1. Size selection of adult Atlantic salmon at fish passage facilities on the Penobscot River, Maine George Maynard 1, Joseph Zydlewski 2,1 1.University of Maine, Dept. of Wildlife Ecology, Orono, ME 04469 2.U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit, Orono, ME 04469

2. Acknowledgements Oliver Cox Bill Halteman Doug Sigourney Dimitry Gorsky Ed Hughes Andrew O’Malley Dan Stich Ken Beland

3. Introduction Fishways have existed on the Penobscot River since the mid 1800s Not all fishways are created equal Many factors influence how well salmon are able to pass through fishways

4. Introduction Water temperature Adapted from Jonsson et al. 2007 Maine DMR 2012

5. Introduction Water temperature Water flow

6. Introduction Water temperature Water flow Time of year

7. Introduction Water temperature River level Time of year Interannual variation

8. Introduction Water temperature River level Time of year Interannual variation Salmon size

9. Salmon Size Maximum swim speed is inversely related to size (Katopodis 1999) Larger Atlantic salmon – require more attraction flow (Laine et al. 2002) – experience longer migratory delays (Jonsson et al. 2007)

10. Study Sites Penobscot River system Six hydropower dams Monitored using PIT arrays 2002-2004 2010-2012

11. Methods: Data Collection Water temperatures from Maine DMR at the Veazie fishway River height from USGS West Enfield gauge Fork length measured during tagging at Veazie

12. Methods: PIT Arrays PIT Receiver Downstream Upstream Antenna 1 Antenna 2

13. Results: Overview Fish Length (cm) But is it significant? Relationships tested using Bayesian logistic regression.

14. Results Four dams exhibited some size selection – Great Works – Milford – West Enfield – Mattaceunk (Weldon)

15. Results: Veazie ΔDIC = 3 n = 409 Time of year and temperature FactorSignificance Fork Length-0.155. QC Height-0.056- QC Temp-0.466*** QC OrdinalDate0.581*** Year0.267**

16. Results: Great Works ΔDIC = 2 n = 1471 Fork length was the most important predictor of success FactorSignificance Fork Length-0.221*** QC Height-0.114** QC Temp-0.156*** QC OrdinalDate0.027-

17. Results: Milford ΔDIC = 5 n = 1609 Fork length was the most important predictor of success FactorSignificance Fork Length-0.345*** QC Height-0.151** QC Temp0.076- QC OrdinalDate-0.148** Year0.156***

18. Results: Howland ΔDIC = 32 n = 1241 Annual Changes Pike jump FactorSignificance Fork Length-0.05- QC Height0.035- QC Temp-0.333*** QC OrdinalDate-0.145** Year-0.616***

19. Results: West Enfield ΔDIC = 29 n = 2444 Annual impacts Fork length still significant FactorSignificance Fork Length-0.147** QC Height0.0277- QC Temp-0.25*** QC OrdinalDate0.258*** Year-1.12***

20. Results: Mattaceunk (Weldon) ΔDIC = 36 n = 587 Annual Changes Fork length still significant FactorSignificance Fork Length-0.248*** QC Height0.224** QC Temp-0.412*** QC OrdinalDate0.546*** Year-0.703***

21. Discussion Small dataset at VZ and HD Influence of Year at WE and HD Average fish size at HD Upstream influence of delays Strongest selection at lowermost dams

22. Why care? Size may be indicative of a more successful individual – Feeding – Lifespan Larger individuals can invest more energy into gamete production Long term population impacts

23. Summary Current changes in river management will benefit adult salmon Construction of new Milford fishway Removal of downstream dams and bypass at Howland Further monitoring of fishways

24. Works Cited Castro-Santos T. and B. Letcher. 2010. Modeling migratory energetics of Connecticut River American shad (Alosa sapidissima): implications for the conservation of an iteroparous anadromous fish. Canadian Journal of Fisheries and Aquatic Science. 67:806-830. Everhart H.W. and R.E. Cutting. 1968. The Penobscot River, Atlantic salmon restoration: key to a model river. Maine Atlantic Sea Run Salmon Commission. 8-14. Fleming I.A. 1996. Reproductive strategies of Atlantic salmon: ecology and evolution. Reviews in Fish Biology and Fisheries. 6, 379-416. Holbrook C.M., J. Zydlewski, D. Gorsky, S.L. Shepard, M.T. Kinnison. 2009. Movements of prespawn adult Atlantic salmon near hydroelectric dams in the lower Penobscot River, Maine. North American Journal of Fisheris Management. 29:495-505. Jonsson, B., Jonsson, N. and Hansen, L. P. 2007. Factors affecting river entry of adult Atlantic salmon in a small river. Journal of Fish Biology 71, 943–956 Kruschke J.K. 2011. Doing Bayesian data analysis: a tutorial with R and BUGS. Academic Press. Laine, A., Jokivirta, T. and Katopodis, C. 2002. Atlantic salmon, Salmo salar L., and sea trout, Salmo trutta L., passage in a regulated northern river–fishway efficiency, fish entrance and environmental factors. Fisheries Management and Ecology 9, 65–77 Lundqvist H., P. Rivinoja, K. Leonardsson, S. McKinnell. 2008. Upstream passage problems for wild Atlantic salmon (Salmo salar L.) in a regulated river and its effect on the population. Hydrobiologia. 602:111-127. Noonan M.J., J.W.A. Grant, and C.D. Jackson. 2012. A quantitative assessment of fish passage efficiency. Fish and Fisheries. 13. 450-464. Penobscot River Restoration Project (PRRP). 2013. Fact sheet. Roscoe, D. W., Hinch, S. G., Cooke, S. J. and Patterson, D. A. 2011. Fishway passage and post-passage mortality of up-river migrating sockeye salmon in the Seton River, British Columbia. River Research and Applications 27, 693–705 Sigourney D.B., J.D. Zydlewski, E. Hughes, and O. Cox. Transport, passage, and size selection of adult Atlantic salmon in the Penobscot River, Maine. In Review. Werner R.G. Freshwater fishes of the northeastern United States. 2004. Syracuse University Press. 190-191. Images from UMaine archive, Wikimedia Commons, and Bangor Daily News Archive

25. Questions?