Table 1: - Nechako White Sturgeon Recovery Initiative

Table 1: Important areas for white sturgeon life history stages, Nechako River, B.C.

Note: The table below uses the two designations of Critical and Important for identified habitats. Critical Habitat is habitat that is essential to white sturgeon survival.

Important Habitat is habitat that is thought to be extremely significant, but at this time lacks sufficient information to designate it as Critical.

Note: It should be noted that we are planning for recovery and therefore will need the minimum number of disproportionably used habitats.

Note: Proposed studies are studies that have been identified to increase our knowledge in areas of recognized Critical Habitat. Required studies are studies that are needed to confirm whether Important Habitat areas are indeed Critical Habitat areas.

Life Requisite Important Important Areas

Map

Comments

Period

Reference

Spawning and Egg

Incubation

Late May to late July

Braided section of Nechako River near Vanderhoof (km 134.8-141) -

Critical

The only confirmed location for spawning in the Nechako River system is the braided section of river near Vanderhoof. The precise location of this spawning area might change from year to year depending on flow conditions.

Data indicate that white sturgeon eggs do not drift far, so incubation habitats are assumed to be coincident with spawning habitats.

This area will likely be deemed as critical habitat for spawning and incubation on an annual basis during May and June.

There is quite a bit of intervening habitat that may be suitable. Eggs have been captured at km 138.5. Tagged fish have also been observed above this point, however no eggs have been captured. At Km 141 there is another braided section where the channel splits again that may also be suitable.

Proposed Studies:

 Examining rate of survival

 Habitat Use (drift dynamics of eggs)

 In-river temperature cycling

 Habitat limitations/changes in geomorphology

 Sediment dynamics upstream of the bridge

 Long term sediment trajectory

 Relationship between flow regime and habitat state (present and retrospective)

 Manipulation of spawning site to increase egg and larval survival

 Flow/sediment dynamics/mapping

 Sediment sources and management

NWSRI – Critical Habitat Meeting Minutes Oct/Nov 2008

Braeside (roughly km 162.5-164.3) -

Important

Upstream of the Nautley (near

Diamond Island – roughly km 191-

213) - Important

Important staging hole area. This is a potential spawning area based on data from 2007. Fish move here during times of higher water. Historically this may have been an area that was just as important as Vanderhoof. Mature fish were there at the same time spawning was occurring downstream in 2007. This is strong evidence to say that this is indeed a spawning site. Afterwards the fish dispersed in the same way – and therefore all the behaviours were similar to the fish spawning downstream.

This area is a candidate as Critical Habitat for sturgeon spawning and egg incubation.

We consider this important habitat but we lack sufficient information to designate this critical.

Required studies:

Spawn Monitoring study

In 2007, mature males were staging in this area. This may be an area of important or critical habitat, but further studies are required.

Required studies:

Spawn Monitoring study


Life Requisite

Rearing

Post-hatch

Larval

0-12 days pre-feeding and 12-40 days feeding

Important

Period

May to

July

Important Areas

Occurs in immediate vicinity of egg incubation area (braided section at

Vanderhoof) and within a short distance downstream (km 132.8-139)

- Critical

Map

Reference


Important

Comments

Larval development includes the period from hatch to exogenous feeding (0 to 12 days). Critical habitat during this period will likely include the braided section of the Nechako River near Vanderhoof, extending downstream beyond the boundaries of the spawning and incubation area, though its lineal extent cannot be defined with certainty at this time.

Although the braided area at Vanderhoof is functioning as spawning habitat, it is believed to be non-functional as habitat for incubation and very early life stages.

At present we don’t have enough information to differentiate 12-40 days from

0-12 days and the range may extend further for 12-40 days.

This habitat is likely critical on an annual basis during May, June and July.

Km 141 to km 132.8 – this is based on available habitat with suitable substrate.

Same specifics as Spawning Habitat section.

Required studies:

Confirmation of sue by post-hatch larvae (0-40 days)

Proposed studies (for all areas):

 Note: many of the studies proposed for the spawning/egg section also pertain to this life requisite

 Feeding

 Habitat (suitability, drift dynamics & where do they go)

 Imprinting – does it occur and at what age

 Habitat and substrate - needs (flow, velocity (S), predation)

 Larval drift – factors affecting drift and larval growth

 Methods to increase total production of 12 day olds (increased survivability, decreased predation, release at higher velocity)


Life Requisite

Early

Juvenile

(40+ days -

Young of the

Year to 2 years – 40 cm)

Important

Period

All year

Important Areas


Critical

Map

Reference


Important

Upstream and downstream of Km

110 (kms 109-110.5) aka Keeler’s Point

- Critical

Sinkut River confluence (115 – 117 km) – Critical

Comments

Follows shift to exogenous feeding; may represent next most critical stage in early survival (i.e., suitability and availability of food items in rearing habitats or predation rates are unknown).

