Animal Science and Zoology, Aquatic Science, Ecology, Evolution, Behavior and Systematics, Agricultural and Biological Sciences
17
Scopus Publications
Scopus Publications
Assessment of the size distribution of the big-scale sand smelt (Atherina boyeri Risso, 1810) in the diet of the Caspian seal (Pusa caspica Gmellin, 1788) using fish otoliths from fecal samples Mirgaliy Baimukanov, Akzhan Iskakov, Anuar Shagilbayev BMC Zoology, 2025 Big-scale sand smelt (Atherina boyeri) is an euryhaline pelagic schooling fish found throughout the Caspian Sea. A specialized fishery does not target this species, and its body length can reach up to 13 cm. A. boyeri serves as prey for many omnivorous and predatory fish and is one of the primary food sources for the Caspian seal (Pusa caspica). The objective of this study was to determine the size composition of A. boyeri in the diet of P. caspica, a declining species of the Caspian Sea. A coprological method was used, involving the collection of seal feces during spring and autumn haul-outs in the Northern and Middle Caspian, followed by examination of fish otoliths. Before this, otoliths from fish were analyzed to assess morphological diversity and growth patterns in relation to Atherina boyeri. Equations were developed to estimate fish length from otolith length and width. Otoliths from feces were classified into three wear categories: lightly, moderately, and heavily abraded. A comparison of otolith sizes from fish and feces allowed the calculation of wear coefficients based on otolith length for each group, which were incorporated into the reconstruction formula. The reconstructed fish length distribution showed that at the Northern Caspian haul-outs, individuals measuring 60-70 mm predominate, while at the Middle Caspian haul-out, individuals measuring 80-90 mm are most common. Overall, this is the first study to confirm that P. caspica feeds on both juvenile and mature A. boyeri, with lengths ranging from 23.1 to 117.1 mm.
Rapid decline of Caspian Sea level threatens ecosystem integrity, biodiversity protection, and human infrastructure Rebecca Court, Matteo Lattuada, Nataliya Shumeyko, Mirgaliy Baimukanov, Tariyel Eybatov, Altynay Kaidarova, Elchin V. Mamedov, Eldar Rustamov, Aselle Tasmagambetova, Matthias Prange, Thomas Wilke, Christopher Hassall, Simon J. Goodman Communications Earth and Environment, 2025 The Caspian Sea is the world’s largest landlocked waterbody, providing habitat for hundreds of endemic and migratory species, along with ecosystem services that sustain millions of people. Global warming is projected to drive declines in water levels of up to 21 m by 2100. Using geospatial analyses, we assessed the impact of sea level decline on habitats, protected areas, and human infrastructure. We show that a water level decline of just 5–10 m will critically disrupt key ecosystems (including habitats for endemic Caspian seals and sturgeon), reduce existing marine protected area coverage by up to 94%, and render billions of dollars of civil and industrial infrastructure obsolete. Replacing traditional static conservation planning with a pre-emptive, dynamic approach that allows protected areas to track shifting ecosystems, is recommended to help endemic Caspian Sea biodiversity adapt to these changes, and to avoid conflicts with mitigation efforts directed at protecting human activities.
Assessment of the fish diet of the Caspian seal (Pusa caspica Gmelin, 1788) during haul out periods on island sites: results, challenges, and perspectives Mirgaliy Baimukanov, Anuar Shagilbayev, Akzhan Iskakov, Assel Baimukanova Frontiers in Marine Science, 2025 The Caspian seal (Pusa caspica), an endemic and endangered obligate piscivore of the Caspian Sea, faces threats to its existence, notably from the reduction of its food resources. Pollution, sea regression, overfishing, and the introduction of non-native species have negatively impacted the seal’s food base. The seals annually gather in haul‐outs during the spring and autumn, a span of approximately 4–6 months. The diet of seals during these critically important periods of life is poorly understood. The fish diet of the P. caspica was assessed by analyzing fish otoliths found in fecal samples collected at haul-out sites in the Northern and Middle Caspian Sea from 2015 to 2022. A total of 8,630 fish otoliths and their fragments were recovered from the fecal samples. The taxonomic status was determined for 94% of the otoliths. Their taxonomic identification was carried out using a reference collection of otoliths obtained directly from 323 individuals representing various fish species. Brief descriptions were made of otoliths from 14 fish species representing Clupeidae, Gobiidae, Cyprinidae, Mugilidae, and Atherinidae. For Cyprinidae, the asteriscus and lapillus were described; for all others, the sagitta. The dietary diversity of seals during their haul-out periods was determined at the species level for golden grey mullet (Chelon auratus) and big-scale sand smelt (Atherina boyeri); at the genus level for shad (Alosa) and tyulka (Clupea); and at the family level for gobies (Gobiidae) and cyprinids (Cyprinidae). Gobies dominate the diet (79.34%), followed by big-scale sand smelt at 15.99%. According to Margalef’s richness index, the diet was more diverse in the deepwater Middle Caspian region. In the future, investigating the seals’ diet in relation to fish distribution at haul-out sites will significantly contribute to understanding their adaptation to rapidly changing conditions and the development of conservation measures for key habitats of this endangered marine mammal of the Caspian Sea. Establishing a comprehensive database of fish otoliths from various regions of the sea is essential for investigating their morphological polymorphism and for applying DNA barcoding in the future to achieve a more accurate assessment of the species composition in the diet of the Caspian seal.
