As we watched the BP Deepwater Horizon oil disaster unfold on beaches and in bays of the Gulf of Mexico four years ago, we wondered, too, about the impacts beyond what we could see on shore. Some of the answers to that troubling question are rolling in. We previously learned about damage to fish embryos, and the latest news involves mahi-mahi, or dolphinfish. These fast-growing, colorful predators are a favorite target of recreational fishermen and restaurant-goers alike across the Gulf, and despite their savage speed, it seems they could not outrun the impacts of BP’s oil.

A new study from the University of Miami last week demonstrated that even “relatively brief, low-level exposure to oil harms the swimming capabilities of mahi-mahi, and likely other large pelagic fish, during the early life stages.” And while it’s troubling to hear that oil reduces the fish’s ability to swim fast – a necessity for finding food and evading predators –the more disturbing revelation is how little oil exposure it takes to cause this damage to such an economically important fish.

The more we find out about impacts to open-ocean swimmers like mahi-mahi, tuna and amberjack, the more concerned I get for their bottom-dwelling counterparts.  If these powerful fish, renowned for the distance they can cover, could not escape harm, then what of the snappers and groupers and triggerfish that live much more closely associated with the bottom of the sea? Red snapper, for instance, spend their vulnerable juvenile years in the muddy nearshore flats around the northern Gulf. Many of these same flats were covered in oil and toxic dispersant in 2010. Has it lingered? If brief, low-level exposure is harmful, what will this mean for these fish as they grow to adults?

In the face of this mounting concern, we have two options. We can watch and wait and hope for more independently-funded studies to offer pieces of the puzzle until the Natural Resource Damage Assessment studies are made public, or we can invest restoration money now into fish and fisheries research. The State of Florida is on the right track—they’ve committed $3 million to collect additional data on reef fish through the National Fish and Wildlife Foundation’s Gulf Environmental Benefit Fund. Florida covers only a portion of the Gulf’s deep waters, however, and in order to properly understand the impacts of oil on offshore fish, we must expand fisheries research to include the entire Gulf.