Gayle B. Zydlewski

Fish interactions with marine

renewable devices: lessons learned, from ecological

design to improving cost-effectiveness

Gayle B. Zydlewski Haley Viehman, Garrett Staines

Haixue Shen, James McCleave, Jeffrey Vieser

N.S.

N. B.

Maine

Eastport

Lubec

DEER ISLAND (CAN)

WASHINGTON COUNTY (MAINE)

Proposed project area

What is the probability that a fish will encounter an MHK device?

1. Near-field – within 5 m of a blade – DIDSON (Viehman and Zydlewski 2014)

2. Far-field –no expected effects of the device – Abundance & distribution (Viehman et al. 2014)

3. Mid-field – within the hydrodynamic effects, 100s m – Proportion of fish at the depth of the device

1000 m

Bottom

ORPC TidGen®

Nearfield Farfield

?

Midfield

Why consider multiple space and time scales?

N 30 m

Space

Subtidal

Vieser, MS Thesis

Fall

Summer

1. Nearfield

N 30 m

Nearfield

ORPC TidGen®

• Pass By (51%)

•Through Turbine (48%): – Into Turbine – Out of turbine

•Active Avoidance (1%):

– Above – Reverse – Below

Approach Depart

Flow

Viehman and Zydlewski. 2014. Estuaries and Coasts.

Spatial Scale: within 5 m

3.3m

2. Farfield

1000 m 15 m

Bottom

N 1000 m

Project Control/reference N 30 m N 30 m

Nearfield

ORPC TidGen®

Project

Control/Reference

Seasonal patterns of relative abundance

Control/Reference Bottom support frame deployed Turbine deployed Project Site

2011

J F M A M J J A S O N D Month

Volu

me

back

scat

ter (

dB)

2012

J F M A M J J A S O N D

Sites different

Proportion of fish at different depths

1000 m 15 m

Bottom

Project

ORPC TidGen®

Control/Reference

N 30 m

Device • Beside • In-line

2011 Project Control/

Reference

Mar

Au

g Se

p

Viehman et al. 2014

2013 Beside turbine

Control/ Reference

In line w/turbine

Proportion of backscatter

0 0.5 0

25 Distance from

bottom

(m)

• Evidence of avoidance (?) – Beside and in-line

• Possible avoidance during construction – Decreased density at project site

• 3 surveys while deployed (not enough!)

3. Midfield: 100s m

NEARFIELD

ORPC TidGen®

N 30 m

60 m 15 m

Bottom

Area viewed by mobile surveys (200 m up- and

downstream of turbine)

Mobile surveys

ORPC TidGen® N 30 m

Beside turbine

In-line with turbine

Spatial scale: 200 m

Fish track Turbine

Flow

Upstream

Wake After wake

0

0.1

0.2

0.3

0.4

0.5

0.6

Transect 1 Transect 2 Transect 4 Transect 8

Fish

per

met

er

UpstreanWakeAfter wake

Upstream

Project integration–Probability of encounter (P) 1. Near-field - DIDSON (Viehman and Zydlewski 2014)

– Within 3.3m, only 1% of fish at turbine level avoided

2. Far-field - Abundance & distribution (Viehman et al. 2014) – Proportion of fish at turbine depth, without the turbine (p1, p2) – Proportion of fish at turbine depth, with turbine (p2)

3. Mid-field - Mobile transects – Proportion of fish at turbine depth, with turbine (p3)

1000 m

Bottom

ORPC TidGen®

Nearfield Farfield

p1 Midfield

p2 p3

px = f(time of day, tide, month, year)

Most of the picture… What about temporal resolution?

NEARFIELD

ORPC TidGen®

N 30 m

Area viewed by mobile surveys (200

m up- and downstream of

turbine)

60 m 15 m

Bottom

Mobile surveys (7° split beam echosounder)

Stationary 24-hr surveys (31° single beam echosounder) Nearfield

(DIDSON) Beside turbine

ORPC TidGen®

In-line with turbine

N 30 m

Determine sampling periodicity to represent variability over a month

Acknowledgments • Zydlewski Lab

– Megan Altenritter – Matthew Altenritter – Matthew Dzaugis – Patrick Erbland – Brittney Fleenor – Andrew George – Alexander Jensen – Amy Wyman

• Chris Bartlett • Captain Butch Harris and crew • Fishermen and community partners • UMaine’s Sustainability Solutions Initiative • ORPC

Award EPS-0904155

Limitations 1. Near-field - DIDSON (Viehman and Zydlewski 2014)

Limitations: resolution and sampling volume, large amount of data, time required for data processing

2. Far-field - Abundance & distribution (Viehman et al. 2014)

Limitations: 24 h surveys representing seasonal data, sampling close enough to device, inability to discriminate species

3. Mid-field - Mobile transects Limitations: low long-term temporal resolution, inability to discriminate species

Area viewed by mobile surveys (200

m up- and downstream of

turbine)

60 m 15 m

Bottom

Mobile surveys (7° split beam echosounder)

Stationary 24-hr surveys (31° single beam echosounder) Area viewed by DIDSONs

(at the test turbine) Beside turbine

ORPC TidGen®

In-line with turbine

Mobile survey data exclusion zone

N 30 m

Natural variation: in Space and Time