278 
Fishery Bulletin 106(3) 
70° W 
\ - 42° N 
23 February - 8 March 
> 69.04 (top 5%) 
IHH = 28.95-69.03 ( 75th— 95th percentile) 
= 12.3 1-28.94 ( 50th— 75th percentile) 
= 5.37-12.30 (25th-50th percentile) 
9 - 22 March 
= 0.01-5.36 (< 25th percentile) 
= 0 (effort > 0) 
no effort 
Figure 5 (continued) 
occurrence in Cape Cod Bay (Allen, 1916; Watkins and 
Schevill, 1982; Schevill et al., 1986). More right whales 
were sighted in December and January of our study 
than by Hamilton and Mayo (1990); likely a result of 
the spatial and temporal expansion of survey effort 
through the surveillance-based monitoring program. 
The shipboard survey effort of Hamilton and Mayo 
(1990) was not consistent throughout all the months 
that were examined in the present study. In the first 
five years of their eight-year study, there were no sur- 
veys in January or February. 
Right whales were present inside the critical habitat 
in December, before the comprehensive gear restric- 
tions were implemented within its boundaries on 1 
January, although low December effort makes it dif- 
ficult to interpret the significance of the sightings. 
Although gear restrictions were in place through 15 
May, no right whales were sighted after 2 May, and 
SPUE dropped to zero throughout the study area dur- 
ing the period 4-17 May. Moreover, although there 
were no sightings of right whales after 2 May during 
our study, there were a few sporadic sightings in the 
study area throughout May in other years (Hamilton 
and Mayo, 1990). Given that the period of peak SPUE 
occurs from February through April, the duration of 
existing fixed gear fishing regulations (1 Jan-15 May) 
appears adequate because it provides a buffer of a few 
weeks on either side of the peak period of right whale 
abundance — a buffer that allows for the interannual 
variation observed. The ship-strike reduction measures 
currently proposed for the period 1 January-30 April 
(Federal Register, 2004, 2006) should be extended to 
