Oysters

Oysters aren’t just delicious to eat, they are also a versatile tool to restore and protect the Louisiana coastline! Oyster reefs protect shorelines from wave energy, filter water, and improve habitat quality. Unfortunately, much of our country’s oyster production is unsustainable because of a combination of activities including over-harvesting, pollution, and habitat destruction through dredging and collection practices. As we restore oyster reefs, they will have positive environmental, economic, and cultural impacts.

In other areas of the United States, these harmful extraction methods have all but ruined the oyster industry. According to the Chesapeake Bay Foundation, their estuary has lost more than 98 percent of its oysters with major economic consequences. [1] In Louisiana, we have not experienced nearly as much damage, so we can more readily restore our reefs. Some benefits we could gain from healthier reefs, according to our partners at BTNEP, include wave energy absorption, reduction of the Gulf Dead Zone, and improved habitat for nearly 300 species of fish, crustaceans, and mollusks. By supporting oyster reefs, you support fisheries as well as resiliency. A single adult oyster can filter up to 50 gallons of water per day, removing excess nutrients and lessening the coast’s eutrophication (nutrient pollution that leads to algal blooms) and dead zones (areas of low dissolved oxygen). [2]

Aside from the numerous important ecological benefits, the price tag for oyster reef restoration is cheaper other protection techniques. According to an article in Scientific American, the adaptation strategy of raising houses onto stilts costs more than the damages it will prevent. [3] Some of the most cost-effective protection methods cited in the article included wetland restoration (nearly a 10:1 protection to cost ratio), oyster reef restoration (just over 7:1) and barrier island restoration (about 5:1). Many of these restoration and protection strategies have been utilized by CWPPRA since the 1990s.

CWPPRA projects are synergistic approaches to protecting and restoring our coast, using the best available science to implement projects in areas of most need, as well as emphasizing cooperation between projects and their managing agencies.  Sustainable innovations in oyster reef restoration is just one way in which CWPPRA achieves its goal of wetland restoration.

[1] https://www.cbf.org/about-the-bay/more-than-just-the-bay/chesapeake-wildlife/eastern-oysters/

[2] web.archive.org/web/20170802173757/http:/www.noaa.gov/media-release/gulf-of-mexico-dead-zone-is-largest-ever-measured

[3] https://www.scientificamerican.com/article/rebuilt-wetlands-can-protect-shorelines-better-than-walls/

Featured Image from https://www.nature.org/en-us/about-us/where-we-work/united-states/florida/stories-in-florida/floridas-oyster-reef-restoration-program/

 

Bio-Engineered Oyster Reef Demonstration (LA-08)

LA-08

Purpose:

The purpose of this project is to test a new, bio-engineered, product to address rapid shoreline retreat and wetland loss along the Gulf of Mexico Shoreline in areas with soils of low load bearing capacity. For example, at Rockefeller Refuge, the direct Gulf of Mexico frontage and extremely low soil load bearing capacity (250-330psf), coupled with an average shoreline retreat of 30.9 ft/yr, present unique engineering challenges with a subsequent direct loss of emergent saline marsh.

Restoration Strategy:

The goal of this demonstration project is to evaluate the proposed technique as a cost effective technique for protecting areas of Coastal Louisiana’s Gulf of Mexico Shoreline with poor load bearing capacities.The demonstration project would consist of an Oysterbreak, approximately 1000′ long. The Oysterbreak is a light-weight, modular shore protection device that uses accumulating biomass (an oyster reef) to dissipate wave energy. The bio-engineered structure is designed to grow rapidly into an open structured oyster reef utilizing specifically designed structural components with spat attractant (agricultural byproducts) and enhanced nutrient conditions conducive to rapid oyster growth.

Required Monitoring: [1]

  • Topographic and bathymetric surveys (elevation, water levels)
  • Ground-level photography
  • Aerial photography
  • Wave attenuation (wave energy effects)
  • Oyster and Water quality monitoring

The Oysterbreak is constructed by placing modular units into an open interlocked configuration. The units are sized to be stable under storm wave conditions. The height and width of the Oysterbreak are designed to achieve a moderate initial wave energy reduction. As successive generations of encrusting organisms settle on the Oysterbreak, the structure’s ability to dissipate wave energy increases.

Location:

The project is located along the Rockefeller Wildlife Refuge Gulf of Mexico shoreline west of Joseph Harbor canal in Cameron Parish, Louisiana.

pic_LA_08

Project Effectiveness: [2]

The oysterbreaks are providing habitat for oyster settlement and the top layers of rings should be the most likely to support oyster colonies. Recommended improvements include:

  • Types of cement applications
  • Lessening the space available for coastal erosion (the gap between coast and oysterbreaks needs to reduce to prevent further erosion).
  • Crest elevation between the oysterbreaks performed well in wave attenuation and shoreline erosion
  • Increase the height of the structure to improve wave breaking potential

aerial_rings

Progress to Date:

The cooperative agreement between the National Marine Fisheries Service and the Louisiana Department of Natural Resources has been executed. Construction was finalized in February 2012. This project is on Priority Project List (PPL) 17.

More Information on this Project:

Further Websites Regarding Oyster Reef Restoration:

 

 

Work Cited:

[1] McGinnis and Pontiff. (pages 4-6) LA-08 2012 Operations, Maintenance, and Monitoring Plan, 30 April 2018, https://www.lacoast.gov/reports/project/4224379~1.pdf

[2] McGinnis and Pontiff. (page 22) 2014 Operations, Maintenance, and Monitoring Report for Bioengineered Oyster Reef Demonstration Project (LA-08)

 

 

Wetland Wonders at Ocean Commotion

Can you figure out the mystery coastal item based on the following clues? It contains a bivalve that a) makes pearls, b) is a filter feeder, and c) we eat here in Louisiana.

Over 1600 elementary and middle school students had the chance to read those clues at LSU Sea Grant’s Ocean Commotion on October 24 in Baton Rouge. Students, teachers, and chaperones then reached their hands into a box and tried to identify the item (oyster shell) they were holding. Other mystery items included a nutria pelt, cypress knees, an apple snail shell, and a magnolia seed pod- all from plants and animals that call Louisiana’s coastal wetlands home.

2017 marks the 20th Anniversary of Ocean Commotion, an annual event meant to give students the chance to get up close and personal with coastal and sea life and the challenges facing those environments. This year 70 exhibitors taught students about topics as diverse as boating safety, mosquito control, and microplastics. CWPPRA outreach staff talked with students about the diversity of species found in Louisiana’s wetlands and the challenges of invasive species, giving students an opportunity to think about how different species impact ecosystems in different ways.