292 
THE PISHING GAZETTE 
[Apkil 22 , 1893 
fisheries of the neighbouring fjords and coast 
are conducted, but also upon the conditions 
■which apply in districts far removed therefrom. 
These experiences should thus contribute to 
strengthen the opinion that a certain degree 
of solidarity exists between one and all of a 
country’s salmon fisheries, an opinion which, I 
am sorry to say, is still far from being held in 
the country which 1 have the honour to repre¬ 
sent, as much as is desirable. 
“Although perhaps superfluous, I think that in 
this connection I ought distinctly to guard 
myself against having the intention of being 
opposed to the generally accepted theory that 
salmon after a residence in the sea return to 
their own river. That is so far from being my 
intention that I may say, on the other hand, 
that we in Norway have very special and obvious 
reasons for believing in the correctness of the said 
theory, which is moreover greatly strengthened by 
the results of the experiments I have carried 
out. I am merely of opinion that the said rule, 
namely, that the salmon returns to its own 
river, like nearly every other general rule, has 
its exceptions, and that we still know very little 
—I had almost said, nothing at all—as to w'hat 
occasions these exceptions, and whether these per¬ 
haps under certain conditions, in certain places, 
and at certain times, might not become much 
more numerous than in general is the case. 
And I have endeavoured to point out that some¬ 
times these exceptions are perhaps so common 
that they play an important part in fishery 
matters, and should, therefore, not be overlooked 
in the arrangement of these. 
“ With regard to the sex of the recaptured fish, it 
is somewhat remarkable that there are so few cock 
fish—only six as against forty-eight female—only 
about 11 per cent, of males. Of tne total number 
of salmon marked, somewhat over one-third, or 
more accurately 36 percent., were males. In such 
a considerab e number of fish as have been re¬ 
taken, it can hardly be mere chance that the 
males are so poorly represented, but at present I 
cannot give any reason for this state of matters. 
A circumstance, however, that may conduce to 
this is the great mortality among the males after 
spawning. 
“ The longest period which has elapsed between 
relea-e and recapture is two years and 231 days 
(say, two years and eight months); the shortest 
time 168 days, apart from a number of fish 
which were retaken or found dead before they 
had left the river. 
“Doubt has often been expressed in salmon 
fishery literature as to whether one and the same 
salmon spawns every or every other year. 
“In Ame-ica e.-pecially, on the strength of 
experiments that have been carried out, the theory 
is strongly upheld that the salmon there (par¬ 
ticularly in the Penobscot river) only spawn 
every other year. The marking experimetits 
undertaken in Norway would seem in the mean¬ 
time, as far as our country is concerned, to con¬ 
tradict this theory. In any case the experiments 
show plainly that a considerable number of 
salmon spawn yearly. No fewer than ten of the 
salmon recajitured—seven in the Suldal and 
three in Sireaaen — were marked the one year, 
either when ready to spawn nr having just com¬ 
pleted that operation, and were retaken t he next 
in the rivers in a similar condition. Four other 
fish also which were recaptured in the sea the 
summer after marking, seemed to have spawned 
the same year Here we have positive proof than 
a comparatively large number of salmon, all 
female fish, have spawned two years ia succes¬ 
sion, anh wlunthe great regulariry is considered 
which holds good in regard to the reproduction 
of animals, the conclusion is very obvious that 
salmon with us generally spawn yearly, which also 
harmonises with the conditions which apply to 
our wild animals in general. 
“On the other hand it must be admitted that a 
difference may be conceived between the so-called 
‘ \ intersioniiinger ’ and salmon that have gone 
back to the sea immediately after spawning. (By 
‘ \ interstonning,’ salmon are meant which after 
spawning remain throughout the winter in the 
river, and descend in spring to the sea.) 
“ Although the latter, therefore, may be ready 
to spawn the following yea>-, it does lollow that 
the ' Vinterstbnninger ’ will be able to recover 
their strength sufficiently for that purpose in the 
short period between spring and autumn. As to 
this, however, I will not at present express any 
opinion. 
