Adult spawning and early larval development of the endangered bivalve Pinna nobilis

Abstract

The development of aquaculture activities has posed an alternative solution for the preservation of some overexploited shellfish fisheries worldwide. In the same way, endemic Mediterranean bivalves such as Pinna nobilis, highly threatened by habitat loss and coastal pollution, could found in aquaculture a solution for preserving the continuity of the species. Given the endangered status of the species, the biological and ecological processes regulating natural populations have been well studied, but there are still important knowledge gaps preventing the development of viable artificial cultures. This study describes for the first time the larval development of P. nobilis (from fertilization until pediveliger larval stages) in captivity conditions. Moreover, different rearing tanks of 5, 16 and 80 L, larvae density from 1 to 600 larvae mL −1 , light conditions, food doses, were tested in order to establish the bases for the optimal rearing of the species and provide a source of individuals for restoring field populations. Results showed that 16 L tanks with a concentration of 2 larvae mL −1 , constant temperature of 21 °C, 12/12 h photoperiod and fed with an "optimal" mixture of 25 cells per μL of Chaetoceros calcitrans + 33.3 cells per μL ofPavlova lutheri + 100 cells per μL of Isochrysis galbana" appear to be the best conditions to rear larvae of P. nobilis. Different captivity conditions such as lower or higher tank volume, larvae density, or food doses; light privation did not report better results for larval development.

Recruitment Disruption and the Role of Unaffected Populations for Potential Recovery After the Pinna nobilis Mass Mortality Event

“…The TRACMASS algorithm (Jönsson et al, 2015) was used to generate Lagrangian trajectories over a 1-month period to approximate larval period duration (Deudero et al, 2017;Kersting and García-March, 2017;Trigos et al, 2018). Virtual particles were released once a week during the recruitment period from July 1st to September 15th (Cabanellas-Reboredo et al, 2009; Kersting and García-March, 2017) from all sites and for all years where recruitment was recorded, with the exception of Mar Menor because of its low exchange with open waters (i.e., semi enclosed coastal lagoon).…”

Identification of potential recruitment bottlenecks in larval stages of the giant fan mussel Pinna nobilis using specific quantitative PCR

“…Samples were preserved in 70% ethanol and separated into different size fractions: 40 lm (egg sizes ranging from 40 to 70 lm and larval sizes from ca. 80-110; Trigos et al, 2017), 125 and 250 lm (to check for additional entangled material) using sieve nets. A preliminary observation of each fraction and sample was also conducted in order to determine the abundance of eggs and larvae and the feasibility of their separation.…”

“…85 lm in length), and fertilized and unfertilized egg samples of P. nobilis (Fig. 3) collected from an in vitro reproduction study performed previously in another institute (Trigos et al, 2017) (Fig. 4).…”

“…Calibration curves, specificity, and assay optimization ( To confirm the specificity of the assay, primers were tested using 50 ng of genomic DNA from the three most abundant commercially produced shellfish species: Crassostrea gigas, Cerastoderma edule, and Mytilus galloprovincialis. Further, the species-specific qPCR was tested on different numbers of eggs and larvae produced by captive spawning (as mentioned above) from individuals located in the Southeast of France and preserved in 70% ethanol (Trigos et al, 2017). Specific numbers of fertilized and unfertilized eggs, and larvae from these lab samples (n = 5, 10, 20 and 50; with two replicates of each), were used for the purpose of establishing a correlation between the C t values obtained and the number of individuals (fertilized/unfertilized eggs or larvae), i.e.,-a calibration curve.…”

Multiple Non-Species-Specific Pathogens Possibly Triggered the Mass Mortality in Pinna nobilis

“…Pinna nobilis lives at depths between 0.5 and 60 m on soft bottoms overgrown by seagrass meadows [ 3 ] and occasionally on the bare sandy substrate and maerl beds [ 4 ]. The length of the larval life cycle, as well as factors influencing survival rates and behavior, remain poorly understood [ 5 ]. In general, the larval duration for the genus Pinna has been estimated to be a maximum of 10 days [ 4 , 6 ].…”