Auburn SFAAS Professor Featured in the Sept/Oct Issue of The Global Aquaculture Advocate



Carbon Footprint Of Aquaculture















The carbon footprint for aquaculture products results mainly from the use of manufactured feed and mechanical aeration. Because aquaculture ponds sequester carbon, they can be carbon dioxide-neutral.



Rising carbon dioxide concentrations in the atmosphere associated with global warming have focused interest on carbon footprints. A carbon footprint is an estimate of the total carbon emissions resulting from the production, use and  disposal of a product or service  Carbon footprints for aquaculture products result mainly from  the use of manufactured feed and  me­chanical aeration. Reflecting only about 0.5% of total global  carbon emissions, aquaculture species compare favorably to chicken and pork with respect to carbon footprint.


Carbon Footprint

The carbon dioxide concentration of the earth’s  atmosphere was thought to be about 280 ppm at the beginning of the indus­ trial revolution in the mid-1700s. Increasing use of fossil fuels since  the onset of the revolution increased  the carbon dioxide concentration in the atmosphere to 316 ppm in 1960 and 394 ppm in 2010. In Mauna Loa, Hawaii, USA, the reference site for measuring atmospheric carbon dioxide concentrations, the first reading above 400 ppm was recorded  in May.

Clouds, water vapor, carbon dioxide, methane and nitrousoxide retain  heat radiated by the earth, causing the planet’s temperature to be considerably greater than it would be otherwise. This natural greenhouse effect is exacerbated by increases in concentrations of greenhouse gases in the atmosphere from air pollution-especially combustion  of fossil fuels.

Carbon dioxide is the major green­ house gas resulting from human activities. The  observed increase in average global surface temperature of0.78• C during  the past century is highly publicized as the result of greater atmospheric carbon dioxide concentration. Of course, not all scientists entirely agree with this conclusion.

Global Warming Concerns

Global warming and associated climate change are blamed for the melting of polar ice and thermal expansion of the oceans, causing rising sea levels, extreme weather, expansion of subtropical deserts and adverse effects on ecosystems.Atmospheric carbon dioxide concentrations are predicted to continue to increase and have more serious effects in the future on ecosystems and humans.

Moreover, a higher carbon dioxide concentration in the atmosphere results in more carbon  dioxide in the oceans, causing ocean pH  to decline and increasing the solubility of the carbon­ ate minerals that form the shells of many marine organisms. This does not bode well for many species, including molluscan bivalves of aquaculture  importance.

Global Response

The alarm over global warming has resulted in efforts to lessen carbon emissions through  energy conservation, greater use of fossil fuels with lower carbon emissions, switching from fossil fuels to biofuels and development of alternative solar, wind and water energy resources. There also are efforts to increase carbon sequestration – removal of carbon dioxide from the atmosphere by incorporating it into organic matter or carbonate minerals through  no-till farming, reforestation, landfilling, underground or deep ocean injection, and chemical precipitation. Governments are developing carbon “cap and trade” pro­ grams in which a company is allotted an amount  of carbon emis­sions, and if it does not use all of its allotment,it can sell or trade the remainder. Carbon exchanges – similar to stock markets – have been established  to facilitate such programs. Carbon emis­sion taxes also are imposed  in some countries.

There is an increasing demand  by consumers for products to bear a label revealing their carbon footprint. The carbon foot­ print is an estimate of the total carbon emissions that result from the production, use and disposal of a product. Carbon footprints also can be evaluated for humanity, countries, individuals and services.

Energy Use In Food Production

The Food and Agriculture  Organization (FAO) of theUnited  Nations recently estimated  end use energy for the world food system (Table 1) in which carbon dioxide emissions mir­rored fuel use closely. Expressed as carbon dioxide equivalents, annual emissions from the greenhouse gases carbon dioxide, methane, nitrous oxide and fluorinated  hydrocarbons used as refrigerants were estimated  at 216 to 270 mmt for capture fisheries and 212 to 220 mmt for aquaculture. Total greenhouse gas emissions from human  activities presently total about 40,000 mmt annually.

