Barrie Creeks, Lovers Creek, and Hewitt's Creek Subwatershed Plan

The Barrie Creeks, Lovers Creek and Hewitt’s Creek Subwatershed Plan
are most often related to changes in land use through land development or intensified
agricultural practices, which can include: cutting of stream bank vegetation, excess
sedimentation and the interception of close-to-surface groundwater, all of which contribute to
cumulative change in tributaries. On-stream dams or barriers are also another significant factor,
as they warm downstream temperatures, act as a silt trap for sediment moving downstream
and prevent movement of fish to colder upstream reaches. The decrease in water quality also
tends to create a more suitable habitat for non-native fish species (such as brown trout and
rainbow trout) that may out-compete the native brook trout for resources.
Successful brook trout reproduction has specific physical requirements. Between October and
December, mature brook trout seek out areas of upwelling groundwater in the streambed to
spawn. These sites may be distributed evenly throughout a tributary or there may be very
limited locations where upwelling can be detected. While they prefer to spawn over a
gravel/sand substrate, the size of the substrate is of less importance than the presence of
upwelling activity. Eggs deposited in a ‘nest’ (commonly known as a redd) are flushed by
constantly moving interstitial groundwater which is stable in temperature and normally slightly
warmer than ambient stream temperature during the winter months. This condition allows the
eggs to develop more quickly, resulting in the emergence of larval brook trout in late March.
Compared to other resident fish species and to the non-resident trout species, this is very early
in the season and provides the young brook trout with a competitive advantage in terms of food
availability and time to grow and mature.
Despite their sensitivity to change, brook trout
and their habitat respond well to stream
rehabilitation. Efforts are focused primarily on
reducing thermal and sediment impacts and
improving in-water habitat. Typical techniques
like adding instream structures, such as bank
stabilizers, deflectors, cedar sweepers,
overhead cover, half logs, and strategic rock
and gravel placement, are used. In addition,
planting stream banks with appropriate native
vegetation, restricting livestock access with
fencing and protecting spring seeps adjacent to
the channel are often undertaken as part of a
stream rehabilitation plan. These methods are
particularly effective where groundwater
continues to provide baseflow and where other
local biophysical features have not been
impacted.
Typical tributary that supports brook trout
Today, it is important that we protect, restore and maintain current and historic brook trout
habitat, as these are areas that are, or have the potential to be, high quality aquatic habitats, in
terms of both water quality and habitat features. As such, additional efforts need to be
undertaken to protect the tributaries of the Lake Simcoe watershed that support these native
fish.
Chapter 5: Aquatic Natural Heritage 215