Quote:
Originally Posted by Feesherman
Available data suggests,This suggests, not conclusive. Yes, my point. No real correlation has been made, just assumptions!
|
There are important differences between conclusive proof and correlations.
Most sound wildlife management decisions are made by a compelling "preponderance of the evidence" rather than conclusive proof that puts the matter "beyond a reasonable doubt." There are several reasons for this:
1. Even in cases where controlled prospective experiments are feasible, hypotheses are rarely absolutely proven in science. Hypotheses can be falsified, but not absolutely verified.
2. Most studies in large ecosystems are retrospective (looking back) rather than prospective (looking forward). Potentially confounding factors can be understood and sometimes mitigated, but not absolutely controlled. It is prohibitively expensive, time consuming, and possibly destructive to repeat the trials many times with varying conditions to isolate the effect of each separate condition.
3. Given the limitations of financial resources, most management professionals try and make decisions based on the best available scientific data on a given ecosystem because the resources are simply not available to gather perfect data for all the systems needing to be managed. Allocating resources to improve the data available for one ecosystem invariably takes money away from improving the data available for managing others.
There are compelling correlations with the limit change in the Calcasieu estuary and the decline in abundance of larger specimens and the decline in body condition (fatness) of the typical specimen.
The available data suggests that raising the limit would decrease the pressure on the spotted seatrout's limited food sources and contribute to an increase in growth rates and body condition. It's not proof, but it is much more compelling than the scientific basis for lowering the limit in the first place, and it represents the preponderance of the evidence that is commonly used in sound scientific wildlife management decisions.
The discussion could be better informed by additional data:
1. Analysis of LDWF weight vs. length data for all available species from 2000 to the present in the Calcasieu estuary to better quantify the relative condition factor of each species over that time period.
2. Analysis of top ten trout weights for all tournaments from 2000 to the present to better quantify the abundance of the larger trout.
3. Acquisition and analysis of weight vs. length data from any available independent sources to quantify the relative condition factor of different species in years when data is available.
4. Analysis of any other data that might be available to assess the stocks and the relative abundance of different species and their food supplies.
5. Analysis of any other data that might be available to quantify variations in growth rates from 2000 to the present.
Even after any proposed limit changes took place, the ongoing discussion and management would be better informed by continuing stock assessments. Using relative condition factor was pioneered in the Calcasieu estuary by Jill Jenkins of the USGS in a 2004 study. This approach is relatively inexpensive to implement compared with other stock assessment methods and usually reveals the relative abundance species to their food sources. An annual assessment of the relative condition factors of several species, along with analysis of the annual tournament data would be much more informative, but a more complete stock assessment would probably be useful every five years, as suggested by Callihan in his 2011 dissertation.