402 
Fishery Bulletin 99(3) 
labile 2 
Results of high salinity bioassays and mean total length (TL) of experimental animals. LE 50 = time required for 50% of experimen- 
tal animals to die, NOEE = no-observed-effect from exposure time. 
Species 
n 
LE 50 (min) 
NOEE (min) 
Mean TL (mm) 
Atlantic croaker 
210 
19 
8 
65 ±11.7 
Red drum 
105 
17 
8 
28 ±2.7 
Spotted seatrout 
90 
35 
16 
72 ±15.5 
Southern flounder 
105 
58 
32 
131 ±23 
Blue crab 
105 
67 
64 
45 ±4.8 J 
; Carapace width for blue crabs = TL. 
Table 3 
Mean (±SD) trawling time (h), catch separation time (min), bay salinity (%o), salinity in the salt-box (%e), and bay temperature (°C) 
for bycatch samples collected from the commercial fishery and separated with (n=15), or without (n= 15), the aid of a salt-box and 
results of Wilcoxon signed rank tests comparing the means. 
Variable 
Salt-box 
No salt-box 
Z 
P 
Trawling time 
1.5 ±0.62 
1.2 ±0.79 
0.634 
0.526 
Separation time 
9.9 ±3.1 
16.5 ±21.5 
-0.605 
0.550 
Bay salinity 
21.0 ±4.7 
22.3 ±2.7 
-1.045 
0.296 
Salt-box salinity 
77.0 ±6.4 
Bay temperature 
26.7 ±0.7 
28.7 ±1.8 
-3.887 
<0.001 
sorted. The mean time that catch remained on deck while 
fishing resumed was 11.7 min (±18.9 min) for fishermen 
not using a salt-box and 7.8 min (±4.2 min) for fishermen 
using a salt-box. Time the catch remained on the deck 
was statistically similar for the two methods (Z=0.6251, 
P=0.9502). The catch separation procedure with a salt-box 
began when fishermen used a large scoop to transfer the 
catch from the boat deck to the salt-box. Fishermen not 
using a salt-box spread the catch on the boat deck or a 
table and began removing shrimp. Once the catch separa- 
tion procedure began, fishermen using a salt-box required 
1.7 min (±1.4 min) to separate the catch, whereas fisher- 
men not using a salt-box required 7.0 min (±12.0 min) to 
separate the catch; mean time required was statistically 
similar between the methods (Z=-l. 44571, P=0.1483). 
Time required to separate the catch once the procedure 
began appeared to depend upon size of the catch, but we 
had only the captain’s estimate of the size of the catch. 
Trawling time, catch separation time (total time bycatch 
was out of the water), and bay salinity at the time sam- 
ples were collected did not differ significantly for samples 
collected by each method (Table 3). Mean bay tempera- 
ture at the time of collection differed significantly between 
samples collected with the salt-boxes and those collected 
with no salt-box. Bay temperature averaged 28.7° (±1.8°)C 
when NSB samples were collected and 26.7° (±0.7°)C when 
SB samples were collected. 
Thirty-three species (30 fishes and 3 invertebrates) were 
collected (Table 4). Atlantic croaker (n= 536) was the most 
common organism and was present in 27 of the 30 sam- 
ples. Other fishes frequently observed were spot (n= 278), 
sand seatrout (n= 90), Gulf menhaden ( Brevoortia patro- 
nus, 71=198), and bay anchovy (Anchoa mitchilli, n- 45). 
The most frequently observed invertebrates were brown 
shrimp (Penaeus aztecus, rz =46) and blue crab (>z =34). Re- 
maining species generally averaged <1 per sample. Some 
differences were observed in the frequency and length of 
some of the by catch species that composed the NSB and SB 
samples. However, differences were generally small and 
were probably biologically insignificant. Atlantic croaker, 
bay anchovy, hardhead catfish ( Arius felis), and brown 
shrimp were found in significantly greater numbers in SB 
samples than in NSB samples (Table 5). Bay whiff (Ci- 
tharichthys spilopterus), bluntnose jack ( Hemicaranx am- 
blyrhynchus), Atlantic spadefish ( Chaetodipterus faber ), 
and inshore lizardfish ( Synodus foetens ) were found in sig- 
nificantly greater numbers in NSB samples than in SB 
samples, although they were rare in NSB samples. Mean 
number of specimens collected for all other species were 
similar in both sample types. Mean length of Atlantic 
croaker, Gulf menhaden, spot, sand seatrout, and pinfish 
(Lagodoii rhomboides) were significantly greater in NSB 
samples (Table 5). Blue crabs collected in SB samples had 
a significantly greater mean carapace width than those 
collected in NSB samples. Mean lengths of all other spe- 
cies were similar in both sample types. 
In general, all three measures of salt-box effect on by- 
catch were highly variable (Table 6). Mean (±SD) initial 
