Scope for growth and dietary needs of Mediteranean Pinnids maintained in captivity

Abstract Background: The measurement of the energy available for growth (scope of growth, SFG) can be used in bivalves to make a long-term prediction in a short-term experiment of the condition of the individual. In order to tackle the best conditions for captive maintenance of Mediterranean Pinnids, a SFG study was conducted using Pinna rudis as a model species. Three diets were examined to test the viability of live microalgae and commercial products: i) a control diet using 100% of live microalgae based on the species Isochrysis galbana (t-ISO), ii) a 100% of commercial microalgae diet based on the product Shellfish Diet 1800®, and iii) a 50/50% mix diet of I. galbana (t-ISO) and Shellfish Diet 1800®. Results: SFG results showed significant differences among diets in the physiological functions measured and suggested lower acceptability and digestibility of the commercial product. Negative SFG values were obtained for the commercial diet which indicates that it should be rejected for both Pinnid maintenance. The mixed diet showed improved physiological performance compared to the commercial diet, resulting in a higher SFG that had no significant differences with the control diet. However, in the long-term, the lower digestibility of the mixed diet compared to the control diet could lead to a deterioration of individuals’ conditions and should be considered cautiously. Conclusions: This work represents the first case study of SFG in Pinna spp. and provides fundamental data on dietary needs for the critically endangered species, P. nobilis.En prens

Wide-Geographic and Long-Term Analysis of the Role of Pathogens in the Decline of Pinna nobilis to Critically Endangered Species

A mass mortality event (MME) affecting the fan mussel Pinna nobilis was first detected in Spain in autumn 2016 and spread north- and eastward through the Mediterranean Sea. Various pathogens have been blamed for contributing to the MME, with emphasis in Haplosporidium pinnae, Mycobacterium sp. and Vibrio spp. In this study, samples from 762 fan mussels (necropsies from 263 individuals, mantle biopsies from 499) of various health conditions, with wide geographic and age range, taken before and during the MME spread from various environments along Mediterranean Sea, were used to assess the role of pathogens in the MME. The number of samples processed by both histological and molecular methods was 83. The most important factor playing a main role on the onset of the mass mortality of P. nobilis throughout the Mediterranean Sea was the infection by H. pinnae. It was the only non-detected pathogen before the MME while, during MME spreading, its prevalence was higher in sick and dead individuals than in asymptomatic ones, in MME-affected areas than in non-affected sites, and it was not associated with host size, infecting both juveniles and adults. Conversely, infection with mycobacteria was independent from the period (before or during MME), from the affection of the area by MME and from the host health condition, and it was associated with host size. Gram (-) bacteria neither appeared associated with MME.En prens

Challenges of the use of new generation massive sequencing (NGS) of the benthic macrofauna for the evaluation of the marine environment quality.

La Directiva Marco del Agua 2000/60/CE obliga al diagnóstico ambiental del ecosistema marino, incluyendo la evaluación de las especies de macroinvertebrados considerados bioindicadores presentes en el medio. Hasta la fecha, este tipo de determinaciones se realizan mediante la identificación taxonómica de visu de la macrofauna bentónica presente en las muestras y el cálculo de bioíndices asociados, un proceso costoso en términos de tiempo y financiación y, en algunos casos, subjetivo por precisar de un equipo humano altamente especializado y por la dificultad de identificar correctamente determinadas especies. En este sentido, las técnicas de DNA barcoding permiten identificar de forma fiable organismos empleando técnicas de secuenciación de DNA y evitando las desventajas de la identificación morfotaxonómica. Por otro lado, el reciente desarrollo de técnicas de secuenciación masiva de DNA de nueva generación (NGS) ha permitido el desarrollo del DNA metabarcoding, o caracterización de poblaciones de organismos presentes en una muestra empleando datos genómicos. Este trabajo plantea los retos fundamentales que presenta, a día de hoy, el análisis de organismos bioindicadores de calidad ambiental marina a través de las técnicas de secuenciación NGS.The Water Framework Directive 2000/60/EC regulates the environmental diagnosis of the marine ecosystem, including the evaluation of species of bioindicator macroinvertebrates present in the environment. To date, these types of determinations are carried out through the morphotaxonomic identification of the benthic macrofauna present in the samples and the calculation of associated biotic indexes, a process that is time-consuming and resource-intensive, being in some cases inaccurate due to the requirement of highly specialized human resources and the difficulty of correctly identifying certain species. In this respect, DNA barcoding techniques allow the reliable identification of organisms using DNA sequencing techniques and avoiding the disadvantages of morphotaxonomic identification. On the other hand, the recent development of New Generation DNA Sequencing techniques (NGS) has allowed the development of DNA metabarcoding, i.e. the characterization of populations of organisms present in a sample using genomic data. This paper shows the fundamental challenges to be overcome in order to establish a NGS sequencing-based assessment of the marine environmental quality.Ciencias Experimentale

Retos del empleo de la secuenciación masiva de nueva generación (NGS) de la macrofauna bentónica para la evaluación de la calidad ambiental marina

