1. School for Resource and Environmental Studies
POTENTIAL SOURCES OF OVERWINTER MORTALITY OF POND-REARED UNDERYEARLING STRIPED BASS (Morone saxatilis)
Kare Tonning
MES Candidate
School for Resource and Environmental Studies
Dalhousie University

2. Obstacle: Overwinter Mortality
Problem: high overwinter mortality in underyearling striped bass stocked in man- made ponds.
Fish are reared at Dal-AC, then transferred to North River Fish Farm (NRFF).
Larger fish suffer negligible mortality.
Hypothesis: lipid quality found in pre-winter diet is having an effect on overwinter survival.

3. Trial 1: Winter 2016-17 3 Diets, 6 Replicates of 30 fish (approx. 50g)
2 Ponds (NRFF)
Periodic Sampling, 6 cages raised (3 diets X 2 ponds)
February, March, April
Survivorship assessed, all fish euthanized
Tissue samples collected
Tissues collected for analysis
Sampling in Feb., 2017.

4. Trial 1: Survival Results

5. Ongoing Trial: Winter 2017-18
5 ponds (over 3 sites)
Diet x 2
Body Size
Smalls ≤ 12cm
Larges > 12cm
Water Quality Parameters
Grading fish before transferring to ponds.

6. Thank you!
Acknowledgements Supervisors: Dr. J. Duston and Dr. P. Tyedmers Committee Member: Dr. S. Budge Collaborator: Dr. S. Colombo Colleagues: Juan Manriquez-Hernandez, Paul MacIsaac, Edyta Ratajczyk, Shanwei Qiu, and Vitoria Daitx. Industry partner: Mike Cameron, North River Fish Farms Limited and the Aquaculture Association of Nova Scotia