Warmer waters aid development of poisonous algae blooms
Climate change may be an abstract idea to many South Floridians, but its effects are real for the fishermen who rely on the ocean’s bounty.
“The guys on the west coast who fish offshore, the party boats there and charter boats, they’re dealing with red tides all the time and all summer, and you can’t eat the fish out of it,” said Dan Kipnis, a Miami-area fish boat captain and an advocate for climate change awareness.
Warming sea waters — which are linked to climate change — are expected to contribute to more occurrences of red tide, which poses a threat to wildlife living in the ocean and on the Floridian shorelines.
Red tide is the common name for a phenomenon where large amounts of harmful algae blooms develop in the ocean and rapidly reproduce when contacting warmer waters.
The mass of algae can take on a reddish hue, giving the phenomenon its name.
Karenia brevis, often called K. brevis, is responsible for the deaths of many aquatic organisms every year.
“It’s naturally occurring in Florida, and it’s been happening for hundreds of years,” said Kelly Richmond, a spokesperson for the Florida Fish and Wildlife Conservation Commission.
Red tide develops offshore and as it reaches shorelines, the algae feed off man-made nutrients found in pollution and continue to spread, Richmond said.
K. brevis red tide becomes deadly to fish when the algae die and release toxins, said Larry E. Brand, professor of marine biology and ecology at the University of Miami.
“This is a toxin called brevetoxin,” Brand said. “It’s a neurotoxin, so it screws up the nerves, and eventually it kills them.”
Matt Garrett, a marine research associate at the Florida Fish and Wildlife Conservation Commission and the Fish and Wildlife Research Institute, knows firsthand how red tide affects fish.
“I immediately recognized a change in the water and then we started seeing dead spotted seatrout, hundreds of them,” Garrett said.
“They were actively dying in front of us and we were just kind of picking them up when they were in their last moments of life.”
Currently, there does not seem to be a way to eradicate red tide. The algae cannot simply be killed. They must also be removed after death before the toxins they release can escape.
Scientists also are reluctant to put an end to red tide because it is naturally occurring and doing so may have catastrophic results on nature.
Right now, rather than attempting to combat the red tide, scientists are making an effort to monitor blooms and predict when red tide will happen. Scientists create satellite images from data provided by NASA and the National Oceanic and Atmospheric Administration and use these results to determine where water sampling should be performed.
The Florida Fish and Wildlife Conservation Commission also surveys more than 100 areas that are known to be bloom “hot spots” and tests the sediment, sea grasses and animal tissue in those areas for toxins. This allows scientists to forecast red tide days in advance.
Bob Weisberg, distinguished professor of physical oceanography at the University of South Florida’s College of Marine Science, has accurately predicted red tide in the past with a new method.
“We’ve been able to begin predicting red tide almost solely on the part of the ocean circulation,” Weisberg said.
Weisberg’s team is using ocean currents to peer into the future in an attempt to predict red tide months before it becomes a reality. His goal is to accurately predict red tide and give people time to prepare.
While scientists continue to examine red tide, fishermen already know the most important thing.
“Without oceans, healthy oceans, the land dies,” Kipnis said.