Oyster Reef and Estuarine Landscape Restoration

K.L. Heck, Jr., S.P. Powers, J. Cebrian, D.A. Byron, S. Scyphers & J. McKee

Why Restore Oyster Reefs?

• Oyster reefs are in major decline along both the Atlantic and Gulf coasts. This is important, because in addition to the multimillion dollar US fishery they support, oyster reefs provide key ecosystem services.

-Oyster reefs stabilize shorelines, serving as living breakwaters -Oyster reefs provide habitat for finfish & shellfish-As filter-feeders, oysters clear the water column by removing suspended solids and phytoplankton -Oysters sequester excess nutrients (nitrogen, phosphorous, and carbon)

Alabama Oyster Fishery(Source: NMFS)

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Land

ings

(kg

mea

t)

Frederic (3)

Opal (3)& Erin (2)

Camille (5)

Ethel (3)

Elena (3)

Ivan and Katrina

X

Source: Smith. 1991. Gulf Coast Asso Geol Soc Trans 40: 793-796

Source: Smith. 1991. Gulf Coast Asso Geol Soc Trans 40: 793-796

Coastal survey data from the 1700’s to the present indicate progressive loss of Alabama coastal shoreline and wetlands.

Areas showing the highest rates of loss include Mississippi Sound north shoreline and islands, Mobile Bay west shoreline, Gulf shoreline of Dauphin Island and north shoreline of Morgan Peninsula.

MISSISSIPPI SOUND

-Aggregate loss of shoreline, including that of islands, exceeds 40 acres per year, a significant loss in as much as no new marsh is being created and the area serves as a major nutrient source for several commercial fishery species.

MOBILE BAY

-Erosion ranges up to 8 feet per year along some sections of west Mobile Bay shoreline.

• Vertical erosion down the barrier

• Loss of critical intertidal habitat

• Net loss of fishery production

Historical Shoreline Armoring

Figure and Image from Douglass & Pickel (1999)

Goals for Living Breakwater Project

• Reef construction, shoreline stabilization, marsh regrowth, faunal utilization and seagrass colonization.

• Sparse biotic community

• Eroding shoreline

• Oyster bar foundation

• Shoreline stabilized

• Seagrass colonization?

• Some small fish and invertebrates

• Large oyster reef

• Expanded emergent marsh

• Expanded seagrass?

• Small and Large fish and invertebrates

• Sparse biotic community

• Eroding shoreline

• Oyster bar foundation

• Shoreline stabilized

• Seagrass colonization?

• Some small fish and invertebrates

• Large oyster reef

• Expanded emergent marsh

• Expanded seagrass?

• Small and Large fish and invertebrates

NGI Oyster Breakwater Project (2007-2009)

Live oyster reef Buried oyster shell deposits Breakwater Reefs - 2007

U of Alabama propertyAt Point aux Pins

Mobile County Bayfront Park

NGI Project Timeline

• Collaborated with Dr. Scott Douglass (USA) on oyster reef design in 2006

• Bid the project and selected contractor• Built two 75 m x 5 m breakwater reefs offshore

of eroding shorelines at Point aux Pines (May 2007) and at Alabama Port (November 2007)

• Conducted two year monitoring of all response variables beginning immediately after construction at each location

Reef Con$truction at Alabama Port (Nov 2007)

Pre-positioned geo-grid laid as a foundation

Shell secured with netting

Monitoring of Replicated Areas (with and w/o reef construction)

• Shoreline Stabilization • Oyster Density and

Settlement• Water clarity • Juvenile and Adult Fish,

shrimp and crabs• Seagrass Cover &

Growth

Shoreline change: Alabama Port(Jan 2008 to Oct 2009)

January 2008May 2008

May 2009October 2009

Veg

etat

ion

retre

at (m

)

0

1

2

3

4

5

6

Control sitesReef sites

Oyster Spat Density

May 2007

July 2007

August 2007

November 2007

May 2008

October 2008

Oys

ter S

pat

m-2

0

200

400

600

800

1000 West East

November 2007

March 2008

June 2008

October 2008

Oys

ter S

pat

m-2

0

50

100

150

200 NorthSouth

Point aux Pins

Alabama Port

Some fisheries species enhanced by oyster reefs

Stone crabGag grouper

Speckled trout

Gray snapper

Southern flounder

Sheepshead Red drum

Blue crab

0

5

10

15

20

25

30

35

40

45

50

REEF CONTROL

Abu

ndan

ce (

#fis

h / H

our)

P-Value = 0.005n= 11

Family Sciaenidae Abundance(Gillnet)

Conclusions• The breakwater reefs are reducing wave energy,

trapping sediments behind the reefs, and reducing shoreline erosion

• To date, little change seen in water clarity at the reefs, and no seagrass colonization

• Recruitment of oyster spat has occurred

• Sport fish and shellfish are attracted to the reefs

• Building such reefs may be a viable alternative to hardening shorelines, with the added benefit of enhanced fisheries production

2-ADCNR (NOAA-EDRP) Goals

• To measure the environmental benefits of building oyster reef breakwaters – Creation of habitat for juvenile and adult

shellfish and finfish– Shoreline stabilization– Improved water clarity

• To measure the effectiveness of a slightly different and improved restoration design

Alabama Oyster Habitat

State Lands propertyat Point aux Pins

Live oyster reef Buried oyster shell deposits Breakwater Reefs -2007

Breakwater Reefs -2009

Reef Con$truction at NE Point aux Pins (Sept 2009)

Shell secured with fencing

Progress to Date

• Conducted one year of pre-construction monitoring of all response variables (Nov 2008 – Aug 2009) to identify existing differences among locations

• Built four 75 m x 5 m breakwater reefs offshore of eroding shorelines at NE Point aux Pins (Sept 2009)– modified original (2007) breakwater design

• Began 2 year post construction monitoring (October 2009) to assess effectiveness

3-Coastal Alabama Stimulus (TNC/NOAA-ARRA) Project

Objectives• Creation of fishery related jobs for South Mobile

County-$2.9 M project during 2009-2011• Stabilization and restoration of eroding

shorelines – Comparing three methods of stabilization:

bagged oyster shell, reef ball & reef blocks• Restoration of oysters and associated

ecological benefits

Three Methods of Stabilization

Bagged Oyster Shell Reef Balls

Reef Blocks

Alabama Oyster Habitat

Mobile County Bayfront Park

State Lands property at Coffee Island

Breakwater Reefs - 2010Live oyster reefBuried oyster shell deposits

Breakwater Reefs - 2007Breakwater Reefs - 2009

Progress to Date

•37 jobs created, 8 jobs maintained, 104,869 labor hours (projected)

•Construction and job creation has taken place in Bayou La Batre, AL

•Nearly 1 mile (1500m) of reef delineated and half now deployed

•Pre-restoration monitoring began in fall 2009

Jeff DeQuattro TNCJeff DeQuattro TNC

Living Breakwater Projects: Summary

• Five restoration sites at various stages of completion in south Mobile County

• Numerous funding sources– USA Oyster Program, Northern Gulf Institute, Mob.

Bay NEP, ADCNR, TNC (NOAA-Stimulus funding)• Multi-investigator collaborations, with grad students• Sites have design and monitoring variations but

overall goals are similar– Restore oyster reefs and their ecological services– Protect eroding shorelines along Mobile Bay