Alien Rainbow Trout Oncorhynchus mykiss in the Balkhash Basin (Kazakhstan, Central Asia): 50 Years of Naturalization Nadir Shamilevich Mamilov, Marlen Tursynali, Gulnur Kuanyshkyzy Khassengaziyeva, Jan Urban, Dinara Bartunek, Sayat Ermukhanbetovich Sharakhmetov, Nazym Sapargaliyeva, Zhansulu Urgenishbayeva, Gulnar Bolatovna Kegenova, Eleonora Kozhabaeva, Mirgaliy Baimukanov, Boris Levin Animals, 2024 Rainbow trout, or mykiss (Oncorhynchus mykiss), is one of the most popular species used in aquaculture and has been naturalized worldwide, including in the Central Asian Balkhash basin, which has unique aboriginal fish fauna. Both rainbow trout from European farms and wild mykiss from Kamchatka were introduced to some mountain lakes and rivers of the Balkhash basin about 50 years ago. This study investigates the current distribution and life history traits of the alien species and its possible impact on the local fish fauna. This study showed that the rainbow trout occupies various habitats in the Ili River basin: mountain lakes, fast-flowing mountain rivers, and lowland rivers with slow currents and warm water (up to +27 °C). Rainbow trout from European fish farms dominate the mountain Middle Kolsay Lake, while the wild trout from Kamchatka occupies the small Ulken Kokpak River. Both co-occur in the Chilik River. Contrary to that in other regions, the distribution of rainbow trout in the Balkhash basin remained almost the same after their introduction. Broad intrapopulation variability in terms of size, growth rate, and maturation age was revealed, apparently as a result of adaptation to the new environment and intrapopulation competition. In particular, the growth rate has decreased, but life span, surprisingly, has increased as compared to the originally introduced fish. Intrapopulation variation in growth and maturity patterns was also noted. Differences in skin coloration between highland (cold-water) and lowland (warm-water) populations were discovered. The feeding mode of naturalized trout is insectivorous (insect imago), indicating that it occupies its own niche in the local fish communities. The largest population of rainbow trout was recorded in the Lower Kolsay Lake, lowering the population of native fish species, while in other localities, no negative impact on local fish communities was recorded.
