Captive parturition and neonatal growth of the dwarf ornate wobbegong (Orectolobus ornatus de Vis, 1883)

• Published in: Zoo biology 2019-10, Vol.38 (5), p.442-447
• Main Authors: Otway, Nicholas M., Ellis, Megan T., Housefield, Graham
• Format: Article
• Language: English
• Subjects: Animal Husbandry; Animals; Animals, Newborn - growth & development; Animals, Zoo; Aquariums; Australia; Breeding; Captive breeding; chondrichthyes; demersal; Euthanasia; Feeding regimes; Female; Females; Growth rate; Litter Size; Male; Males; Monitoring; Neonates; Orectolobidae; Orectolobus ornatus; Parturition; Predation; Pregnancy; shark; Sharks; Sharks - growth & development; Survival; Tanks; Ultrasonic imaging; Ultrasound
• ISSN: 0733-3188; 1098-2361
• DOI: 10.1002/zoo.21503

Neonatal predation in multispecies aquarium exhibits can prevent detection of captive breeding by wobbegong sharks. We used ultrasonography and isolation strategies to prevent neonatal predation and maximize survival/growth of the dwarf ornate wobbegong (Orectolobus ornatus de Vis, 1883). We captured seven free‐living wobbegongs (two males and five females) and subjected each animal to a health assessment which led to the euthanasia of one female with a retained hook. Ultrasonography showed that females were pregnant, one was preovulatory, and one was in a resting phase. Two females (one pregnant) and one male were placed in isolation in each of two tanks. In October 2006, 25 neonates were born overnight with the two litters placed into separate neonate tanks. Over the ∼6.5‐month monitoring period, four neonates with reduced body condition died without premonitory signs resulting in a 63.0% annual survival rate. Finite growth rates did not differ between sexes or litters and averaged (±SE) 12.2 (1.5) cm/year and 156.4 (26.4) g/year. At the cessation of monitoring, total length had increased by ∼30%, whereas total weight had almost doubled with neonatal body condition in line with free‐living wobbegongs. Our efficacious, six‐step manipulative, the approach should be applicable with all wobbegongs given their reproductive similarities, but we recommend that efforts focus on the dwarf ornate, tasselled and Japanese wobbegongs because all are small in size and have bred in aquaria. Ultimately, this approach should produce self‐sustaining aquarium populations, place less reliance on the wild acquisition and provide animals for other aquaria, population restocking, or scientific research. HIGHLIGHTS 1. Capture and isolation of pregnant wobbegongs from the main exhibit aquarium enables predation‐fre parturition. Continued isolation enables public exhibition of neonates and the monitoring of growth, survival and the effects of enhanced feeding regimes.