Size selection of adult Atlantic salmon at fish passage facilities on the Penobscot River,

Maine

George Maynard1, Joseph Zydlewski2,1

1. University of Maine, Dept. of Wildlife Ecology, Orono, ME 044692. U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit, Orono, ME 04469

Acknowledgements

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

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

Introduction

• Water temperature

Adapted from Jonsson et al. 2007

Maine DMR2012

Introduction

• Water temperature• Water flow

Introduction

• Water temperature• Water flow• Time of year

Introduction

• Water temperature• River level• Time of year• Interannual variation

Introduction

• Water temperature• River level• Time of year• Interannual variation• Salmon size

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)

Study Sites

• Penobscot River system• Six hydropower dams• Monitored using PIT

arrays• 2002-2004• 2010-2012

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

Methods: PIT Arrays

PIT Receiver

Downstream Upstream

Antenna 1 Antenna 2

Results: OverviewFi

sh L

engt

h (c

m)

But is it significant? Relationships tested using Bayesian logistic regression.

Results

• Four dams exhibited some size selection– Great Works– Milford– West Enfield– Mattaceunk

(Weldon)

Results: Veazie

• ΔDIC = 3• n = 409• Time of year and

temperature

Factor Significance

Fork Length -0.155 .

QC Height -0.056 -

QC Temp -0.466 ***

QC OrdinalDate 0.581 ***

Year 0.267 **

Results: Great Works

• ΔDIC = 2• n = 1471• Fork length was the

most important predictor of success

Factor Significance

Fork Length -0.221 ***

QC Height -0.114 **

QC Temp -0.156 ***

QC OrdinalDate 0.027 -

45 50 55 60 65 70 75 80 85 900

0.20.40.60.8

1

p(Passage | Fork Length)

Fork Length (cm)

p(Pa

ssag

e)

Results: Milford

• ΔDIC = 5• n = 1609• Fork length was the

most important predictor of success

Factor Significance

Fork Length -0.345 ***

QC Height -0.151 **

QC Temp 0.076 -

QC OrdinalDate -0.148 **

Year 0.156 ***

45 50 55 60 65 70 75 80 85 900

0.5

1

p(Passage | Fork Length)

Fork Length (cm)

p(Pa

ssag

e)

Results: Howland• ΔDIC = 32• n = 1241• Annual Changes• Pike jump

Factor Significance

Fork Length -0.05 -

QC Height 0.035 -

QC Temp -0.333 ***

QC OrdinalDate -0.145 **

Year -0.616 ***

Results: West Enfield• ΔDIC = 29• n = 2444• Annual impacts• Fork length still significant

Factor Significance

Fork Length -0.147 **

QC Height 0.0277 -

QC Temp -0.25 ***

QC OrdinalDate 0.258 ***

Year -1.12 ***

45 50 55 60 65 70 75 80 85 900

0.5

1

p(Passage | Fork Length)

Fork Length (cm)

p(Pa

ssag

e)

Results: Mattaceunk (Weldon)• ΔDIC = 36• n = 587• Annual Changes• Fork length still significant

Factor Significance

Fork Length -0.248 ***

QC Height 0.224 **

QC Temp -0.412 ***

QC OrdinalDate 0.546 ***

Year -0.703 ***

45 50 55 60 65 70 75 80 85 900

0.5

1

p(Passage | Fork Length)

Fork Length (cm)

p(Pa

ssag

e)

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

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

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

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

Questions?