“ I will next proceed to refer to the result 
which the marking experiments have given with 
regard to the growth of salmon. I will first of 
all recall the fact that salmon, after having for 
the first time left the river in which they spent 
their youth, practically speaking only grow 
during their stay in the sea, while during their 
residence in fresh water they rather fall oil 
than increase in weight. When a salmon, after 
having been out at sea, has returned to the river, 
two or more years of its growth have elapsed, 
although several months may be wanting to 
complete the calendar year. (I do not include small 
streams where salmon are in the habit of going up 
and down with almost every flood.) Regarding 
the fish on the other hand which have been 
recaptured in the sea, and as to which also it 
cannot be known how long they would have re¬ 
mained there had they not been taken, it may be 
assumed that the year of growth was interrupted 
by capture, and the difference in weight at the 
time of recapture and that of release, can there¬ 
fore, as a rule, not be assumed to be the full 
increase which the salmon would have attained 
in that or the year in question. 
“The fish caught in the sea, therefore, do 
not give so accurate an idea of the growth of 
salmon from one year to another as those retaken 
in the rivers. But even in regard to these, it 
roust be rememembered, that fish at spawning 
time lose a considerable portion of their ori<rinal 
weight. As regards the hen fish this loss of 
weight may be put, according to investigations 
made, at about one-fifth of the weight before 
spawning. As to the males, accurate obsei ra¬ 
tions have not been made, but the loss is un¬ 
doubtedly less, and according to my calculations 
it may be taken for granted that the loss can be 
put at about half of the hen’s, that is one-tenth of 
the fish’s weight before spawning, a calculation, 
however, which may be a somewhat low one. 
Thus when a fish is marked and weighed after 
Spawning, and a year later is recaptured before 
it has spawned or afterwards, in order to arrive 
at as correct an idea as possible of its real weight 
from one year to the other, I have increased the 
weight in the latter case by a fifth for female 
fish and a ninth for males. As the growth pro¬ 
ceeds at an unequal rate during the fish’s different 
astes, quicker more especially during its youth 
than later on, when investigating the question we 
ought to take individual fish of different sizes ; 
the different sexes also should be taken each for 
itself. For this purpose I have divided the 
different recaptured fish of each sex according to 
size in five separate groups thus : 
“(1) Fish at time of markingof lesser weigh than 
3 kg. (called “Laeksing’’ in Norway); (2) from 
3 to 5 kg. in weight; (3) over 5 to 7 kg ; (4) over 
7 to 9 kg.; (o) over 9 kg. 
“ As I have already remarked, there are only 
very few recaptured mtle fish, and of these there 
are individuals belonging to the two first groups 
only, a-i all the other larger fish which were retaken 
were females. 
“ E ven with so rough a grouping the irregularity 
of the salmon’s growth is very apparent. It will 
nut be possible to give a clear idea of this, or 
generally to render intelligiblethe results obtained 
in regard to the conditions of growth without 
going inio details ; and I am compelled therefore 
to inflict some figures upon you, which I will 
epitomise as much as is compatible with explain¬ 
ing the matter in hand. The more easily to 
understand the summary, I will give all the 
increases of weight in percentages of the fishes’ 
weights at the time of marking. (A growth of 
100 per cent, will thus show that the fish has 
doubled its weight; 200 per cent., that it is three 
times as heavy as at the time of marking, and so 
on ) And in these details of weights there is 
included the addition referred to above of a fifth 
or a ninth, for female and for male fisn re¬ 
spectively, which had done spawning either at 
the time of marking or recapture, but which on 
the other of these occasions was not in that 
condition. 
“ In the first group (fish under 3 kg.), thera 
are only two female and one male fish. Of the 
two first, one increased 63 per cent, in about e 
year (it was retaken in the sea), the other 316 per 
cent, in two years, which percentage is the largest 
increase furnished by any of the fish recaptured up 
till now. (The fish’s original weight was l.okg.) 
The male fish increased 235 per cent, in three 
years. 
