Economic Impacts of the Opening of the Bonnet Carré Spillway on the Mississippi Oyster Fishery
Abstract. We evaluated the negative economic impacts on the Mississippi oyster fishery of the prolonged opening of the Bonnet Carré Spillway in 2011 using two assessment methods: (1) a preliminary assessment conducted before data on landings after 2010 were available and (2) an updated assessment conducted when landings data after 2010 became available. We prepared the preliminary assessment in late 2011 to support the state’s application for a federal fisheries disaster declaration. Recently, a more rigorous assessment of the impacts of the freshwater flooding was part of an overall assessment of the individual and joint impacts of natural and technological disasters to the Mississippi oyster fishery since 2005. The preliminary assessment model used the pre-Hurricane Katrina years 2002–04 as the baseline period. With disaster funding, the state of Mississippi was in the process of restoring the oyster reefs after Hurricane Katrina in 2005 and the Deepwater Horizon oil spill in 2010, when the prolonged Bonnet Carré Spillway opening in 2011 resulted to 86 percent oyster mortalities. These massive mortalities halted the recovery of the fishery to its baseline levels in 2002–04. Prolonged exposure to fresh water required restoration projects to enable the oyster fishery to recover to its baseline status. Restoration efforts included, but were not limited to, dredging nonaffected oyster seed stock and relaying it to affected reefs between 2006 and 2008. Cultch materials consisting of oyster shells and limestone were planted at affected public oyster reefs between 2006 and 2011. These restoration efforts were expected to replenish the damaged oyster populations and provide adequate shellfish for harvest when they reached market size. Direct losses in oyster harvesting associated with the prolonged Bonnet Carré Spillway opening ranged from 80–100 percent of the baseline average annual commercial landings from 2002–04. The cumulative foregone landing values of commercial oyster harvesting were estimated to range from $21.8 million to $46 million. The negative output impacts reached $9.6 million in 2011, $19.6 million in 2012, $19.9 million in 2013, and $8.9 million in 2014. As a resulting of the downturn in oyster harvesting, the state lost between 145 and 324 jobs per year during the period. Labor income lost ranged from $1.8 million to $8 million per year.
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