Abstract
Cuttlefish are popular animals in public and private aquarium displays and have additionally been used as laboratory and food animals. They are cephalopod mollusks, along with octopus and squid. Like other cephalopods, cuttlefish are characterized by a highly developed neurological system and complex behaviors, contrasted by a relatively brief lifespan, with death typically following shortly after reproduction.
An approximately 10 month old, 220 g female European cuttlefish (Sepia officinalis) from a public aquarium was presented for treatment of an eruptive skin lesion of the dorsal mantle. Radiographs, hemolymph collection, and excisional biopsy were performed under anesthesia with ethanol 1.5-3% in seawater. Elastic and freely mobile skin permitted closure with minimal tension following wide excision around the granulomas. Lesions did not appear to penetrate deep to the underlying cuttlebone. Total anesthesia time was 44 minutes, and recovery was rapid following return to ethanol-free seawater. Biopsy revealed hemocyte granulomas surrounding thin, septate, infrequently branching fungal hyphae, and fungal culture yielded Cladosporium sp. Itraconazole at 5 mg/kg PO daily for 14 days was administered in food items. Skin healed well and the animal recovered to normal feeding and activity levels. Two months following the anesthesia and surgery, the animal was found dead in exhibit. Pathologic examination revealed multisystemic fungal infection.
The moderately long anesthesia event with surgical excision of dermal fungal granulomas was well tolerated by this cuttlefish, with rapid recovery and incision healing. The skin proved to be more mobile, elastic and durable than expected, which facilitated the excision and skin closure. An unanticipated consequence of the skin excision was the loss of one false eyespot, indicating loss of specific nerve endings or chromatophores or both, which might have limited this cuttlefish's intraspecific signaling repertoire or its ability to startle potential predators. Post-mortem findings indicated treatment failure, suggesting that more aggressive excision or more prolonged antifungal treatment would have been warranted. However, female European cuttlefish typically live only 12-14 months, so this animal was near the end of its expected lifespan in any case, and senescence may have contributed to recrudescence of the fungal infection.
Organism complexity, suitably large but manageable size, visual appeal, popularity as exhibit animals and utility as laboratory animals would usually favor individual animal veterinary interventions on the scale described here, when indicated for a cuttlefish patient. An inherent drawback of performing more involved medical and surgical procedures on cephalopods, however, is their pre-programmed brief lifespan. Such procedures might still be useful in some situations, for example, to allow completion of a reproductive cycle.