 This results from an increased hematocrit and mean cellular hemoglobin content (MCHC).The erythrocyte content in the blood ranges from 2.13-2.90 million/l which is at least twice that of adult Atlantic salmon, reflecting the active nature of southern bluefin tuna.Because the MCHC is high, more blood can be delivered to tissues without an increase in energy used to pump more viscous blood.