“ In the next group (from 3 to 5 kg.), there are 
five female and three male fish. Tne former 
increased—One fish in one year, 49 per cent.; 
four in two years, between 84 and 102 per cent., an 
average of SH per cent. The latter—One fi'h jin 
about two years (retaken in the sea), 200 per 
cent.; the two others in two years, respectively 
only 63 and 137 per cent., or an average of 1<M} 
per cent. 
“ In the third group (over 5 up to and including 
7 kg.), there are eleven female, no male fish. 
These increased as under:—Four fish in one 
year between 7 and 28 per cent., or an average of 
18'5 per cent.; one in about two years (taken in 
the sea). 92 per cent.; six in two years, between 
25 and 101 per cent., an average of 72 per cent. 
“In the fourth group (over 7 up to and including 
9 kg.), there are 13 fish, all females. These in¬ 
creased—One fish in about one year (caught in 
the sea), 24 per cent.; five in one year between 
0 and 23 per cent., an average of 11 per cent.; 
one in about two years, 36 per cent.; five in two 
years between 20 and 76 par cent., an average of 
44 per cent.; one in about three years, 60 per 
cent. 
“In the fifth group (over 9 up to 11.6 kg.), there 
are 11 fish, all females, which had increased as 
under:—Two fish in about one year, 19 and 21 
per cent, respectively, or an average of 20 per 
cent.; one in one year, 5 per cent.; seven in about 
two years between 5 and 49 per cent., an average 
of 35 per cent.; one in three years, 43 per cent. 
“ To this group the fish belongs which has in the 
shortest time attained the greatest absolute 
increase in weight, namely a female which was 
marked on the I6th of January, 1889, having done 
spawning, and which in that condition weighed 
140 hg., in other words an increase in about five 
and a half months of 47 hg., or 8^ hectograms per 
month. *, 
With such great differences in the rate of 
growth which these figures show in practically . 
every single group, it is evident that a much »; 
larger number of observations than-the foregoing 
are required to enable us with any certainty to - 
give the average growth per year tor such single 
group. If with the help only of the foregoing 
observations, one wishes to arrive at the average 
rate of growth, the results would be as follows 
“ 1, First group, salmon from 1| to 3 kg., in one ^ 
year a fish grows on an average about 100 per 
cent^; 1, Second, 3 to 5 kg . 50 per cent ; 1, Tnird, 
5 to 7 kg, 40 per cent.; 1, Fourth, 7 to 9 kg., 25 par 
cent.; 1, Filth, 9 lo 12 kg., 20 per cent. 
“ But I repe it that the ob-er vations before us are 
far too few, a id the variations in the growth of 
the fish far too great to admit of these statements 
of weight laying claim to being even moderately , 
near the truth. With regard to the first two 
groups, however, they harmonise with the con¬ 
clusions which we have been able to draw of the 
rela ive frequency of salmon of thedillerent sizes. 
In the part of the country at any rate where the 
most comprehensive observation respecting thera 
have beenmade, namely in theTrondnjem district, 
young salmon make their appearance in summer 
principally of two sizes, about 1 kg. and about! kg. A 
in weight, or la trifle over, while there are com- 
parativ’ely few fisn between these weights, or 
which are much larger or smaller. Further, there 
are comparatively many fish of about 6 kg. 'I'he 
conclusion has therefore been drawn that 4 kg. 
is about the normal weight of the salmon which 
m the previous ye ir weighed about 2 kg., and 
which the following year weignabout 6 kg. This 
corresponds, as will be seen, to the growth shown 
above of 100 per cent, in the first, and 50 per 
cent, in the second weight or age group. The 
great irregularity of growth indicated in the 
different fisii of about the same size (and pre¬ 
sumably of about the same age) has of course its 
particular reasons ; but as to what these are, we 
are still practically wanting in any certain know¬ 
ledge, as far as I am aware. The main cause 
would seem to lie in the more or less favourable 
supply of food which the different years and the 
different places afford. That such an irregu¬ 
larity in the supply of nourishment can easily 
take place is obvious, as the herring, which with 
us forms the salmon’s most important food, is 
very capricious aud uncertain in its movements. 
With us also there is another obvious explanation 
I 
