Event Title
Effects of salinity on growth and behavior of invasive Rio Grande cichlids (Herichthys cyanoguttatus) in Louisiana
Collaborator(s)
Maiadah Bader, Manalle Alsalamah
Faculty Sponsor
Tom Lorenz
Submission Type
Poster
Description
There is a wide range of salinity tolerance within the family Cichlidae. The most impactful and widespread invasive cichlids species appear to all have a high salinity tolerance. The spread of non-native Rio Grande cichlids (Herichthys cyanoguttatus) in the Greater New Orleans Metropolitan Area (GNOMA) has included the brackish habitats of Lake Pontchartrain and the La Branche Wetlands. It is possible that these habitats serve as corridors to further spread, or that these brackish conditions are actually suitable for cichlid survival. We studied / the effects of three different salinity levels on the biology of H. cyanoguttatus. Our aim was to determine: 1. the effects of salinity on growth, 2. the effects of salinity on behavior, 3. the potential for H. cyanoguttatus to invade brackish or even marine habitats. We collected thirty live H. cyanoguttatus and split them evenly into three treatments of ten fish each. The control treatment never experienced salinity above 1 psu, the brackish treatment eventually was acclimated to 15 psu over approximately two weeks, and the marine treatment was acclimated to 35 psu over approximately five weeks. The highest salinity tolerated, before cessation of feeding and eventual death, was 30 psu. No cichlids survived to the acclimation point of full seawater (35 psu). Body mass increased significantly less with the higher salinity treatments, and behavior was also observed to change with treatments. The significance of this study is that most higher-salinity habitats in Louisiana, even those approaching sea water, can be tolerated by this species.
Effects of salinity on growth and behavior of invasive Rio Grande cichlids (Herichthys cyanoguttatus) in Louisiana
There is a wide range of salinity tolerance within the family Cichlidae. The most impactful and widespread invasive cichlids species appear to all have a high salinity tolerance. The spread of non-native Rio Grande cichlids (Herichthys cyanoguttatus) in the Greater New Orleans Metropolitan Area (GNOMA) has included the brackish habitats of Lake Pontchartrain and the La Branche Wetlands. It is possible that these habitats serve as corridors to further spread, or that these brackish conditions are actually suitable for cichlid survival. We studied / the effects of three different salinity levels on the biology of H. cyanoguttatus. Our aim was to determine: 1. the effects of salinity on growth, 2. the effects of salinity on behavior, 3. the potential for H. cyanoguttatus to invade brackish or even marine habitats. We collected thirty live H. cyanoguttatus and split them evenly into three treatments of ten fish each. The control treatment never experienced salinity above 1 psu, the brackish treatment eventually was acclimated to 15 psu over approximately two weeks, and the marine treatment was acclimated to 35 psu over approximately five weeks. The highest salinity tolerated, before cessation of feeding and eventual death, was 30 psu. No cichlids survived to the acclimation point of full seawater (35 psu). Body mass increased significantly less with the higher salinity treatments, and behavior was also observed to change with treatments. The significance of this study is that most higher-salinity habitats in Louisiana, even those approaching sea water, can be tolerated by this species.