Fishery bulletin of the Fish and Wildlife Service - NOAA

STUDIES ON THE STRIPED BASS OF THE ATLANTIC COAST 27
1937 exhibited approximately the same amount of growth (8-9 cm.) from June through
October as fish of the same age in 1936, but it wpl be noticed that they consistently
averaged at least 2 cm. larger over this entire period. Thus the modes of the lengthfrequency
curves of the 2-year-olds of 1937 moved from 31 cm. in June to 39 cm. in
October. However, the 3-year-olds of 1937, although growing the same amount as
fish of the same age in 1936 over an equivalent period of tune, averaged 2 cm. smaller
throughout, the modes moving from approximately 38 cm. in June to 46 cm. in October.
The comparison of any of the monthly length-frequency curves in 1936 with its
counterpart in 1937 clearly shows that the 2-year-olds m 1937 were distinctly larger
than those of 1936, while the 3-year-olds of 1937 were definitely smaller than fish of the
same age in 1936. The members of the dominant year-class of 1934 (2 years old in
1936 and 3 years old in 1937) therefore appear to have been below average size.
GROWTH OF 2- AND 3-YEAR-OLD STRIPED BASS SEINED IN
CONNECTICUT WATERS DURING 1936 AND 1937
193 в l»37
l- VtAM-OLDB
Э-YEAR-OLD!
L E N G T H S
OCTOBER
j U CHI.
tO INCNCS
FIQUEI 18.—The growth of the 2- end 3-year-old striped bass seined In Connecticut waters during 1938 and 1937. The curves are
smoothed In every ease by a moving average of threes. The numbers of fish making up each curve have not been equalized
except In that for September 1936, where the total number of fish was divided by three. The dotted line In the June 1937,
length-frequency curves Is a repetition of curve for the 2-year-olds In October 1936, and Is Included f or the purpose of comparing
the 2-year-olds of October 1938, with the 3-year-olds of June 1937 (members of the same year-class) (see Table 12 for original
measurements).
They were consistently smaller than the fish which were born in 1933 or 1935 were
at equivalent ages; both the 1933 and 1935 year-classes were few in numbers by comparison
to the dominant 1934 year-class. It is quite clear that this lesser average
length of the members of the dominant 1934 year-class developed before the individuals
became 2 years old. The smaller sizes of the individuals making up this dominant
age-group agree well with Jensen's (1932) studies on plaice (Pleuronectes platessa) in
the North Sea, where it was shown that a strong year-class checks the growth of the
fish in this age-group. Jensen (loc. cit.) also points out that the principle of the
smaller-than-average size of the individuals making up a dominant year-class, at least
in plaice, also appears true from Thursby-Pelham's work, where it is shown that the
rich year-class of 1922 was distinguished by a small average length. This is explained
by Jensen on the basis of increased competition for food among the members of the