Sunday, March 19, 2017

CAMA Protection of Coastal Resources: Shellfish Closures and Water Quality

Jennifer Ryan is a student in the Coastal and Ocean Policy Master's program, and is set to graduate this spring. She graduated from the University of Scranton in 2015 with a BS in Political Science with a minor in Biology and a concentration in Environmental Studies. She has developed interests in water quality issues and conservation through her education and internships in Wilmington.
Signage used in North Carolina to indicate a closed down shellfishing area due to excessive fecal coliform levels.
When vacationing on the coast of North Carolina, many tourists frequent restaurants hoping to indulge in fresh seafood, including shellfish like scallops, crabs, clams, and mussels. The occasional interested patron will ask the server where the restaurant gets their shellfish.

While many hope or assume their food comes from the local area or from within the state’s coast, it is common that the actual answer is usually, Louisiana, Maine, Washington, or even China.

This may come as a surprise to many because North Carolina’s coast is host to abundant shellfish habitats and harvesting areas. Shellfish are considered an important natural resource to North Carolina’s coast and are protected under the Coastal Area Management Act. However, elevated levels of fecal coliform bacteria in coastal waters have impacted shellfish harvesting areas in the state, particularly in southeastern North Carolina where coastal development has increased. The high quantity and concentration of development in the southeastern part of the state has caused a decline in water quality in the rivers, creeks, and bays in the area.

Fecal coliform describes a group of bacteria with potential health risks that are found in the feces of warm-blooded animals such as people, pets, livestock, and wildlife. The Clean Water Act (CWA), establishes federal water quality standards including limitations on fecal coliform concentrations for swimming and for shellfish harvesting waters. Shellfish harvesting areas with fecal coliform bacteria levels that exceed water quality standards are closed down either temporarily or permanently.

North Carolina’s Coastal Area Management Act (CAMA) assigns responsibility for carrying out CWA quality standards to the Shellfish Sanitation and Recreational Water Quality Section within the NC Division of Marine Fisheries. Yet, despite their efforts they are not adequately addressing and protecting water quality. Currently, cities and towns can adopt their own land-use plans to mitigate stormwater runoff, but it is not mandatory under CAMA. As a result, few follow through with the recommendation.

Scientists link increased shellfish closures from heightened fecal coliform levels to an increase in population and impervious surfaces. Population increase, especially on the coast, leads to more development. More development creates more impervious surfaces. Impervious surfaces transport fecal coliform into coastal waters via stormwater runoff. Since 2000, the Shellfish Sanitation and Recreational Water Quality Section has permanently closed 2,318 acres of productive shellfish waters due to stormwater runoff.

The relationship between the percent of impervious surface coverage to the density of fecal coliform bacteria in five watersheds in southeastern North Carolina. Graph credit to M. Mallin 
The water quality standard for shellfish harvest is 14 CFU/100 mL. The graph above demonstrates that impervious surface coverage at about 10% and above indicates impairment.

Increased closures of polluted shellfish harvesting waters are an indicator of poor water quality, which has public health, economic, and cultural impacts. Eating polluted shellfish can make people sick with illnesses such as Shigella, Salmonella, and Hepatitis A. Increased shellfish closures reduce access to various commercial shellfish fisheries that are economically beneficial to the state and citizens involved in the industry. The shellfishing industry has also long been a cultural part of coastal communities, and increased shellfish closures are a detriment to keeping that culture alive and thriving.

Effective stormwater mitigation is critical for protecting the public health and the economic and cultural dimensions of shellfish.

Improved and mandatory land use and stormwater plans under CAMA that better account for nonpoint pollution sources like stormwater runoff are key to reducing shellfish pollution. Implementing Low Impact Development (LID) strategies also helps mitigate stormwater runoff through development strategies such as rain gardens, pervious surfaces, and rain cisterns. Increasing incentives to implement LID strategies such as, tax cuts and reducing green infrastructure permit pricing, may assist in making these development strategies more appealing. As well, increasing outreach and education efforts to inform the public about the dangers and impacts of fecal coliform pollution and stormwater runoff aim to inform and involve the public in solutions.


  1. Stormwater runoff and its consequences are definitely a large issue here in North Carolina. I like how you relate it back to the economic implications. With local food sources being a concern or desire of consumers, this issue can have large economic impacts. It definitely seems like the land use suggestions should be implemented in each city. Maybe it should be the case where the state comes up with the amount of stormwater runoff that needs to be reduced in each city, and then it is left up to the city on how they want to go about it (incorporating it into their zoning laws, tax breaks, tradeable credits). Obviously this factors in a sense of accountability that would need to be established by the state if the city or township does not comply. It seems like that could allow each city to gear solutions toward their community's needs and functions.

  2. I'm also astounded by the quantity of oysters that North Carolina waters have to offer that are not open to public consumption. I spend a lot of time around the intracoastal waterway, marshes, and mud flats, and there are beds thick with oysters. It's a great habitat for them! And I would personally love to be able to go anywhere around the estuary and bring some home for my dinner plate. However, fecal coliform is a real issue, and stormwater runoff is a driving factor. A stricter application of a town or county's land use plan would really help this situation, but the reality is that zoning and development drive the land use plan and not the other way around. A town creates a land use plan to have control over their own planning and not have to defer to the county land use plan. Although they have their own LUP, they can change it whenever, and however they want to meet zoning and development needs. There's no state agency that requires towns to follow their LUP's, and therefore, no enforcement if a town decides to make changes that benefit development.

