Today, European mollusc production mainly relies on spat collected from the wild. However, in some countries this practice can have negative environmental impacts. In other countries, in contrast, hatcheries have developed to the point that mollusc selective breeding programs are becoming a reality. Hatchery seed production is accordingly increasing but it does not yet fulfil consumer demand and is highly variable between countries and species.
'Here you can listen to an employee at the OSTREIRA hatchery, located in Grove, Spain, talking about the different facilities for each stage of larval rearing and indoor algal culture.'
Four molluscs were chosen for study, due to their economic importance in Europe and the different challenges they present:
- A species with “established” hatchery production :
- Pacific oyster, Crassostrea gigas, is the most important bivalve species produced in European hatcheries, notably since the development of triploids, and it is the species for which scientific knowledge is the most advanced among the four studied.
- A species with “emerging” hatchery production :
- King scallop, Pecten maximus, also known as great scallop, is hatchery-produced in France and Norway, although it still presents rearing difficulties.
- Blue mussels (Mytilus edulis and M. galloprovincialis) culture relies entirely on wild seed and there are increasing concerns about seed availability or fluctuating seed quality.
- European clam, Ruditapes decussatus is an emerging species, but there is little technological development for production requested by hatcheries (in contrast to the introduced Manila clam R. philippinarum).
The first objective is to reduce dependence on wild seed that is subject to high year-to-year fluctuations and so maintain production to meet market needs. In REPROSEED, the RTDs and SMEs of the consortium are working together to improve methodologies that will ensure reliable production of quality seed for each species. They are firstly focusing on the various limiting factors at different stages of the bivalve life cycle, but also addressing the weakening effects caused by external threats, maintenance of sufficient food and effects of biotic (micro-algal diet, bacterial communities, etc.) and abiotic (temperature, salinity, etc.) factors on developmental processes and gamete quality.
Moreover, REPROSEED is working on ways to reduce production costs, concentrating on an automated micro-algae culture system requiring lower maintenance and a recirculating system that will maintain optimal environmental conditions.
Fields of study
The present project will also have an impact on two other fields of study:
- At the scientific level, it will provide new insight into several biological processes
- On an applied level, it will provide new technologies: nutritionally adapted feed solutions, manipulation of the microbial flora and low-cost algal production that will enhance and secure larval and post-larval production in commercial hatcheries
The project not only uses pure and applied approaches to examine biological processes and provide innovative technology, but also aims to apply knowledge from bivalve species with established hatchery production to emerging species with common needs. Such ‘generic’ methods could yield benefits immediately or in the longer term. As these different species also have different biological characteristics (e.g. some species can be strip-spawned, others not; some remain motile after metamorphosis, other not), a comparative approach of will directly contribute to a better understanding of the physiological basis of these traits at both cellular and molecular levels.