Research has shown that Young of Year prefer sand substrates perhaps in the main channel.

An important attribute to define with respect to early juvenile habitat needs is connectivity.

Critical habitat during the early juvenile stage (21 days to 2 years) will likely be deemed critical year-round.

Proposed studies (for all areas identified in this life requisite):

 Migration (Post winter migration & Tributary use)

 Increasing Survival (examining cannibalism and density dependence and carrying capacity)

 Investigation of larval survival from age 40 days to age 1+.

Since this is a potential spawning area based on data from 2007, it may also be important habitat for early juvenile white sturgeon. Following confirmation of this as a spawning area, this area could be designated critical habitat for early juvenile white sturgeon.

Required study:

Confirmation of use by early juveniles

Three critical areas have been identified between km 109 and the Vanderhoof spawning area - upstream and downstream of km 125, upstream and downstream of km 116 and upstream and downstream at km 110.

Holes and the connecting environment between these holes (i.e., the entire reach) in these areas are critical.

There has been confirmed use of young juveniles at Kms 110, 116 and 125.

See km 109-110.5


Leduc Creek confluence (122 – 127 km) - Critical

Between Kms 131.8-132.4 (aka

Culvert Hole) - Critical

Between Kms 129-130 (aka Powerline

Crossing) - Critical

See km 109-110.5

Confirmed use of fish < 1m in length, This is the first available deep water site downstream of spawning area.

Confirmed use of fish < 1m in length, This is the first available deep water site downstream of spawning area.

Additional Important holding and feeding areas include Sturgeon Point in the

Stuart River (based on captures and historical information, (Toth and Yarmish

2003; Carrier Sekani Tribal Council 2005), confluence of Tachie and Middle rivers, and Pinchi Bay in Stuart Lake. Despite extensive sampling and telemetry, the area from Vanderhoof to Engen and Nadleh has been little used from 1995 to 1999, yet this continues to be an area where fish are observed in FSC fisheries and during helicopter flights. Other sites likely include the confluences of streams where sockeye concentrate.


Life Requisite

Juveniles/Ad ults

(greater than

2 years)

Important

Period

All year

Important Areas


110 (kms 109-110.5) aka Keeler’s

Point- Critical

Map

Reference

Comments

Three critical areas have been identified between km 109 and the Vanderhoof spawning rear - upstream and downstream of km 125, upstream and downstream of km 116 and upstream and downstream at km 110.

*

Holes and the connecting environment between these holes (i.e., the entire reach) in these areas are critical. Confirmed use.

Connectivity is important, as fish need to have connectivity to all points within the watershed.

Proposed studies (for all areas identified in this life requisite):

 Factors affecting habitat suitability (i.e., substrate, flow, photoperiod, temperature, etc…)

 Identifying methods to improve habitat suitability (i.e., microchemistry, population level analyses, mitochondrial DNA, etc…)

 Identification of other sites

See km 109-110.5 Sinkut River confluence (115 – 117 km) – Critical

Leduc Creek confluence (122 – 127 km) – Critical

Nechako River at 67 – 79 km Isle

Pierre - Critical

See km 109-110.5

Nechako River at 89 – 95 km - Critical

Trembleur and Stuart Lakes –

Confirmed Use – Critical

Note: Stuart Lake – lower half for habitat use, entire lake for productivity - Critical

Fraser Lake – confirmed use throughout the lake - Critical

Confirmed high use site

Required studies:

Juvenile Sampling


Trembleur, Stuart, Fraser Lakes are all critical as they are important feeding areas for white sturgeon. In addition, access and the productivity of the lakes are also essential to white sturgeon survival and recovery. Therefore, the designation takes into account both the direct use of the lakes for feeding and the indirect, but equally important, attribute of connectivity and food production/abundance.

Fish spend significant time in these areas and usually do this in between spawning (however, this is not limited to spawners).

Stuart Lake: The lower half of Stuart Lake is critical, but at this time we do not know about the rest of the lake. It should be noted however, that the whole lake has to be functional in order for there to be adequate productivity.

Is should also be understood that while these areas are critical in terms of productivity and access, these attributes are not limited to these locations.


Francois Lakes. Takla and Tezereon –

Suspected Use - Important

Francois, Takla and Tezereon Lakes are suspected for use but are also important in terms of productivity. The productivity in these lakes ultimately affects food production in the lakes as well as food production in locations other than lakes. The attribute of productivity (i.e., salmon productivity) is critical to the recovery of the species.

