| dc.description.abstract | A dynamic growth model for Southern Flounder (SFL) Paralichthys lethostigma was developed and evaluated, to promote understanding of this species' ecophysiology in the cause of its improved management. The new model, labeled E.F-RMD, and parameterized specifically for SFL, was based on the Stella® model Ecophys.Fish (E.F); but, E.F-RMD included a more mechanistic representation of tissue oxygen-delivery called the "respiratory model, dynamic" (RMD). The integrated model E.F-RMD uses simulation of cardio-respiratory processes to estimate oxygen availability in support of bioenergetic growth for SFL. A unique feature of E.F-RMD is the inclusion of cutaneous-sourced oxygen supplementation.
The combined model was evaluated by comparing E.F-RMD estimated juvenile SFL growth, expressed as weight-over-time (Wt) and percent weight change per day (%Wtchg/day), to growth data collected by the Texas Parks and Wildlife Department’s Coastal Fisheries Division for juvenile SFL raised in cool (17 – 22°C) and warm (20 – 26°C) recirculating systems indoors, and in outdoor ponds. For the indoor growth trials, routine respirometry also was performed, to measure metabolic responses. Published data on SFL growth also were used in E.F-RMD evaluation.
Correlation (R2) and Consilience (C, a provisional measure of holistic goodness-of-fit) analyses compared modeled to observed values for Wt and %Wtchg/day. For Wt, all C values were significant (α = 0.05). For %Wtchg/day, C values varied from significant to marginally significant. JointC values (all datasets considered together) were significant both for Wt and %Wtchg/day.
From these evaluations, the following conclusions were drawn: 1) E.F-RMD can reliably simulate juvenile SFL growth as measured by Wt and %Wtchg/day. 2) Growth results suggest ṀO2 via cutaneous respiration in flounder is significant for juvenile fish, but declines exponentially as the SFL grows. Rather than being a set percentage, cutaneous ṀO2 declines as weight and skin thickness increase with age. 3) Growth comparison to literature data indicates E.F-RMD accommodates well to changes in temperature and O2, but less so to salinity. | en |
