Gulf Killifish: Late to Hatch and Slow to Grow

Important questions about the impacts of the BP Deepwater Horizon oil disaster still linger. Some effects could go undetected for years. To fully restore the Gulf, and to make sure the Gulf and its people are recovering, we need to establish a long-term monitoring and research program. While we wait for confidential government studies to become public, little clues are emerging that give us insight into which species were injured and what this might mean for the Gulf ecosystem.

A study reported in Environmental Science and Technology tells us that one species to keep an eye on is the Gulf killifish. Through their ongoing research, the authors (Dubansky et al., 2013) determined that killifish from oil-contaminated marshes in Louisiana were impacted by the disaster. Specifically, they collected eggs from oiled and non-oiled sites before and after the disaster and raised them in a lab. The eggs from oiled sites took longer to hatch than eggs from non-oiled sites. When the late eggs did hatch, the larval fish were smaller and more likely to have heart defects than those from non-oiled sites. This indicates that the developing fish will not be able to survive and reproduce as well as eggs from non-oiled sites.

The researchers concluded that the impacts to individual fish may mean long-term impacts for the Gulf killifish population, and organisms living nearby or in other oiled habitats.

Many questions came to my mind as I read about this study and the impacts to killifish. What do the impacts to individual killifish fish mean for the Gulf population as a whole? Will the population of killifish be significantly reduced, or will other killifish that were less impacted make up for the lag in reproduction? If the killifish population is smaller, what does this mean for the food web? Will the organisms that eat killifish decline as their food declines, or will another animal fill the niche vacated by the killifish?

There are so many questions that we need to answer, which is why it is imperative that we continue to monitor and track fish populations and other marine species in the Gulf. This is another reason why we need a comprehensive long-term, monitoring and research program to measure the full extent of impact, track recovery and restore the Gulf.


Dubansky, B., Whitehead, A., Miller, J., Rice, C. D., & Galvez, F. (2013). Multi-tissue molecular, genomic, and developmental effects of the Deepwater Horizon oil spill on resident Gulf killifish (Fundulus grandis). Environmental Science and Technology. DOI: 10.1021/es400459p.


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