Morphological characteristics of haemocytes and haemogram of the red king crab

Based on the materials of research work in July-August 2023 on board the R/V ‘Professor Boiko’ in the Barents Sea, the haemolymph parameters of the Kamchatka crab Paralithodes camtschaticus are presented. Haemolymph samples were taken from the heart of 9 freshly caught crabs, then preparations were made immediately in a Goryaev chamber and haemocytes were counted in all large squares of the Goryaev chamber. Agranulocytes, semigranulocytes, granulocytes and transparent cells were noted among the haemolymph cells, which is generally similar to the crustacean haemolymph. The size and morphological characteristics of the cells of the haemocytic series of the Kamchatka crab are similar to those of other invertebrate species such as Fenneropenaeus chinensis, Paranephrops planifrons, Hyas araneus, Homarus americanus, Panulirus interruptus, Loxorhynchus grandi, Astacus astacus, Astacus leptodactylus. The dominant type in haemolymph is agranulocytes, their proportion averaged 42.1±5.4% for the moult stages studied. The proportion of semi-granulocytes and granulocytes is 32.2±3.1 and 22.8±3.9%, respectively, and the proportion of clear cells is 2.9±0.6% of all cellular elements in haemolymph. The percentage of haemocytes in haemolymph at different stages of the larval cycle of male Kamchatka crab differed but not significantly at p > 0.05. The total number of haemocytes ranged widely from 1719 to 11250 units/μL, with an average cell count of 4.2±1.1 ×109 cells/L. Differences in hemolymph BSF at different stages of the larval cycle of male Kamchatka crab were also statistically unreliable (p > 0.05).