Required study:

Confirmation/degree of use

Additional holding and feeding areas include Sturgeon Point in the Stuart River

(based on captures and historical information, (Toth and Yarmish 2003; Carrier

Sekani Tribal Council 2005), confluence of Tachie and Middle rivers, and Pinchi

Bay in Stuart Lake. Despite extensive sampling and telemetry, the area from

Vanderhoof to Engen and Nadleh has been little used from 1995 to 1999, yet this continues to be an area where fish are observed in FSC fisheries and during helicopter flights. Other sites likely include the confluences of streams where sockeye concentrate. Important

Required study:

Confirmation/degree of use

Note: There is some uncertainly about the designation of lakes, whether it is a portion or the whole lake. Tola will discuss this further with her CH team to help provide some guidelines and clarity.


Life Requisite

Overwintering

(Adults and

Juveniles)

Important

Period

October to May

Important Areas


110 (kms 109-110.5) Keeler’s Point-

Critical

Sinkut River confluence (115 – 117 km) - Critical


Stuart Lake (Tachie River confluence ) – Critical

Stuart Lake (Pinchi Bay ) – Critical

Trembleur Lake (Middle River

Confluence with Trembleur Lake )-

Critical

Isle Pierre (65-79 km) - Important

Trembleur, Stuart and Fraser Lakes –

Suspected Use – Important

Francois Lakes. Takla and Tezereon

Lakes – Suspected Use - Important

Map

Reference





Comments

Proposed studies:

Degree of over wintering use in Tachie River.


Proposed studies:

Degree of over wintering use in Pinchi Bay.

The designation is based on the capture of few fish; and similarities between this location and the documented use of the Tachie R. confluence with Stuart

Lake.


Required studies:

Degree of over wintering use of Stuart, Trembleur and Fraser Lakes

Required studies:

Degree of over wintering use of Francois Lakes. Takla and Tezereon Lakes needs to be studied.


Life Requisite

Staging by

Pre-spawners

Important

Period

November to July

Important Areas


110 (kms 109-110.5) Keeler’s Point-

Critical

Sinkut River confluence (115 – 117 km) – Critical


Nechako River Kms 129-134.8 -

Critical


Critical


Important

Map

Reference

Comments

Nechako River Upstream and Downstream of kms 125, 116, 109-111, all seem to have mature fish that hold there post winter use.



Just downstream of confirmed spawning location – staging has been observed in this area.

Confirmed spawning location.

Braeside is a suspected staging area - needs more study and may have had more use at higher historical flows.

Required study:

Confirmation of staging


Table 2 Summary of known or suspected uses of identified habitats by white sturgeon in the Nechako River, BC.

Suspected is based on data, P is based on attributes we think are available

Confirmed (√), Suspected (S), or Possible (?) Use by Life Stage and

River Area

Degree of Use (H=High, M=Moderate, L=Low)

Spawning

Larval

Rearing

Juvenile

Rearing

Juveniles/

Adults

Over

Wintering

Braided section at

Vanderhoof km

138.8-145

Braeside km 154-

155

Upstream of

Nautley (near

Diamond Island)

Sinkut River

Confluence (km

115-117)

Leduc River

Confluence (km

122-127)

Nechako River km

65-79


89-95


109-111


128-129


129-138.8

Isle Pierre (km 65-

79)

Stuart River

(Sturgeon Point)

Stuart Lake (Tachie

(√) H

(S) H

(?) L

(√) H

(S) H

(?) L

(√) H

(√) H

(√) H

(√) H

(√) H

(√) H

(√) H

(√) H

(√) H

(√) H

(√) H

(√) H

(√) M

(√) H

(√) H

(√) H

(√) M

(S) M

(S) M

(√) M

Staging

(√) H

(√) M

(√) H

(√) H

(√) M

(√) H


River Confluence)

Stuart Lake (Pinchi

Bay)

Stuart Lake (lake area below the

Tachie R. confluence)

Middle River

Confluence with

Trembleur Lake

Trembleur Lake

Francois, Takla and

Tezeron Lakes

Fraser Lake (entire lake)

(√) H

(√) M

(√) M

(√) M

(S) M

(√) M

(√) M

(S) M

(S) M

(S) M

(S) M


CRITICAL HABITAT ATTRIBUTES

Note: These attributes are based on current understanding and will be refined every year

Definitions:

HIGH – significant annual use

MEDIUM – significant intermittent use

LOW – suspected historical use but unconfirmed based on either degree or frequency of sampling or based on degree of present use

