The value of Louisiana’s Gulf Coast fisheries is etched into the nation’s economy, accounting for about 25 percent of the total catch weight in the continental United States and 75 percent of the landing in the Gulf of Mexico. While some scientists contend that the ecosystem is on the verge of collapse because of exhaustion, a study headed by a group of University researchers in the Department of Oceanography and Coastal Science said the fish populations in the area are not much different from those of 50 years ago. Jim Cowan, oceanography and coastal sciences professor, said the reasons some scientists think the ecosystem is breaking down are complex. “Overexploitation and consumptive use of natural resources is a real threat to our way of life, especially in the long term,” he said. “It is up to the scientific community to provide information to resource managers and policy makers about ecosystem health, but ultimately, the responsibility to make things happen falls on the citizens and the politicians they elect, at least in the developed world.” The study began as the basis for graduate student Kim DeMutsert’s dissertation. The researchers became interested in the Gulf Coast’s ecosystem because they were studying the effects of coastal land loss and restoration on fish populations and Louisiana’s estuarine ecosystems, where those fish live. “When studying how ecosystems change, we need indicators of ecosystem health and some indication of what the historical baseline looked like,” Cowan said. “This allows us to compare current conditions to the past, and to determine what our restoration goals should be. When we first started looking at the [Mean Trophic Level Index], we were trying to decide if it really tells us anything about the status of ecosystems.” DeMutsert, first author in Cowan’s research group, concentrated on the Mean Trophic Level Index, an indicator of water quality, and Cowan focused on the fishery collapses. “Studies are really never complete because good studies generate more questions than they answer,” Cowan said. “It took us about a year to complete the paper, but we are continuing to work on this with data from all the world’s 64 large marine ecosystems.”
—-Contact Angelle Barbazon at [email protected]