Local dolphins and the UNF Bottlenose Dolphin Research Program

“It is a challenging time to be in marine mammal work. We must just keep telling ourselves we are documenting this so that future generations may learn from it and not make the same mistakes.” This is what University of North Florida Associate Professor of Coastal and Marine Biology, Quincy Anne Gibson, Ph.D., told me in a recent conversation. Since 2011, Gibson has been studying bottlenose dolphins in Northeast Florida with her students.

Gibson has an army of undergraduate and graduate students who help her understand the relationships and hardships bottlenose dolphins in the St. Johns River face daily. Three research students per semester work on photographing dolphins in the St. Johns River. And three students work in the lab processing data, analyzing results, writing papers, and attending conferences.

One of the graduate students in the program is trying to understand why so many dolphins are emaciated and starving in the St. Johns River. Gibson told me “Their stomachs are flattened and their ribs are showing; we can count their ribs.”

The situation is getting worse with each passing year. Gibson and her team have been talking about this with the National Oceanic and Atmospheric Administration (NOAA) and other researchers worldwide. No one seems to know what to do about it. Andrea is a graduate student on the UNF Bottlenose Dolphin Research team looking at areas where dolphins forage for food in the St. Johns River.

Andrea has mapped out areas that are consistent dolphin feeding areas over time. The data revealed that dolphins are moving further upriver to feed. This data supports reports of dolphins being seen upriver in fresh water. The question becomes, why are they foraging for fish in fresh water? Bottlenose dolphins historically do not feed on freshwater fish in the St. Johns River.

Next, Andrea looked at the stomach contents of dolphins that died in the region. UNF researchers partnered with the Florida Wildlife Commission (FWC) marine mammal recovery team to analyze the contents of deceased dolphins retrieved in the St. Johns River.

The team found plenty of Atlantic croaker in the stomach contents, which was no surprise. This is the number one food fish for bottlenose dolphins up and down the East Coast. The big surprise was the number two species dolphins were consuming. That turned out to be the violet goby fish. No one had documented bottlenose dolphins eating violet goby fish before, according to Gibson.

Croaker. (NOAA - Physical Science Laboratory)

Violet goby fish are not your typical goby with large eyes and small bodies. They are nicknamed the dragon eel. They look like eels. They are long and skinny and “rather creepy looking,” according to Gibson. The FWC team told UNF researchers that they see these eels being caught in the Ortega River, a freshwater tributary of the St. Johns River. Did the dolphins move upriver looking for food or did they switch prey items when they arrived and found them in abundance?

Violet goby

Gibson tells me we have known for a while that dolphins move between fresh water and salt water. Skin lesions are a key indicator that dolphins are spending too much time in fresh water. Dolphin skin begins to break down in fresh water and turns white in color. Skin lesions eventually become open wounds. The question then becomes, why would they spend so much time in fresh water?

Britney, a former graduate student of the UNF research team, compared year-round resident dolphins to seasonal and transient dolphins. Seasonal dolphins visit the St. Johns River only in the summer for feeding and breeding. Transient dolphins appear in the St. Johns River infrequently.

Britney looked at skin lesions observed on members of the three groups. She discovered that resident dolphins have far more lesions than the seasonal dolphins. And, the seasonal dolphins have far more lesions than the transient dolphins. Gibson said, “These results indicate that there is something about the habitat that is causing the lesions, clearly.”

I asked Gibson if dolphins from the Indian River Lagoon have similar lesions. Gibson said that yes, they do have lesions but they are fungal lesions. Fungal lesions are easy to distinguish from the freshwater water lesions found in resident St. Johns River dolphins.

Wendy Durdan is a bottlenose dolphin researcher in the Indian River Lagoon. She was part of a paper published recently that documented that when there was an algae bloom in the Indian River Lagoon, it affected fish populations. Each mass fish die-off created a starvation mortality event in dolphins. All mass fish die-offs in the Indian River Lagoon in the past decade are connected to nutrient pollution.

Gibson said she gets asked all the time, “There are so many horrible things happening with dolphins, what do we do about it?”

First, Gibson said when boating, slow down when you see dolphins in the area. There has been a sharp increase in dolphin deaths due to boat strikes. People have the misconception that they can go as fast as they want in the channel and these dolphins will get out of their way. That is not the case said Gibson. “These are dolphin family units, moms trying to feed themselves and take care of their young. There are a lot of distractions in the water for a dolphin to process at once. If more than one boat is present in an area with dolphins, you must give them a chance to move out your way. They may be trying to figure out which way to go while directing their young to stay with them.”

Other causes of dolphin mortality include entanglement in fishing gear. Make sure to keep track of all your fishing gear and dispose of it properly.

For those who live near a river or creek, think twice about fertilizer and when to use it on your lawn. Fertilizer runoff from rain events increases nitrogen in local waterways. Increased nitrogen in waterways leads to harmful algae blooms that kill fish. Fish kills lead to marine mammal starvation.

When refueling your boat, pay close attention so that you do not spill fuel in the water.

By practicing these simple steps, we can help dolphins remain healthy.

Also, the UNF Bottlenose Dolphin Research Program has an “Adopt a Dolphin” campaign to raise awareness about local dolphins and raise funding for future research. Gibson told me that she personally writes the full biography of each dolphin adopted through the program. By telling the personal story of each dolphin, it creates a connection between the public and the dolphin said Gibson.

I am so grateful for the opportunity to speak with Quincy Gibson. Her leadership, enthusiasm and dedication to our local bottlenose dolphin population is invaluable. The entire UNF Bottlenose Dolphin Research Program deserves high praise for its work. They are the voice of local dolphins.

May we all stop, take a deep breath, and remember dolphins are messengers from the creator. What happens to dolphins and other marine mammals will happen to us. We are all connected by water, the lifeline we share.