Fisheries and Aquaculture Journal

Fisheries and Aquaculture Journal
Open Access

ISSN: 2150-3508

+44 1478 350008


Condition Index and Neutral Red Assay Response of Cultured Mytilus edulis L. Stored in a Wet Holding Facility during Winter and Spring in Northeastern Newfoundland

Jessica Wyatt, Sharon Kenny, Terry Mills, Dawn H Marshall and Harry M Murray

In order to determine the effects of extended wet-holding on cultured blue mussels under ambient conditions during the winter and spring in Newfoundland, we investigated physiological stress response using the Neutral Red Assay, change in dry and wet weight and in overall condition based on the dry tissue weight/dry shell weight ratio and the dry tissue weight/wet tissue weight ratio of animals held for up to three months in a commercial holding facility and compared with field controls. During the winter season, dry weight and condition of mussels in the holding facility increased significantly over the three month period when compared with samples from the field. Spring-held mussels were observed to lose dry weight and condition in holding as compared with field controls. The Neutral Red Assay indicated an observed but not statistically significant change in physiological stress response for mussels held during the winter season. No observed change was noted for field controls. During the spring no overall change was noted in Neutral Red response for held or field control samples Dry weight and condition analysis indicated that the winter season was the most stable for long term holding of harvested mussels. Overall analysis of lysosomal neutral red retention time did not reveal a statistically significant response for mussels held during winter or spring suggesting that low temperatures may affect the haemocyte lysosomal response to Neutral Red retention. Based on the observed change in condition and dry weight across season, we recommend that mussels can be held for atleast two months during the winter season and at a limit of one month for spring (especially late spring i.e. May and June) before a significant loss in condition and potential quality is observed.