Differences in hematocrit of blood samples obtained from two venipuncture sites in sharks.
OBJECTIVE
To evaluate differences in Hct between 2 venipuncture sites in captive and free-ranging sharks.


METHODS
32 healthy adult captive sharks (Carcharhinus melanopterus, Carcharhinus plumbeus, Stegastoma fasciatum, Orectolobus japonicus, and Triaenodon obesus) and 15 captured free-ranging adult sharks (Carcharhinus limbatus and Carcharhinus acronotus).


METHODS
Blood samples were collected from the caudal tail artery followed by collection from the sinus located immediately caudal to the cranial dorsal fin. The Hct was determined for each sample and results were compared. Additionally, results for sharks that were highly active and used aerobic metabolism were compared with results for sharks that were less active and tolerant of anaerobic conditions.


RESULTS
Mean Hct for all sharks was significantly less (8% less) in blood samples obtained from the cranial dorsal fin sinus, compared with the Hct for samples obtained from the caudal tail artery. When compared on the basis of metabolic class, sharks that were more tolerant of anaerobic conditions had lower Hct values and smaller differences between the 2 venipuncture sites.


CONCLUSIONS
Hct values were significantly lower in blood samples collected from the cranial dorsal fin sinus compared with values for samples collected from the caudal tail artery. It is important to recognize this difference when evaluating hematologic variables in sharks and when establishing reference ranges for Hcts for shark populations. Sharks that were more active and relied on aerobic metabolism had higher Hct values than did anaerobic-tolerant sharks, and the difference in Hct values between venipuncture sites was more pronounced.
Mylniczenko
Natalie D
ND
John G. Shedd Aquarium, 1200 S Lake Shore Dr, Chicago, IL 60605, USA.
Curtis
Eric W
EW
Wilborn
Rachel E
RE
Young
Forrest A
FA
D000704:Analysis of Variance; D000818:Animals; D001800:Blood Specimen Collection / Q000662:veterinary*; D001808:Blood Vessels; D006400:Hematocrit / Q000662:veterinary*; D012754:Sharks / Q000097:blood*; D013045:Species Specificity