Which Freshwater Game Fish are on Sanibel?
One of the resources that makes Sanibel unique is our freshwater bodies. As a result, many wildlife species on the island thrive due to water availability. In June 1961, at least two species of freshwater game fish were released on the island at separate locations from a U.S. Fish & Wildlife Service fish hatchery.
Today, four Florida native freshwater game fish species exist throughout the island in freshwater bodies, plus at least three exotic species. Native freshwater game fish did not exist on Sanibel until they were released.
Thousands of juvenile bluegill, aka copperhead bream, (Lepomis macrochilus) and largemouth bass (Micropterus salmoides) were released into the Sanibel River at several locations and also into a manmade lake (Palm Lake) as part of a development in 1961. Within a couple years, it was evident that this introduction was successful.
Today, two other Centrarchid fish (the sunfish family) are also established. The redear sunfish (Lepomis microlophus) and warmouth (Lepomis gulosus) are found throughout the Sanibel River corridor. These two species were likely brought in with the bluegill and largemouth bass and established as well.
These game species are considered abundant in most areas on the island. However, in 2008, small numbers of an exotic fish species, with similar preferences, began to appear in fish surveys conducted by SCCF in the Sanibel River basin. Pictured here is the structure on Tarpon Bay Road that separates the east basin of the Sanibel River (the water on the right within the concrete enclosure) from the west basin (the water outside the concrete enclosure.
The Mayan cichlid (Mayaheros urophthalmus), an exotic fish from Mexico and Central America, was documented in the east basin of the Sanibel River in a swale. In 2009, their density had increased, and by 2010 it had equaled the number of game species captured at trapping locations. The first example of this species in the west basin was captured in 2012. Capture frequency had increased every year following. Today, the Mayan cichlid is the most common “large” freshwater fish species in the Sanibel River.
It is unknown how this fish arrived to Sanibel, but it is considered a nuisance species in Florida, especially right off island in Fort Myers. It may have been released on the island intentionally or possibly swam across the bay during heavy rain/storm events when the salinity was really low.
Freshwater from the Sanibel River is released into the bay from the Tarpon Bay Weir when water levels reach high levels to control flooding. At this point, species from the bay can infiltrate the Sanibel River basin. However, if the Mayan cichlid was released and isolated in the east basin originally, then the opening of the structure at Tarpon Bay Road, to control flooding of the west end, allowed this fish to move into the west basin.