416 
Fishery Bulletin 108(4) 
a3 
Aouenbejj 
m 
CJ 
•2 ^ oi 
^ 0) o 
o ° 
<D CM 
>> 
O 
GO 
o 
o 
53 cm 
S (D 
* a 
T3 (D 
<D O 
be o> 
SPQ 
C 
<D 
0> 
£ 
03 
3 
03 
<D 
"S 
T3 
O) 
03 
3 
4-* 
CO 
_ w 
u ^ 
d o 
.S g 
"cj K*"} 
m 
"§ j§ 
C0 
6 T3 
03 G 
b cd 
bo 
o >» 
oo 
o 
o 
CM 
^ -Q 
^ S 
-2 ° 
^ > 
a o 
C/3 <h 
^ -a 
s § 
s ° 
a ° 
° CM 
of the estuary without first being 
detected at the inner gate. However, 
this individual was later detected 
at the inner gate when it emigrated 
from the estuary in May. 
A quantitative assessment of the 
efficiency of the outer gate receivers 
in Plymouth Bay is more difficult. 
It is unlikely that winter flounder 
were able to pass between adjacent 
receivers without being detected, 
because tagged winter flounder were 
commonly detected simultaneously 
at two or three adjacent receivers 
in Plymouth Bay, indicating that 
these receivers had overlapping 
detection radii. Unfortunately, the 
receivers that were lost (P and Y) 
were each at the edges of the outer 
gate. Therefore, it is difficult to as- 
sess how many fish may have moved 
from Plymouth Bay to Cape Cod 
Bay without being detected. 
Discussion 
Using acoustic telemetry, we were 
able observe the movements of adult 
winter flounder in the southern Gulf 
of Maine with high spatial and tem- 
poral resolution. In particular, we 
were able to investigate the spawn- 
ing behavior of tagged winter floun- 
der in the vicinity of Plymouth Bay 
and assess the seasonal distribution 
of tagged flounder in the region. This 
approach yielded valuable insight 
into the life history of this species. 
Spawning behavior of 
winter flounder 
Our observations support the hypoth- 
esis that winter flounder spawning 
in the Gulf of Maine is not restricted 
to estuaries. Two sympatric con- 
tingents of winter flounder were 
observed, both of which exhibited 
divergent spawning migrations. The 
majority of adults tagged in coastal 
waters (76%) were absent from the 
estuary during the peak spawning 
months of March through May. In 
addition, eight of the eleven tagged 
winter flounder that were observed 
to be gravid did not enter the estuary 
during the spawning period. 
Evidence of coastal spawning by 
winter flounder in Plymouth Bay 
