You may recall that out team recently competed data collection for our 2011-2015 fish condition factor study on Calcasieu Estuary. We are grateful to all the anglers that have participated. Since 2011, we have weighed and measured over 1450 fish. Such a large data set not only allows us to estimate mean fish body condition of each species with a typical accuracy of 1% or so, five years of data allows us to estimate the forage overlap between species. These estimates allow questions like "How strongly do redfish and specks compete for food?" to be addressed.
The answers to the forage overlap questions are shown in the attached graph. Of course, every species has a 1.0 (100%) forage overlap with the same species. It was also expected that specks have a fairly strong forage overlap of 0.63 (63%) with red drum, and a weal overlap of 0.158 with black drum. It was a bit of a surprise to find gafftops competing so strongly with specks (0.534) and red drum (0.556). We believe that due to the depletion of the benthos caused by oyster overharvesting, that gafftops have moved up higher in the water column and are feeding much more strongly on fish than normal. The gafftops have consistently been about 10% underweight during the study period.
06-11-2015, 08:24 AM
2011-2015 Calcasieu Condition Factors Preliminary Results: Forage Overlap
Linear Mode
