Íslenskar landbúnaðarrannsóknir - 01.09.1978, Blaðsíða 172

170 ÍSLENZKAR LANDBÚNAÐARRANNSÓKNIR
Fig. 8. Mixing areas ofcold water current system (solid lines) and warrn water systems (broken lines).
Reproduced and modified from Mosley 1960.
In the particular case of Iceland it ap-
pears that an imaginary line drawn from
Isafjördur to Vatnajökull will divide the
salmon streams into a southwestern group
and a northeastern group. As will be dis-
cussed below the smolts from these two
groups are attached to different current
systems and a mixing of these two groups
ofgene pools should be avoided in the face
of prevailing uncertainties regarding sal-
mon genetics.
However, the environmental condi-
tions, the temperature regime, and the
current system are similar within each
group. This eradicates the primary basis
for evolution of widely different genotypes
in individual streams. The primary ob-
jective, therefore, must be to obtain sufFi-
cient but separate production centra of
smolts.
Were the objective only to satisfy the
needs of recreational fisheries, this goal
could be reached with a few high capacity
hatcheries. But one of the potential large
expansions of the Icelandic salmon
fisheries lies in salmon production for
meat, for which the term „ocean ranch-
ing“ has been coined.
It originated as an offspring of the pen
culture of warm-water species used for
centuries. Depending upon the market
need, the product is pan-sized fish, as cur-
rently is the custom in the United States,
or steaks as is preferred in Norway. The
idea is to convert cheaper forms of fish and
other food items into the high-priced flesh
of the salmonid. Capelin has been used
extensively for this purpose in recent
years. Normally the brood stock is also
penned permanently.
However, two potential problems exist.
In the first place, cheap fish for food is
becoming increasingly scarce, as most fish
are not utilized directly. Next, a labor-in-