SPAWNING

 Flows: o localized velocities in specific reaches which can be the attractant or driver for spawning site selection - Medium to High o timing based on hyrdograph: it is preferential for sturgeon to spawn at the timing of the historic freshet - High o level of discharge - High

 River flow interaction with river form (flow, substrate and sedimentation): creating appropriate morphological conditions for sturgeon to spawn – High

 Temperature: increasing thermograph to near 14C instigates the cue for spawning – High

 Turbidity: turbidity could possibly impact spawning site selection – Low

 Substrate: appropriate substrate is created by the interaction between flow and river morphology as well as bed load dynamics. Interstitial habitat must also be available given our current understanding – High

 Water quality and chemistry: this includes oxygen, organics, pollutants and pathogens – Low

 Isolation from disruption and disturbance - High

LARVAL REARING

 Flows: o it is suspected that low velocity habitats are important - High o level of discharge - High

 River flow interaction with river form (flow, substrate and sedimentation): creating appropriate morphological conditions for larval rearing – High

 Temperature: this is an important attribute that affects growth rate and food abundance. Rapid fluctuations and temperature extremes could be detrimental to larvae – High

 Turbidity: turbidity could possibly affect larval survival by decreasing predation – Low


 Water quality and chemistry: this includes oxygen, organics, pollutants and pathogens, and in the case of larvae, this attribute is ranked higher than for other life stages since larvae represent the most sensitive life stage and are unable to move location - Medium

 Food availability: fresh clean gravel with appropriate food. Presently there is a lack of knowledge around habitat use for larva at 12-40 days - High

 Appropriate habitat (to avoid predation): includes both substrate and cover. Substrate is just one feature that allows larvae to escape predation. Other types of cover are also important. Predation rates are probably high, so habitat attributes (i.e., edges, depth, velocity, interstitial spaces, vegetation, woody debris) that diminish predation are important - High

 Connectivity: connectivity between habitats is an important factor to larval survival – High



JUVENILE REARING

 Flows: o deep sites with low velocity - High o level of discharge - High

 River flow interaction with river form (discharge and geomorphology): early juveniles seem to preferentially occupy deeper habitat (i.e., deep holes) – High

 Temperature: this attribute affects growth rate and food abundance. Rapid fluctuations and temperature extremes could be detrimental to larvae – High

 Turbidity: turbidity could possibly decrease predation – Low


 Water quality and chemistry: this includes oxygen, organics, pollutants and pathogens - Low

 Food availability: fresh clean gravel with appropriate food - High

 Appropriate habitat to avoid predation: includes depth, cover and food abundance - High

 Connectivity: connectivity between habitats is an important factor to juvenile survival – High

 Isolation from disruption and disturbance - Low

JUVENILES/ADULTS (RIVER)

 Flows: adults and juveniles (over 2 years) show a preference for deep sites with low velocity – Low

 Food availability: sufficient quality and quantity of food for survival - High

 Connectivity: connectivity between habitats is an important factor to juvenile and adult survival – High



JUVENILES/ADULTS (LAKES)

 Food availability: Lakes are essential for providing food for white sturgeon. This includes mussels, salmon (particularly Sockeye) and other fish. In addition, suitable escapement of sockeye salmon to ensure lake productivity is necessary – High

 Connectivity: access to lakes is also very important – High


OVER WINTERING (RIVER)


 Depth: deep holes – High

 Connectivity: this may be particularly of issue during extreme low flows - High

 River flow interaction with river form: interaction of discharge and river geomorphology – High


OVER WINTERING (LAKES)

 Critical over wintering attributes in lakes are currently unknown, although it is highly suspected that lakes are used as over wintering habitat.


STAGING

 Flows: o localized velocities in specific reaches which can be the attractant of driver for staging and subsequent spawning site selection - Medium to High o timing based on hydrograph: it is preferential for sturgeon to spawn at the timing of the historic freshet - High o level of discharge - High

 Temperature: increasing thermograph to near 14C instigates the cue for staging and spawning – High

 Depth: precise depth criteria are not yet known, although sufficient depth to allow for sturgeon passage or access to spawning areas is essential - High

 Connectivity: proximity to spawning and over wintering sites – High



Table 1: - Nechako White Sturgeon Recovery Initiative

Table 1: Important areas for white sturgeon life history stages, Nechako River, B.C.

CRITICAL HABITAT ATTRIBUTES

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Table 1: - Nechako White Sturgeon Recovery Initiative

Table 1: Important areas for white sturgeon life history stages, Nechako River, B.C.

CRITICAL HABITAT ATTRIBUTES

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