Bivalve aquaculture transfers in Atlantic Europe. Part B: Environmental impacts of transfer activities

Abstract

For centuries human populations have moved live shellfish around the world for consumption or aquaculture purposes; being relayed from their area of origin for growout or sale. This is in contrast to the inadvertent anthropogenic spreading of species via e.g. ballast waters. There are inherent risks associated with transfer of shellfish including introducing of alien species, diseases, pests, bacteria and viruses associated with the translocated species in addition to the potential impact on genetic integrity and biodiversity of local stocks. Many examples of severe ecological impacts have been documented worldwide owing to the intentional or unintentional translocation of animals. It is therefore important to develop risk reduction methods which have not yet been documented to be incorporated into current fish health or environmental legislation. This part of the study describes the impacts of transfer activities of cultured bivalve shellfish along the European Atlantic coast; identifies hitch hiker species, fouling organisms or infectious agents which can be translocated with a target species. Further, the study highlights the need for thorough, standard risk reduction measures designed to minimise the impact on ecosystems worldwide. In a companion paper details of actual transfer activities in Atlantic Europe are presented and all levels of legislation dealing with transfer activities on a global, regional and national scale are carefully reviewed. Highlights► We provide a full list of threats related to bivalve transfer activities. ► We draw the intention to the large spectrum of non-target species transferred with bivalves. ► We show the impact of transfers as potential vectors for the introduction of alien species. ► We provide detailed recommendations for a suitable risk assessment for impacts reduction.MS to be submitted Bivalve Aquaculture Transfers (Part B) 3

A literature review as an aid to identify strategies for mitigating ostreid herpesvirus 1 in Crassostrea gigas hatchery and nursery systems

“…a pathogen) should be the priority (Brenner et al . ), although early detection of disease trends or drivers relies on good quality surveillance data. Tables summarize the strategies detailed below related to surveillance, biosecurity and mitigation factors, respectively, for potentially avoiding the entrance and survival of OsHV‐1 in hatchery and nursery systems.…”

“…This is also supported by Brenner et al . () who recommended: ‘…the need for comprehensive health surveillance strategies involving procedures to systematically look for early signs and assess the adverse effects on the health‐status of a country…’, which has important implications for translocation of wild C. gigas into hatcheries as broodstock.…”

“…However, there are inherent risks associated with the transfer of shellfish, such as the introduction of diseases, including viruses, associated with any translocated species (Brenner et al . ). In addition, subsequent control measures rely on an understanding of factors such as the spatial distribution of mortalities, the hydrodynamics within a bay and other environmental aspects that, in the case of OsHV‐1, still require scientific input to determine the relationships that lead to pathogen dissemination (Paul‐Pont et al .…”

Evidence that the major hemolymph protein of the Pacific oyster, Crassostrea gigas, has antiviral activity against herpesviruses

“…It has formed the basis of a global aquaculture industry with one of the largest annual productions of any marine organism. The intentional movement of C. gigas, and other marine molluscs, around the world to develop aquaculture industries has aided the introduction of bivalve associated organisms, such as viruses, to new areas (Breener et al, 2014;Murray et al, 2012). Translocation of C. gigas outside its natural distribution range has also exposed it to new viruses (Breener et al, 2014;Murray et al, 2012).…”

“…The intentional movement of C. gigas, and other marine molluscs, around the world to develop aquaculture industries has aided the introduction of bivalve associated organisms, such as viruses, to new areas (Breener et al, 2014;Murray et al, 2012). Translocation of C. gigas outside its natural distribution range has also exposed it to new viruses (Breener et al, 2014;Murray et al, 2012). Not surprisingly, a new variant of the Ostreid herpesvirus type 1, termed OsHV-1 lvar, has emerged globally and has had a devastating impact on world production of C. gigas (Jenkins et al, 2013;Martenot et al, 2011;Segarra et al, 2010).…”