Journal of Ichthyology最新文献

Abstract

Cytogenetic studies in Sturisoma are rare; this genus had 11 valid species distributed in basins in South America. In this article, we aimed to expand on the cytogenetic data available for Sturisoma, contributing to the record of the karyotype and other chromosomal characteristics of both minor and major ribosomal DNA of S. barbatum from the upper Paraguay River basin. This population had diploid chromosome number 66, a karyotype composed of 20 metacentric, 14 submetacentric, 14 subtelocentric, and 18 acrocentric chromosomes, and a fundamental number of 114 for both sexes. Heterochromatic regions were observed in the short arms of the nucleolus organizer regions (NOR)-bearing chromosome pair. Fluorescence in situ hybridization revealed a single 18S site and multiple 5S ribosomal DNA sites. Data from NORs confirmed the tendency of this family to present simple NORs sites, as well as multiple sites of 5S ribosomal DNA. Pericentric inversions (or other types of centromeric shift) and/or deletions appear essential in the karyotype evolution and differentiation among S. barbatum. The present data are valuable to help in understanding karyotypic evolution in Loricariidae.

Abstract

The analysis results for morphological variability in the Lower Amur grayling Thymallus tugarinae, one of the five species of grayling fish (Thymallinae) inhabiting the Amur River basin has been reported. Overall, 16 samples of juvenile specimens of the same size class, collected in different parts of the habitat area, are analyzed. A discriminant analysis revealed high-level morphological speciation in grayling fish from different rivers, based on the classification accuracy comprising, on average, 96%. The hiatus in a range of morphological traits was revealed, when comparing certain samples. Clustering classified the grayling fish into groups considered morphologically different because of the variable habitat conditions. The fish from the rivers of the Amur River estuary area were well differed from each other by the morphotype, despite the similarity of the rivers conformed to the same comparatively small region. The graylings inhabiting different sections of a large river were more morphologically distinct, than the fish of small rivers isolated from each other. In addition, increases or shift in the limits of variations of the values of the morphological diagnostic traits of the species were revealed.

Abstract—

The results of a study of the ovaries and testes of the Pacific ocean perch Sebastes alutus are presented based on the materials collected in the spring of 2019 and 2021 in the Bering Sea. Histological methods were used to accurately determine the phases of maturity and to visually identify the scale of gonad maturity. The maturity scale includes IX maturity phases for ovaries, and VI phases for testes. Females are characterized by synchronous development of larvae and their hatching; males have multiple-batch spawning. After larvae hatching, the gonads of females are transformed to the developing phase IX–III. According to the physiological state of the gonads, three groups of individuals were identified which differ in size: immature, maturing and mature, taking part in the current year spawning. The maturation of the gonads in the Pacific ocean perch begins at a fork length of 25 cm (FL), 50% of individuals became mature at a fork length of ∼30 cm, and the maturation of all fish occurs at 35 cm or more.

The study of diversity in characters of the skull in generalized and specialized morphotypes of the large African barbs Barbus (Labeobarbus auctorum) in Ethiopia is carried out using the multivariate analysis methods. It has been proven that in Lake Tana exhibiting great diversity in morphotypes, the eigenvector loadings on the first principal component of characters of bones, which form the jaws, compose a distinct self-standing cluster in specimens of a generalized form reaching over 15 cm in length. In barbs inhabiting other lakes, where only a generalized form is found, the lack of such cluster is observed, while the eigenvector loadings on the second principal component generate a cluster similar in composition. The same pattern is discovered in the Altai osmans (genus Oreoleuciscus) in Lake Orog within the Central Asian Closed Basin (Mongolia). In this case, however, the specimens of the generalized form tend to exhibit the characters of a bigmouth form after transition to feeding on fish whereas the progeny of bigmouth barbs in Lake Tana exhibit the parental characters even in the aquarium-based experiments. It is assumed that in the Altai osmans from Lake Orog we observe an early stage of morpho-ecological divergence between forms, when it is still reversible, while the divergence at a later stage, when it is irreversible, is detected in the barbs from Lake Tana, which may be regarded as an example of genetic assimilation.

Abstract

The inner ear position and structure, related parts of the brain and neurocranium, as well as the morphology of the lapillus, sagitta, and asteriscus, are described in climbing perch, an obligate air-breathing fish capable of terrestrial movements. The olfactory bulbs and telencephalon are well developed. The dorsal protrusion with two symmetrical lobes is observed on the dorsal posterior surface of the telencephalon. The almost triangular rear part of the brain capsule and a narrow posterior region of the neurocranium represent the border of the suprabranchial chamber. The pars superior of the inner ear is located along the internal triangular part of the brain capsule, and both crus communis and ductus semicircularis posterior are located close to each other in the narrow extreme rear region of the brain capsule. The sacculus is enclosed in the large oval bony capsule (saccular swelling), and the sagitta is large with the average otolith length–total body length (TL) ratio equal to 0.06. Linear growth of the lapillus and sagitta is characterized by negative allometry in relation to body length. Despite the slow growth rate of the lapillus, its shape substantially changes during the growth of the fish 36–205 mm TL that, most likely, reflects increasing locomotion complexity. Possible adaptations of climbing perch inner ear to terrestrial movements are discussed.

Abstract

The article presents an illustrated description of early larvae of the smooth lumpsucker Aptocyclus ventricosus from Avacha Bay and Vilyuchinskaya Bay in southeastern coast of Kamchatka. The larvae differ from previously described larvae from Japanese and Korean waters in their earlier development: the urostyle bending, the formation of fin rays, and the development of pigmentation occur earlier. The growth of the larvae is uneven. The head and torso increase in relation to the length of the body, while the tail part practically does not grow. Eye diameter, maxillary length, and the length of the pectoral fin rays relatively decrease. The first dorsal fin is difficult to distinguish, which can cause difficulties in the larva diagnoses. The larvae are coastal, lead an attached lifestyle.