Exposure of wild Caspian seals (Pusa caspica) to parasites, bacterial and viral pathogens, evaluated via molecular and serological assays Aidyn Kydyrmanov, Kobey Karamendin, Yermukhammet Kassymbekov, Marat Kumar, Shynar Mazkirat, Symbat Suleimenova, Mirgaliy Baimukanov, Ian M. Carr, Simon J. Goodman Frontiers in Marine Science, 2023 Disease surveillance of marine mammal populations is essential to understand the causes of strandings, identify potential threats to animal health, and to support development of conservation strategies. Here we report the first large multi-pathogen screening of prevalence for viruses, bacteria and parasites in a sample of 177 live, healthy, wild Caspian seals (Pusa caspica), captured and released during satellite telemetry studies 2007-2017. Employing molecular and serological assays we assess prevalence of pathogens known to be of significance for marine mammal health worldwide, and evaluate the results in relation to Caspian seal health and conservation. RT-PCR, and PCR assays find evidence for infection by Canine Distemper Virus (CDV), Phocine herpes virus, phocine adenovirus and Influenza A at prevalences of 5%, 6.4%, 21.7%, and 4% respectively. The genomes of CDV isolates collected in 2008 showed 99.59% identity with the 2000 Caspian seal CDV epizootic strain. A partial coding sequence for the Us2 gene from the Caspian seal herpes virus was identical to PhHV-1 isolate PB84, previously reported from a harbor seal (Phoca vitulina), while amplicon sequences for the adenovirus polymerase gene indicated a novel strain. ELISA assays detected exposure to Influenza A (55% of tested samples), adenovirus (25%), coronavirus (6%), CDV (8%), herpes virus (94%), Toxoplasma gondii (2.6%) and heartworm (1%). Hemagglutination inhibition (HI) tests detected exposure to Influenza B at a prevalence of 20%, and Leptospira microscopic agglutination tests detected suspected exposure to Leptospira serovars in 9% of tested samples. Overall, the risks, profile and prevalence of pathogens in Caspian seals appear comparable to other wild phocid seal populations. Our results suggest Caspian seals have exposure pathways to pathogens with epizootic potential or ability to cause significant morbidity, and that disease impacts could reduce the resilience of the population to other conservation threats. Caspian seals are listed as Endangered by the International Union for Conservation of Nature (IUCN), and we recommend that resources are invested to support further surveillance programs and to understand how anthropogenic pressures may influence future disease risks. A translated version of this abstract is available in Russian and Kazakh in the Supplementary Material (Presentation 1 and Presentation 2)
A Method for Counting and Identifying the Linear Sizes of Caspian Seals (Pusa caspica) on Rookeries Using Multicopters M. T. Baimukanov, L. A. Zhdanko, T. T. Baimukanov, E. S. Dauynev, S. E. Ryskulov, A. M. Baimukanova Biology Bulletin, 2021 A method is developed for processing pictures taken from multicopters in order to identify the number of Caspian seals and their linear sizes on rookeries. A special protocol records the location (coordinates), date, time, survey altitude, the cloudiness across a scale ranging from one to ten, air temperature, wind speed, and picture numbering. A photo software editor (for example, Adobe Photoshop CS5) is used for counting the individuals and taking their measurements. Each seal image is allotted an individual serial number within one picture. By flying over and photographing a rookery at different times of the day, quadcopters allow for an assessment of the daily dynamics of the seal numbers to be made. In cases when the groups under assessment are numerous, counts are recommended to be performed along transects. Knowing the angle of the field of vision (FOV) of the multicopter and the altitude it operates at, the following formula can be applied, “A cathetus lying opposite the angle equals the product of the second cathetus multiplied by the tangent angle,” to calculate the distance between the extreme points of a picture’s diagonal in the International System of Units (m, cm, or mm) (SI). As the resolution in pixels is also known, calculating the size of a pixel in SI can be performed per picture. The measurements of individual seal images in the pictures are converted from pixels into SI units. As a result, the length and the maximum width of the seals can be established, this being of importance for identifying the size structure of the seal concentrations on rookeries. Subsequently, having compiled a size–age key, the age structure of the groups of seals on rookeries can be calculated.
Comparative genetic analysis of grayling (Thymallus spp. Salmonidae) across the paleohydrologically dynamic river drainages of the Altai-Sayan mountain region Steven Weiss, Jacqueline Grimm, Duarte V. Gonçalves, Giulia Secci-Petretto, Gernot K. Englmaier, Mirgaliy Baimukanov, Elsa Froufe Hydrobiologia, 2020 A high number of grayling (Thymallus) species have been described from the Altai-Sayan mountain region, for which little to no genetic information is available. We investigated genetic relationships within this genus of salmonid fishes using mtDNA and microsatellite markers. The analysis focused on three putative species, Markakol grayling (T. brevicephalus), Upper Ob grayling (T. nikolskyi) and Mongolian grayling (T. brevirostris). We integrated these data with mtDNA sequences from eight other grayling species, including two of geographic proximity to the study area. Phylogenetic results revealed three pairs of reciprocally monophyletic sister species, two of which were phylogenetically juxtaposed across isolated drainage systems. Based on microsatellite analysis (up to 10 loci) no evidence of hybridization or introgression was found among species, supporting the mtDNA phylogeny. Based on a time-calibrated tree, divergence times between the focal taxa ranged from 0.36 to 1.1 MY. The genetic data support the distinction of these species and underscore the importance of paleohydrological dynamics in this biogeographically complex region. Well-documented mega-flood events in the region provide a model of how the contemporary cross-basin distribution of these species may have evolved.
