Reduced Tank Cleaning Frequency and Impacts on Larval Sablefish Survival, Water Quality, and Microbial Communities

The larval stage of marine finfish rearing is particularly sensitive to mortality, and survival is dependent on maintaining water quality in rearing tanks. An overabundance of organic matter from feed and water additives (i.e., greenwater) can quickly deteriorate water quality and is attributed to bacterial proliferation, including pathogens. Daily, labor intensive cleaning methods are often employed by aquaculture facilities to mitigate the negative effects of excess organic material. Cleaning activities, however, inadvertently cause stress and physical damage to larvae. Further, the eradication of potentially probiotic biofilm communities may be detrimental to fish health. In this study, we employed a reduced tank cleaning frequency schedule and assessed its impact on water quality, microbial community composition, total bacterial counts, and larval sablefish survival.