Identifying Two Ectoparasite Species of Mackerel Icefish based on Mitochondrial Gene and Morphology
Research article published in Microsc Microanal (2025)
Abstract
As the most common ectoparasites on mackerel icefish (Champsocephalus gunnari Lönnberg 1905), which has great economic and ecological importance in the Southern Ocean, parasitic copepods and leeches can significantly affect fish health and survival and thus influence the sustainable use of this commercial fishery resource. Accurate identification of these parasites is essential for understanding their specific impacts on hosts and ecosystems, as well as for developing effective fisheries management. This study investigated 34 ectoparasites from 28 C. gunnari specimens at South Georgia in August 2023 using microscopy and mitochondrial cytochrome c oxidase I (CO I) markers. Morphological analysis tentatively identified 10 leeches as Notobdella nototheniae and 24 copepods as Eubrachiella antarctica. Microscopic examinations and morphological measurements revealed marked differences between male and female copepods. Additionally, CO I sequencing confirmed the leeches as N. nototheniae (98.81% similarity) but suggested the copepods were Parabrachiella merluccii (81.97-82.25% similarity). All sequences have been uploaded to Genbank. Maximum Likelihood phylogenetic trees were also constructed using the CO I sequence of both ectoparasites. The 10 leeches were identified as N. nototheniae, and the 24 copepods were E. antarctica in this study.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
34 ectoparasites from 28 Champsocephalus gunnari mackerel icefish at South Georgia; 10 leeches identified as Notobdella nototheniae by morphology and COI sequencing.
Why This Matters for Hirudotherapy
This study investigated the identification of ectoparasites, including parasitic leeches, found on mackerel icefish in the Southern Ocean using morphological and mitochondrial DNA analysis. The researchers examined 34 ectoparasites from 28 fish specimens and successfully identified ten leeches as *Notobdella nototheniae* using COI gene sequencing. While this research accurately documents and identifies specific parasitic leeches affecting commercial fish species, it has no relevance to the American Society of Hirudotherapy. The study is strictly an exercise in marine parasitology and taxonomy, providing no insights into human medical applications, therapeutic secretomes, or clinical use of leeches.
Citation
Identifying Two Ectoparasite Species of Mackerel Icefish based on Mitochondrial Gene and Morphology.
Zheng Z et al. · Microsc Microanal, 2025
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