Settlement, Survival, and Post-Larval Growth of Red Abalone, Haliotis rufescens, on Polycarbonate Plates Treated with Germlings of Ulva sp.

The adequate development of the first stages of the red abalone, Haliotis rufescens, is an important step for the successful commercial cultivation of this species. The companies cultivating H. rufescens in Chile utilize plastic plates, colonized by a mixture of diatoms, as settlement substrate and food for larvae, but with poor results on abalone survival and growth. Here, we report the utilization of recruitment plates conditioned with Ulva sp. germlings, in order to evaluate larval settlement, survival and growth rate of H. rufescens postlarvae. The results were compared with traditional methods as control. Settlement was lower with Ulva sp. (52 +/- 3%) than the control treatment (86 +/- 2%). However, at Day 15, the post-larval survival in the control group was lower than the Ulva sp. treatment, reaching 59 +/- 18% and 77 +/- 8%, respectively. Survival decreased on Day 30 in both treatments. The specific growth rate of the postlarvae was higher in plates conditioned with Ulva sp. (1.9 +/- 0.1% growth/d), than control plates (0.8 +/- 0.1% growth/d). Our results support the use of germlings of Ulva sp. on plastic plates as a good option for the cultivation of the first stage of development of the red abalone, improving the post-larval growth rate, with a positive impact on commercial farms.