Enhancing oocyte maturation and fertilisation in the black-foot limpet Patella candei d′Orbigny, 1840 (Patellidae, Mollusca)

Abstract

Limpet species are subjected to pressures of high exploitation. In the Madeira Archipelago (Portugal), the limpes are an economic and traditional fishing resource whose exploitation is regulated, to reduce the impact over the native populations. The effectiveness of the NaOH-alkalinized seawater baths to enhance the artificial maturation of Patella candei (D′orbigny, 1840) oocytes and fertilisation success in laboratory has been studied. First, the optimal combinations of pH and activation time to obtain the active oocytes were tested. Then, the viability of those oocytes was studied in a three factorial assay (pH x activation time x fertilisation time). Finally, the results obtained in the previous assays were cross tested to find a relationship between both. The viability of the oocytes over time were tested for methodology improvement. Results showed that the optimal conditions for the production of larvae was a pH of 9.5, activation time between 2 and 3 h and fertilisation time of 24:00 h, obtained a ratio of development between 0.65 and 0.75. The refrigeration could help to maintain the oocyte viability over time, but further research is required. This study establishes a foundational step towards the study the larval biology of Patella candei in laboratory, which is required to understand the ecological requirements for the early life stages of this species and promote aquaculture production.