Public aquariums as a potential source of marine fish for exhibits and conservation

The marine aquarium trade relies on wild fisheries for 98% of ornamental reef species for display. Overexploitation and harmful collection techniques threaten native fish populations and reef ecosystems. Public aquaria can contribute an untapped source of fishes by rearing eggs and larvae from volitional spawning events. The aim of this study was to demonstrate that pelagic eggs and larvae collected from the mixed species Living Coral Reef (LCR) exhibit at the Texas State Aquarium (TSA) can be distinguished to species level based on unique morphological characteristics and barcoding. A floating collector was placed into the exhibit once per week for nine weeks to collect eggs and larvae from volitional spawning events. Fin clips were obtained from adult fishes in the exhibit for genetic reference and preserved in 20% salt-saturated dimethylsulfoxide (DMSO) until processing. Eggs and larvae were identified molecularly using DNA barcoding at the CO1 sequence region. Eggs of smallmouth (Brachygenys chyrsargyreum) and cottonwick (Haemulon melanurum) grunts were genetically identified and showed significantly different (p > 0.0001) mean egg diameters (± s.d.) of 860 ± 45 µm and 972 ± 30 µm, respectively. Bicolor damselfish (Stegastes partitus) larvae, 1 day post hatch, were recognized by characteristic brain, stomach, and ventral pigmentation. This work provides a verification of techniques for collecting eggs and larvae in public aquariums. Identification of eggs and larvae in mixed species exhibits may allow for more efficient sorting and subsequent larval culture. Further research can increase conservation efforts in public aquaria by strengthening the capacity to promote sustainable sources of marine ornamentals through exhibits and outreach.