An international team of researchers, which included CIIMAR, has developed a new tool that could help produce clams that are more resistant to disease and climate change, whilst also strengthening the conservation of these species’ genetic diversity. The study, published in the journal Aquaculture, represents a significant step forward for sustainable aquaculture and for the management of two of the most economically important clam species: the Japanese clam (Ruditapes philippinarum) and the good clam (Ruditapes decussatus).

Habitat degradation, disease and climate change

The species studied are among the most widely produced worldwide in terms of volume and economic value, playing a vital role in the economies of many coastal communities. However, their production has been declining due to habitat degradation, climate change and an increase in the incidence of disease.

To address these challenges, researchers have developed a new genomic tool that enables the rapid and cost-effective analysis of thousands of small variations in the DNA of clams. These variations act as genetic markers, helping to identify individuals with desirable traits, such as greater resistance to disease, better adaptation to climate change or greater growth potential.

According to the researchers, “this tool will, in the future, enable us to support coastal communities through the implementation of new genetic improvement programmes for both species of clam, with a significant impact on the Blue Economy sector.”

A new genetic tool

The technology used, known as an SNP chip, is the first high-density genotyping platform developed for these two species of clam. The tool comprises around 63,000 genetic markers, of which more than 45,000 have been validated for the Japanese clam and 15,000 for the common clam. As well as supporting genetic improvement programmes, this tool enables the identification of kinship relationships between individuals, the monitoring of genetic diversity and the tracking of inbreeding levels within populations, thereby contributing to the more sustainable management of these marine resources. In particular, the work carried out by the Aquatic Animal Health (A2S) group has identified over 13,000 markers of resistance/susceptibility in the common clam to the parasite Perkinsus olsenii, one of the major problems in its production; this work was published in the journal Evolutionary Applications.

Made openly available to the scientific community, this platform will help to accelerate selective breeding programmes, studies on the association between genetic traits and traits of economic interest, as well as the monitoring of natural populations, making it an important tool for both aquaculture and the conservation of these species.

Far beyond aquaculture

As well as benefiting aquaculture, the new platform also opens up new opportunities for population genomics studies and for gaining a better understanding of how these species respond to environmental changes, thereby helping to protect marine biodiversity and increase the resilience of aquaculture production.

In addition to CIIMAR, the project brought together researchers from the University of Padua (Italy), the University of Santiago de Compostela (Spain), the Roslin Institute at the University of Edinburgh (United Kingdom), the Institut Universitaire Européen de la Mer – Brest-Morlaix (France), as well as companies specialising in aquaculture genetics such as Benchmark Genetics and Thermo Fisher Scientific. This collaboration demonstrates how joint work between research and industry can transform scientific knowledge into solutions with direct applications in aquaculture production and the sustainable management of marine resources.

This tool was developed with funding from the IGNITION and ShellfishBoost projects and the PRR (Italy).