Characterization of Haplosporidium pinnae's biogeographical distribution by means of Ecological Niche Modelling techniques and consequences of climate change upon its range

Nicholas Alexander Vaz Reay 

This study provides a biogeographical characterization of protozoan endoparasite
Haplosporidium pinnae's distribution following the associated Mass Mortality Event of
endangered bivalve Pinna nobilis in 2016. The epizootic has reached mortality rates
between 80% - 100% and was first reported in the south-western Mediterranean Sea. It
has since spread to north-western waters, followed by the Tyrrhenian and Ionian seas of
the central Mediterranean, and has most recently (2023) reached the Aegean sea and the
Çanakkale Strait in Turkey, most likely due to oceanic currents or intermediate host
transmissions. In this study, we use presence-only Ecological Niche Modelling (ENM)
techniques with the Maximum Entropy (MaxEnt) software, in order to accurately predict
habitat suitability as a proxy of distribution range of H. pinnae in relation to biotic and
abiotic conditions, such as definitive host presence, surface current velocity, water
temperature and salinity by collecting occurrence data from published articles and
websites like the Global Biodiversity Information Facility (GBIF), as well as gathering
environmental information from the Bio-ORACLE database. By comparing ENM
projections under present and future scenarios, taking anthropogenic interferences, such
as climate change, exploitation and global warming into account, we can analyse the
consequences of these variables upon H. pinnae and other Haplosporidian parasite
populations, as these species are highly sensitive to environmental conditions and are
often extremely host-specific.