I have a friend that caught Red fish in th Florida Gulf. He took these fish home and put them in a fresh water pond two years ago. Two weeks ago, he caught one of these Red fish and it was doing great and had gained weight. How can this happen?
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Anonymous
ANSWERS: 3
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How does he know it was the same one? In general, one should not simply transfer one species from one place to another because that may change ecological balance in the latter place. For example, different types of vines were brought to American North East from Asia for decorative purposes. The vines adapted to the climate, escaped in the wild and now have started replacing trees that endemic to the area.
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Alot of fish have the ability to move from freshwater to saltwater. They produce different hormones to assist in osmoregulation as well as using other mechanisms to balance out the water flux. Many redfish are born in estuaries with salinities in the 5ppt or less, then move into 35-37ppt gulf and back again. They can live in freshwater, they just won't reproduce there. Funny sidenote, one of the hormones produced is prolactin, the same that causes lactation in mammals, obviously the fish don't lactate but I thought it was interesting that it serves this role.
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Redfish are one of several saltwater species that can be relocated to fresh water. When transferring them however it is usually a several hour long process in which fresh water is introduced slowly so the fish can adapt to the change in salinity without hyperhydrating its tissues and cells. If the fish is just thrown in to fresh water it is most of the time fatal, but if it survives it will do just fine. In fresh water environments, redfish do best in waters that are warm year round. In this case you can also be assured it was one of he original redfish introduced into the pond because redfish do not spawn in fresh water and would have no way to produce offspring. As far as the redfish being an invasive species to this environment, that is also false. Across the US, Wildlife agencies stock redfish in to warm water lakes without drastically changing the overall dynamic or balance of the lake.
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