P. V. Esipova, M. A. Solovyeva, V. V. Rozhnov, E. G. Mamaev, I. V. Suvorova, V. A. Yachmen - Blood Cell Morphology of Common (Harbor) Seals <i>Phoca vitulina</i> Linnaeus, 1758 from the Commander Islands

BIOLOGIYA MORYA, 2025, Vol. 51, No. 2, pp. 101-110

Blood Cell Morphology of Common (Harbor) Seals Phoca vitulina Linnaeus, 1758 from the Commander Islands

¹Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok 690041, Russia;
²Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow 119071, Russia;
³Marakov National Park "Commander Islands", Kamchatka Krai, Aleutsky District, Nikolskoye Village 684500, Russia;
⁴Center of Oceanography and Marine Biology "Moskvarium", Moscow 129223, Russia

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The blood cells of common (harbor) seals, Phoca vitulina L. 1758, from the Commander Islands population are characterized in detail for the first time. Data on composition, size and ratio of erythrocytes, leukocytes, and platelets in the peripheral blood of immature and mature seals are given. A micrograph library for all types of peripheral blood cells of harbor seal is presented. The blood cells morphology of this seal generally corresponds to that of other pinniped species; however, neutrophils with Dohle bodies, reactive lymphocytes, and hypersegmented neutrophils were found in blood smears. An increased number of eosinophils (10-25%) were observed in the leukocyte formula of all seals examined. Mature seals had higher numbers of eosinophils (p = 0.04) and large lymphocytes (p = 0.005); immature seals had higher numbers of monocytes (p = 0.04) and Howell–Jolly bodies in erythrocytes (p = 0.03). Microfilariae and nucleated erythrocytes were found in blood smears of two mature seals.

Key words: common seal, harbor seal, Phoca vitulina, blood cells morphology, leukocyte formula, erythrocytes, leukocytes, platelets.