prof. HDR. MSc. Volodimir Sarabeev, PhD.
senior researcher
parasitology, helmintholgy
Since I was young, my life has revolved around research in a biological station on the Azov Sea, where work on the introduction and growing of the so-iuy mullet was in progress. I was fascinated by parasite biodiversity and parasitic life forms that predetermined the further choice of my job. I got a Ph.D. in parasitology and research leadership qualification in the domain of life science and health. My main area of research is the study of parasitological aspects of introduced hosts in marine ecosystems. Since 1997, I work on parasites of Planiliza haematocheila, which was deliberately introduced in the Azov-Black Seas from the Sea of Japan. My early studies were focused on the taxonomy, morphology and phylogeny of grey mullet parasites, and shifted recently on host-parasite relationships and community ecology. As monogenean parasites are being co-introduced, my taxonomic and phylogenetic studies were predominantly focused on this group. The taxonomic work resulted in the description of 17 new species (all described in co-authorship): 10 monogeneans, 2 digeneans, 2 acanthocephalans and 2 myxosporeans. Between 2004 and 2009, I supervised the PhD thesis of Nataliya Rubtsova. We reviewed the taxonomy of 39 species of Ligophorus (Monogenea: Dactylogyridae) in the Atlantic and Pacific areas. Among them, 33 were considered valid species of Ligophorus, one incertae sedis, one species inquirendae, two junior synonyms and two species were allocated in a new genus. Through the detailed analysis of the morphology, we defined diagnostic features useful for the identification of grey mullets dactylogyrids. The taxonomy of dactylogyrids from grey mullets was re-evaluated from a phylogenetic reconstruction based on the analysis of 38 morphological characters, confirmed by a tree built from molecular data (28S rDNA and ITS1 DNA sequences). This result supports the monophyly of Ligophorus. In collaboration with Yves Desdevises, we suggested that host switching is a common event in the evolution of this host-parasite association, following dispersal via vicariance and parallel speciation.
I supervised the PhD thesis of Ievgen Tkach. We have worked on the taxonomy and phylogeny of acanthocephalan parasites. The taxonomic status of Neoechinorhynchus agilis was reviewed from morphology and two new species in this genus were described. More recently, we obtained 18S rRNA partial sequences from Neoechinorhynchus spp., and their analysis confirms our morphological observations.
In collaboration with Serge Morand and Juan Antonio Balbuena, we studied the patterns of parasite infection and distribution in the introduced so-iuy mullet across its native and invasive ranges. We proposed an original concept regarding the mechanisms acting in host-parasite systems that ensure the success of a host introduced in new areas. We used the comparative approach at different organizational (populations and communities) and hierarchical (infra- and component community) levels, applying epidemiological (abundance and prevalence) and ecological (species richness, aggregation, abundance-occupancy and abundance-variance relationships) parameters. We showed this is a useful tool to uncover the hidden relationships in invasive host-parasite systems. This is the first comparative analysis that combines different approaches and various helminth taxa to show how the spatial distribution of parasites in hosts is linked to their invasive nature. We showed that co-invasive and acquired parasite species could be detectable using different macroecological models. This approach can be used to assess how invasive hosts integrate new ecosystems, and to predict their invasive potential. In addition, I studied larval digeneans to investigate the impact of native naïve parasites on fry and juveniles of so-iuy mullet in the Sea of Azov. I showed that metacercariae, especially Timoniella imbutiforme, are associated with the mortality of juvenile P. haematocheila. Fish lost due the parasite was estimated to more than 50% for the first-year cohort born in the Molochny Estuary.
I supervised the PhD thesis of Ievgen Tkach. We have worked on the taxonomy and phylogeny of acanthocephalan parasites. The taxonomic status of Neoechinorhynchus agilis was reviewed from morphology and two new species in this genus were described. More recently, we obtained 18S rRNA partial sequences from Neoechinorhynchus spp., and their analysis confirms our morphological observations.
In collaboration with Serge Morand and Juan Antonio Balbuena, we studied the patterns of parasite infection and distribution in the introduced so-iuy mullet across its native and invasive ranges. We proposed an original concept regarding the mechanisms acting in host-parasite systems that ensure the success of a host introduced in new areas. We used the comparative approach at different organizational (populations and communities) and hierarchical (infra- and component community) levels, applying epidemiological (abundance and prevalence) and ecological (species richness, aggregation, abundance-occupancy and abundance-variance relationships) parameters. We showed this is a useful tool to uncover the hidden relationships in invasive host-parasite systems. This is the first comparative analysis that combines different approaches and various helminth taxa to show how the spatial distribution of parasites in hosts is linked to their invasive nature. We showed that co-invasive and acquired parasite species could be detectable using different macroecological models. This approach can be used to assess how invasive hosts integrate new ecosystems, and to predict their invasive potential. In addition, I studied larval digeneans to investigate the impact of native naïve parasites on fry and juveniles of so-iuy mullet in the Sea of Azov. I showed that metacercariae, especially Timoniella imbutiforme, are associated with the mortality of juvenile P. haematocheila. Fish lost due the parasite was estimated to more than 50% for the first-year cohort born in the Molochny Estuary.