1 restored oyster reef, chesapeake bay 1 putting the reef back into “ridge to reef” catchment...

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Restored oyster reef, Chesapeake Bay

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Putting the reef back into “Ridge Putting the reef back into “Ridge to Reef” Catchment Management to Reef” Catchment Management

for Pumicestone Passage.for Pumicestone Passage.

Ben DigglesBen DigglesDigsFish Services Pty Ltd DigsFish Services Pty Ltd

www.digsfish.com www.digsfish.com

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We We needneed catchment catchment management…management…

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We We needneed a Catchment Action Plan… a Catchment Action Plan…

44www.digsfish.com www.digsfish.com 44

PP Catchment Action PlanPP Catchment Action Plan• Oysters Oysters areare mentioned in “Actions for mentioned in “Actions for

future consideration”:future consideration”:• FC23 (pge 40). Investigate potential FC23 (pge 40). Investigate potential

health risks associated with eating health risks associated with eating wild oysters harvested from wild oysters harvested from Pumicestone Passage and its Pumicestone Passage and its tributaries.tributaries.

• A commendable goal, but suggests A commendable goal, but suggests “oysters only for eating” - nothing “oysters only for eating” - nothing could be further from the truth. could be further from the truth.

• We already know the answer, “dodgy We already know the answer, “dodgy if it rains”if it rains”


Is this good enough ?Is this good enough ?• No. There is no mention of restoration No. There is no mention of restoration

of oysters or other bivalves…..of oysters or other bivalves…..

• This is despite their undoubted This is despite their undoubted ecosystem benefits to water quality, ecosystem benefits to water quality, habitat and biodiversity, and overall habitat and biodiversity, and overall sustainability.sustainability.

• Bivalves are also culturally significant, Bivalves are also culturally significant, especially to traditional owners, as well especially to traditional owners, as well as socially and economically important. as socially and economically important.

• In essence they tick all the boxes – In essence they tick all the boxes – they cannot be ignored. they cannot be ignored.


Oysters = Ecosystem Oysters = Ecosystem engineersengineers

• Bivalves, being filter feeders, are the “lungs of Bivalves, being filter feeders, are the “lungs of the estuary”. Oysters in particular provide the the estuary”. Oysters in particular provide the following “following “ecosystem engineering” servicesecosystem engineering” services::

• Food and reef habitat for fish and Food and reef habitat for fish and crustaceans.crustaceans.

• Filtration of water (decreased turbidity).Filtration of water (decreased turbidity).• Carbon sequestration (into shells). Carbon sequestration (into shells). • Nutrient cycling (e.g. dendrification of N).Nutrient cycling (e.g. dendrification of N).• Bentho-pelagic coupling (consuming nutrients Bentho-pelagic coupling (consuming nutrients

from water and energy from sun (via from water and energy from sun (via phytoplankton) and converting these into phytoplankton) and converting these into animal material useful to other animals in the animal material useful to other animals in the system).system).

• i.e. They are the foundation of a healthy i.e. They are the foundation of a healthy estuary.estuary.


Declining bivalves – global Declining bivalves – global trendstrends

• But…. Despite being a vital link in the But…. Despite being a vital link in the estuarine food chain, natural oyster reefs estuarine food chain, natural oyster reefs are at risk in many parts of the world. are at risk in many parts of the world.

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Case study- rock oysters in Case study- rock oysters in Pumicestone PassagePumicestone Passage

• Historically, Sydney rock oysters were Historically, Sydney rock oysters were massively abundant in Pumicestone Passage. massively abundant in Pumicestone Passage.

• Ninghy = Aboriginal word for “plenty of Ninghy = Aboriginal word for “plenty of oysters”. Early settlers in the mid 1800’s oysters”. Early settlers in the mid 1800’s described subtidal oyster reefs down to 4+ described subtidal oyster reefs down to 4+ meters and intertidal reefs 300 yards long.meters and intertidal reefs 300 yards long.

• But today subtidal oyster reefs are extinct and But today subtidal oyster reefs are extinct and around 96% of oyster zonation has been lost.around 96% of oyster zonation has been lost.

• Underlying cause is due to recruitment failure Underlying cause is due to recruitment failure from poor water quality and habitat change. from poor water quality and habitat change. Disease is the symptom, NOT the cause.Disease is the symptom, NOT the cause.


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Case study- rock oysters in Case study- rock oysters in Pumicestone PassagePumicestone Passage



Estuaries without bivalves – Estuaries without bivalves – what do you get ?what do you get ?

• Reduced food and biogenic reef habitat for Reduced food and biogenic reef habitat for fishes and crustaceans = unhealthy fishes and crustaceans = unhealthy fisheries.fisheries.

• Reduced bentho-pelagic coupling = poor Reduced bentho-pelagic coupling = poor utilisation of available nutrients which utilisation of available nutrients which favours the algal-microbial loop = favours the algal-microbial loop = Undesirable algal growth and/or algal Undesirable algal growth and/or algal blooms, microbial problems in shellfish.blooms, microbial problems in shellfish.

• Increased turbidity, which reduces seagrass Increased turbidity, which reduces seagrass growth and survival.growth and survival.

