These are photos from a visit to Blue Spring State Park. It was a relatively warm day so there were very few manatees in the Run.
The most interesting thing we saw that day were several male tilapia fish who were nest building very close to the end of Blue Spring Run where it enters the St. Johns River.
Tilapia are considered an invasive species by the Florida Fish and Wildlife Conservation Commission (FWC), as they are native to northern Africa and were likely intentionally released in to the Florida ecosystem. They are the same fish commonly sold in grocery stores.
Male tilapia create nests to encourage females to spawn. The males create a depression in shallow water by sucking up sand and gravel with their mouths and spitting it out along the edge of the nest. Once completed, they swim out to find a female and lead her back to the next for courtship. The female will release her eggs, the male fertilizes them and the female immediately collects them in her mouth and swims away.
It’s common for both sexes to repeat the behavior with other partners. The female keeps the eggs in the mouth and even when the young hatch, they live for awhile in their mom’s mouth with occasional forays out to feed. That continues for about 3 weeks.