Bring Back the Missing Fish

Ocklawaha River – Silver Springs – St. Johns River

After the construction of the Rodman/Kirkpatrick Dam, fish species like these disappeared or were greatly reduced in Silver Springs and the Ocklawaha and St. Johns Rivers. The Dam prevents migration of these fish between their feeding and breeding grounds from Silver Springs to the Atlantic Ocean. Reduced natural downstream flow caused by the Dam also affects many other non-migratory fish, plants, and wildlife. These fish species are at high risk for disappearing from the Ocklawaha River forever. Many could face extinction.

A free-flowing Ocklawaha River, by breaching the Dam on one side, is expected to return many of these species.

Striped Bass (Morone saxatilis)

This anadromous species spawns in fresh water and lives in its adult form in brackish or salt water. Large numbers of “stripers” used to swim up the Ocklawaha River to spawn. The fertilized eggs must flow down river for several days to successfully hatch. Before the Dam, the Upper Ocklawaha River provided optimal conditions for their reproductive success. Hybrid hatchery-raised stripers or “sunshine bass” are still caught below the Rodman/Kirkpatrick Dam, indicating that this popular gamefish could return to a free-flowing Ocklawaha River.

White Catfish (Ameiurus catus)

While still found in the Ocklawaha their numbers are very low when compared to surveys done prior to the construction of the Rodman Dam. These fish were a major attraction at Silver Springs. Today they are rarely seen.

In 1966, three kinds of catfish could be seen through Silver Springs’ glass-bottomed boats – the channel. white and mud catfish. The white catfish, the second largest of the three, appeared dark blue in color. Hundreds of them congregated at the Silver Springs’ Catfish Hotel and along the Silver and Ocklawaha Rivers. (From Ross Allen’s field notes)

American Eel (Anguilla rostrata)

Eels help regulate the population of other animals and are a significant source of food for fish, mammals, turtles and birds. As adults, this catadromous species spawns in the ocean in the Sargasso Sea, drifts at sea for 1-2 years, then stays in freshwater or estuarine habitats from 3-20 years before migrating back to the Sargasso Sea. A single adult female may produce more than 2 million eggs. Dams are a significant barrier on both the upstream and downstream eel migrations, resulting in a precarious conservation status.

American Shad (Alosa sapidissima)

This species, an important commercial and sport fish, is no longer found in the Ocklawaha River above the Rodman Impoundment where it used to breed in large numbers. The breeding adults would swim upstream many miles from the Atlantic Ocean to spawn in early summer. Dense schools numbering thousands of fish still make the trip up spring-fed rivers that are not dammed (e.g., Wekiva River and Rock Springs Run). The fry then grow to 1.5 inches before migrating to the ocean in the fall.

Southern Tessellated Darter (Etheostoma olmstedi maculaticeps)

The Southern Tessellated Darter its an imperil species that have only be found in the Ocklawaha River basin in Florida. Their current population status is unknown and studies are being conducted to determine their distribution through Florida.  This small fish or not more than 4 inches long tends to live on the bottom of the river feeding on small fish, crustaceans and insect larva.

Big-claw River Shrimp (Macrobrachium carcinus)

The male Big-claw River Shrimp can grow to nearly 12 inches while the females are usually from 5-8in. in length.  As adults these shrimps live in freshwater, but their larva develops in brackish water. These shrimps are mostly nocturnal going into deeper water during the day.  While omnivores, the juveniles tend to feed on algae and aquatic insects but changing to  larger prey  as they grow and move upstream. River impoundments may have cause a major decline on this species as it create a barrier to upstream migration necessary for this species to complete its life cycle.

Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus)

This anadromous fish is currently endangered throughout its range because of loss of habitat spawning grounds. Water control structures and dams have blocked their access to breeding grounds upstream. Their only chance to breed in Florida is the Ocklawaha River system. The female swims upstream in the spring to deposit her eggs and goes back to the ocean 3-5 weeks later. The males stay in freshwater rivers until the fall. Sturgeons are considered living fossils with records more than 130 million years old.

Commonly Found Fish of the Ocklawaha River

Striped Mullet (Mugil cephalus)
Status: Declining

In the 1950s large schools of striped mullet were a common herbivore in the Silver River and Silver Springs. With closing of the Rodman dam in 1968, mullet populations at Silver Springs plummeted and numbers finding their way through the barge canal lock are very limited. At the same time officials with the Silver Springs tourist attraction noticed an increase in nuisance algae in the Silver River and springs. The hundreds of clown-faced mullet were no longer sucking the loose algae off of the tape grass, like sheep grazing an underwater pasture.

Bluegill (Lepomis macrochirus)

Commonly known as "bream", the Bluegill is a member of the sunfish family. This omnivorous fish is commonly found around submerged trees and structures where it feeds on nearly anything they can fit in their mouth but aquatic insects, snails and smaller fish a make up most of their diet. They also play an important role in the food chain as food for larger fish, birds and mammals. These fish are  a popular panfish which are easily caught with worm, crickets or minnows.

Red Breast Sunfish (Lepomis auritus)

This panfish belongs to the family Chetrarchidae of the order Perciformes which means "perch-like".  Red Breast prefers vegetated areas of the river where it feeds on insects, snails and small invertebrates. They are a popular panfish among freshwater anglers. Their feeding habits are very similar to those of the Bluegill, but they are most active in cooler waters near springs. They breed in early spring with young reaching maturity 2 years later.

Largemouth Bass (Micropterus salmoides)

Perhaps the most sought after species by freshwater anglers, the Largemouth Bass gain it's reputation for it's vigorous fights when caught on the line. These large predatory fish ambush their prey from submerged vegetation.  They prefer to eat smaller fish and frogs, but they are know for taking snakes, small birds and even baby gators. They are highly adaptable to water conditions and temperatures making them highly successful  on a variety of freshwater ecosystems.

Bowfin (Amia calva)

The bowfin belongs to a very ancient family of bony fish related to gars. They are the only surviving member of the Amiiformes characterized by having a long cylindrical bodies and long dorsal fins. These fish are capable of breeding air directly by means of a gas bladder that acts as a rudimentary lung -  an adaptation that allows them to survive in low oxygen conditions that would be lethal to other fish.  Bowfins are fun to catch putting up a fight only expected from a game fish. As piscivores they like to ambush live prey which are swallowed in one gulp.

Channel Catfish (Ictalurus punctatus)

Channel Catfish are found throughout Florida and are commonly served at restaurants as its one of the most commercialized freshwater species.  These fish have an amazing sense of smell that allow them to find food in low visibility waters. These fish are most active from sundown until midnight when they forage for food which includes other fish, crabs, worms and even dead animals. In Florida they breed when the water reaches about 80°F by releasing the eggs in  a depression or hollow log where they are guarded by the male. They are one of the most common recreational freshwater fish.

Blue Tilapia (Oreochromis aureus)

Tilapias are a very successful introduced species that can live in a variety of ecosystems including freshwater and brackish waters.  Tilapias are highly adaptable and can easily replace other species as water quality degrades. They can be found on clear  springs as well as ditches, ponds and canals where water quality makes it hard for other species to survive. They feed mainly on water plants, diatoms, green algae and detritus.  Considered a good food source they are rarely caught with hook and line. They can reach and average of 5 pounds as adults.