The Cost in Fish
roomfordebate.blogs.nytimes.com
By James H. Cowan, Jr. - a professor in the Department of Oceanography and Coastal Sciences at Louisiana State University:
In the Gulf of Mexico, estuarine-dependent species dominate the large and valuable commercial and recreational catches; the shrimp harvests alone are valued at hundreds of millions of dollars a year.
Louisiana accounts for 75 percent of the fishery landings in the U.S. Gulf of Mexico, yet it also accounts for 60 to 80 percent of the nation’s total annual coastal wetland loss. Continued alteration, degradation, and loss of Louisiana’s wetland habitats makes better understanding of the relationship between habitat stability and its effects on nursery-ground function and fish production critical.
Unfortunately, we may see a steep decline in fish production in the northern Gulf as cumulative stresses on the coastal ecosystems reach a tipping point. Is the oil spill now threatening the northern Gulf capable of affecting the tipping point? It is still hard to say, but there are few directions in which the spill can move without negatively affecting fisheries production, especially if the problem becomes chronic (i.e., the flow of oil is not stopped quickly).
Clearly, if the spill reaches coastal marshes and wetlands, it is likely to harm these habitats as nursery areas for commercially and recreationally important marine life like oysters and swimming crabs among others, as well as sea birds and marine mammals.
The scale of the impact will depend upon how much oil reaches the coast and, for how long the well continues to leak oil. In the western Gulf, the distribution of oil along the coast will likely be influenced by the strong Louisiana coastal current that can reach well beyond the Texas-Louisiana border.
Another important factor is the hurricane season that begins on June 1. It is expected to be a busy one, and oil stranded in more saline marshes that gets transported by storm surge into intermediate and brackish marshes, or possibly even into coastal rice and sugarcane farms, could add to the economic injury.
But even if the oil stays offshore it could potentially affect the numerous shallow-shelf and shelf-edge hard-bottoms off the coast of Louisiana and Texas, which have been considered the center of the important red snapper stock in the northern Gulf.
In both the eastern and western Gulf, the shelf edge supports some hard corals, large populations of soft corals, sponges, gorgonians, sea fans, mollusks, as well as many hundreds of fish species, and are among the most sensitive habitats in the northern Gulf.
In short, there is really no place for the spill to go without bad consequences, except perhaps due south. There is likely to be damage. The question is how much? |
