Journal
of Fish Biology, 60(4): 933-950Evidence for genetic
differences in the offspring of two sympatric morphs of Arctic charr
A. Klemetse, J.M. Elliott, R. Knudsen, P.
Sørensen-2002
Journal
of Fish Biology, 60(4): 933-950
Abstract :
The sub-arctic Lake Fjellfrøsvatn,
northern Norway, has two morphs of Arctic charr that are reproductively
isolated because they spawn 5 months apart. The smaller
morph (
14cm
LF) is confined to the profundal zone
of the lake and the larger morph is mainly littoral.
Three hypotheses were tested: (i) the offspring of the
profundal Arctic charr grow slower than the offspring
of the littoral Arctic charr under identical conditions,
thus indicating a genetic basis for the slow growth of
the profundal Arctic charr in the wild; (ii) the wild
phenotypes of the two morphs are morphometrically
different and the differences are persistent in
the offspring; (iii) the offspring of the two morphs
have different behaviour traits under similar
treatments. The first hypothesis was rejected; offspring
of the profundal morph grew slightly better than offspring
of the littoral morph at 10°C in the laboratory. The
second and third hypotheses were supported by the
data. Wild-caught fish of the two morphs differed in
several morphometric characters and most of the
differences persisted in the offspring. In the laboratory,
offspring of the littoral morph were more active, more
aggressive and more pelagic than offspring of the
profundal morph and naive offspring of the profundal
morph were more effective in eating live chironomid larvae
than were offspring of the littoral morph. The data
for morphometry and behaviour, but not growth, provide
evidence for genetic differences between the two
Arctic charr morphs of Fjellfrøsvatn.
(Department of Marine and Freshwater Biology, The
Norwegian College of Fishery Science, University of Tromsø, Breivika,
N-9037, Tromsø, Norway, Tel.: +47 77644517; fax: +47 77646020; email: andersk@nfh.uit.no)