Welfare of bivalves in aquaculture? : A first literature scan and plan for a comprehensive search

Samenvatting

The welfare of the animals that we produce for our food consumption is increasingly becoming a socially relevant topic. In bivalves, however, assessing their welfare in aquaculture is not common practice. There is still a lot of uncertainty regarding the question on whether bivalves are sentient beings and whether welfare is a relevant topic in the production of bivalves or not. On behalf of the Dutch Shellfish Quality Foundation (SKS, Stichting Kwaliteit Schelpdieren) and the Foundation for the Protection of Fish (Stichting Vissenbescherming), Wageningen Marine Research (WMR) started a literature search in the Scopus database to assess whether the literature about welfare issues surrounding bivalves in aquaculture already exists. During the literature search in Scopus, no scientific papers that were specifically focused on the welfare of bivalves in aquaculture could be located. In addition, no papers were found which directly provided evidence to show whether bivalves are sentient or not. However, a few scientific studies focusing on the behavioural adaptations in bivalves to the presence of predators (Robson et al., 2010; Garner & Litvaitis, 2013), learning in bivalves (Selbach et al., 2022) and information on the physiological role of serotonin (Liu et al., 2018) could be identified. These types of papers indicate that bivalves might indeed be sentient. However, the quantity and nature of these available biological studies do not sufficiently demonstrate a firm conclusion that the welfare of bivalves in aquaculture is a relevant topic at the moment. On the other hand, these studies do provide evidence, although very limited, that bivalves can perceive feelings and are even capable of learning. Our report describes the start of a literature search and a route map towards a comprehensive literature study on the welfare of farmed bivalves in the Scopus database. A thorough evaluation of the identified literature was not carried out, as this was beyond the assignment given by the sponsors. Therefore, we recommend a follow-up project to initiate a complete literature review that would provide a clear description of what is known about the sentience, instead of welfare, of bivalves. We would recommend to focus more on sentience as aanimal welfare is relevant when an organism is sentient. Moreover, by conducting a more-extensive literature review, knowledge gaps regarding the sentience of bivalves could hopefully then be identified and elaborated upon. Subsequently, based on these knowledge gaps, experimental studies can then be designed to answer the fundamental question of whether bivalves are sentient and whether bivalve welfare is indeed a relevant topic in aquaculture.