research on sahtu(great bear lake) fisheries and the ...sdw.enr.gov.nt.ca/nwtdp_upload/sahtu...
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K.L. Howland, C.P. Gallagher, L. Chavarie, Y. Janjua, M. LeClaire D. Leonard, C. Podemski, D. Simmons, W. Bayha, R.F. Tallman, and W.M. Tonn
Research on Sahtu (Great Bear Lake) fisheries and the aquatic ecosystem:
2000-2015
Jane Baptiste Doug Baton Moise Beyonnie Morris Betsidea Gloria Gaudette Les Harris Bruce Kenny Greg Kenny Hughie Kenny Jonas Kenny Mike Legge Morris Lennie Mike Low George Menacho Morris Modeste Nathan Modeste Melissa Lindsay
Isreal Neyelle Lyle Neyelle Zoya Pawlychyn Aaron Swietzer Clyde Takazo Lucy Ann Takazo Freddie Vital Cameron Yukon Cyre Yukon Tyrone Yukon Charity Yukon Chris Yukon Jean-Guy Chavarie Archie Vital John Betsidea Barbara Yukon
Field Work 2000-2014
BRANSON’S LODGE
Areas fished by lodges
ARCTIC CIRCLE LODGE
KEITH ARM McVICAR ARM (TAH – 1500)
GREAT BEAR LODGE
PLUMMERS GREAT BEAR LAKE LODGE
GREAT BEAR TROPHY LODGE
DELINE (FORT FRANKLIN)
GREY GOOSE LODGE
KEITH ARM
Subsistence use only
DEASE ARM (TAH – 2000)
SMITH ARM (TAH – 2500)
Management zone boundaries
PLUMMER’S GREAT BEAR LAKE LODGE (Original location closed 1968)
1) Fisheries independent monitoring of relative abundance, catch rates and biological indicators of harvested and unharvested large bodied fish species in all areas of GBL
Track changes that may occur with changing harvest levels, development and the environment (cumulative impacts)
Stock assessment - model
sustainable harvest levels
Tirato (Smith Arm)
2006, 2011, 2016 Kwit la
(McTavish Arm) 2004, 2009, 2014
Tugacho (Dease Arm)
2005, 2010, 2015
Sahtu (Great Bear
Lake)
Tirato (Keith Arm)
2000-2007, 2012
Turili McVicar Arm
2003, 2008, 2013
Methods
multi-mesh and large (5 inch) mesh gillnets (for consistency with previous studies)
Sample fish for biological characteristics (length, weight, age, sex, maturity, etc.)
dryfish from sampled fish in remote camps, for community distribution
Collect environmental information: temperature, depth, pH, clarity, weather conditions
Local sampling technicians (2-5) from the community of Deline hired to assist with the field component each year.
otoliths
muscle
gill rakers
gonads pectoral fin
Life-history
Diet
Life-history (fecundity, maturity)
stomach
Diet
Morphology
Genetics + Life-history (age)
stomach
Diet
muscle
Diet
gonads
Biological Sampling for Fish
Weight Length
Area of Great Bear LakeKeith McVicar McTavish Dease Smith
Age
(yea
rs)
0
10
20
30
40
Mean (+1 std) 1984-85 Mean (+1 std) 2000-2006 Mean (+ 1 std) 2007-2011 Mean (+ 1 std) 2012-2016
Trout Mean Age – Lake-wide comparison
Spawner
Resting
Spawner
Resting
Females
Males
Lake Trout Maturity % Spawners in adult component of population: Smith Arm: Female 29%, Male 53% Dease Arm: Female 48%, Male 77% McTavish Arm: Female 18%, Male 52% Keith Arm: Female 30%, Male 55% McVicar Arm: Female 43%, Male 82%
Minimum age at maturity:
Female Male Smith 10 13 Dease 12 12 McTavish 15 14 McVicar 14 13 Keith 16 13
• Annual reporting to SRRB and DRRC, meetings
• Contributions to associated follow-on studies
• Need for formal science review (DFO Regional Advisory Process (RAP) meeting) and publishing through DFO Canadian Science Advisory Secretariat.
• Recommend continued monitoring to allow for detection of change
Lake trout
Harvested stocks (fin clips from lodges): • Lack of differentiation among arms due to low levels of gene flow (12/596 =
first generation migrants), recent colonization and large founding populations
2) Compare genetic relationships among fish from different arms of GBL to determine stock structure as it relates to current management zones within GBL
Harris, L., K. Howland, M. Kowalchuk, R. Bajno, M. Lindsay and E. B. Taylor. 2013. Microsatellite and mtDNA Analysis of Lake Trout, Salvelinus namaycush, From Great Bear Lake, Northwest Territories: impacts of historical and contemporary evolutionary forces on Arctic ecosystems. Ecology and Evolution 3:145-161.
