Physical changes to fish species may be linked to SWFL water quality issues

A small fish could provide researchers with big clues to what’s happening in our water in Southwest Florida.

The question they are trying to answer: Why are some female mosquitofish in local waterways developing male features?

And the biggest worry is that whatever is causing this may also hurt humans.

FGCU researchers are looking for answers to what is potentially causing female mosquito fish to develop male characteristics, prevent potential harm to people and find deeper answers to water quality issues in Southwest Florida.

Dr. Nora Demers, an FGCU professor, told us chemicals found in herbicides, pesticides, medications and shampoos may affect the development of some changes being seen in mosquitofish.

Demers and her students collect fish and then take a closer look in the lab.

“So we’re noticing two things that are very evident from looking at them,” Demers said. “One of them is female fish that are masculinized.”

They are seeing female mosquito fish develop an anal fin that looks like a male.

“And the other one we’re seeing is precocious development of the males,” Demers said. “So they’re more sexually mature at a much smaller size.”

Demers said these changes are brought about by endocrine disruptors, which are chemicals that can impact developmental and reproductive systems in animals.

“We’re not finding very many females that aren’t showing some evidence of disruption,” Demers said.

This also raises the question: Are humans experiencing similar impact from chemicals?

“I think it’s impossible not to see,” Demers said. “People seem to forget that we’re animals, and these chemicals are affecting animals.”

The next steps in Demers’ research involves how to remove what’s causing the changes she and her students are seeing on the mosquito fish.

“The direction I want my research to go is studying effects and how to best remove these chemicals from the water,” Demers said. I don’t have as much interest in the basic science of the mechanisms or each chemical impact.”