Ultrasound-guided sampling of the lateral abdominal vein in the grey nurse shark (Carcharias taurus, Rafinesque 1810).

The paired lateral abdominal veins (LAV) provide alternative venipuncture sites in grey nurse sharks (Carcharias taurus, Rafinesque 1810) and their efficacy was assessed using morphometrics, necropsies, ultrasound-guided blood sampling and by comparing serum biochemistry between the LAV and caudal vein (CV) with values from the latter published previously. The mean length of the CV was 2.8% of total length (TL) whereas each LAV was 22.4% of TL and, when combined, was approximately 16 times longer than the CV. The mean tissue thickness overlying each LAV increased significantly (p < .001) with increasing TL and ranged from 3.5 to 33.8 mm in the smallest to largest shark. The mean internal diameter of the paired LAV also increased significantly (p < .001) with increasing TL and was equal to or exceeded the CV. Experienced SCUBA divers captured 56 free-living grey nurse sharks and 46 healthy animals were sampled for blood from the LAV and CV with minimal risk to the animals or staff. Venipuncture of the LAV (n = 16) was easily accomplished using ultrasound guidance with a 38 mm/18-gauge needle, whereas standard methods were used with the CV (n = 30). Serum biochemistry was compared (t-tests) and none of the biochemical analytes differed significantly between the LAV and CV. The paired LAV produced representative blood samples and could also be used for fluid therapy and/or intravenous anaesthesia as has been done in other sharks. It is recommended that veterinary/husbandry staff familiarize themselves with the paired LAV and consider their use in the future.