Growth and survival analysis of early stages in the pen shell Atrina maura during pilot-commercial production

Abstract

Abstract Hatchery spat of pen shells is difficult to obtain as production runs generally end in failure. We present a successful case of commercial pilot spat production of Atrina maura in hatchery, describing each phase in detail and determining growth of larvae and post-larvae using multi-model inference (MMI). Growth rates from D-larvae to umbo stage (D-larvae = 65 ± 5.1 µm height and 75 ± 5.1 µm length) increased from 4.33 µm/day up to 675.6 µm/day during post-larvae stage (spat = 10.9 ± 2.2 mm height and 28.1 ± 4.4 mm length). Survival presented a significantly daily decrease from 22.5% (beginning) to a final absolute survival of 0.042%; from 120 million D-larvae, 50,000 commercial spat were produced. MMI showed that the best models describing growth correspond to Gompertz model for shell length and exponential model for shell height. Critical phases are the transition from D-larvae to umbo stage (> 80% collapse of cultures) and high mortality during metamorphosis. Further studies are required to find solutions to these problems. The results of this study contribute to improving the management of pen shells in hatchery, as the production protocol is different of those for other bivalve species.