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Economic impacts of coastal hazards on the Mississippi oyster fishery

By: Ben Posadas / Published: May 09, 2019

Figure 1. Mississippi oyster landings. Source of raw data: NOAA Fisheries.
Figure 1. Mississippi oyster landings. Source of raw data: NOAA Fisheries.

*The information in this blog was revised on 5/22/19.*

It has been more than 13 years since Hurricane Katrina devastated the coastal areas in the Northern Gulf of Mexico States in August 2005. The closures of significant portions of Gulf waters to commercial and recreational fishing due to the Deepwater Horizon (DWH) or Gulf of Mexico oil spill (Gomos) in April 2010 altered the production, recreation and consumption decisions of households in affected communities. Mississippi was in the process of restoring the public oyster reefs after Hurricane Katrina and the DWH oil spill when the prolonged Bonnet Carre Spillway (BCS) opening in May-June 2011 resulted to massive oyster mortalities in the shellfish growing waters.

Figure 2. Economic recovery model.
Figure 2. Economic recovery model.

These mortalities halted the recovery process of the oyster fishery to its baseline levels in 2002-2004. The prolonged exposure to freshwater, which caused massive mortalities of the oyster populations required restoration projects to enable the fishery to recover to its baseline status. The restoration efforts included but were not limited to the dredging of non-affected oyster seed stock and relaying them to affected reefs. Oyster shells and other cultch materials were purchased and planted in affected areas. These restoration efforts were expected to enable the oyster reefs to replenish the damaged oyster populations and became available for harvest when the resources reached market size.

Long-term data were compiled to develop economic recovery models (ERM) for the Mississippi oyster fishery. The ERM explains the individual and joint effects of the recent natural and technological disasters, coastal hazards, output and input markets, environmental conditions, and regulatory and management strategies on the levels of commercial oyster harvests and dockside values.

Figure 3. Combined direct economic impacts of Hurricane Katrina, Gulf of Mexico oil spill, Bonne Carre Spillway opening, and Harmful Algal Blooms on the monthly Mississippi commercial oyster deflated dockside values.
Figure 3. Combined direct economic impacts of Hurricane Katrina, Gulf of Mexico oil spill, Bonne Carre Spillway opening, and Harmful Algal Blooms on the monthly Mississippi commercial oyster deflated dockside values.

The recent coastal hazards which affected the coastal areas in Mississippi since 2015 are the following:

  • Opening of the Bonnet Carré Spillway due to the Mississippi River flooding events in March 2018, February-April 2019 and May 2019.  
  • Opening of the Bonnet Carré Spillway due to the Mississippi River flooding events in January 2016. About 40,000 sacks were relayed from St. Joe Reef to designated growing areas.
  • Freshwater intrusion due to the Pearl River flooding event in March 2016.  
  • Toxic algal blooms in November and December 2015 in the Mississippi Sound led to massive fish kills in Harrison and Hancock counties and closure of oyster reefs from December 2015 to February 2016.  

Long-term estimates of the combined direct economic impacts of Hurricane Katrina, Deepwater Horizon oil spill, Bonnet Carre Spillway opening and harmful algal blooms on the monthly Mississippi commercial oyster deflated dockside values are shown in Fig. 3. The vertical axis shows the negative impacts per month since Aug. 2005 to Dec. 2016. The monthly dockside values are deflated by the consumer price index (CPI) with 2016 as the base year.

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