey manipulation in ectrichodiines, which will facilitate future studies on the adaptive evolution of feeding habits in Reduviidae. Species in Ectrichodiinae are known for their prey specialization on millipedes. However, knowledge of the morphological adaptations to this unique feeding habit was limited. In the current study, we examined the microstructures of the antennae, mouthparts, and legs of four millipede feeding ectrichodiines, Ectrychotes andreae (Thunberg, 1888), Haematoloecha limbata Miller, 1953, Labidocoris pectoralis (Stål, 1863), and Neozirta eidmanni (Taueber, 1930), and compared them with those of three species of tribelocephalines, a group closely related to Ectrichodiinae. On the antennae, we found four types of antennal sensilla. On the mouthparts, we recognized four types of labial sensilla. Sampled ectrichodiines have distinctly more and denser slightly transverse ridges on the external side of mandibles than tribelocephalines. E. andreae and H. limbata possess numerous small papillae fringed with densely arranged finger-print-like grains on the trochanter and femur; these probably facilitate the immobilization of prey. Overall, our study illustrates, at a microstructural level, the remarkable morphological adaption of prey manipulation in ectrichodiine, and has enhanced our understanding about stenophagy in the family Reduviidae. [ABSTRACT FROM AUTHOR]

Phyllodistomum is the large digenean group of fish parasites, with 25 species described so far in the Indian subcontinent. Here, we redescribed two adult species of Phyllodistomum (P. srivastava Rai 1964 and P. parorchium Jaiswal 1957) collected from freshwater fish Heteropneustes fossilis Bloch, 1974 and Glossogobius giuris Ham, 1822, respectively, and an unknown Phyllodistomum metacercaria from shrimp (Macrobrachium dayanum Henderson, 1893). These parasites were genetically characterized using 28S and first and second internal transcribed spacers (ITS1 and ITS2) regions of the nuclear ribosomal DNA and CoxI region of the mitochondrial (mt) DNA to establish the link between metacercaria and adult. Morphologically, both the unknown metacercaria in shrimp and adult Phyllodistomum srivastava in fish, resembled in terms of crenulated margin of hind body, arrangement of diagonal testes, bipartite seminal vesicle, and compact paired vitelline masses. The two adult parasite species, P. srivastava from P. parorchium, were different in terms of shape and size of the body, ratio of suckers, the absence of crenulated margin of hind body, a single chambered seminal vesicle, and deeply lobed paired vitelline masses, in the former species. Comparison of the 28S, ITS, and mtCoxI sequence data suggested P. srivastava and Phyllodistomum metacercaria belong to the same species, and supported the distinction between P. srivastava and P. parorchium. Exploring the potential impact of Phyllodistomum infection on host behaviour and health would be prospective areas for future research. [ABSTRACT FROM AUTHOR]

With the sustainable development of intelligent fisheries, accurate underwater fish segmentation is a key step toward intelligently obtaining fish morphology data. However, the blurred, distorted and low-contrast features of fish images in underwater scenes affect the improvement in fish segmentation accuracy. To solve these problems, this paper proposes a method of underwater fish segmentation based on an improved PSPNet network (IST-PSPNet). First, in the feature extraction stage, to fully perceive features and context information of different scales, we propose an iterative attention feature fusion mechanism, which realizes the depth mining of fish features of different scales and the full perception of context information. Then, a SoftPool pooling method based on fast index weighted activation is used to reduce the numbers of parameters and computations while retaining more feature information, which improves segmentation accuracy and efficiency. Finally, a triad attention mechanism module, triplet attention (TA), is added to the different scale features in the golden tower pool module so that the space attention can focus more on the specific position of the fish body features in the channel through cross-dimensional interaction to suppress the fuzzy distortion caused by background interference in underwater scenes. Additionally, the parameter-sharing strategy is used in this process to make different scale features share the same learning weight parameters and further reduce the numbers of parameters and calculations. The experimental results show that the method presented in this paper yielded better results for the DeepFish underwater fish image dataset than other methods, with 91.56% for the Miou, 46.68 M for Params and 40.27 G for GFLOPS. In the underwater fish segmentation task, the method improved the segmentation accuracy of fish with similar colors and water quality backgrounds, improved fuzziness and small size and made the edge location of fish clearer. [ABSTRACT FROM AUTHOR]

