I'm taking the Florida Master Naturalist course and last week we went to Blue Spring State Park in central Florida. It is on the St. Johns River and is home to one of the largest natural springs in Florida, the Blue Spring. Blue Spring is famous for it's winter time manatee population. We toured the river via platoon boat and got to see a lot of the plants we cultivate in our ponds out growing in nature. Very cool.
The purpose of this topic, is to share some information from the lecture discussion by Dr. Melissa Gibbs. She is an Ichthyologist (sp?) at Stetson Univ and is studying the ecology of the plecostomus and other invasive fish in the Blue Spring 'boil' and 'run'. The boil is where the springs come out of the aquifer and the run is the stream bed of the spring water to meet up with the St. Johns River. She has been studying the fish in the spring for several years, has published one paper and has another in progress.
This is an example of a pleco spear gunned in the springs. I can tell you from up close and personal experience, they are truly big and ugly. Full grown, about 2 feet. There is a team from the University and from the park biologist services that go in weekly and pull out hundreds. They say there is no way to get them all out. They have no natural predators, and after they get to a certain size, nothing can eat them because of the armored scales. This is how Dr. Gibbs describes the pleco:
Pterygoplichthys disjunctivus (Sailfin Suckermouth Catfish) - This species was first seen in in Blue Springs run in 1999.Armored catfish are usually 20-50 cm (not counting the tail), have very large heads relative to body size, large pointed fins, and spiny armor plating. You will see these fish draped on or around fallen trees, on the floor of the spring run, in the boil cave, and coming up for air.
She told us that in the years that she has been studying the fish they have been adapting. Where they use to go sexually dormant in the winter, they are now able to continue to produce, and to start producing earlier. A lot of the invasive pleco's and tilapia were killed off in the freezes we had in 2010, but many survived and are reproducing. The pleco's like the spring run water in the wintertime because it is a constant 72 degrees. Interestingly, the Koi in the St. John's don't go into the spring run. The spring boil and run, for reason's I didn't hear, have a lower oxygen content than the river water. Koi don't like the lower oxygen. But the pleco's can handle it just fine. There are some Koi in the St. Johns, but they are not invasive from the standpoint they don't crowd out native populations.
Here is a youtube video link of a pleco in the Blue Spring Cave.
A few more interesting finds about the pleco. They are algae eaters, and will latch onto the sides of the manatees to, well, eat algae. The manatees hate it. Dr Gibbs says you can watch the manatees on the live cam twitching and rolling trying to get rid of them. An article here. Now, she is studying the impact on the water quality from the volume of pleco poop. Something about the content of the poop causes the water tests to report high nutrients. High like you would expect to find from over fertilization. Oh, and they are 100% air breathers. They get oxygen only from air, not from water. They can live for a whole bunch of days out of the water, provided they don't dry up in the sun. They can also navigate land well enough to make their way back to water if they are left, say on shore. Or in the back of a truck. They lock their fins, which combines with their armored scales to make them a nasty meal option. Apparently, even the alligators don't eat them.
Interesting stuff.
The purpose of this topic, is to share some information from the lecture discussion by Dr. Melissa Gibbs. She is an Ichthyologist (sp?) at Stetson Univ and is studying the ecology of the plecostomus and other invasive fish in the Blue Spring 'boil' and 'run'. The boil is where the springs come out of the aquifer and the run is the stream bed of the spring water to meet up with the St. Johns River. She has been studying the fish in the spring for several years, has published one paper and has another in progress.
This is an example of a pleco spear gunned in the springs. I can tell you from up close and personal experience, they are truly big and ugly. Full grown, about 2 feet. There is a team from the University and from the park biologist services that go in weekly and pull out hundreds. They say there is no way to get them all out. They have no natural predators, and after they get to a certain size, nothing can eat them because of the armored scales. This is how Dr. Gibbs describes the pleco:
Pterygoplichthys disjunctivus (Sailfin Suckermouth Catfish) - This species was first seen in in Blue Springs run in 1999.Armored catfish are usually 20-50 cm (not counting the tail), have very large heads relative to body size, large pointed fins, and spiny armor plating. You will see these fish draped on or around fallen trees, on the floor of the spring run, in the boil cave, and coming up for air.
She told us that in the years that she has been studying the fish they have been adapting. Where they use to go sexually dormant in the winter, they are now able to continue to produce, and to start producing earlier. A lot of the invasive pleco's and tilapia were killed off in the freezes we had in 2010, but many survived and are reproducing. The pleco's like the spring run water in the wintertime because it is a constant 72 degrees. Interestingly, the Koi in the St. John's don't go into the spring run. The spring boil and run, for reason's I didn't hear, have a lower oxygen content than the river water. Koi don't like the lower oxygen. But the pleco's can handle it just fine. There are some Koi in the St. Johns, but they are not invasive from the standpoint they don't crowd out native populations.
Here is a youtube video link of a pleco in the Blue Spring Cave.
A few more interesting finds about the pleco. They are algae eaters, and will latch onto the sides of the manatees to, well, eat algae. The manatees hate it. Dr Gibbs says you can watch the manatees on the live cam twitching and rolling trying to get rid of them. An article here. Now, she is studying the impact on the water quality from the volume of pleco poop. Something about the content of the poop causes the water tests to report high nutrients. High like you would expect to find from over fertilization. Oh, and they are 100% air breathers. They get oxygen only from air, not from water. They can live for a whole bunch of days out of the water, provided they don't dry up in the sun. They can also navigate land well enough to make their way back to water if they are left, say on shore. Or in the back of a truck. They lock their fins, which combines with their armored scales to make them a nasty meal option. Apparently, even the alligators don't eat them.
Interesting stuff.
