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 medustc) in their ra])id 

 movements in the water. 



In addition to these annual migrations the Mackerel, 

 like several other tishes, often makes irregular wander- 

 ings. Thus, for a jjeriod 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 dee]) 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'', 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 ^vay 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 incrediblj^ 

 quick and active. It darts forward witli 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 ^vhat- 

 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 certaiidy a fable, for if, as often happens, a ])iece of 

 a jelly-fish sticks to the hook or the bait, it ^vill not 

 bite. On the other hand, it is higlily 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 {Hi/peria f/aJha), that 

 live in the genitals and tlie other parts of the jelly- 

 fish. As a retribution for its OAvn voracity, the Macke- 

 rel is the victim of several large fishes of prey, which 

 seem to prefer its flesh to other food. Slices of ]\Iac- 

 kerel, too, are one of the best baits for sea-fishing, 

 even when meant for its own kind. 



On the coast of Bohuslaii the spawning-season of 

 the Mackerel generally occurs, accoi-ding to Ekstrom's 

 observations, in June; but still one may find speci- 

 mens with ripe roe imtil late in July'', 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 ott' Kiinso, 

 in the middle of July" (Malm''). The eggs are about 

 1 millimetre in diameter, and may be distinguished, 

 according to Sars, l)y a large, clear oil-bubble in the 

 upper pole. The fry grow quickly. According to Dunn's 

 observations, given by Day^, 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 2(J3 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-^): 



" This is still more clearly proved in the courjtries where there are statistics as to the changes in the Mackerel- fisheries during a long 

 period. Thus EaRll reports (Rep. Coinm. 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 fa.st that from 1839 to 1845 

 the average annual quantity was (57,674 barrels. About 1860 the Mackerel again became common, and for eight years the average quantity of 

 Mackerel annually salted in Massachusetts was 240,877 barrels. Again the Mackerel became rare, and iu 1877 oidy 105,017 barrels were 

 submitted to inspection. But then the catch once more increased. In 1880 the total qunnlity of Mackerel taken in Massachusetts was cal- 

 culated to amount to 95'/., million lbs. or about 400,000 barrels. In tlie 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 27^ million dollars. 



' Cf. Bairij, as quoted by Brown-Goode, Fisher, a. Fisher.-Imlustr., sect. I, pp. 287 and 288. 



' "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 Bohusliin were bought in Stockholm, which were not quite, but very nearly, ready to deposit their spawu. 



'' Cf. Saks, Indber. for 1865, p. 28; for 1875, p. 14. 



'■ 1. c, p. 89. 



■' The number.s in tin' table which are enclosed in parentheses are not tlie average ones. The marks < and > respectively denote 

 the ma.xinnim or ininimum aiiiuiig the specimens of the same age. 



