1. Winter Flounder Stock Enhancement: Examining the Onset of Wild Weaning in Pellet-Reared Fish
Stacy Farina, Michelle L. Walsh, and W. H. Howell
The Department of Biological Sciences
University of New Hampshire, Durham, NH 03801

2. A Little About Myself

3. Science Consortium for Ocean Replenishment (SCORE)
Enhancement of natural marine populations
Invertebrates and Fish
Sponsored by NOAA NMFS & NOAA Aquaculture
UNH: Winter Flounder

4. Why Winter Flounder?

5. Commercial Importance

6. Recreational Importance

7. Why Winter Flounder? * * Gulf of Maine

8. Possible Solution: Stock Enhancement
Winter flounder vulnerable in early life stages
Spawn and raise fish in captivity
Release to enhance natural stocks
Problem: Weaning onto Wild Diets

9. Transitioning to a wild diet once released
Weaning?
Transitioning to a wild diet once released

10. Winter Flounder Diet Captivity Wild Formulated Pellets (most common)
inexpensive and easy
Wild
Live diet (worms, zooplankton, etc)

11. Why is weaning important?
Transitioning to a live diet can be stressful!
YIKES!

12. Our Project
Examine the transition of pellet-reared winter flounder onto a wild diet once released

13. Methods Spring 2007 Juvenile winter flounder reared in the Laboratory
Summer 2007
Released in cages (10 fish per cage) in a cove
UNH’s Coastal Marine Laboratory
Cages were retrieved every 3 hours after release up to 51 hours

15. Mick Walsh and Laughlin Siceloff
Nate Rennels

16. Methods Fall 2007 – Summer 2008 Fish dissected
Stomach contents were examined and quantified

17. Results and Discussion
Get ready for some graphs!

18. Onset of Feeding
% Fish With Food in Stomach per Retrieval
After 18 hours, the number of fish feeding was significantly higher than at 12 hours after release. (p < 0.05)

19. Most commonly selected prey: Polychaetes (48.2%) and Copepods (31.2%)
Diet Composition
Most commonly selected prey: Polychaetes (48.2%) and Copepods (31.2%)

20. Polychaete Worms
Copepods
Nematodes
Bivalves

21. Diet Composition
First 12 hours
Inorganics
(rocks)

22. Diet of Wild Fish (Katie Robertson)
Values Based on IRI Calculations

23. Extent of Feeding

24. What Can We Conclude?
After 18 hours, most fish had food in their stomachs.
Inorganics were common within the first 12 hours, but minimal after.
Diet was composed of mainly polychaete worms and crustaceans (copepods and amphipods), and was similar to that of wild fish.
Gut fullness increased with time.

25. Ongoing Work

26. Ongoing Work
Long-term studies of feeding, growth, and survival after release
Examine impact of live laboratory diets on onset and quality of weaning
Assess feeding behavior of winter flounder raised on formulated pellets

27. Acknowledgments
We gratefully acknowledge Elizabeth A. Fairchild, Nate Rennels, Travis Ford and Laughlin Siceloff for their assistance with experimental design and field work, and Kristin Garabedian and Katie Robertson for help with dissections and data entry. We thank the laboratories of Jim Haney and Larry Harris for use of their equipment. This project was funded by the University of New Hampshire’s Hamel Center for Undergraduate Research, The Graduate School and the Science Consortium for Ocean Replenishment (SCORE), a division of the National Oceanic and Atmospheric Administration (NOAA).