Environmental and evolutionary correlates of morphological, genetic, and lifehistory variability in extreme northern populations of Arctic charr (Salvelinus
alpinus)
Dr. Jeff Hutchings* and David Hardie
Department of Biology, Dalhousie University, Halifax NS B3H 4J1
*Principal investigator: Email: Jeff.Hutching@dal.ca ; Phone: (902) 494-2687 ; Fax:
(902) 494-3736
The species range of Arctic charr (Salvelinus alpinus) reaches from Maine to
northern Ellesmere Island, at higher latitudes than any other freshwater fish species. This
species, and others in the same family (trout, charr and salmon), are known to exhibit
extreme variability in many characteristics including behaviour (e.g. migration,
spawning, feeding), size, and growth rate. This variability occurs both across different
geographic areas, as well as within single populations. For example, it is quite common
for Arctic charr populations, especially in the far northern lakes, to b made up of several
different “types”, each specialized for different ways of surviving in their environment.
This can include “dwarf charr”, which don’t have to grow very large before they can start
spawning, and which stay small throughout their lives, medium-sized charr specialized
for feeding on different food sources, and large cannibalistic charr, which grow more
quickly and specialize in eating other charr. In many cases, it is not known whether these
different “types” of charr spawn with each other, or whether they are separate spawning
sub-populations. In many of these lakes, especially in the Arctic, charr are the only fish
species present in these lakes, so the populations are often managed as a single unit.
When two or more charr “types” do not spawn together, they are really behaving like
different species, and should be managed separately. By understanding how many
different charr “types” exist in different lakes, we will have a better understanding of the
amount of diversity that is present in the lake, which will allow for better management.
In order to study this question, we will collect samples and data from charr in
Lake Hazen and other lakes in Quttinirpaaq National Park and work towards two main
goals. The first will be to compare the amount of variability in life history (e.g. age-atmaturity, frequency of spawning, number of eggs produced), body size and shape
(different “types” of charr are often of different sizes and are even shaped differently),
and genetic variability (if different “types” of charr do not spawn together, then we will
be able to measure genetic differences between them that will show that they are not
closely related). We propose to carry out this research in Quttinirpaaq National Park
because we expect that these differences will be very strong in these northernmost
populations of charr, because food is so scarce in these lakes that the charr must
specialize to take advantage of particular food or habitats. Once we understand variation
in these features, our second goal will be to try to understand which environmental (e.g.
lake size, depth, food) or historical (e.g. ice-ages, number of charr which initially
colonized the lake, etc…) caused different charr “types” to arise in these lakes. This may
help to predict which other lakes might contain numerous charr “types”, information that
will be useful for Parks Canada’s management policies in Quttinirpaaq National Park.