Nichols et al.: Spatial and temporal distribution of Eubalaena glacialis in Cape Cod Bay 
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70° 40' W 70° 30' W 70° 20' W 70° 10' W 70° 00' W 69° 50' W 
42° 10' N 
42° 00' N 
41° 50' N 
41° 40' N 
Figure 1 
Cape Cod Bay, Massachusetts, including the boundaries of the 
right whale (Eubalaena glacialis ) critical habitat (diagonally 
hatched area), Seasonal Area Management (SAM) West zone 
(gray shaded area), limit of state-regulated waters (dotted line), 
and outside boundaries for shipping lanes (dashed lines). 
the bays by mid-May (Hamilton and 
Mayo, 1990). Nearly one third of the 
population of photographically identi- 
fied and catalogued individual right 
whales has been sighted in Cape Cod 
Bay in recent years (see Hamilton et 
al., 2007). 
To reduce right whale mortality 
from ship strikes and entanglements, 
state and federal agencies have en- 
acted a number of management mea- 
sures. Cape Cod Bay was designated 
as federal critical habitat under the 
ESA in 1994 (Federal Register, 1994). 
The critical habitat includes all of 
Cape Cod Bay, except the segment of 
the bay west of 70°30'W, as well as 
a portion of the waters immediately 
to the north (Fig. 1), and was defined 
according to ESA criteria based on the 
knowledge of right whale distribution 
and patterns of habitat use available 
at the time (Hamilton and Mayo, 1990; 
Federal Register, 1994). In 1997, the 
state of Massachusetts instituted a 
Right Whale Conservation Plan that 
included modifications to fixed-gear 
fishing practices within state waters 
and a surveillance-based monitoring 
program that provided data on right 
whale presence to mariners and man- 
agement agencies (Brown et al., 2007). 
Also enacted in 1997, the federal At- 
lantic Large Whale Take Reduction 
Plan (ALWTRP) included measures de- 
signed to reduce entanglements in U.S. Atlantic waters 
(Federal Register, 1997). Regulations under both plans 
have affected fixed-gear fishing activities in Cape Cod 
Bay, including those of the lobster trap and anchored 
sink-gillnet fisheries. The most stringent regulations 
have been implemented within the boundaries of the 
critical habitat from 1 January through 15 May. Regu- 
lations governing the critical habitat during this period 
have included a more comprehensive modification of 
lobster gear than that required from 16 May to 31 De- 
cember and the prohibition of all gillnetting operations 
(Federal Register, 2002b). Additional state and federal 
regulations have been in effect outside the critical habi- 
tat, including the seasonal area management (SAM) 
component of the ALWTRP, which provides additional 
restrictions on fixed-gear fishing in an area immediately 
east of the critical habitat (SAM West) from 1 March 
through 30 April (Fig. 1; Federal Register, 2002a). Al- 
though the above are the most relevant spatially and 
temporally defined management measures, there are 
several additional and often overlapping regulations af- 
fecting fixed-gear fishing in the study area. Ship-strike 
reduction strategies currently under consideration in- 
clude measures to reroute ships and to implement speed 
restrictions from 1 January through 30 April in Cape 
Cod Bay, as well as speed restrictions in the waters 
immediately north and east of the critical habitat, or 
in the proposed Off Race Point Proposed Management 
Area (Federal Register, 2004, 2006). 
As part of the state conservation plan for right 
whales, a systematic aerial survey program was imple- 
mented in Cape Cod Bay during winter and spring be- 
ginning in January of 1998 (Brown et al., 2007). These 
surveys were designed with an emphasis on detecting 
right whales and notifying mariners and managers of 
their presence, and have resulted in a systematic data 
set that allows right whale occurrence and patterns 
of habitat use in the bay to be quantified for the first 
time. The objectives of this study were to use the aerial 
survey data to describe the spatial and temporal distri- 
bution of right whales in Cape Cod Bay, and to compare 
these data with the extent and timing of present and 
proposed management measures to evaluate their po- 
tential effectiveness. We examined the following critical 
management strategies: the specification of location and 
duration for the use of modified fishing gear; the use of 
critical habitat boundaries as a management unit: and 
the specification of critical periods when reduced ship 
speed would be mandated to reduce the mortality of 
right whales cause by ship strikes. 