• In other words, exactly what we see in In other words, exactly what we see in Pumicestone Passage today.Pumicestone Passage today.

• Dead zones (low or no ODead zones (low or no O22) to come next ?) to come next ?

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• Obviously catchment management that Obviously catchment management that reduces sediment and nutrient inputs is vitally reduces sediment and nutrient inputs is vitally important.important.

• Riparian buffer zones / artificial wetlands to Riparian buffer zones / artificial wetlands to recover nutrients and clean runoff/stormwater.recover nutrients and clean runoff/stormwater.

• Restoration of oyster reefs – precedents from Restoration of oyster reefs – precedents from the Chesapeake Bay Program are worth the Chesapeake Bay Program are worth examining.examining.

• Dead zones in Cheasapeake Bay made things Dead zones in Cheasapeake Bay made things very difficult for them – don’t let it happen very difficult for them – don’t let it happen here.here.

What can be done about it ?What can be done about it ?

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They are doing it !They are doing it !

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• Three pronged catchment management Three pronged catchment management effort to restore their waterways.effort to restore their waterways.

• 1. Reduce Pollution1. Reduce Pollution

• 2. Restore Habitats2. Restore Habitats•Restoring oyster reefsRestoring oyster reefs

•Replanting seagrassesReplanting seagrasses

•Restoring wetlandsRestoring wetlands

•Restoring fish passageRestoring fish passage

• 3. Manage Fisheries3. Manage Fisheries

http://www.chesapeakebay.net/track/restorationhttp://www.chesapeakebay.net/track/restoration

Chesapeake Bay ProgramChesapeake Bay Program

At top of the list At top of the list because because restored oyster restored oyster reefs help with reefs help with both 1. and 3. as both 1. and 3. as well as well as restoration of restoration of seagrasses seagrasses (through (through improved water improved water clarity) and clarity) and wetlands wetlands (through bank (through bank stabilisation)stabilisation)

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• Australia’s first oyster reef restoration Australia’s first oyster reef restoration program recently announced in Port Phillip program recently announced in Port Phillip Bay, Victoria.Bay, Victoria.

• Partnership between a local fishing club, Partnership between a local fishing club, Victoria Fisheries and The Nature Victoria Fisheries and The Nature Conservancy (TNC, an eNGO).Conservancy (TNC, an eNGO).

• TNC is world authority on oyster reef TNC is world authority on oyster reef restoration.restoration.

• I am corresponding with them re: the Port I am corresponding with them re: the Port Philip Bay project and suggesting to them Philip Bay project and suggesting to them that Pumicestone Passage should be next. that Pumicestone Passage should be next.

Oyster Reef Restoration in Oyster Reef Restoration in AustraliaAustralia

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Oyster Reef Restoration in Oyster Reef Restoration in AustraliaAustralia

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• Significant community support to do Significant community support to do something tangible for Pumicestone Passage something tangible for Pumicestone Passage by conducting our own pilot oyster reef by conducting our own pilot oyster reef restoration project.restoration project.

• Seed funding up to $55,000 available from Seed funding up to $55,000 available from Toorbul Fish Stocking Association.Toorbul Fish Stocking Association.

• Support from traditional owners (Ngunda- Support from traditional owners (Ngunda- Joondoburri, Gubbi Gubbi), Sunfish, BIEPA, SEQ Joondoburri, Gubbi Gubbi), Sunfish, BIEPA, SEQ Catchments, QLD Fisheries, and TNC.Catchments, QLD Fisheries, and TNC.

• Aquaculture facilities (at Woorim) if needed.Aquaculture facilities (at Woorim) if needed.• Restoring oyster reefs is a key to restoring and Restoring oyster reefs is a key to restoring and

maintaining a healthy Pumicestone Passage in maintaining a healthy Pumicestone Passage in the face of ongoing urban development.the face of ongoing urban development.

Community supportCommunity support

2020

• Get oyster reef restoration onto the Catchment Get oyster reef restoration onto the Catchment Action Plan. Oysters to be placed in Action Plan. Oysters to be placed in subtidalsubtidal reefs reefs for environmental remediation for environmental remediation onlyonly (not to eat). (not to eat).

• Aim to top up seed funding from local community Aim to top up seed funding from local community with FRDC/TNC and other sources (offsets ?) to with FRDC/TNC and other sources (offsets ?) to conduct initial data collection to enable site conduct initial data collection to enable site selection, baseline mapping and analysis.selection, baseline mapping and analysis.

• Community, scientific and stakeholder review.Community, scientific and stakeholder review.

• Blueprint – budgeting, permitting, sourcing funds Blueprint – budgeting, permitting, sourcing funds and raw materials, setting restoration goals.and raw materials, setting restoration goals.

• Implementation, monitoring and evaluation.Implementation, monitoring and evaluation.

Our Plan Our Plan (courtesy Harris Creek oyster restoration, (courtesy Harris Creek oyster restoration,

MD)MD)

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Thank you .Thank you .

1 restored oyster reef, chesapeake bay 1 putting the reef back into “ridge to reef” catchment...

Documents

wild oysters

sydney rock oysters

case study rock oysters

ecosystem engineersbivalves

reef catchment management

subtidal oyster reefs

biogenic reef habitat

natural oyster reefs