Fish Surgery

Enucleation in a Cownose Ray (Rhinoptera bonasus)

“…A safe and effective anaesthetic protocol can contribute to a successful surgical outcome [ 7 ]. Injectable anaesthesia such as ketamine [ 14 ] can be employed in sharks.…”

“…However, MS-222 is acidic in aqueous solution with pH of approximate 3 and must be evaluated in marine system before induction although salt water contains adequate inherent buffering [ 18 ]. Eugenol (Clove oil) can result in rapid induction and prolonged recovery when compared to MS-222 but has a narrow margin of safety which may be seen as respiratory failure in higher dose [ 7 ]. Isoeugenol (brand name: Aqui-S) which is structurally similar to eugenol was effective at low concentration compared to eugenol and has less adverse reaction [ 18 ], although it will caused impaired ventilation and cardiovascular depression [ 19 ].…”

“…Ocular damage can occur in a female Cownose Ray during mating season in aquarium setting resulting from avoidance from being mated by aggressive male rays, limited space, presence of plenty artificial decorations, and anatomical structure of the forehead [ 5 , 13 ]. Enucleation is the best option for case of severe ocular trauma if the traumatized eye was not viable [ 7 ]. This procedure also yielded a good outcome because impaired vision was not necessary to affect predatory behaviour of a Cownose Ray [ 17 ].…”

“…The Cownose was left in the anaesthetic bath for 10 minutes until its ventilation rate ceased to 40 breaths per minute and dropped in pectoral fin stroke activity ( Figure 3 ). Later she was transferred by using canvas hammock to surgical tank with wet towel at the bottom and covered with another wet towel on her dorsum to maintain skin moisture [ 7 ] ( Figure 4 ). The maintenance of surgical plane and establishment of rebreathing system was done by flushing water with anaesthetics agent through the gills via right spiracle (respiratory opening caudal to eye) with a 20 mL syringe.…”

“…The Cownose was presented in ventral recumbency and assistants aided in restraining by gently exerting force at the dorsum as a part of tonic immobilization. Routine skin preparation around the left eye was done by using diluted chlorhexidine gluconate (dilution ratio 1 : 30) and diluted povidone iodine (dilution ratio 1 : 30) [ 7 ].…”