Simple Summary: Activities such as the digestion and absorption of feeds occur into the gastrointestinal tract (GIT), which also serves to excrete waste products of digestion. These processes occur thanks to the different species of microorganisms inhabiting the GIT, the microbiota, which contribute to the health status of fish by providing metabolic benefits and counteracting pathogen infection. The microbiota is affected by environmental conditions and by the dietary habits of fish species, and it may be modulated by the administration of feed additives based on prebiotics and probiotics. These represent a very useful tool to improve the health status of fish since they are able to enhance gut efficiency, nutrient uptake, defense against pathogens, and growth performance, as may also be assessed by histological endpoints. Overall, a better understanding of the appropriate administration of feed supplements for individual fish species is a promising strategy for improving of the quality and sustainability of the aquaculture sector. The gastrointestinal tract (GIT) promotes the digestion and absorption of feeds, in addition to the excretion of waste products of digestion. In fish, the GIT is divided into four regions, the headgut, foregut, midgut, and hindgut, to which glands and lymphoid tissues are associated to release digestive enzymes and molecules involved in the immune response and control of host-pathogens. The GIT is inhabited by different species of resident microorganisms, the microbiota, which have co-evolved with the host in a symbiotic relationship and are responsible for metabolic benefits and counteracting pathogen infection. There is a strict connection between a fish's gut microbiota and its health status. This review focuses on the modulation of fish microbiota by feed additives based on prebiotics and probiotics as a feasible strategy to improve fish health status and gut efficiency, mitigate emerging diseases, and maximize rearing and growth performance. Furthermore, the use of histological assays as a valid tool for fish welfare assessment is also discussed, and insights on nutrient absorptive capacity and responsiveness to pathogens in fish by gut morphological endpoints are provided. Overall, the literature reviewed emphasizes the complex interactions between microorganisms and host fish, shedding light on the beneficial use of prebiotics and probiotics in the aquaculture sector, with the potential to provide directions for future research. [ABSTRACT FROM AUTHOR]

Dryocampa kendallin. sp.—a diminutive North American saturniid—is described from buckeye-rich bottomlands of the Hill Country of Texas. Adults have subdued yellow and pink maculation and often a dusky aspect that distinguishes them from their eastern sister species D. rubicunda. While the new species COI barcode differs from that of D. rubicunda by only 1.3%, the adult, larva, and hostplant association differ from those of D. rubicunda. The adult, eggs, larva, and genitalia of the new species are illustrated and its life history briefly characterized. [ABSTRACT FROM AUTHOR]

Fishes, including elasmobranchs (sharks, rays, and skates), present an astonishing diversity in inner ear morphologies; however, the functional significance of these variations and how they confer auditory capacity is yet to be resolved. The relationship between inner ear structure and hearing performance is unclear, partly because most of the morphological and biomechanical mechanisms that underlie the hearing functions are complex and poorly known. Here, we present advanced opportunities to document discontinuities in the macroevolutionary trends of a complex biological form, like the inner ear, and test hypotheses regarding what factors may be driving morphological diversity. Three-dimensional (3D) bioimaging, geometric morphometrics, and finite element analysis are methods that can be combined to interrogate the structure-to-function links in elasmobranch fish inner ears. In addition, open-source 3D morphology datasets, advances in phylogenetic comparative methods, and methods for the analysis of highly multidimensional shape data have leveraged these opportunities. Questions that can be explored with this toolkit are identified, the different methods are justified, and remaining challenges are highlighted as avenues for future work. [ABSTRACT FROM AUTHOR]

Parasites play a key but overlooked role in the functioning of marine systems. Understanding the drivers of parasite infection in fish is thus crucial. Anisakis levels in the Atlantic horse mackerel Trachurus trachurus resulted from both biotic and environmental drivers. Ontogenic variation of the diet was the first driver of Anisakis level. The nonlinear pattern confirmed that the variation in parasitism was related to ontogenetic dietary shifts. The impact of depth on diet also explained the effect of depth on parasites. In deeper areas, fish only access pelagic prey, where Anisakis presence is high, consistent with the pelagic nature of the parasite. Finally, relative proportions of parasitic burden by tissue appeared to be driven by lipid content. In lipid-rich species like T. trachurus, Anisakis can find favorable conditions in the body cavity and in muscle and avoid the liver. Parasitism levels in fish are thus the result of patterns at play at different levels, and these factors should be better considered before being able to include parasites in an integrated vision of marine ecosystem functioning. [ABSTRACT FROM AUTHOR]