NWT 2011-2015 - NWT Species at Risk

6.4
4. Data Sources
Fishes
and Methods – How did we rank species?
Arctic Grayling
Photo Credit:
P Vecsei
Fish are vertebrates, with gills, that live in water. Three
major groups of fish are recognised: the jawless fishes
(e.g., lampreys), the cartilaginous fishes (e.g., sharks and
skates) and all the others, bony fishes (e.g., chars, whitefishes,
and herring). Fish are excellent indicators of water quality and
ecosystem health. The presence or absence of certain species
can provide immediate clues about the conditions within
a given area. Fish are one of the most important food and
economic resources in the NWT. We are known for our trophy
sized fish, for healthy populations, and for delicacies.
In 2010, we reviewed all ranks for freshwater species and
updated the list of all marine fishes known to occur in the
NWT’s section of the Beaufort Sea and western Arctic Ocean.
Recent work includes the following initiatives.
Diversity of Ciscoes and Lake Trout
Shortjaw cisco is thought to occur in Great Slave Lake and
possibly in Great Bear Lake. Work to confirm this was initiated
on Great Slave Lake. This work has so far uncovered substantive
and previously unknown diversity of ciscoes in this large lake.
Preliminary results suggest that a shortjaw cisco-like form
occurs, a blackfin cisco-like form and at least three other forms
of cisco also occur in one bay of this large lake. Other bays
may hold similar or different forms. Future research is needed
to determine if these ciscoes are distinct species, if they are in
fact shortjaw or blackfin ciscoes, and how they are related both
to each other and to ciscoes found elsewhere. Similar work is
also being conducted in both lakes on diversity of lake trout,
which appears to also exhibit different forms.
Salmon Collection Project
Fisheries and Oceans Canada (DFO) is collecting samples of
salmon for research. The study aims to chart the occurrence
of vagrant salmon and to ultimately relate the movement
of salmon in the NWT to potential climatic changes in the
Pacific Ocean and the western Arctic. DFO is working with
local resources councils throughout the NWT to obtain as
many samples as possible. Salmon can be turned in for rewards
to local DFO offices, attention to Fisheries Management
staff. Documenting any evidence of occurrence and possible
colonisation of the western Arctic Ocean by vagrant species
and ultimately relating this to climate change is a key part of
the study. This will allow for a better understanding of how to
manage new fisheries if they arise.
Research on Broad Whitefish
Broad whitefish is a key food fish of the lower Mackenzie River
basin. Research includes work to understand the different
forms present (lake-dwelling, river-dwelling, and sea-run or
anadromous) and how these mix together when in fresh water.
This work contributes to better understanding of fisheries and
improves our management of whitefish.
Research on Burbot
Research is being conducted to better understand the ecology of
this common but poorly understood species, which is important
in many local fisheries. Focus of this research is on reproduction
and the importance of sound to their mating behaviour, as well
as understanding the role of burbot in food webs.
Research on Chars
Both bull trout and dolly varden occupy key habitats within
the Mackenzie River basin, however, their distributions are
poorly known. This project is mapping the distribution of
bull trout in the context of other species of char, such as
dolly varden, and is helping to ensure proper identification
of this group of fish. Bull trout is presently being assessed
by COSEWIC. Research on dolly varden in the NWT includes
38 NWT Species 2011-2015