Fisheries and aquaculture are minor players, each reflecting about 0.5% of total global carbon emissions. This leads one to wonder if concerns communicated by environmental non-gov­ernmental organizations about carbon dioxide emissions from aquaculture are justifiable.

Of course, energy conservation in aquaculture is wise because it avoids wasteful use of fossil fuels and electricity generated mainly from fossil fuels. Moreover, energy conservation  reduces aquaculture production costs – the major incentive for adoption of energy use reduction practices by producers. Of course, reduction in fossil fuel use also lessens carbon dioxide emissions.


Fisheries and aquaculture are minor players, each reflecting about 0.5% of total global carbon emissions.

Aquatic Species Footprint

The carbon footprints of individual species from capture fish­eries and aquaculture have been reported to range 1-3 kg carbon dioxide/kg meat and 2-7 kg carbon dioxide/kg meat, respectively (Table 2).The greater carbon footprint for aquaculture products results mainly from the use of feed and mechanical aeration.

In carbon footprints for farmed species, the production and transportation of feed ingredients and manufacturing of pelleted diets and their transport to farms contribute 50 to 60% of the car­ bon footprint. Aeration may contribute another 20 to 25% of the footprint. Of course, products from aquaculture systems that do not employ feed or aeration probably have carbon footprints similar to those of products from capture fisheries.

It is interesting to note that aquaculture species compare favorably to chicken and pork with respect to carbon footprint (Table 2). Beef has a much higher carbon footprint than do aquaculture species. Extrapolation of the carbon footprint of the few aquaculture species for which data are available to all aqua­ culture production provides an estimate of about 200 mmt of carbon dioxide equivalent-about the same as the FAO estimate made by a different  method of counting.

One point is overlooked in the computation above- aquacul­ture ponds sequester carbon. Data collected by researchers at Auburn  University suggested that global sequestration of carbon dioxide by aquaculture ponds is about 60.5 mmt annually. When subtracted  from the 200-mmt estimate of gross carbon dioxide emissions, this provides a net emission of about 140 mmt or 0.35% of global emissions. Because a major component of aqua­culture carbon dioxide emissions results from feed ingredient production and feed manufacturing, pond aquaculture often is carbon dioxide neutral or results in net carbon dioxide sequestration at the farm level.


There is no doubt  a basis for concern over excessive use of fossil fuels because the proven reserves of most are adequate for only 50 to 100 years at current global use rates. However, aqua­ culture is such a minor player in global carbon emissions that the efforts by environmental groups to alert the public regarding the carbon footprint of aquaculture could be better used in promoting the development of alternative energy sources. Humanity is facing a very serious conundrum with respect to its energy future. This issue is much more serious than most people -including the scientific community – seem to realize.

 Aquaculture species compare favorably to chicken and pork with respect to carbon footprint.


Zhen Tao, PhD student awarded the outstanding international student award

Tao's award2Zhen Tao, PhD student of Dr. Cova Arias, was awarded the outstanding international student award presented by the International Student Association and the Graduate School. Tao was selected among all international students within the College of Agriculture as the overall outstanding international student. He received his award from Dr. Joe Molnar in a banquet at the Student Activity Center on April 25, 2013.

Braxton Setzer with 48 lb Common Carp from Pond S-1

Braxton Setzer State Record Common Carp 2.27.13


Dr. Bill Walton’s Oysters Featured in News Article

Offshore Innovation: How Point aux Pins Highlights the Alabama Oyster













It was Shakespeare who first penned it.

“The world’s mine oyster / Which I with sword will open”—a phrase that has come to signify endless opportunity.

For Dr. Bill Walton, the oyster is his oyster.

Walton, assistant professor and marine fisheries extension specialist at Auburn University, is a pioneer of sorts when it comes to the oyster industry. Walton is advising and working with independent oyster farmers to implement an off-bottom farming technique that yields some of the finest premium oysters on the Gulf Coast.

