Mather et al.: Use of non-natal estuaries by migratory Morone saxatilis in summer 
335 
Table 1 
Recaptures of adult striped bass (Morone saxatilis) tagged and released in the Great Marsh region (GM), and for all Massachu- 
setts estuaries combined (MA). Data are shown for striped bass recaptured within the first summer of release (<104 days and 
before 21 September), after the first summer (2-7 years after tagging), and at all times. Detailed recapture locations are divided 
into two spatial scales; Great Marsh (GM) and Massachusetts (MA). For example, row 1 shows that 22 fish were recaptured in the 
Great Marsh in the first summer and of those 17 were released there. Recapture data are shown as numbers ( n ) and percentages 
(%). Numbers for recapture across scales are not exclusive and therefore columns do not sum to total recaptures. Also shown are 
fish tagged and released in MA in summer and recaptured in other New England states in the first summer. ME=Maine, NH = 
New Hampshire, RI = Rhode Island, CT= Connecticut. 
Recaptures 
Release location 
Total GM MA 
ME NH RI CT 
(n) ( n ) (%) ( n ) (%) (n) ( n ) ( n ) in) 
First year 
GM 
MA 
2-7 years after tagging 
GM 
MA 
Total recaptures 
GM 
MA 
22 17 77 
41 
24 
108 41 38 
198 
22 100 0 
41 100 0 
79 
120 61 
0 0 0 
0 0 0 
Table 2 
Observed proportion of first summer recaptures of striped bass ( Morone saxatilis) in release location from field data and weekly 
probabilities of model fish remaining where tagged if striped bass movements were random. Observed proportions correspond 
to data in Table 1. For weekly probabilities of remaining, shown are two different model scenarios (RM-1 and RM-2). Data are 
shown for two regions of release and recapture: the Great Marsh (GM) and all Massachusetts estuaries combined (MA). P, is the 
proportion that would need to remain in the recapture location each week to obtain the observed proportion of recaptures over 
10 weeks. 
Observed 
recaptures 
(Proportion) 
GM-weekly probability 
of remaining where tagged 
Observed 
recaptures 
(Proportion) 
M A- weekly probability 
of remaining where tagged 
Release location 
RM-1 
Pe 
RM-2 
Pe 
RM-2 
Pe 
GM 
MA 
0.77 
0.95 
0.75 
1.00 
1.00 
1.00 
1.00 
tagging (Table 1). Thus, in subsequent migration cycles, 
many fish were recaptured in the location where they 
had been tagged. 
Recapture patterns were not caused by effort alone. 
Striped bass recaptures in both Massachusetts and the 
Great Marsh in the first summer after tagging were 
highest in July and August in 1999 and 2000 (Fig. 5, 
white bars), the same months when recreational fishing 
effort was concentrated (Fig. 5, black bars). However, 
when scaled by kilometer of coastline, the fishing effort 
for striped bass in summer was as high in Connecticut 
and Rhode Island as in Massachusetts and higher in 
New Hampshire (Fig. 6). Nevertheless, in spite of heavy 
effort across the entire New England coast, no striped 
bass tagged in Massachusetts during the summer was 
recaptured in any of the other four New England states 
in the first summer (Spearman correlation P= 0.55). 
Discussion 
Our study provides the first evidence that smaller striped 
bass make repeated, seasonal, long distance movements 
between natal and non-natal estuaries. The striped bass 
we tagged in Massachusetts in the summer were caught 
in late fall, winter, or early spring, south of the location 
where they had been released. If striped bass that were 
tagged in Massachusetts in summer were spawning or 
