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Executive Summary
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Chart of transects flown over
Cape Cod Bay -
transect numbers and latitudes shown
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Right whales were present in the
Cape Cod Bay Critical Habitat area and in state waters west of the
critical habitat and along the outer coast of Cape Cod between
Chatham and Race Point for 134 days from 19 December 2000 to 1 May
2001. There were a total of 545 sightings of right whales of which
452 were photographed during 32 aerial survey days and 33 vessel
trips. All sightings were reported upon completion of each survey to
the National Marine Fisheries Service Sighting Advisory System.
These aerial and vessel surveys are the principle source of right
whale sightings for the NMFA/SAS in the winter months for waters in
the northeast north of latitude 41°N.
A total of 87 right whales were
seen in Cape Cod Bay and adjacent waters. Of these 75 were matched
an individual in the Right Whale photo-identification catalogue. The
12 whales not in the catalogue included seven calves that migrated
from the southeast US calving ground with their mothers, three
whales that are new to the catalog and two whales that were seen
several times but not matched yet.
The highlight of the season was the observation of seven mother calf
pairs, the first year since 1997 that calves have taken up residency
in Cape Cod Bay. The first mother calf pair was recorded on 26
March, 47 days after their last sighting in the southeast US calving
ground. The last mother calf pairs were seen 29 March. Mothers and
calves were resident in Cape Cod Bay for 34 days. The mean maximum
transit time between the calving ground in the southeast US and Cape
Cod Bay for the seven mothers with calves was 40 ± 5 days. There was
an eighth mother identified, she was seen in Florida with a calf,
but no calf was recorded during all three sightings over 17 days in
Cape Cod Bay, she has likely lost her calf. Of the 31 mothers
identified in all areas in 2001, 18 mothers have been seen at least
once in Cape Cod Bay over the last twenty years and 11 (61%) of
those were seen in Cape Cod Bay in 2000. This indicates, assuming a
12 to 13 month gestation, that a portion of this year’s mothers were
feeding in Cape Cod in the early part of their gestation in 2000.
The season of occurrence of right whales in Cape Cod Bay is
generally considered to extend from early January through mid-May
based on data collected between 1984 and 1991. However, during two
pre-season surveys flown on 13 December 1998 and 19 December 2000,
right whales were recorded in the critical habitat. Over the last
four years right whale sightings have been few in number after the
end of April. These data indicate the seasonal residency of right
whales, for at least the last four years, is December to the end of
April. There are now sufficient data to reevaluate the dates gear
restrictions are required in the critical habitat to assess if they
reflect current presence of right whales.
In 2001, there were nine sightings of a total of 32 identified right
whales in nearby adjacent waters outside the critical habitat area.
These whales were seen in state waters west of the critical habitat
along the Manomet and Plymouth shore and east of the outer Cape from
Chatham to Race Point. The records extralimital to the critical
habitat represented the only sighting of three right whales and the
last sighting of 12 animals. The other 17 whales were seen in the
critical habitat area before and after the extralimital record.
These data indicate that the present boundaries of the critical
habitat may need to be reevaluated to assess if they reflect the
recent distribution and movements of right whales. The present
boundaries were based on historical data collected prior to 1991;
expanded survey efforts over the last four years have been more
effective at covering the periphery of the critical habitat.
Cape Cod Bay has long been known as an important winter and spring
feeding ground. Since 1980, 72% of the cataloged right whales have
been seen in Cape Cod and Massachusetts Bays. Over just the last
four years of this program, 51% (n=153) of the catalogued population
in the western North Atlantic have been recorded in the winter and
spring in Cape Cod Bay and adjacent waters. |
