Correlations of capture, transport, and nutrition with spinal deformities in sandtiger sharks, Carcharias taurus, in public aquaria

Baseline Health and Nutritional Parameters of Wild Sand Tigers Sampled in Delaware Bay

Species-specific hematological reference values are essential for diagnosis and treatment of disease and maintaining overall health of animals. This information is lacking for many species of elasmobranchs maintained in zoos and aquaria, thus reducing the effectiveness of care for these animals. Descriptive statistics and reference intervals were calculated for hematocrit and complete blood cell counts, biochemistry and protein electrophoresis parameters, trace minerals, vitamins, heavy metals, reproductive hormones, and fatty acids in the blood of 153 wild Sand Tigers Carcharias taurus of both sexes and a range of sizes caught in Delaware Bay (Delaware, USA). Mean hematocrit, total white blood cell counts, lymphocyte differentials, glucose, phosphorus, amylase, and aspartate aminotransferase levels were significantly higher in juveniles than in adults. Levels of estradiol, progesterone, testosterone, and differences in selenium and eicosapentaenoic acid (a polyunsaturated fatty acid) between males and females suggest that they are important parameters for improving Sand Tiger breeding success in managed care. Finally, blood metal levels for arsenic, cadmium, lead, and mercury suggest low levels of contaminant exposure for Sand Tigers during their summer residence in Delaware Bay. The results of this study provide baseline health parameters for wild Sand Tigers that will aid in effective maintenance of aquarium animals and contribute to a greater understanding of the biology of these sharks and efforts to accomplish sustainable management of their populations.

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.

Considerations for Treatment of Large Zoologic Collections: Fish

Aquatic species live most or all their lives in water; therefore, the health of the environment is intimately connected to their health and medical care. Understanding and maintaining appropriate husbandry and nutrition for the housed aquarium species are essential to sustain health. Most diseases of fish are secondary opportunistic infections; prevention and early diagnosis are recommended. Treatments involve environmental and/or nutritional management first, followed by targeted pharmacologic treatment to control a specific pathogen. Pharmacokinetic research evaluating the effects and safety of medications in fish are greatly needed in the peer-reviewed literature.

Serum biochemical reference intervals for free-living Sand Tiger sharks (Carcharias taurus) from east Australian waters

BACKGROUND

Sharks are top-order predators in ocean food chains and the star attractions in aquaria worldwide. Unfortunately, blood biochemistry reference intervals (RI) have been determined for few species.

OBJECTIVE

The study aims to establish serum biochemical RI for free-living Sand Tiger sharks (Carcharias taurus) off eastern Australia.

METHODS

Thirty-seven sharks were captured and their sex, length, weight, reproductive maturity, and health status were recorded. After blood collection, serum analytes were quantified using standard analytical and statistical methods. Reference intervals, means, medians, and 90% confidence intervals were generated. Physiologic data from live and necropsied sharks were used to enhance the study results.

RESULTS

Thirty healthy sharks were included in the study. Albumin could not be detected. With the exception of ALP activity, values were unaffected by sex, length, weight, age, and life-history stage. The means (RI) were: sodium 258 (249-267) mmol/L, potassium 5.0 (4.3-5.7) mmol/L, chloride 242 (227-257) mmol/L, inorganic phosphate 1.8 (1.7-2.0) mmol/L, total calcium 3.9 (3.3-4.4) mmol/L, magnesium 1.9 (1.6-2.2) mmol/L, glucose 2.7 (2.2-3.2) mmol/L, urea 377 (360-394) mmol/L, ALP 20 (8-31) U/L, ALT 3 U/L (no RI), AST 29 (13-45) U/L, CK 42 (5-79) U/L, total protein 30 (24-36) g/L, triglyceride 0.3 (0.1-0.6) mmol/L, cholesterol 1.4 (0.9-2.1) mmol/L, creatinine 32 μmol/L (no RI), total bilirubin 1.5 μmol/L (no RI), and osmolarity 1082 (1027-1136) mmol/L.

CONCLUSIONS

These preliminary RI will assist with the clinical evaluation and treatment of captive and free-living Sand Tiger sharks worldwide. Studies with more animals will increase the precision of upper and lower reference limits.

Supplements for exotic pets

The use of supplements has become commonplace in an effort to complement traditional therapy and as part of long-term preventive health plans. This article discusses historical and present uses of antioxidants, vitamins, and herbs. By complementing traditional medicine with holistic and alternative nutrition and supplements, the overall health and wellness of exotic pets can be enhanced and balanced. Further research is needed for understanding the strengths and uses of supplements in exotic species. Going back to the animals' origin and roots bring clinicians closer to nature and its healing powers.

Mechanical properties of sand tiger shark Carcharias taurus vertebrae in relation to spinal deformity

Approximately 35% of sand tiger sharks Carcharias taurus in public aquaria exhibit spinal deformities ranging from compressed vertebrae and loss of intervertebral space to dislocated spines with vertebral degeneration and massive spondylosis caused by excessive mineralization both within vertebrae and outside the notochordal sheath. To identify the mechanical basis of these deformities, vertebral centra from affected (n = 12) and non-affected (n = 9) C. taurus were subjected to axial compression tests on an MTS 858 Bionix material testing system, after which mineral content was determined. Vertebral centra from affected sharks had significantly lower mineral content and material behavior in nearly all variables characterizing elasticity, plasticity, and failure. These mechanical deficiencies are correlated with size at capture, capture method, vitamin C and zinc deficiency, aquarium size, and swimming behavior in public aquaria. Non-affected C. taurus had greater stiffness and toughness even though these properties are generally incompatible in mineralized structures, suggesting that the biphasic (mineralized, unmineralized phases) nature of chondrichthyan vertebrae yields material behavior not otherwise observed in vertebrate skeletons. However, vertebral centra from non-affected sharks had lower mineral content (33%), stiffness (167 MPa), yield strain (14%), and ultimate strength (16 MPa) than other species of sharks and bony vertebrates, indicating that biomechanical precautions must be taken in the husbandry of this species.