466 
Abstract.— A total of 1,237 tagged 
American lobsters, Homarus ameri- 
canus, with a carapace length (CL) 
range of 48 to 198 mm (mean CL of 104 
mm ) were liberated at three release sta- 
tions off the eastern shore of Cape Cod, 
MA, between 1969 and 1971. By 1973, 
332 (26.8%) of the tags were returned. 
Mean time at large was 112.5 days 
(range 0-897 d). 
One hundred and thirty (39.2%) of 
the recaptured lobsters moved less than 
10 km from their points of release. One 
hundred and fifty-one (45.5%) were re- 
captured within 10 to 40 km from their 
points of release; 51 (15.4%) at 40 km 
or more. 
Recapture depths and distances trav- 
eled were significantly greater in colder 
months. The distribution of these re- 
captures with time, depth, and location 
indicates seasonal movement to and 
from the edge of the continental shelf 
between fall and spring. 
The apparent reshoaling of these in- 
shore-tagged lobsters to the eastern 
shore of Massachusetts in successive 
summers and the greater movement 
shown by females with ripe eggs at tag- 
ging, versus the movement of sublegal 
and nonovigerous female classes, sug- 
gest that the migration of this group of 
offshore lobsters is stimulated by sea- 
sonal changes in environmental cues in 
relation to hatching or reproductive 
needs (or both). Their relation to the 
Georges Bank-Southern Offshore stock 
unit, reproductive potential, and exten- 
sive seasonal movement into the south- 
ern and western Gulf of Maine, repre- 
sent important considerations for re- 
source managers and emphasize the 
need for further research on rate of 
stock interchange. 
Manuscript accepted 11 February 1997 
Fishery Bulletin 95:466-476 (1997). 
Seasonal movement of offshore 
American lobster, Homarus americanus, 
tagged along the eastern shore of 
Cape Cod, Massachusetts 
Bruce T. Estrella 
Massachusetts Division of Marine Fisheries 
50 A Portside Drive 
Pocasset, Massachusetts 02559 
E-mail address: Bruce. Estrella@state.ma. us 
Thomas D. Morrissey 
7 Horseshoe Circle 
Sandwich, Massachusetts 02563 
The traditional American lobster, 
Homarus americanus, fishery con- 
sists of a small-boat fleet that fishes 
with traps within a few miles of 
shore in depths up to 20 fathoms. 
This inshore fishery is centered in 
the northern Gulf of Maine and pro- 
duces annually approximately 47% 
of the U.S. pounds landed. Massa- 
chusetts, the next largest producer, 
contributes about 28% of U.S. land- 
ings. Exploitation of inshore stocks is 
intensive. In the coastal waters of 
Maine, over 85% of the commercial 
inshore catch consists of new recruits 
(Krouse et al. 1 ). In Massachusetts 
coastal waters, approximately 90% of 
the inshore catch falls into this cat- 
egory (Estrella and Armstrong 2 ). 
Prior to 1948, small numbers of 
lobsters were caught incidentally by 
trawls in groundfish operations. 
These incidental catches accounted 
for less than 1% of U.S. landings. 
About 1945, trawlers began to fish 
specifically for lobsters, principally 
in deep water in the offshore region 
south of the Gulf between southeast 
Georges Bank and Hudson Canyon. 
This fishery was developed moder- 
ately and by 1968 offshore lobsters 
accounted for 16.9% of all U.S. lob- 
ster landings (Skud and Perkins, 
1969). The introduction of deep-wa- 
ter trap fishing in the late 1960’s 
rapidly accelerated development of 
the offshore fishery. Vessels that 
fish with traps have largely re- 
placed the original trawl fleet, and 
the number of vessels in the off- 
shore lobster fishery have increased 
greatly. Substantial numbers of ves- 
sels in the 40' to 60' class, as well 
as larger vessels, were built or con- 
verted specifically for offshore trap 
fishing. Offshore landings averaged 
24% of U.S. landings (3,400 metric 
tons [t]) between 1970 and 1974 but 
declined to a 1978-83 average of 
17% or 2,500 t per year (NEFC, 
1983). Despite short-term increases 
(5,000 t in 1990), offshore landings 
have not accounted for more than 
18% of total U.S. lobster landings 
since the mid 1970’s (NEFSC, 1994). 
1 Krouse, J. S., K. H. Kelly, G. E. Nutting, 
D. B. Parkhurst Jr., G. A. Robinson, and 
B. C. Scully. 1994. Maine Dep. Marine 
Resources lobster stock assessment project 
3-IJ-61-2. Maine Dep. Mar. Resources, Ma- 
rine Resources Laboratory, P.O. Box 8, 
West Boothbay Harbor, ME 04575. Annual 
Rep., 53 p. 
2 Estrella, B. T., and M. P. Armstrong. 1995. 
Massachusetts coastal commercial lobster 
trap sampling program, May-November, 
1994. Mass. Div. Mar. Fish., 20 p. 
