Plasma biochemistry reference values of wild bonnethead sharks, Sphyrna tiburo

Elasmobranchs (sharks, skates, and rays) are of commercial, sport, research, and exhibit importance, however, blood chemistry reference values have been determined for few of these species.

The purpose of this study was to establish plasma biochemistry and PCV reference values for wild bonnethead sharks (Sphyrna tiburo).

Heparinized blood samples were collected from 24 bonnethead sharks at the time of capture in trawl nets off the coast of South Carolina and Georgia. Weight, length, PCV, total solids (TS, by refractometry), and plasma biochemical analyses were done using standard techniques. Wilcoxon rank-sum and Kendall tau b tests were used to compare values by animal size, boat and sex; 1-way ANOVA was used to compare TS and total protein (TP) concentrations.

Median (quartile; minimum-maximum) values were as follows: PCV 22% (22%, 26%; 17-28%), TS 6.3 (6.0, 6.8; 5.8-7.5) g/dL, total protein 2.9 (2.7, 3.4; 2.2-4.3) g/dL, albumin 0.4 (0.4, 0.4; 0.3-0.5) g/dL, globulins 2.6 (2.3, 3.0;1.9-3.8) g/dL, sodium 282 (279, 285;273-292) mmol/L, potassium 7.3 (6.4, 7.9; 5.7-9.2) mmol/L, chloride 290 (285, 296; 277-304) mmol/L, total CO2 3 (2, 4; 0-5) mmol/L, calcium 16.8 (16.2, 17.4;15.8-18.2) mg/dL, phosphorus 8.8 (7.5, 10.0; 5.9-12.7) mg/dL, urea nitrogen 1004 (986, 1028; 944-1068) mg/dL, creatinine <0.1 mg/dL, glucose 184 (165, 191; 155-218) mg/dL, aspartate aminotransferase 42 (33, 66; 15-132) U/L, lactate dehydrogenase <5 U/L, creatine kinase 82 (47, 233; 18-725) U/L, and osmolality 1094 (1078, 1111; 1056-1139) mOsm/kg. No differences based on sex were detected. TS and TP values were related by the fitted line TS = (1.006 X TP) + 3.318.

Values reported here will be useful for evaluating the health status of bonnetheads in wild and captive research conditions and in exhibits.