The Water Framework Directive 2000/60/EC regulates the environmental diagnosis of the marine ecosystem, including the evaluation of species of bioindicator macroinvertebrates present in the environment. To date, these types of determinations are carried out through the morphotaxonomic identification of the benthic macrofauna present in the samples and the calculation of associated biotic indexes, a process that is time-consuming and resource-intensive, being in some cases inaccurate due to the requirement of highly specialized human resources and the difficulty of correctly identifying certain species. In this respect, DNA barcoding techniques allow the reliable identification of organisms using DNA sequencing techniques and avoiding the disadvantages of morphotaxonomic identification. On the other hand, the recent development of New Generation DNA Sequencing techniques (NGS) has allowed the development of DNA metabarcoding, i.e. the characterization of populations of organisms present in a sample using genomic data. This paper shows the fundamental challenges to be overcome in order to establish a NGS sequencing-based assessment of the marine environmental quality.La Directiva Marco del Agua 2000/60/CE obliga al diagnóstico ambiental del ecosistema marino, incluyendo la evaluación de las especies de macroinvertebrados considerados bioindicadores presentes en el medio. Hasta la fecha, este tipo de determinaciones se realizan mediante la identificación taxonómica de visu de la macrofauna bentónica presente en las muestras y el cálculo de bioíndices asociados, un proceso costoso en términos de tiempo y financiación y, en algunos casos, subjetivo por precisar de un equipo humano altamente especializado y por la dificultad de identificar correctamente determinadas especies. En este sentido, las técnicas de DNA barcoding permiten identificar de forma fiable organismos empleando técnicas de secuenciación de DNA y evitando las desventajas de la identificación morfotaxonómica. Por otro lado, el reciente desarrollo de técnicas de secuenciación masiva de DNA de nueva generación (NGS) ha permitido el desarrollo del DNA metabarcoding, o caracterización de poblaciones de organismos presentes en una muestra empleando datos genómicos. Este trabajo plantea los retos fundamentales que presenta, a día de hoy, el análisis de organismos bioindicadores de calidad ambiental marina a través de las técnicas de secuenciación NGS

Can we save a marine species affected by a highly infective, highly lethal, waterborne disease from extinction?

Anthropogenic drivers and global warming are altering the occurrence of infectious marine diseases, some of which produce mass mortalities with considerable ecosystemic and economic costs. The Mediterranean Sea is considered a laboratory to examine global processes, and the fan mussel Pinna nobilis a sentinel species within it. Since September 2016, fan mussels suffer a die-off, very likely provoked by the protozoan Haplosporidium pinnae. Population dynamic surveys, rescue programmes, larvae collector installation and protection of infected adults from predators, have increased knowledge about the factors conditioning the spread of the die-off; previous model simulations indicate that water temperature and salinity seem to be related to the manifestation of the disease, which at the end are strongly influenced by climate change and anthropogenic actions. The absence of natural recruitment implies that fan mussel populations are not recovering, but the survival of populations living in paralic environments provides an opportunity to study the disease and its conditioning factors. The fan mussel disease outbreak provides a case example for how climate change may mediate host-protozoan dynamics and poses several questions: are we witnessing the potential extinction of a sentinel species? Can we avoid it by applying active measures? If so, which measures will be more effective? How many other more overlooked species might experience a massive and unnoticed die-off before it is too late to implement any preservation action? This is especially relevant because the loss of keystone species can drive to community effects that influence marine ecosystem processes.This research was partially funded by the Spanish Ministry for the Ecological Transition, project 28-5310 “Rescate de 215 ejemplares de nacra (Pinna nobilis) y su mantenimiento en 5 centros especializados en el marco del Proyecto UFE IP-PAF INTEMARES (LIFE15 IPE ES 012)”, “Gestión integrada, innovadora y participativa de la Red Natura 2000 en el medio marino español” as well as those agreements and contracts with the participating entities (IFAPA, IRTA, IEO) derived from this project, and by the Prince Albert II of Monaco Foundation to project BF/HEM 15-1662, “The study, protection and possible breeding of pen shell (Pinna nobilis) in the Boka Kotorska Bay”. Maite Vázquez-Luis was supported by the postdoctoral contract, Juan de la Cierva-Incorporación (IJCI-2016-29329) of Ministerio de Ciencia, Innovación y Universidades. G. Catanese was supported by a research contract from the INIA-CCAA (DOC INIA 8/2013) MINECO programme. The M. López-Sanmartín contract is co-financed by the State Plan for Scientific and Technical Research and Innovation 2013–2016, MINECO, ref. PTA215-11709-I

Tracking the dispersion of a pathogen causing mass mortality in the pen shell Pinna nobilis

Peer reviewe

Tracking a mass mortality outbreak of pen shell Pinna nobilis populations: A collaborative effort of scientists and citizens

A mass mortality event is devastating the populations of the endemic bivalve Pinna nobilis in the Mediterranean Sea from early autumn 2016. A newly described Haplosporidian endoparasite (Haplosporidium pinnae) is the most probable cause of this ecological catastrophe placing one of the largest bivalves of the world on the brink of extinction. As a pivotal step towards Pinna nobilis conservation, this contribution combines scientists and citizens’ data to address the fast- and vastdispersion and prevalence outbreaks of the pathogen. Therefore, the potential role of currents on parasite expansion was addressed by means of drift simulations of virtual particles in a high-resolution regional currents model. A generalized additive model was implemented to test if environmental factors could modulate the infection of Pinna nobilis populations. The results strongly suggest that the parasite has probably dispersed regionally by surface currents, and that the disease expression seems to be closely related to temperatures above 13.5°C and to a salinity range between 36.5–39.7 psu. The most likely spread of the disease along the Mediterranean basin associated with scattered survival spots and very few survivors (potentially resistant individuals), point to a challenging scenario for conservation of the emblematic Pinna nobilis, which will require fast and strategic management measures and should make use of the essential role citizen science projects can play