[a] During 1963-1984, BMV oval doors were used in the
spring and autumn surveys; since 1985, Portugeuse polyvalent doors have
been used in both surveys. Adjustments have been made to the 1963-1984
catch per tow data to standardize these data to polyvalent door equivalents.
Conversion coefficients of 1.56 (numbers) and 1.62 (weight) were used
in this standardization (NEFSC 1991).
[b] Spring surveys during 1973-1981 were accomplished with a '41 Yankee'
trawl; in all other years, spring surveys were accomplished with a '36
Yankee' trawl. No adjustments have been made to the catch per tow data
for these differences.
[c] In the Gulf of Maine, spring surveys during 1980-1982, 1989-1991
and 1994, and autumn surveys during 1977-1978, 1980, 1989-1991 and 1993
were accomplished with the R/V DELAWARE II; in all other years, the surveys
were accomplished using the R/V ALBATROSS IV. Adjustments have been made
to the R/V DELAWARE II catch per tow data to standardize these to R/V
ALBTATROSS IV equivalents. Conversion coefficients 0.79 (number) and
0.67 (weight) were used in this standardization (NEFSC 1991). |