Bless you: Red tide can make dolphins 'cough' and 'sneeze'
Dolphins have respiratory systems that can become congested or infected, which can cause them to cough hard enough to clear the airways and remove mucus, irritants, or other substances that may be blocking the airways or causing discomfort.
They do not teach you in journalism school how to capture in writing the way dolphins "cough," but it sounds like somebody snorkeling underwater who surfaces, then uses the air left in their lungs to expel the water up and out.
Marine scientists that have been tracking the Sarasota Bay resident bottlenose dolphin population have discovered when the animals swim within a strong red tide they will "cough" and "sneeze" in ways similar to humans with a bad cold.
That's because red tide can cause respiratory irritation in dolphins just as in humans, which can cause both species to become congested or infected and “cough” hard enough to clear the airways and remove mucus, irritants, or other substances that may be blocking the airways or causing discomfort.
"When they're exposed to breathing in an irritant like red tide the air goes straight to their lungs. They don't have the protective measures that humans have to filter things out, so the response to that could be this explosive breath, or this "chuff," said Randy Wells, director of Chicago Zoological Society's Sarasota Dolphin Research Program at Mote Marine Laboratory and Aquarium. "It could also be be that the explosive exhalation clears a pathway to cleaner air above the concentrated (red tide) toxins sitting at the surface. We just don't know."
Just like a cold can kill a human, but normally doesn’t, red tide can cause death in dolphins, but more often the animals just get stuffy and cough and sneeze their way through the day. Dolphins just don’t have access to DayQuil.
Both humans with an everyday cold and dolphins swimming through a red tide bloom seem otherwise undistracted. We both go wherever we were going. We both eat along the way, even though both colds and red tide toxins can dull the flavor of a meal.
When congested, we blow stuff out of the holes in our nose. Dolphins use their blowholes.
“We found that the rate of ‘chuffing,’ an explosive type of exhalation, was significantly greater in dolphins observed during the bloom,” Wells, along with co-authors Spencer E. Fire and Glenn A. Miller, wrote recently in Heliyon, a monthly peer-reviewed mega journal covering research in all areas of science, the social sciences and humanities, and the arts. “This chuffing behavior is analogous to respiratory irritation in humans exposed to red tide events.”
The Chicago Zoological Society's dolphin research program based at Mote has been ongoing since 1970.
The goal of the long-term research is to study the biology, behavior, ecology, health, and human impacts on dolphin populations both in Florida and in other places on the planet. Researchers involved in the effort also teach conservation techniques, one of which is to just leave dolphins alone.
Fire worked on the study with Wells at Mote and with Miller, who is associated with the Florida Institute of Technology’s Department of Ocean Engineering and Marine Sciences in Melbourne on Florida’s east coast roughly across the state from Tampa Bay.
Chicago Zoological Society's researchers have been following generations of a community of bottlenose dolphins that stay put in Sarasota Bay year-round. Most of the roughly 150 animals in the pod are identifiable by their dorsal fins.
Some researchers are working on ways to predict and mitigate the impacts of red tides, while others are studying the toxins produced by these algal blooms and their effects on marine life and human health.
Did You Know?
Bottlenose dolphins are one of the most intelligent animals on earth, and they have a complex social structure and a wide range of vocalizations that they use to communicate with each other. They have been observed exhibiting a variety of problem-solving behaviors and adapting to new environments. The dolphins have a layer of fat, called the "melon," in their forehead that helps them focus sound waves for echolocation. They use this to locate prey and navigate their environment so as to be able to swim at high speeds to catch their food.
The effort also strives to protect dolphins from from human-caused factors such as the untold amount of pollution washed into Southwest Florida waters during Hurricane Ian in late September.
"Even before the hurricanes, too much in the way of nutrients are going into the waters of Southwest Florida, either nutrients that comes from lawns, agriculture or industry," Wells said. "With the hurricanes, a great deal more in the way of nutrients have come in from overflowed sewage systems, from runoff from the ground and from other sources.
"We need to be eliminating all the nutrients going into the water because the ecosystem can only handle a certain limited load and anything more than that is going to create problems for the dolphins."
Dolphins are considered to be a sentinel species because they are a top predator in their ecosystem and, being homebodies sensitive to changes in their environment, they serve as a early-warning system if things are changing for the worse.
They also live 25 years or longer and have a high reproductive rate, which makes them useful for monitoring the effects of environmental hazards over time. And because dolphins are intelligent and social animals they are easier than others to study and monitor.
“They breath the same air, they swim in the same waters, they eat the same fish," Wells said. "And so what happening to them is an indication of what is happening to the greater environment -- and could be happening to us."
Environmental reporting for WGCU is funded in part by VoLo Foundation, a non-profit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health.
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