Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 20/09/2023 15:30:0020/09/2023 15:45:00Europe/ViennaAquaculture Europe 2023SEAWATER CONDITIONED WITH CRUSTOSE CORALLINE ALGAE AS SETTLEMENT INDUCER FOR PATELLID LIMPETSSchubert 4The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


Diego Castejón1,2 *, Pedro Sousa1 and Carlos A. P. Andrade3


1. Centro de Maricultura da Calheta. Av. D. Manuel I, n.º7. 9370-135 Calheta, Madeira (Portugal)

2. CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, Universidade do Porto, s/n 4450-208 Matosinhos (Portugal)

3. MARE – Marine and Environmental Sciences Centre | ARNET – Aquatic Research Network, Regional Agency for the Development of Research, Technology and Innovation (ARDITI), 9020-105 Funchal, Madeira (Portugal)





 The fishery of the limpets  Patella aspera and  Patella candei (Patellogastropoda : Patellidae ) in Madeira surpasses 100 annual tons and concerns about overexploitation of the stocks led to  different  legislative  protective  measures

. Recently, the  research on the limpets’ aquaculture achieved key methodological advances at hatchery level

 , being highlighted the potential role of the crustose coralline algae ( acronym: CCA) to induce the limpet settlement

 . This study took a step further  to  explore the seawater conditioned with CCA as settlement inducer for P. aspera and P. candei.

Material and Methods

The adult limpet s were captured  during  the breeding period (February to March 2022 ) and kept  in captivity using an open system (20 ± 1 °C and 36 ± 1 psu) .  The production and culture of larvae used gametes obtained by dissection following the procedures described by   . The oocytes were matured artificially using a solution of NH4OH at pH 9 during 20–30 min. Fertilization used 105 sperm cells ml-1. Incubation and larval culture were done in glass beakers and plastic jars at 16 ± 1 °C. Incubation used 50 oocytes ml-1 and lasted 24h. Larval culture used 5  individuals ml-1 and lasted 48h.

 The CCA were obtained from adult limpet shells  of which the soft body was removed a nd the aperture was cleaned  thoroughly  following  . Then, the shells were broken into pieces that were kept in small containers with filtered seawater treated with UV (acronym: FSS) during four days to obtain the conditioned seawater (acronym: CSW).

 Two assays were done  for each limpet species (P. aspera and P. candei) : 1)  different CSW concentrations (ca. 17, 5, 2 and 0.7 mm2 CCA · ml-1 ) and 2) influence of  frozen  CSW  (-24 °C)  obtained  from three different CCA communities (Pneophyllum sp., Neogoniolithon sp. 1  and Neogoniolithon sp. 2) .  In  P. candei , the influence of different treatments applied to the CSW was tested : raw and autoclaved  kept  at room temperature (0, 24 and 48h), raw kept in the fridge 2–4 °C (24 and 48h), raw frozen at -24 °C (48h) and f iltered (0 h). All the assays used FSS as negative control and CCA as positive control. Settle rs  were identified by the loss of the velum (metamorphics ) and the  teleoconch  development (post-larvae ).  The  ratio of metamorphics and the ratio of settlers (metamorphics + post-larvae) were calculated.

Results and Discussion

T he  ratios of metamorphics and settlers decreased with lower concentration of CSW in both P. aspera and P. candei , but the values were markedly  lower in the former (Fig. 1A–B) .  Regarding the frozen CSW, only Neogoniolithon sp. 2 induced the settlement in P. aspera , while  all  the frozen CSW treatments  induced the  settlement in P. candei .  In P. candei , all the treatments applied to the CSW (raw  kept at room  or fridge temperature, autoclave and frozen) induced the settlement  independently of the timing after obtaining the CSW (0 to 48h); being the single treatment without effect the filtered CSW ( glass microfiber 2.7 μm ) (Fig. 1C).

 CSW  promoted  P. candei post larvae  settlement in  at a ratio positively related to its concentration with the potential to be  preserved frozen. In P. aspera  an efficient settlement response  required the  physical presence of CCA.  Altogether, these results showed inter-specific differences in the sensitivity to the soluble cues released by the CCA, highlighting that limpet settlement requires to be studied at species level.