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

A Little About Myself

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

Why Winter Flounder? http://www.nefsc.noaa.gov/sos/spsyn/fldrs/winter/

Commercial Importance http://weblogs.baltimoresun.com/entertainment/dining/reviews/blog/WholeFlounder.jpg

Recreational Importance http://mordantorange.com/images/comics/animals/shinybait.gif

Why Winter Flounder? * * Gulf of Maine http://www.nefsc.noaa.gov/sos/spsyn/fldrs/winter/

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

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

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

Why is weaning important? Transitioning to a live diet can be stressful! YIKES! http://www.nmfs.noaa.gov/fishwatch/species/winter_flounder.htm

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

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

Mick Walsh and Laughlin Siceloff Nate Rennels

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

Results and Discussion Get ready for some graphs! http://www.nmfs.noaa.gov/fishwatch/species/winter_flounder.htm

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)

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

Polychaete Worms Copepods Nematodes Bivalves

Diet Composition First 12 hours Inorganics (rocks)

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

Extent of Feeding

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.

Ongoing Work

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

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).