Shark and ray radiography: keep the clinical question in frame

A cartilaginous skeleton does not make radiography irrelevant to sharks and rays. Mineralised cartilage, teeth and other calcified structures can be visible, as can some foreign material and changes in body shape. The examination is most valuable, however, when the team agrees on a clinical question before capture. An unfocused search for “anything abnormal” may simply add another handling event and produce images that are hard to interpret.

In a public aquarium, logistics shape diagnostic quality. Species, size, behaviour, respiratory needs, pool access and the route to the imaging area all matter. The aim is not a cosmetically perfect plate at any cost. It is to obtain enough reliable information while protecting the animal and the people involved.

Start with the decision the image must support

Radiographs may help investigate an abnormal spinal contour, dental disease, trauma, altered mineralisation or a radiopaque foreign object. Unusual gas patterns can also redirect a differential diagnosis. Soft-tissue contrast remains limited, though. A suspected mass, inflammatory lesion or organ disorder may require ultrasound, endoscopy, laboratory testing or another imaging method.

The request should identify the anatomical region, affected side, time course, relevant events and previous findings. Standardised photographs and measurements taken in water help define the field. If a deformity is being assessed, the team should agree which projections are essential and which are optional if the animal remains stable.

Elasmobranch anatomy is highly diverse. A flattened ray, a small benthic shark and a large pelagic shark cannot share a single handling recipe. Reference images from the same species and a comparable life stage can reduce the risk of labelling normal anatomy as disease.

Design a short, wet and rehearsed pathway

Before capture, the team checks every item, rehearses transfers and assigns responsibilities. The detector is protected from water according to its manufacturer’s instructions, supports are ready, the floor is secure and radiation-safety controls are in place. Exposure settings can be estimated from measured thickness or checked with an appropriate phantom; they should not be improvised while an animal is restrained.

The contact surface should be wet, smooth and padded. Body weight must be distributed without compressing gills, spiracles, the abdomen or fins. Large animals require a sling or stretcher shaped for them and enough trained handlers to prevent twisting and falls. If assisted gill irrigation is part of the veterinary protocol, its hoses, water supply and backup are prepared before transfer.

Water used for ventilation must remain appropriate in temperature, oxygenation and chemistry. A temperature shift or poorly adjusted flow can turn a brief examination into a physiological problem. The route must allow immediate return to suitable water if breathing, colour, muscle tone or monitored variables deteriorate.

Restraint does not automatically mean anaesthesia

Some small, calm individuals may tolerate very brief physical restraint. Others require anaesthesia after veterinary assessment of species, size, temperament, respiratory status and expected benefit. A drug dose or technique reported for one elasmobranch should not be extrapolated to another species.

Anaesthesia does not replace good planning. It adds induction and recovery phases, requires monitoring and needs a contingency plan. Conversely, extending conscious restraint to chase an ideal image may increase stress and injury risk. A written protocol should therefore set simple stopping points: maximum duration, maximum attempts, respiratory or motor warning signs, and the minimum image quality that answers the question.

Branchial ventilation remains central. Animals that depend strongly on forward movement, and compromised patients, demand particular care. The veterinarian decides what to monitor and records observations throughout the procedure, including recovery in an appropriately quiet, controlled space.

Prefer a small number of comparable views

The beam is centred on the region of interest and collimated. When safe, the detector is kept close to reduce magnification and motion blur. Side markers and a radiopaque scale belong in the field without covering anatomy. For spinal studies, straight and reproducible positioning is crucial: a curve imposed by the support can imitate or exaggerate a deformity.

Orthogonal projections are often desirable, but feasibility depends on the animal. A dorsoventral view may be straightforward in a ray while a lateral view requires substantial adaptation. Several focused exposures may be safer in a large shark than an attempt to include the entire body. The clinical question, not a rigid standard series, should decide.

Interpretation must return to the history and examination. A radiograph documents structure at one point in time; it does not prove cause. The clinicopathological report of a sandtiger shark with spinal deformity shows why imaging, clinical progression and tissue findings need to be combined. Anderson and colleagues found correlations between capture, transport, nutritional histories and spinal deformities across aquariums, but retrospective associations do not establish one mechanism for an individual shark.

Turn the study into a useful baseline

A carefully archived baseline becomes valuable during follow-up. The record should retain exposure data, positioning, orientation, measurements, restraint conditions, medication if used and respiratory events. Repeat images only become comparable when geometry is reproduced; a positioning difference should not be mistaken for progression.

The report separates observations, interpretation and uncertainty. It explains limitations caused by superimposition, movement or incomplete coverage, then recommends only those additional tests likely to alter management. When a finding fits the history but is nonspecific, explicit caution prevents disproportionate decisions.

Every procedure should end with a short team review: time away from the pool, image quality, safety events, recovery and whether the result changed care. That feedback improves equipment and workflow before the next case. Vetofish can help aquarium teams frame the imaging question, build a species-appropriate procedure and integrate radiographs into a complete clinical assessment.