UM researchers study Bluefin tuna in the Gulf
The BP oil spill in the Gulf of Mexico was an ecological disaster that has been getting a decreasing amount of media attention since its height during the summer of last year. Although there have been massive efforts to control the spill since then, environmental researcher Molly Lutcavage and her team of scientists believe that there is more work left to be done.
Lutcavage is the head of the Large Pelagics Research Center located in Gloucester Mass., as well as an expert on bluefin tuna. Large Pelagics Research Center is a facility of the University of Massachusetts for research.
She has suggested that money be diverted from the BP recovery fund in order to gauge the long-term effects of the oil spill on the gulf ecosystem, as well as the organisms that call it home. Once the damage is assessed, she said strategies for recovering the affected populations can be developed.
“It is not too late to invest funds from BP to support teams of experts to develop effective strategic plans that identify, prioritize and provide methodologies for collecting essential data,” Lutcavage said in the current issue of the journal Science.
In particular, Lutcavage is focusing on the spill’s effect on the bluefin tuna. She is worried about this species because the spill coincided precisely with the animals spawning period. In an article from the Working Waterfront, Lutcavage said, “If bluefin eggs and larvae come in direct contact with surface oil, it will kill them.” She also added that slightly older larvae and juvenile tuna could die from indirect effects through ingesting copepods or other prey.
Prized for its dark, rich meat, the bluefin tuna often sells for high prices to be used in sushi. Overfishing during the past 30 years has nearly brought this species to its knees, and the oil spill is not making things any better.
Many scientists have stated that the Gulf of Mexico is the only spawning area for the Western Bluefin tuna. For a species that was already on the verge of making the endangered species list, this set back could be devastating to future generations.
Last October, the European Space Agency published a study estimating that nearly 20% of the Bluefin tuna population has been eliminated as a result of the spill. However, there is some debate as to the accuracy of this study because the group used computer models to develop their findings, which are often thought to be inexact and dependent upon circumstantial evidence.
A parallel study conducted by NOAA laboratories predicted a much more conservative loss, estimating that only 10% of the bluefin tuna population would be killed.
Along with graduate students and fellow researchers from the University of Massachusetts, Lutcavage headed a team that implanted tracking tags on 41 Bluefin tuna off the coasts of Nova Scotia and Cape Cod. Of these 41, 56% traveled to the Gulf of Mexico during spawning periods, according to the study published in the Canadian Journal of Fisheries and Aquatic Sciences.
According to Lutcavage, these results indicate that there may be other spawning areas for the fish that are unknown to researchers. Another possibility is that the organisms do not reproduce each year. In any case, these findings are good news for researchers because it indicates that there may not be as large an effect on the species as once thought.
Though Lutcavage said she is worried about the possible effects on the Bluefin tuna population, she also notes that net impact of the spill is difficult to determine because so much about these animals is still unknown. She said, “The impact of that loss is difficult to assess because bluefin migration paths, reproductive habits and early life history are inadequately resolved.”
To further complicate things, scientists do not agree on the effect oil has on fish populations. After the infamous Exxon Valdez spill in Alaska, scientists studied the local populations closely. After the spill, the population of herring dropped significantly, but this drop could not be directly attributed to the presence of oil in the water. According to scientists, the decrease in population could have been a result of a number of different pollutants unrelated to the oil spill.
The net effect of the BP oil spill is yet to be determined. However, one thing is for sure, Dr. Lutcavage and her team will continue to research the bluefin tuna in hopes of learning more about their habits. One day, they may be able to use this information to bring the population back to what it once was.
Zachary Weishar can be reached at firstname.lastname@example.org.