Fishery bulletin of the Fish and Wildlife Service - NOAA

BIOLOGY OP THE ATLANTIC MACKEREL 187
That it did not do (1) or (2) is proved by the relative scarcity of larvae of appropriate
sizes at stations of the Chesapeake section and the outer station of the Winterquarter
section; though the few caught at Chesapeake II, III, and Winterquarter III
indicate a slight tendency for southward and outward streaming. That (3) was the
major result is shown by the "snubbing" of the southern center in its southward travel
and by the increase in numbers of larvae in the southern center relative to the number
76
1
WIND MOVEMENT
BETWEEN DATES
REFERRING TO
' NORTHERN CENTER
LARVAL DRIFT
NORTHERN CENTER
SOUTHERN CENTER
MOVEMENT
// BETWEEN DATES
/ REFERING TO
ош(з-гг) SOUTHERN
CENTER
36
71* 70*
FIOUBI I«.—Drift of the 2 centers of distribution of the S group compared with wind movements, as recorded at Winterquarter
Lightship.
in the northern center, 17
as if indeed the water and its burden of larvae did pile up in
the vicinity of Winterquarter I. This piling up very likely was in the nature of a
thickening of the surface stratum of light water offset by a depression of the lower
layers of heavier water rather than an outright raising of the water level. Of course,
the depressing of the subsurface stratum would set up a subsurface flow to restore
equilibrium. This flow would not transport the main body of larvae, since they were
" It is not supposed that the entire Increase In relative number at the southern center was duo to the mechanism being discussed.
Fart of it could have been due to random fluctuations of sampling.
40*