Genoa National Fish Hatchery
Encouraging Results for a New Mussel Culture Strategy
BY NATHAN ECKERT, GENOA NFH
Recent changes in how we run the mussel cage culture operation at Genoa National Fish Hatchery (NFH) have dramatically increased the number of sub-adult mussels that need to be held in the lab over winter. Over the last two winters these sub-adult mussels have been placed in a flow through system that utilizes pond water from the hatchery. This system has been quite effective, yielding 90 – 95 % survival in animals from fall to spring distribution. The drawback to the system is that the animals will not grow in the cold winter temperatures, and the increase in numbers has us needing additional room.
This winter we initiated a trial using our mucket buckets, a recirculating downweller system that is normally used for new juveniles, to grow some of our smaller sub-adults to larger sizes and spread out the culture load. Both fatmucket and Higgins’ eye were placed in a mucket bucket and both growth and survival were monitored. Seven hundred animals were stocked in the chambers (500 Higgins’ eye, 200 fatmucket) at 100 animals per chamber. The 60 day experiment concluded at the end of February. For this initial trial sub-adult survival was acceptable, but lower than anticipated (Higgins’ eye 85.4%, fatmucket 76.0%). Growth of individuals is where results were particularly interesting. Higgins’ eye grew 51.1% while fatmucket grew 66.7%. These numbers are very promising considering the time of year and duration of the study. This short term study indicates that below average size sub-adult mussels can be caught up to the larger individuals in their cohort by utilizing this method over winter.
Additional trials are planned to determine optimal feed rates and temperatures in an effort to improve survival. By taking advantage of existing technology in new ways the mussel restoration program at Genoa NFH can continue to grow and expand.