Rising Mississippi has Gulf Fisheries on Edge

nina | May 20th, 2011 - 9:00 am

One year after the catastrophic oil spill, the U.S. Gulf seafood industry could take another big hit this spring as the Mississippi River’s rising waters are diverted into the Gulf of Mexico to prevent the destruction of homes and businesses in big cities like New Orleans and Baton Rouge.

Already 113 gates have been opened on Louisiana’s Bonnet Carre Spillway to avoid flooding.  The Morganza Spillway was opened for the first time in nearly four decades, as water sprayed 6 feet into the air.  The water will flow 20 miles south into the Atchafalaya Basin, and from there it will roll on to the oil-and-seafood hub of Morgan City.

The influx of fresh water could significantly reduce salinity levels in Lake Ponchartrain and the bays and estuaries of the Mississippi Delta, killing oysters, shrimp, blue crab and finfish.

Now, at a time when we need more production and more inventory, we are going to get hit pretty hard.  If a minimal amount of gates are opened for a short period of time, there would be a minimal impact on marine resources.  But, if additional gates are opened for long periods of time, it would have detrimental to catastrophic effects on marine resources.

If all 350 gates have to be opened, and this much freshwater gets into the Mississippi Delta region, oysters and shrimp will be among the hardest hit species. 

The primary ones that would feel this very harshly would be oysters, because they cannot get out of the way.  We could have catstrophic killoff on the frees.  The oyster beds could handle a few days of fresh water, but it may be a month.  It is going to be a very weak summer for oysters.

The flooding and influx of fresh water could not come at a worse time for the Gulf shrimp industry.  While the larger shrimp will swim out to sea away from the fresh water, the larval shrimp will likely die.  White shrimp do not have much of a problem with fresh water, but brown shrimp do. 

In addition, larval and small blue crabs and finfish will likely be destroyed by fresh water, but the adult crabs and finfish will swim out of the way.

One upside to all of this, is that wild crawfish production should increase and the marshes will be cleansed.  

At 1.4 billion pounds, the Gulf region represents 18 percent of total U.S. seafood landings of 7.8 billion pounds in 2009.

Source:  seafoodsource.com, 5/18/11

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