Colura and Bumguardner: Effect of the salt-box catch-bycatch separation procedure, as used by the Texas shrimp industry 
407 
Table 10 
Mean (±SD) of initial percent survival, final percent survival, and mortality rate (M) and results ofWilcoxon signed rank tests used 
to compare the means of bycatch (all species), Atlantic croaker, spot, and sand seatrout from bycatch samples collected in control 
experiments and separated with or without the aid of a salt-box. 
Variable 
Salt-box 
Mean ±SD 
n 
No salt-box 
Mean ±SD 
n 
Z 
P 
Bycatch 
initial survival 
48.4 ±39.7 
14 
43.6 ±39.3 
14 
-0.460 
0.643 
final survival 
5.4 ±8.9 
14 
9.5 ±18.7 
14 
-0.322 
0.748 
M 
0.10 ±0.04 
14 
0.10 ±0.05 
14 
-0.277 
0.782 
Atlantic croaker 
initial survival 
41.1 ±38.2 
8 
56.0 ±40.1 
8 
0.790 
0.430 
final survival 
18.3 ±24.1 
8 
16.8 ±34.1 
8 
-0.373 
0.709 
M 
0.41 ±0.77 
8 
0.82 ±1.27 
8 
0.105 
0.916 
Spot 
initial survival 
70.9±30.3 
12 
71.7 ±27.3 
12 
-0.206 
0.837 
final survival 
24.9±34.8 
12 
21.5 ±36.4 
12 
-0.695 
0.519 
M 
1.30±2.71 
12 
2.07 ±3.26 
12 
0.799 
0.424 
Sand seatrout 
initial survival 
85.7 ±28.8 
11 
72.3 ±26.7 
11 
-1.242 
0.214 
final survival 
29.2 ±38.0 
11 
14.1 ±20.0 
11 
-0.774 
0.439 
M 
3.58 ±6.31 
11 
4.27 ±6.38 
11 
0.417 
0.677 
Table 11 
Spearman correlation coefficients (r s ) and probability (P) that the coefficient values were greater than 0, of variables which demon- 
strated relationships with bycatch (all species) mortality rate (M), initial percent survival and final percent survival and Atlantic 
croaker M. Samples were collected in Texas Parks and Wildlife trawls and separated from shrimp with or without the aid of a salt- 
box during control experiments. A space indicates the probability that the variables r s value was greater then 0 was >0.05. 
Variable 
M 
Initial survival 
Final survival 
r s 
P 
'7 
P 
r s 
P 
Bycatch 
separation time 
0.522 
0.004 
0.445 
0.018 
Atlantic croaker 
0.765 
<0.001 
0.630 
<0.001 
spot 
0.681 
<0.001 
0.530 
0.004 
sand seatrout 
0.792 
<0.001 
least puffer 
0.692 
0.039 
bay temperature 
-0.4249 
0.025 
salt-box salinity 
-0.680 
<0.001 
-0.635 
0.015 
bay anchovy 
-0.795 
<0.001 
-0.655 
<0.001 
gulf menhaden 
-0.466 
0.012 
bay whiff 
0.444 
0.018 
brown shrimp 
0.433 
0.021 
brief squid 
-0.588 
0.001 
blue crab 
0.494 
0.008 
0.631 
<0.001 
silver perch 
-0.386 
0.042 
-0.480 
0.010 
bluntnose jack 
-0.568 
0.002 
Atlantic croaker 
bay temperature 
0.829 
0.042 
bay salinity 
-0.514 
0.028 
Atlantic brief squid 
-0.833 
0.039 
