Sweating the Small Stuff: Application of Scientific Management Increases Laboratory Reproduction in Staghorn Coral (Acropora cervicornis)
Propagation of staghorn coral (Acropora cervicornis) by sexual reproduction for reseeding of reefs in the Florida Keys is an ongoing conservation effort by Florida Aquarium and the Coral Restoration Foundation involving multiple partners (Conservation of Reef Life: CORL). Gamete bundles collected from offshore nurseries were dispersed and separated into oocytes and sperm using a transfer pipette. Oocytes were incubated in 5-gallon buckets with lemonade concentration sperm, a visual concentration historically used for large-scale field production (actual concentration: 9x106/ml), or 1x105/ml, calculated using a hemocytometer. After 2 hours, presumed embryos were collected and cleaned three times before transferring to different types of tanks: a) kreisel, b) modified kreisel, c) static tank, or d) Artemia cone. After 10 hours, approximately 100 eggs/embryos were counted to determine fertilization rates and embryo development. Higher fertilization rates (64±5.4% versus 47±11.3%) and embryo development rates (32±4.4% versus 22±9.9%) were obtained with lower sperm concentrations. Higher embryo development rates were obtained using the Artemia cone (44±6%) versus the kreisel, modified kreisel, and static tanks (21±4.8%, 26±6.3%, 34±7.3%, respectively), even though fertilization rates were similar. Further, embryos from the Artemia cone were subjectively assessed as more uniform in shape and healthier. Future studies will investigate whether improved larval settling rates are linked to improved embryo morphology. Application of scientific management and attention to detail can improve reproductive rates in marine invertebrate species in large-scale field propagation efforts.
Authors thank Coral Restoration Foundation, CORL: Akron Zoo, California Academy of Sciences, Columbus Zoo, Georgia Aquarium, Mote Marine Laboratory and Aquarium, Omaha Zoo, SeaWorld Orlando.