  3. I'm also astounded by the abundance of oysters throughout North Carolina's estuaries that are not open to public consumption. It is a shame that fecal coliform is so bad that it has afflicted most of the edible oysters in our area. Stormwater is definitely an issue but I wonder how much of fecal coliform is coming from runoff compared to what is seeping out from septic systems? Regardless, a towns Land Use Plan (LUP) should incorporate stormwater management with a goal that will reduce the deposition of fecal coliform from runoff. The unfortunate reality of the situation is that Land Use Plans don't drive development, instead, development is driving the Land Use Plans. A town develops a LUP to have control over the planning of its town instead of having to defer to the county. The town can also change the LUP to incorporate any zoning or development changes they want. There is no state agency that oversees whether towns are sticking to their land use plans, so towns are not left accountable. The only real enforcement is through the public by voting or complaining.

  4. Poor water quality is a problem that is common in coastal areas with high levels of development. High levels of fecal coliform are one of the major reasons for shellfish closures in these areas. From what I've learned, most fecal coliform come from pet owners not cleaning up after their dogs. Although Wilmington has a position specifically for giving out tickets to those that fail to clean up after their dog, it does not seem to be working. I don't think many people who have dogs realize the combined effect that dog droppings have on water quality. The most practical way to combat fecal coliform, I think, is through public education and investing in green infrastructure such as permeable surfaces instead of concrete or asphalt.

  5. The bacteria polluting Wilmington waterways is a direct product of domestic animal waste entering the stormwater system. There are thousands of pet dogs in New Hanover County generating over 12 tons of waste per day. That is way, way more than the natural system can capacitate, with or without impervious surfaces to counteract it. It has been years since Wilmington's sewage outfall issue on Hewlett's creek climaxed and the problem has long since been correct, leaving a powerful public misconception and displacement of accountability for individual actions in its wake. My point here is that I agree with you and many comments above, that BMPs and mandatory regulation is only going to be effective with complementary education and outreach--particularly when it comes to picking up pet waste and the public health consequences of not.

  6. It is incredible to me that the shellfish in this region cannot be consumed because of poor storm water management and pet waste. Most people who visit the coast, my family included, want to eat local seafood. Not only is it troubling that shellfish isn’t safe enough to eat, but inconsumable local seafood raises other questions for visitors. For example, tourists may become concerned that the water at the beach isn’t clean enough for swimming. This reminds me of Gigi’s project. I can see poor storm water management and pet waste issues becoming worse in the long term and causing this area to have swim advisory issues like Myrtle Beach. I also agree with above commenters about pet waste. It seems like many people do not understand the impacts pet waste has on water quality and shellfish. We need to find creative ways to educate pet owners about this problem.

  7. Shellfish closures are not exclusively caused by poor storm water management and animal waste. Improperly sited and functioning septic systems and failures of central sewage collection systems contribute as well, although we do not yet have good numbers to facilitate comparisons. Bear in mind that big rain events exacerbate all these problems simultaneously.
    Cahoon, L.B., and M. Hanke. Rainfall effects on inflow and infiltration in wastewater treatment systems in a coastal plain region. Water Science and Technology. Available Online 7 February 2017, wst2017072; DOI: 10.2166/wst.2017.072.
    Cahoon, L.B., J.C. Hales, E.S. Carey, S. Loucaides, K.R. Rowland, and B.R. Toothman. 2016. Multiple modes of water quality impairment by fecal contamination in a rapidly developing coastal area: Southwest Brunswick County, North Carolina. Environmental Monitoring and Assessment 188(2): 1-13. DOI 10.1007/s10661-015-5081-6.
    Cahoon, L.B., J.C. Hales, K.R. Rowland, E.S. Carey, S. Loucaides, and J.E. Nearhoof. 2006. Shellfishing closures in southwest Brunswick County, North Carolina: Septic tanks vs. storm water runoff as fecal coliform sources. J. Coastal Research 22 (2):319-327.

  8. When you think about it, North Carolina should be quite embarrassed that it can't provide fresh shellfish to its residents and visitors. As mentioned above, many people expect local seafood when visiting the coast of North Carolina. If they can't get it here, they're going to go somewhere else. NC government should see these closures as a threat to tourism, thus many coastal communities' economies. I agree that mandatory stormwater ordinances need to be in place for each coastal municipality's LUP.

  9. Like everyone else, I find it astounding that there is a large amount of shellfish in North Carolina that cannot be consumed because of the pollution. Many people want to buy locally, so the fact that that fishery cannot be utilized is shocking. Pet waste in our waters should be reduced, which can be done through education and outreach. By educating communities about the importance of cleaning up after their pets, it could encourage pet owners to pick up after their pets. Many people may not know the impact their pet waste has on their surrounding waters. Stormwater mitigation is also important because it is important to protect public health and to reduce the impact it has on shellfish in the area.

  10. I was pretty familiar with this issue because it is similar to what is going in Myrtle Beach; instead of beachgoers you are dealing with fisherman. Water quality seems be one of the largest issues facing coastal communities. I agree with you that low impact development needs to be a mitigation method for decreasing stormwater runoff. For swim advisories researchers are developing better forecasting systems, I wonder if they could do same thing for fisheries if they can improve the water.