ASAP Base Assessment Model Goodness of Fit - Overall the base model provided a generally good qualitative fit to the available data. The predicted recreational and commercial catch (Figure 4.1) fit the observed data throughout the time series; however, the predicted recreational catch in recent years underestimated the observed catch rates. The trend in predicted catch was the same as the observed recreational catch but did not predict the relatively high catch levels (2009 to 2013). - ASPIC Alternative Assessment Model Goodness of Fit - The primary reference configuration Spotted Seatrout of the surplus production model had some discernible patterning in the residuals that are exhibited as “runs” of positive and negative residuals and large positive residual deviations are apparent in the early years in the time-series, 1997 to 1999 (Figure 4.9). Similarly, there are runs of positive and then negative residuals in the CFRD gillnet IOA, relative to the expected value. Negative residuals are consistently observed in the later part of the time series. Because these large positive and negative anomalies are not randomly interspersed, they may influence and potentially bias information on the population trajectory and model parameter estimates. - ASAP Base Assessment Model Selectivity, Spawning Stock Biomass, Stock Numbers and Fishing-Mortality Estimates - The estimated selectivity pattern was not time-varying and was the same for each of the two sectors (Figure 4.10A and 4.10B). The mean total instantaneous fishing mortality (unweighted) remained relatively constant (F = 0.7 to 0.9 y-1 with an observed spike in 2004) until 2009 when fishing mortality increased. The mean of the fishing mortality rate in the terminal three years in the time series is 1.43 y-1 (Figure 4.11). The number of total stock number (Figure 4.12), SSB (Figure 4.13), and total biomass (Figure 4.14) exhibited similar temporal trends. Specifically, the number of individuals in the stock, SSB, and total biomass remained relatively constant in the beginning of the time series (1993 to 2003), increased steadily during the middle of the time series (2003 to 2009) and steadily declined in the most recent years (2010 to 2014). A peak in SSB occurred in 2009 and the estimated SSB was 538 metric tons. Similar trends were observed in the age-specific stock number estimates with the most notable trends in the ages one and two cohorts (Figure 4.15). For the time period analyzed, the Mississippi Spotted Seatrout stock was primarily composed of age-1 and age-2 individuals (Figure 4.15). The estimated number of age-3 through age-6+ individuals did not compose a large portion of the population (in numbers) during any part of the time series. - ASPIC Alternative Assessment Model Biomass and Fishing-Mortality Estimates - Temporal estimates of stock biomass and fishing mortality were estimated (Figure 4.16). Results of the primary reference configuration of the stock and fishery status indicate that the patterns of increased fishing mortality and reduction of population size are similar to those reported in the age-structured base model. The trajectory of the stock in the early part of the time series indicates a relatively low fishing mortality rate until 2009. After this year the F level is consistently greater. A pattern of decrease in biomass is coincident with the change in 2009, in fishing mortality (Figure 4.16). - ASAP Base Assessment Model Stock Status - Although no target SPR has been set for the Mississippi Stock by management; during the early years of the assessment period until 2009, %SPR values in Mississippi ranged from 15 to 23%. Since 2009 SPR has decreased and in 2014 the estimated %SPR decreased to 9.3%. - ASPIC Alternative Assessment Model Stock Status - We have used Blimit as BMSY because this point is calculated internally in the ASPIC model. We find that, given this reference point, the biomass of the stock is below BMSY (Table 4.2). - ASAP Base Assessment Model Fishery Status - The F30%SPR and F18%SPR values are 0.35 and 0.77 y-1, respectively. Based on these fishery reference points, the Mississippi Spotted Seatrout stock F rates are greater than F30%SPR and F18%SPR. - ASPIC Alternative Assessment Model Fishery Status - We have used Flimit equal to FMSY because this point is calculated internally in the ASPIC model. We find that, given this reference point that the F rate for the terminal year is less than FMSY (Table 4.2).