Fishery bulletin of the Fish and Wildlife Service - NOAA

18
FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE
this river. The capture of only three juvenile striped bass, however, is significant,
and probably indicates that striped bass spawn in the Parker River. Added evidence
that this is a spawning area is seen in the fact that striped bass are known to winter in
this river, as is shown by their capture through the ice by bow-net fishermen. It is
considered likely that this is an example of an isolated spawning area in northern
waters, supported at least in part by a resident population, and possibly added to by
migrants from the south in exceptional years. Although this is the northernmost
point from which juveniles have been definitely reported in recent years, there can be
no doubt that they were commonly taken in the coastal rivers of the Gulf of Maine in
old tunes (Bigelow and Welsh, 1925), and there is good reason to believe that other
isolated spawning areas still exist north of Cape Cod.
Another area in which juvenile striped bass were taken was in the Delaware River,
near Pennsville, N. J. On November 8, 1937, the author was present when the game
protectors for the State of New Jersey Board of Fish and Game Commissioners took
104 small striped bass from the intake wells of a large power plant on the Delaware
River, where fish of all sorts are regularly trapped against the screens by the strong
flow of water, and are removed and liberated in other regions. A length-frequency
curve of this material is shown in figure 11. The examination of scales from these fish
showed that the bulk of this sampling was composed of yearlings, and that only a few
juveniles from about 9.0-12.5 cm. long were present. It is considered probable, therefore,
that the Delaware River region, including some of the smaller streams that enter
Delaware Bay, forms another area in which striped bass spawn.
LENGTH FREQUENCIES OF
STRIPED BASS TAKEN IN
DELAWARE RIVER NEAR
PENNSVILLE. N. J.,
NOV. 8, 1937
L E N O T H
FIGURE 11.—Length-frequency curve of juvenile and yearling striped bass taken In the Delaware River, near Pennsville, N. J., on
Nov. 8,1937. The number of fish included in this graph is 104. The data have been smoothed by threes (see Table 9 for original
measurements).
It has long been known from the observations of Worth (1903 to 1912) at Weldon,
N. C., that striped bass spawn in the Roanoke River. The main observations on the
eggs and larvae of the striped bass that are recorded in the literature for the Atlantic
coast are taken from Worth's papers, and were made during the time that he conducted
a hatchery at this point. Bigelow and Welsh (1925) sum up the available
information as follows:
The eggs (about 3.6 into, in diameter) are semi-buoyant—that is, they sink but are swept up
from the bottqm by the slightest disturbance of the water—and this is so prolific a fish that a female
of only 12 pounds weight has been known to yield 1,280,000 eggs, while a 75-pound fish probably
would produce as many as 10,000,000. The eggs hatch in about 74 hours at a temperature of 58°;
in 48 hours at 67°.
In recent years the hatchery at Weldon has again resumed operations, thus affording
an excellent chance for the study of the eggs and larvae of the striped bass. Others
have already accumulated detailed information on this subject (Pearson, 1938), and
the following material (from data collected in 1937 and 1938) included herewith, is
therefore nothing more than a brief account of some of the more interesting highlights
of the spawning and early life history of the striped bass.
Spawning in the Roanoke River normally occurs in April and May, although
occasionally there are a few stragglers that appear as late as June. It is probable
that spawning takes place over a goodstretchof theriverfrom Weldon down. (Weldon
is over 75 mues by river from Albemarle Sound.) At Weldon the river flows about
4 miles an hour, and is approximately 100 yards wide. Water samples taken on
March 29, 1937, showed the chlormity to be less than 5 parts per million (fresh water),
the pH 7.7, and the alkalinity 53.1 estimated as milligrams of bicarbonate per liter.