Fishery bulletin of the Fish and Wildlife Service - NOAA

20 FISHERY BULLETIN OF THE FISH AKD WILDLIFE SERVICE
To the author's knowledge, the smallest striped bass that have ever been taken
in their natural habitat were seined along the shore of Albemarle Sound from Mackeys
to Rea's Beach, N. C., on May 11, 1938. Since the first spawning fish were taken
on April 11 in this year at Weldon, it is likely that these individuals were not more
than 1 month old. A length-frequency curve of the 85 juveniles taken at this time is
shown in figure 14, and it will be seen that they ranged in size from 1.9-3.1 cm., the
peak falling at 2.7 cm. The growth of the striped bass from this age on is further
discussed in a later section.
In general, then, it may be said that all the evidence points to the fact that the
striped bass is anadromous, spawning in the spring of the year, the exact time probably
depending on temperature and latitude. It is not definitely established, however,
how high a salinity the eggs and larvae of bass will tolerate. Considering the wide
variation in the type of river in which bass are known to reproduce, it does not seem
unlikely that spawning may at times take place successfully in areas where the water
is at least strongly brackish and perhaps even strongly saline. Worth (loc. cit.) first
noticed that in raising artificially fertilized eggs of striped bass, an apparatus similar to
MacDonald jars—in which the eggs are kept in a strong circulation of water—was
necessary hi order to get a high percentage of normal development. It would seem,
therefore, that a fairly strong current is probably essential for the development of the
eggs, but that this may be either tidal, such as that in the Parker Eiver, Mass., or
mainly fresh water, as m the Roanoke River. Some possible evidence that spawning
does not necessarily always take place in waters of extremely low salinity is provided
by the irregular and inconstant manifestation of what appear to be distinct spawning
marks on the scales of mature striped bass (see p. 24), for it is generally assumed that
such marks are only found on fish that enter fresh water. It would be logical to expect
that if all striped bass entered fresh water for spawning purposes, spawning marks on
the scales would be more common than they actually are. Such spawning marks are,
of course, particularly well-known on scales from salmon (Salmo solar), which do not
feed to any great extent during their sojourn in fresh water for spawning purposes,
and whose scales are probably partially resorbed during this period, thus forming the
characteristic spawning mark. It should be pointed out, however, that striped bass
undoubtedly do not stop feeding to the same extent or for a similar length of tune
during spawning.
SEX AND AGE AT MATURITY
It is impracticable to get large quantities of striped bass for sex determinations
and stomach-content analyses anywhere along the Atlantic coast. This is so because
this fish is almost universally shipped to market, and frequently even sold to the
individual customers, without being cleaned ; hence it was not possible to examine the
body cavities in large numbers in the wholesale markets. Since there is no valid
method of determining sex without inspecting the gonads, the collection of quantitative
data on this phase of the work was necessarily limited to the study of fish
caught on rod and line by sportsmen and cleaned by the author, to a number of small
random samplings of bass that were seined during tagging operations, and to a few
fish that were examined on different markets as they were being sold.
A total of 676 striped bass caught in northern waters (Long Island and New
England) from April to November 1936 and 1937 were examined for sex. These
fish ranged in size from 25 to over 110 cm., and in age from 2 years old to over 12
years old. Of these 676 fish, only 9.7 percent were males. One hundred and eightythree
of them were 3 years old or more, and only 4.4 percent of these were males. No
males above 4 years old have been found in northern waters. The remaining 493
fish examined were 2-year-olds, 11.8 percent of which were males. Although the
number of fish examined for sex is too small to permit any final conclusions, there is
little doubt that the number of males in northern waters seldom reaches much over
10 percent of the entire population. And the evidence so far is that the percentage
of males is greatest among the 2-year-olds—that age at which this species first undertakes
the migration from further south (see p. 44), and appears in large quantities
in northern waters; the percentage of males apparently decreases in the age categories
above the 2-year-olds.