Ethics Guidelines

Part A - Guidelines for Projects Involving Work on Free-living Vertebrates

Section 4.1 - Sedation and/or Anaesthesia of Seals

The specific modifications to the respiratory system and cardiovascular anatomy and physiology of phocid seals which are associated with diving, present problems for the safe sedation or anaesthesia of these species. In particular, the dive response consists of apnoea and bradycardia which may cause anoxia in the vital tissues of anaesthetised animals, and changes in the peripheral circulation which can result in pooling of drugs in the circulation and dramatically reduced response to the administration of emergency drugs. Collapsible upper airways can obstruct air flow despite the apparent movement of chest wall and nostrils. Thermoregulation can be compromised by the administration of some drugs. Species idiosyncracies, changes in body condition, state of excitement of the animal, proximity to water, substrate, presence of conspecifics, weather conditions, age and sex, can all influence choice of technique and dose rate. Anaesthetic protocols for some species are still developmental, requiring a deep understanding of anatomy, physiology, pharmacology, anaesthetic monitoring and resuscitative techniques. Protocols for other species are well established and can be practised with safety by experienced field personnel.

It is recommended that:

Where an established protocol is to be employed (>80 successful procedures in that species with less than 5% mortality), there be at least one operator with a working knowledge of the procedure and its associated problems in that species, patient monitoring, and relevant resuscitative techniques.
Where a technique is developmental (<80 successful procedures in that species or >5% mortality), there be one veterinarian in the party with experience in anaesthesia (preferably of wild animals) and a thorough knowledge of pinniped anaesthesia, and one operator with knowledge of the behaviour of that species.
Unless contraindicated, atropine should be used as a pre-medication, with due consideration to lactational status of animals, to decrease upper respiratory tract secretion and possibly prevent bradycardia.
During chemical restraint the following parameters should be monitored and recorded throughout the procedure: respiratory rate and depth, heart rate, gum colour (if sufficiently sedated), pupil size (if sufficiently sedated), rectal body temperature (if sufficiently sedated), depth of anaesthesia, drugs and doses administered and time to effect and recovery. Monitoring during chemical restraint has been discussed (Woods, R. 1994, pp 67-83). Those interested in detailed information on monitoring of anaesthetics in seals are referred to this document.
The operator should be in possession of and familiar with the use of resuscitative drugs (ie reversal agents, adrenaline, doxapram) and equipment (endotracheal tubes, solid mouth gags and oxygen demand/resuscitation valve, oxygen, flow meter (optional) and nasal tubing (optional). Indications for the use of supplementary ventilation are - apnoea, unproductive breathing, off pink or blue gums, dilated pupils. If the animal is too awake to allow safe tracheal intubation, it can be ventilated through a nasal tube by pinching off the nostrils around the tube, but this is much less effective. The operator should be aware that laryngeal spasm, apnoea, regurgitation and operator injury are all potential complications with tracheal or nasal intubation. The use of mouth to tube ventilation is much less effective than positive pressure oxygen and carries with it the risk of disease transmission (eg TB transmitted from pinnipeds to humans).
A summary of anaesthetic records is to be submitted at the completion of the season. This information is to be made available to future operators and permits should be issued on the condition that the operator possesses this information from at least the last 20 procedures on the relevant species and age/sex.
Remote injection techniques (darts, pole syringes, extension tubing) be used where physical restraint is deemed dangerous to the operator or animal (see physical restraint Section 1). Operators using these techniques should be properly trained in their safe use.
If a seal dies during anaesthesia, the Antarctic Animal Ethics Committee (AAEC) Secretary is to be notified immediately at aaec@aad.gov.au. A post-mortem should be conducted to investigate the cause of death and a report forwarded to the AAEC Secretary as soon as is practical after the event, but no longer than three days after the death. Work with anaesthesia should cease until the Committee has considered this report and confirmed approval to proceed.
The operator must have a relatively accurate method for determining the mass of the seal prior to drug administration in order to calculate dose rate, with particular care taken to consider fat loss during the moult and lactation.
The operator must have a means of re-establishing normal body temperature, (e.g. heat packs, ice packs, water, shade, etc.) if thermoregulatory problems occur.
The seal must be observed until all visible drug effects have dissipated. During this recovery time it must be protected from attack by other animals.
The operator must reduce, to a negligible level, the chance that the animal will return to the sea in a sedated or disoriented state.
Neuromuscular blocking agents must not be used for anaesthetic purposes without appropriate prior general anaesthesia.
Operators should be aware of the relevant first aid procedures in case of accidental injection of a human.

Chemical capture

Air and carbon dioxide powered dart rifles and those which have sound modifiers may be used where circumstances require it and in the hands of a skilled operator. Fur seals and elephant seals have been darted routinely with blow pipes (Baker et al. 1990, Boyd et al. 1990). When darting is used, mechanisms must be in place to reduce, to a negligible level, the chance that the animal will return to the sea in a sedated or disoriented state.

An anaesthetics trial for leopard and crabeater seals was conducted during the 1996-97 season. This trial included the initial administration of low dose-rate anaesthetics remotely via dart guns to determine suitable dose rates. Once suitable dose rates had been established they were delivered via the dart gun method to minimise/eliminate physical contact and disturbance.

(ASP&C)
May 2002

See also table of Guidelines for seal anaesthesia

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