Walton’s most successful oversight is the Point aux Pins oyster farm in Grand Bay, owned and operated by Steve and Dema Crockett. With Walton’s help, the Crocketts have crafted a premier oyster that’s getting a lot of attention. And thanks to Bon Secour Fisheries in Bon Secour and Crimson Bay Seafood and Johnson Sea Products in Bayou La Batre, Point aux Pins oysters can be found on restaurant menus throughout the state.

But for Walton and the Crocketts, success didn’t happen overnight.

Walton, a native of New Jersey, began independently farming oysters in Cape Cod after finishing his PhD at the University of Maryland and working related jobs for several years. “For us, it was a labor of love,” said Walton, who tended the farm with his wife, Beth. “We’d work the farm on the weekends or on very early or late low tides.”

The Waltons grew Bee’s River oysters, which they would sell to restaurants in Boston and Cape Cod. But Walton spent his work week as the Marine Fisheries & Aquaculture Specialist for Cape Cod Cooperative Extension and Woods Hole Sea Grant, where he provided academic expertise and applied research to industry representatives, resource managers and the general public.

So when it came time to find a more suitable home for his growing family, Walton began looking for a new job. That’s when the Gulf Coast began calling his name.

“With two young boys, Beth and I were having a hard time finding a home that we could afford,” Walton said. “I saw an advertisement for a position with Auburn University Department of Fisheries & Allied Aquacultures—and the work looked a lot like the work I loved.”

It did not take much convincing for the Waltons. “I interviewed, and my wife and I fell in love with the Gulf Coast,” said Walton, who began working in January of 2009 at the Auburn University Shellfish Laboratory on Dauphin Island.

But these days, Walton has become rather famous for his passion project: getting a new “blue green” industry started in Alabama’s coastal communities, where oyster farmers are cultivating the highest quality oysters imaginable such as those grown at the Point aux Pins farm. And their particular off-bottom method, one that Walton and the Crocketts adopted from Australian oyster farmers, has been gaining plenty of attention from the Alabama Gulf Seafood community.

The idea behind the off-bottom method is a simple one: juvenile oysters (provided by the Auburn University Shellfish Laboratory) are loaded into wire baskets that remain underwater yet suspended above the ocean floor. This system raises the oysters above the water about once a week, which allows the air and sun to kill undesirable organisms like barnacles and seaweed that can affect the growth of the oysters.

Of course, this technique has its drawbacks, the biggest being a lower quantity when compared to commercial oyster fisheries. “This method of oyster farming doesn’t produce the quantities of oysters that nature can,” said Walton. “Oyster farming won’t compete with our local oyster fishery, where the vast majority of those oysters are sold by the sack.”

It is also not the least expensive method of cultivation for those who are new to the world of oyster farming. “There are certainly significant start-up costs,” said Walton. “Someone doing this has to be prepared to make an investment.”

But the benefits are many. Off-bottom oyster farming allows the oysters to grow faster with a higher chance of survival. In addition, without the threat of bio-fouling, the oysters grow and excel in a way that nature simply would not allow.

And the flavor? Well, you have to taste them to believe it. Point aux Pins oysters are sold live and in the shell for a premium price to high-end restaurants and oyster bars, and they’re popping up on menus like Hot and Hot Fish Club in Birmingham, in Montgomery, and Compleat Angler along the Alabama coastline.

But Point aux Pins oysters are not just another entry into the premium oyster market—as Walton notes, the Crocketts are building a brand.

Thanks to a mixture of salts, nutrients and phytoplankton (that grow naturally in the area), oysters take on the flavor of the seas where they are grown. This means that oysters grown in different regions have their own unique taste. When grapes take on the flavor of the earth, this event is called “terroir”—so oysters experience what Walton calls “merroir.”

“Branding is simply taking the idea of ‘merroir’ and formalizing it,” said Walton. “Each Gulf oyster, like each East Coast oyster, has its own taste. Oyster farms tend to provide a more consistently flavored product, since they are all raised in the same area.”

