114 
SCANDINAVIAN FISHES. 
water that the spray drifts like snow or clouds of dust. 
Their presence, too, is often betrayed by the gulls and 
other seabirds which prey upon them. The fishermen 
state that at night the Mackerel emits a light which is 
visible at a long distance. This is the ordinary phos- 
phorescence created by disturbed lower animals (for the 
most part small crustaceans and medusae) in their rapid 
movements in the water. 
In addition to these annual migrations the Mackerel, 
like several other fishes, often makes irregular wander- 
ings. Thus, for a period of about ten years it may 
be more plentiful in one part of the island-belt than 
in another". 
The Mackerel passes the winter in very deep water 
and, it is generally supposed, where the bottom is of a 
loose nature. The fishermen believe that at this time 
of year the eye of the Mackerel is covered by a mem- 
brane which prevents it from seeing. This is, of course, 
false; but still the adipose lid increases in thickness 
and extent even in autumn 6 , while it becomes thinner 
and smaller between spring and summer. It is seldom 
that a single Mackerel is found in the island-belt of 
Bohuslan at the end of November, for when the westerly 
storms commence, which is generally at the beginning 
of this month, it makes its way out into deep water. It 
is stated, however, that in England half-grown Mackerel 
have several times been taken in great numbers in the 
middle of winter, in December and January. 
The movements of the Mackerel are incredibly 
quick and active. It darts forward with the speed 
of an arrow and leaps out of the water 'with no less 
rapidity. When drawn out of the water and taken 
into the boat, it beats a lively tattoo, as it were, on 
the bottom; but this does not last long, as it dies 
very soon. 
The Mackerel is a voracious glutton and eats what- 
ever comes in its way. Besides small fishes and fry, 
Ekstrom also found in its stomach fragments of cru- 
staceans and mollusks. That it feeds on jelly-fishes, 
is certainly a fable, for if, as often happens, a piece of 
a jelly-fish sticks to the hook or the bait, it will not 
bite. On the other hand, it is highly probable that, as it 
has often been seen snapping at jelly-fishes, it does so, 
as Mobius and Hkincke have assumed, in its attempts 
to catch the parasitic crustaceans (Hyperia galba ), that 
live in the genitals and the other parts of the jelly- 
fish. As a retribution for its own voracity, the Macke- 
rel is the victim of several large fishes of prey, which 
seem to prefer its flesh to other food. Slices of Mac- 
kerel, too, are one of the best baits for sea-fishing, 
even when meant for its own kind. 
On the coast of Bohuslan the spawning-season of 
the Mackerel generally occurs, according to Ekstrom’s 
observations, in June; but still one may find speci- 
mens with ripe roe until late in July 0 , the month, ac- 
cording to Sars, during which the Mackerel spawns in 
Norway. “It spawns in the open sea, where the roe 
drifts about until fully developed. I have found float- 
ing roe in Koster Fjord, as well as 6 miles off Kanso, 
in the middle of July” (Malm**). The eggs are about 
1 millimetre in diameter, and may be distinguished, 
according to Sars, by a large, clear oil-bubble in the 
upper pole. The fry grow quickly. According to Dunn’s 
observations, given by Day 0 , in August and September 
the young Mackerel are about 76 mm. in length, in No- 
vember from 152 to 157 mm. and in the following June 
from 203 to 228 mm. In the 13 specimens which have 
been available for examination at the Royal Museum, 
the following changes due to age are especially notice- 
able (the respective averages are given for each length 7 ): 
a This is still more clearly proved in the countries where there are statistics as to the changes in the Mackerel-fisheries during a long 
period. Thus Earll reports (Rep. Comm. Fish. a. Fisher. 1881, p. 217) that in 1804, in the United States, 8,079 barrels of Mackerel were 
salted in Massachusetts, in 1814 only 1,349. In 1831 the number had increased to 383,658, but it then sank so fast that from 1839 to 1845 
the average annual quantity was 67,674 barrels. About 1860 the Mackerel again became common, and for eight years the average quantity of 
Mackerel annually salted in Massachusetts was 246,877 barrels. Again the Mackerel became rare, and in 1877 only 105,017 barrels were 
submitted to inspection. But then the catch once more increased. In 1880 the total quantity of Mackerel taken in Massachusetts was cal- 
culated to amount to 9 5 1 / 2 million lbs. or about 400,000 barrels. In the same year, in the six states of the Union which are engaged in 
this fishery, Mackerel were taken to a quantity of about 132 million lbs., with a first-hand value (as sold in the market) of 2 1 /. i million dollars. 
b Cf. Baird, as quoted by Brown-Goode, Fisher, a. Fisher. -Industr., sect. I, pp. 287 and 288. 
c “Towards the end of July”: Malm, Gbgs, Boh. Fn., p. 409. This year (1887), on the 19th of July, both male and female Macke 
rel from Bohuslan were bought in Stockholm, which were not quite, but very nearly, ready to deposit their spawu. 
d Cf. Sars, Indber. for 1865, p. 28; for 1875, p. 14. 
e 1. e., p. 89. 
f The numbers in the table which are enclosed in parentheses are not the average ones. The marks <C and )> respectively denote 
the maximum or minimum among the specimens of the same age. 