Abstract

The palatability of L-α- and D-α-isomers of alanine, aspartic and glutamic acids, and tryptophan, as well as L-α- and L-β-isomers of alanine for the Mozambique and Nile tilapias (Oreochromis mossambicus and O. niloticus, respectively), golden mbuna Melanochromis auratus, lemon cichlid Neolamprologus leleupi, and the tailbar cichlid Vieja hartwegi has been compared. Consumption of agar-agar pellets with L-α- and D‑α-isomers of aspartic and glutamic acids and tryptophan differs in Mozambique tilapia and tailbar cichlid, pellets with alanine and tryptophan, in golden mbuna, with aspartic acid and tryptophan, in lemon cichlid, and with aspartic acid, in Nile tilapia. The palatability of L-α- and L-β-isomers of alanine is significantly different for the Mozambique tilapia, lemon cichlid and tailbar cichlid. The feeding behavior exhibited by cichlids during orosensory testing of pellets is similar and little depends on the palatability of the pellets. All cichlids make a small number of rejections and repeated grasps of pellets; most cichlids retain pellets in the oral cavity many times longer in experiments that ended by consumption. The different taste properties of optical and structural isomers of amino acids for the studied cichlids confirm the species specificity of taste preferences in fish and indicate the importance of these substances as chemical regulators of trophic relationships in aquatic communities.

Abstract—

The structure of the olfactory organ is studied in five species of anemonefishes of the genus Amphiprion: A. polymnus, A. clarkii, A. frenatus, A. perideraion, and A. ocellaris. All fish have one nostril, olfactory rosette of the arrow-shaped type with no secondary folding on olfactory lamellae, and two ventilation sacs (ethmoidal and larger lacrimal). The rosette is located on the medial (A. clarkii and A. perideraion) or ventromedial (A. polymnus, A. frenatus, and A. ocellaris) sides of the olfactory cavity; the number of lamellae in the rosette increases as a fish grows. The greatest total number of lamellae is 24 in A. polymnus. Intercalary (in four species) and dichotomous (in three species) lamellae are found in the rosette of most anemonefishes, which is an extremely rare case in other fishes. Atypical lamellae emerge later than regular ones in the ontogeny of the fish, but their number in different parts of the rosette differs between anemonefishes, and in some A. polymnus species, lamellae are predominantly atypical. The slope of the medial and lateral sides of the rosette toward the openings of the ventilation sacs (A. polymnus and A. frenatus) is considered a structural adaptation that improves water exchange near the surface of the olfactory lamellae and reception of odor information by the fish. The relationship between the structure of the olfactory organ and the generality of anemonefishes, their specialization, and strength of association with symbiotic sea anemones has not been revealed. The idea of an evolutionary trend from a simple structure of the olfactory organ (A. clarkii) to a morphologically more complex structure (A. polymnus and A. frenatus) in the genus Amphiprion after early separation from the general stem of the subgenus Actinicola (A. ocellaris and A. percula) is presented.

Abstract

The paper describes the first finding of the European hake Merluccius merluccius (Linnaeus, 1758) in the northern part of the Black Sea, off the coast of Crimea, in December 2022 with a sea surface temperature of 13°C. The individual was found in the catch of a bottom trap installed at a depth of 24 m. The specimen with a total body length of 30.6 cm and a weight of 213.5 g was a sexually mature 3 years old male. According to the results of back-calculations obtained during the analysis of the otolith section, the individual growth of the caught fish occurred as follows: the total length was 17.7, 25.5, and 30.6 cm by the end of the first, second, and third years of life, respectively. No food items have been found in the gastrointestinal tract of the caught specimen. The geographical variability of the hake life cycle is considered. The species reaches its maximum size and age at high latitudes and at low water temperatures. Presumably, the maximum size and age of the hake in the Black Sea may be slightly higher than in the Mediterranean Sea, but lower than in the Northeast Atlantic. The prospects for further resettlement and increase in the number of the hake in the Black Sea are analyzed. Apparently, low salinity and competition with the native ichthyofauna may prevent successful naturalization of the species. However, the continuation of the trend of increasing salinity of the Black Sea under warming conditions will increase the possibilities of the hake naturalization.

Abstract

This study investigated the sagittal otolith morphometry of the red mullet Mullus barbatus inhabiting the Aegean, Black Sea and Mediterranean coastal waters of Turkiey. In the comparison of otolith shape of M. barbatus, elliptic Fourier and Wavelet analyses were used as well as otolith shape indices with multivariate statistical techniques. Totally, 180 specimens were examined for otolith shape analyses. Otolith shape indices, including form factor, aspect ratio, circularity, roundness, and rectangularity, have been determined. A principal component analysis and canonical discriminant analysis were carried out for the discrimination of the three M. barbatus populations. The PERMANOVA test was used to evaluate differences between populations. The overall classification success for the canonical discriminant analysis in separating red mullet in these three seas was 53.9% in elliptic Fourier analysis and 57.8% in wavelet analysis. The Aegean and Mediterranean Seas have the highest classification success rates, at 65%. Elliptic Fourier analyses (68.6%) separated the Black Sea from the Mediterranean and Aegean Seas while Wavelet analyses (69.3%) separated the Aegean Sea from the Mediterranean and Black Seas.