By Christine Blank, SeafoodSource contributing editor
Published on 09 January, 2014
While many mainstream media articles spread the notions that coastal aquaculture is not safe for its surrounding environment, the National Oceanic and Atmospheric Administration (NOAA) has released a new report dispelling those myths.
In its extensive Marine Cage Culture and the Environment report, scientists from NOAA’s National Centers for Coastal Ocean Sciences (NCCOS) evaluated more than 400 studies reviewing environmental interactions with coastal aquaculture.
“A lot of the negative things we read about aquaculture in the media are folks citing one bad example or citing something that isn’t in practice anymore. We wanted to look at this very critically from a scientific standpoint and provide a fair and balanced analysis,” James Morris, PhD, ecologist for NCCOS and one of the report authors, told SeafoodSource.
The researchers primary findings were that coastal aquaculture “can be quite sustainable when you do it right, including siting and adequate monitoring,” Morris said.
For example, researchers found that concerns about antibiotics and other medications leaching into the surrounding marine environment are not a concern in coastal aquaculture. “The use of antibiotics, therapeutants and antifoulants at marine fish farms has declined greatly (up to 95 percent) in the last 20 years,” the researchers wrote. “Heavy metals from feed and antifoulants are known to accumulate beneath cages, but are often in low concentrations and sequestered in the sediment.”
Effects from marine cage culture on water quality are also minimal, according to the researchers. “Usually, there are no measurable effects 30 meters beyond the cages, when farms are sited in well-flushed waters….iamprovements in feed formulation and feeding efficiency are the major reasons for decreased nutrient loading and acceptable water quality in and near farms.”
The researchers also dispelled concerns about the impact of marine cage culture on the surrounding marine life. “At appropriately-sited and well-managed farms, natural processes can be sufficient to assimilate nutrients. In nutrient-limited marine environments, these inputs may even fertilize marine food webs, boosting overall productivity,” the researchers wrote.
Morris hopes the research will help seafood buyers, consumers and aquaculture managers better understand the sustainability of marine cage aquaculture. “There has been so much attention put on sustainable wild harvest. What we are seeing now is the ability to think about sustainable aquaculture production. This report helps us get further down that road to making better decisions locally about sustainable aquaculture,” Morris said.
The Marine Cage Culture report is just one in a series of coastal aquaculture planning and environmental sustainability tools that NOAA is developing.
“There are a number of things that are happening right now, such as the Gulf of Mexico Fisheries Management Plan to provide infrastructure for aquaculture in federal waters. We are confident that there is existing data allowing for environmentally sustainable aquaculture, but we still have to develop pathways and tools that mangers can use to do it right,” Morris said.