Abstract

Introduction

Since the initial survey on spinal problems in captive sandtiger sharks (Carcharius taurus),¹ over ten additional cases have been identified (eighteen reported previously). The clinical presentation is similar to previous descriptions and involves a marked spinal curvature, usually in the region between the pectoral girdle and cranial dorsal fin. Gingival hyperplasia,² permanent protrusion of the jaw, and curled pectoral fins have also been noted in several specimens but it is unknown if the conditions are related. Radiographic studies reveal scoliosis and kyphosis of the vertebral column with single or multiple incremental subluxations and occasional compressed vertebral bodies. Histologic examination of skeletal tissue reveals remodeling, cartilaginous proliferation and degeneration of intervertebral material. Degeneration and fibrosis is noted in the epaxial muscle from affected areas. Numerous etiologies have been suggested including nutritional (dietary excess vs. essential nutrient deficiencies), trauma (capture, transport, aggression), exhibit constraints, musculoskeletal disease and atypical biomechanical stresses (i.e., juxtaposition of an air inflated stomach (typical in this species) to the vertebral column). Although studies have been initiated in many of these areas, given the continuing numbers of cases being reported, obtaining detailed information on each animal is vital to delineate contributing factors. The following guidelines have been developed to assist facilities with collection of as much information as possible.

Data and Sample Guidelines

1.  Newly acquired animals and animals currently on inventory

a.  Sex

b.  Measurements (photographic computerized techniques being developed to enable husbandry staff obtain measurements through acrylic)

i.  Total and precaudal length (cm)

ii.  Girth (cm) (two measurements)

a)  Behind the pectoral fins

b)  Just cranial to the cranial dorsal fin

iii.  Weight (kg)

c.  Blood samples

i.  CBC (EDTA)

ii.  Chemistry panel (serum)

d.  Vitamin/antioxidant levels in serum--protocol and materials to be made available for specific tests, contact address given below; freeze at -80 °F if possible; arrange shipment

e.  Radiographs

i.  As a minimum, radiograph the area between pectoral fins and cranial dorsal fin (DV and lateral)

ii.  If possible do head and full body length (DV and lateral)

f.  Examination of gingival tissue (excessive proliferation, masses, hyperemia)

g.  Behavior and swimming

i.  Hotographs and videos of animal swimming--in transport, after arrival and then periodically throughout it's life

ii.  Observations on how frequently the animal appears to inflate the stomach (this species will gulp air, thought to assist with buoyancy), when it is sitting on the bottom, swim patterns, etc. (quantification may initially be difficult given staffing levels and time constraints, but assessment of any tendencies could enable staff to develop more specific methods)

h.  Capture records

i.  Where the animal was captured (latitude and longitude if possible, GPS)

ii.  Who captured the animal

iii.  Time of year animal was captured

iv.  Method of capture

v.  Length of time it took to capture the animal

vi.  Any problems noted at time of capture

vii.  Any medications given post-capture

i.  Transport records--please provide information for all transport events including transport after capture, transport to holding, transport to exhibit, transport between exhibits, etc.

i.  Type of transport container (dimensions, capacity in gallons)

ii.  Length of transport

iii.  Method of transport--O₂ supplementation, water temps

iv.  Any problems encountered

v.  Any medications given during transport

vi.  If held in temporary holding tanks please note size of tanks and length of time held in these systems

j.  Exhibit records

i.  Size of exhibit--gallonage, dimensions

ii.  Water chemistries, special tests (minerals, trace elements), temperatures

iii.  Elasmobranch only tank or exhibited with teleosts and other animal groups

iv.  Natural vs. artificial seawater (if artificial, what brand or formula are you using)

v.  Open vs. closed systems

vi.  Light cycle, current flow

vii.  Traffic patterns

k.  Feeding records

i.  Amount and type of food, condition of food (fresh or frozen and if frozen--for how long?), supplier

ii.  Frequency of feeding

iii.  Vitamin supplementation

iv.  Method of feeding--broadcast vs. pole fed vs. diver in the water

v.  Kcal of food items if it can be calculated

vi.  Assays for vitamins, antioxidants, nutritional composition

l.  Misc. observations or procedures--transport between exhibits, "burping" (deflating excessively inflated stomachs), aggression, mating, etc.
If possible, do a yearly exam (measurements, bloods, etc.).
If an animal begins to develop spinal curvature, excessive gingival hyperplasia, curved fins, or a permanent jaw drop, please note date when you became first aware of the problem, any preceding events or procedures, how rapidly it appears to progress, and provide some type of visual documentation (photos, videos, radiographs).

2.  On any animal that dies or has to be euthanatized, please do the following (contact address given below to arrange for shipments of certain samples)

a.  Measurements--as listed previously

b.  Radiographs

i.  Head and full length, DV and lateral; radiograph the animal before it is eviscerated; if you note that the stomach is not inflated, please inflate and repeat films

ii.  Special techniques (MRI, CAT scan) B only if possible

c.  Blood samples (pre-euthanasia--as listed previously)

d.  Tissue samples

i.  Formalin--please do a complete necropsy and save tissue samples in 10% buffered formalin; please collect the following: skin, muscle (affected and non-affected), gill, eye, gingival tissue, tongue, esophagus, stomach, intestine, spiral valve, colon, heart, pancreas, spleen, kidney, liver, reproductive tissue, brain and a section of normal spinal column with cord

ii.  Vitamin/antioxidant levels B serum tests only available at this time, tissue studies being planned; contact address below for protocol and materials; freeze at -80°F and arrange shipment

iii.  Lesion area--take a "steak" section that encompasses the lesion area and freeze, preferably at -80°F; arrange for shipment; if unable to ship the specimen, please take samples of any abnormal tissue for histology

iv.  Abnormal jaw B freeze head; arrange for shipment; if unable to ship, please radiograph the head and take samples of any abnormal tissue for histology (gingival tissue, jaw ligaments, mandible, maxilla, etc.)

e.  Photographs, video of affected animals prior to euthanasia

If possible, please send copies of radiographs, photographs, videotapes and histology slides to The Florida Aquarium so that a central library of case material can be established. The full address is: Ilze K. Berzins, Ph.D., D.V.M. The Florida Aquarium 701 Channelside Drive Tampa, FL 33602 phone: (813) 273-0917fax: (813) 209-2067 Email: IBerzins@FLAquarium.org

Acknowledgments

We would like to thank Karla Jeselson, Michael Richard, Brent Whitaker, and Andrew Stamper for their input and critique of these guidelines.

References

1.  Berzins IK, K Jeselson, M Walsh, F Murru, B Chittick, S Mumford, H Martel-Bourbon, SB Snyder, MJ Richard, H Land, R Lerner. 1998. Preliminary evaluation of spinal deformities in the sandtiger shark (Odontaspsis taurus). International Aquatic Animal Medicine Proceedings. 29:146-147.

2.  Campbell TW, D Buesse, MT Walsh, R Davis. 1994. Fibromyxomatous gingival proliferation in a sandtiger shark (Eugomphodus taurus). Proceedings of the American Association of Zoo Veterinarian. pp. 186-187.