Page 19 - Sella_M_1929

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In the Catalogue of Fishes of the North Sea, edited by the Conseil
perm. p. 1 'Exploration de la Mer (Publo Circ,:, n. 12), there is a record
of the occasional presence of tuna on the Mirman coastj a notice of which
I do not know the source, and which I judged to be extraordinary before
I came into possession of the following information, Dro Hoeg wrote me^,
in fact, that in August 1927, the geologist Dr, Th, Vogt saw in the
Laksefjord of Finmark, beyond Worth Cape, a school of about 20 tuna, and
he learned on the spot that the phenomenon was not a new one„

The tuna probably even frequ.ents the waters of Iceland, because the
bones of tuna have been found on those coasts

Do our tuna cross the Atlantic and is there an interchange of tuna
between Surope and America? It is taken in Canada (Nova Scotia) and on
the North Atlantic coast of the United States, where it even appears to
be very abundant. I have launched an appeal to the American sporting
clubs and in the Canadian Fisherman (ilarch 1927) in order to try to
recover hooks found in tuna on the other side of the ocean, but without
any success up to the present timeo

The affirmation that the area characterized by means of tuna
carrying hooks, converging in the Mediterranean, is the habitat of a
single race of tuna may still appear too bold, but in reality only two
hypotheses are possibles either that of a single race, or that of the
coexistence of local races together with a race diffused over the whole
area. And the second hypothesis seems worthy of little attention.

With regard to soraatometric investigations of tuna from different
regions, in 1913 I took multiple measurements on 50 tuna from the
fishery of S. Petri in Spain, measurements which I immediately repeated
on a similar number of tuna from Calabria and Tripolitania, without
finding variations sufficient to set apart distinct raceso I hope in
another work to re-examine my measurements in comparison with those taken
by Heldt on Tunisian tuna (Ann. Station Ocean. Salammbo, N. IV, 1927),
publishing my data; but there cannot be any difference between the tuna
of Tripolitania and the bordering Tunisia.

This identity is also confirmed by the rates of growth, practically
equal for Spain and for different regions of the Mediterranean, while it
is kno^^^l that the growth of Atlantic and northern races, for fish in
general, is greater than that of the Mediterranean races. Thus even the
hypothesis brought forward by Steuer , of the possible existence of a
large Atlantic race and _a small Mediterranean race of tuna is eliminated .

I note that such a belief is prevalent among many tuna fishermen
for the curious reason that in certain traps they catch small tuna and
in others large tuna, while in reality one encounters all of the inter-
mediate sizes.

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