12 Blood Sample Collection and Preparation in Fish

It is generally recommended to use a general anesthetic to reduce the stress of handling during blood collection in active fish. If a general anesthetic is not used, the procedure of blood collection should take place in less than 30 seconds. Blood collection can be performed without completely removing the fish from the water. Blood collected from major blood vessels generally represents blood in the primary circulation; however lymphatic fluid dilution of the sample is possible. Blood can be collected from elasmobranch fish (cartilaginous fish, such as sharks, rays, and skates) by caudal venipuncture or by using vascular sinus located caudal and slightly ventral to the dorsal fins. The advantage of using the vascular sinus as a site for blood collection instead of venipuncture of the caudal vertebral vessels in large elasmobranch fish is the relative ease of access to the sinus with proper restraint.