Jellyfish exhibits remain as one of the most popular exhibits for guests in aquariums worldwide, with significant resources invested to maintain them. Despite their appearance as simple, gelatinous animals, the successful culture and upkeep of these marine invertebrates for display are notoriously difficult. Two key issues pervade this: i) the availability and supply of jellyfishes, and ii) the rearing of attractive individuals. Supply of jellyfishes are often greatly limited by fluctuating catch rates and dependability on seasons, while those cultured in-house can often result in deformed individuals – unattractive to guests. Here, we focus on Mastigias papua (Lesson, 1855), commonly known as the ‘Spotted’ or ‘Golden’ Jellyfish, we relate our experiences into creating a sustainable supply of individuals and rearing ones attractive for display, alleviating the aforementioned problems.
Mastigias papua is a cosmopolitan species that is widely distributed across the Indo-West Pacific and are often part of aquarium displays worldwide. We define attractive individuals to have the following morphological traits for display: bell diameter of >80 mm, a distinct hemispherical-shaped bell, an exumbrella with fine granulations and white spots, eight velar lappets, and oral arms about half the length of the bell diameter. To ensure a sustainable supply of desirable individuals, we adopt strict husbandry practices. This included maintaining the cleanliness of the exhibit, providing a 100% water change, and relocation of larger individuals to more spacious enclosures. We found that adult individuals were healthier when tanks had a density of 30 individuals/m3; crowded tanks lead to higher food competition, and insufficient space for proper growth. We also adopted in-water methods to reduce air-exposure to the jellyfish, also avoiding netting damage during transfers. These strict practices ensure the reduces deformities in M.papua individuals, improved their growth rates, and decreased mortality.
Further, our attention to simulate the nutrition levels and the abiotic conditions experienced by this species in the wild impacted our success in culturing healthy M. papua. Individuals were provided freshly hatched Artemia spp. nauplii larvae as feed, along with phytoplankton for enrichment. Along with nutritional supply, the jellyfish were also exposed to strong LED lighting 200PAR, with adequate photoperiods, water salinity 29 ±1 ppt, and temperatures 26 ±1 °C, corresponding to those experienced in the wild. Our experiences shared here will be relevant to partners who are interested in breeding these elegant and enigmatic marine invertebrates, be it for display, or as a source of sustainable protein for food production.