National Oceanic and Atmospheric Administration Publishes Misleading Information on Gulf of Mexico"Dead Zone"

Mississippi River nutrient loads and water stratification on the Louisiana-Texas shelf contribute to an annually recurring, short-lived hypoxic bottom layer in areas of the northern Gulf of Mexico comprising less than 2% of the total Gulf of Mexico bottom area. Many publications demonstrate increases in biomass and fisheries production attributed to nutrient loading from river plumes. Decreases in fisheries production when nutrient loads are decreased are also well documented. However, the National Oceanic and Atmospheric Administration (NOAA) persists in describing the area adjacent to the Mississippi River discharge as a “dead zone” and predicting dire consequences if nutrient loads are not reduced. In reality, these areas teem with aquatic life and provide 70-80% of the Gulf of Mexico fishery production. On June 18, 2013, NOAA published a misleading figure purporting to show the “dead zone” in an article predicting a possible record dead zone area for 2013 (http://www.noaanews.noaa.gov/stories2013/20130618_deadzone.html). This area is not a region of hypoxic bottom water at all nor is it related directly to 2013 predicted hypoxia. This figure appeared as early as 2004 in a National Aeronautics and Space Administration (NASA) article (http://www.nasa.gov/vision/earth/environment/dead_zone.html) as a satellite image where the red area represents turbidity and is much larger than the short-lived areas of hypoxic bottom water documented in actual NOAA measurements. Thus, it is misleading for NOAA to characterize the red area in that image as a “dead zone.” The NOAA has also published other misleading and exaggerated descriptions of the consequences of nutrient loading. Introduction and Background The authors have been following the literature on nutrient loading and hypoxia in the Gulf of Mexico (Bianchi et al. 2010, Rabalais et al. 2007, Rabalais et al. 2002) for several years. Characterizations of these areas as “dead zones” are perplexing, and the Louisiana-Texas shelf teems with life. Louisiana harvests tremendous quantities of seafood and supports one of the best sport fisheries in the Gulf of Mexico. Our anecdotal observations and review of available data suggest that several sport species of fish (red drum, spotted sea trout, red snapper) are both plumper and more plentiful in Louisiana waters, and we have often considered hypothetical explanations for these observations. In 2011, the last time a record “dead zone” area was predicted, (Thean 2011, Rice 2011) we were actively conducting creel surveys in the Port Fourchon and Calcasieu areas of the Louisiana Gulf Coast to study the impact of the Deepwater Horizon oil spill. (Courtney et al. 2012) These areas showed some slight impacts from the oil spill near Port Fourchon and the effects of overfishing in the Calcasieu area, but these areas were far from being accurately characterized as “dead zones.” The area of the Louisiana-Texas shelf shown as a “dead zone” in the figure accompanying the NOAA report of 18 June 2013 (NOAA 2013) is well known for the recent resurgence and impressive growth in the population of red snapper (Lutjanus campechanus). This population recovery has been widely attributed to oil platforms and other artificial reefs (Shipp and Bartone 2009, Gallaway et al. 2009). While reviewing Melissa Monk's doctoral thesis (Monk 2012, Figures 1.14 – 1.22), we noticed the apparent decrease in faunal biomass (SEAMAP trawl surveys) with increasing distance from the Mississippi River discharge as well as the greater animal biomass in the area with higher nutrient loading and seasonal bottom water hypoxia. Monk's suggestion that Mississippi River outflow and nutrient loading should be considered to explain the temporal variability in both total biomass and how the biomass is distributed among species led us to formulate and assess the literature for evidence supporting the hypothesis that nutrient loading from the Mississippi River also has contributed significantly to the recovery of the red snapper population (Courtney et al. 2013) in the regions shown in red in the figure from the NOAA article (also Figure 1, present paper).