The effects of elevated concentrations of dissolved inorganic phosphate in seawater on the growth and survival of juvenile abalone, Haliotis iris

摘要

Seawater sampling from three abalone farms in New Zealand showed average ambient concentrations of dissolved inorganic phosphate (P_i) varying between 2.36 and 238?μM. The P_i concentration within each system appeared to be directly linked to the percentage of water that was replaced each day. An experiment was conducted over 5 months to examine the effect of elevated P_i concentrations on the growth of two juvenile abalone (Haliotis iris) size classes (small: average shell length=23.9 ± 0.1 and large: average shell length=61.9 ± 0.1?mm). Abalone from each size class were exposed to P_i concentrations of; (a) natural incoming seawater (average 0.12 ± 0.12?μM), (b) 10.7 ± 1.3?μM, (c) 60.9 ± 5.8?μM and (d) 113.1 ± 5.6?μM. The results suggest that over the course of the 5-month period of this experiment there was a significant negative impact on growth (shell length and wet weight) when the smaller size class of abalone were exposed to P_i concentrations greater than 10.7?μM and for the large size class of abalone when exposed to greater than 60.9?μM P_i. However, elevated P_i concentrations did not significantly impact on abalone survival during the course of the experiment.