With this in mind, the future for the Gulf oyster industry is bright.

“We’ve seen an oyster renaissance in the U.S.,” said Walton. “Oyster bars in Boston, Chicago, Las Vegas and so on have embraced the idea of having oyster ‘menus,’ where they might offer over a dozen appellations. We’re seeing restaurants and raw bars start to embrace this idea of branded oysters. This is an opportunity for the Alabama oyster industry to add our own ‘product.’”

That’s why he is working to secure an oyster farming enterprise zone in Portersville Bay. There, Walton and his associates, along with help from Mississippi-Alabama Sea Grant and funding from National Sea Grant, will train individuals who are interested in starting up their own oyster farms and continuing to promote and brand premium oysters.

“In Alabama,” said Walton, “I can see a day where we have Alabama oysters from Point aux Pins, Portersville Bay, Dauphin Island and Bon Secour Bay—each a distinct brand. How great would it be to go into an oyster bar and order three of each?”

At the end of the day, that’s what drives Walton and his teammates—helping to improve both the Alabama Gulf Seafood industry and the state’s economy as a whole. And because Alabama is historically the #1 processor of oysters in the U.S., this new oyster farming technique will only increase the economic impact of an industry that already accounts for hundreds of millions of dollars per year in Alabama.

“I really enjoy working on questions that matter to people who make their living on the water,” Walton said. “You can call it applied science, but I just consider it ‘putting science to work.’”

FAA Faculty Research Featured in the December Issue of Ag Illustrated

Researchers Aim To Make Fish Ponds More Profitable

AT YOUR LEISURE Recreational fish ponds can be money makers for their owners, but management recommendations that two Auburn aquatic ecologists are developing should help make pay-to-fish operations even more profitable.

Some 280,000 recreational fish ponds dot Alabama’s landscape, claiming close to 650,000 acres and providing a significant source of income as part of pay-to-fish operations and fishing resorts located throughout the state. Two Auburn fisheries scientists are in the midst of Alabama Agricultural Experiment Station–funded work aimed at helping pond owners improve the management and profitability of those ponds.

“Given that pond fishing businesses are most often found in some of the most economically challenged parts of Alabama, any support that can help them enhance their fish pond populations and attract more anglers would be significant,” says Rusty Wright, Extension specialist and associate professor in the Department of Fisheries and Allied Aquacultures.

In the project, Wright and departmental colleague Dennis DeVries, professor, are specifically focusing on two management practices commonly used to improve the growth and abundance of largemouth bass and bluegill in recreational ponds. The first is stocking threadfin shad as a supplemental prey fish for largemouth bass; the second is adding pelleted feed for bluegill.

“These enhancement techniques are often used, but it is not consistently clear whether they work or how they act in a pond food web,” Wright says. “This research will help us make better science-based recommendations as to the addition of pellet feeding and the stocking of threadfin shad.”

For largemouth bass, the addition of threadfin shad as a prey species translates into a more abundant, calorically rich and easily caught food source, Wright says; however, shad species can have a negative effect on the abundance and growth of other prey species, such as bluegill, through competition for food.

To offset that competition, or to enhance ponds without shad, pond owners often feed the bluegill with pelleted feeds. Direct feeding of bluegill can improve growth and increase egg production. Plus, feeding in a specific location can lure bluegill to anglers.

In general, however, study of the potential impacts of pellet feeding has only been partially tested scientifically, and often

in laboratory settings. Wright says such research is best carried out in the field, where conditions are the same as those pond managers are going to experience. For their project thus far, he and DeVries have conducted a pond experiment at the E.W. Shell Fisheries Center and have sampled fish from established ponds at the fisheries center as well as some that are privately owned.

“We get a lot of questions about pond management, and our main goal in this research is to truly determine the efficacy of these practices, to refine rate recommendations for stocking and feeding and to understand how the enhancements work,” Wright says. “Our science-based assessment of pond enhancements should help pond managers avoid spending money on overfeeding or excess prey fish additions.

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