Lake trout
Different morphotypes (assessment samples): • morphotypes of Lake Trout from GBL are genetically differentiated • but…they are still genetically more similar to one another than to outside
populations • colonized GBL from a single glacial refugium – intra-lake divergence
2) Compare genetic relationships among fish from different arms of GBL to determine stock structure as it relates to current management zones within GBL
Harris,L., L. Chavarie, R. Bajno, K. Howland, S. Wiley, W. Tonn, and E. Taylor. 2014. Evolution and origin of sympatric shallow-water morphotypes of Lake Trout, Salvelinus namaycush, in Canada's Great Bear Lake. Heredity (avail. online, accepted July 14, 2014)
Cisco
Different morphotypes (assessment samples): • similar to trout, morphotypes of cisco from GBL are genetically differentiated • morphs within a lake genetically more similar to one another than to outside
populations • similar pattern in lakes across North America • only 2 areas of GBL analysed
2) Compare genetic relationships among fish from different arms of GBL to determine stock structure as it relates to current management zones within GBL
Turgeon, J., S.M. Reid, A. Bourret, T.C. Pratt, K.L. Howland, A.M. Muir, J.D. Reist. Morphological and genetic variation in Cisco (Coregonus artedi) and Shortjaw Cisco (C. zenithicus): Evidence for repeated sympatric origin of Shortjaw Cisco in deep inland lakes. Conservation (submitted)
Further work
• Lake wide analysis of cisco • Analysis of whitefish
2) Compare genetic relationships among fish from different arms of GBL to determine stock structure as it relates to current management zones within GBL
zls
2002
Age (years) 0 5 10 15 20 25 30 35 40 45
Fork
leng
th (m
m)
0
200
400
600
800
1000
1000 mm
600 mm
3) Documentation of morphological variation and ecological roles of major fish species:
Lake Trout Growth
Body Shape
Fin and Body Lengths
Head Shape
3 morphs identified
4th morph: rare; difficult to identify as a distinct cluster, but distinguished using MANOVA
Discrimination Analysis:
N=555 adults UPGMA cluster
88-93% classification success
Chavarie, L., K. Howland and W. Tonn. 2013. An exceptional case study of Lake Trout, Salvelinus namaycush, diversity: the coexistence of multiple shallow-water morphotypes in Great Bear Lake, NT. Transactions of the American Fisheries Society 142:814-823.
ƛ = 0.075 p≤0.01 (81 %)
ƛ = 0.17 p≤0.01 (88 %)
ƛ = 0.24 p≤0.01 (74 %)
DF2
DF1 CV1
ƛ = 0.078 p≤0.01 (73%)
CV2
ƛ = 0.086 p≤0.01 (72 %)
ƛ = 0.094 p≤0.01 (59 %)
Keith
McVicar
McTavish
Dease Smith Significant body shape variation
within a morph across arms
Suggests parallel evolution among arms or several colonization events
Morph 1 Morph 2 Morph 3
Chavarie, L., K. Howland, L. Harris and W.Tonn. 2014. Polymorphism in Lake Trout in Great Bear Lake: intra-lake morphological diversification at two spatial scales. Biological Journal of the Linnaean Society, (avail. online, accepted July 24, 2014)
Sahba forms in shallow water (Tahdǝ gosahba )
Dárélı GoSahba (named for outflow of Great Bear Lake) Sahba that will grow large – scientists identify this type as having a longer head and smaller fins.
Sahba k’áht’a (fin) – scientist identify this type as having a shorter head and intermediary fins.
Sahba k’áht’a Nedǝ *(with long fın) Also lives ın deep water – scientists identify this type as having a deeper caudal peduncle and longer fins
Sahba Yéhkw’ene Hızégǝ* (curved jaw) A newcomer (~20 yrs.) – scientists identify this type by the large lower jaw; it is rare and mostly in one area of Great Bear Lake
Sahba Dek’odze (red) Only seen in the spring and in fall in the shore – not identified as a distinct type by scientists; known as a spawner
*New term developed as cross-cultural tool for dialogue about morphology ; forms known but no Dene name existed
Diet- Fatty acids
Discriminant analysis: λ= 0.031 p≤0.01 DF1
DF2
Morph 2
Morph 4
Morph 1
Juvenile
Morph 3
Significant distinction among morphs, especially Morphs 2 and 4
Some overlap among Morphs 1, 3 and
juveniles
Chavarie, L., K. Howland C. Gallagher and W. Tonn. 2014. Fatty acid signatures and stomach contents of four sympatric Lake Trout: assessment of trophic patterns among morphotypes in Great Bear Lake. Ecology of Freshwater Fish (avail. online, accepted September 17, 2014)
Morph 2
Morph 3
Diet: Stomach contents
Morph 4 Rel
ativ
e in
dex
0
10
20
30
40
50
60
70
80
90
100
Fish Invertebrate Benthic Pelagic Surface
0
10
20
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50
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80
90
100
Fish Invertebrate Benthic Pelagic Surface
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Fish Invertebrate Benthic Pelagic Surface
0
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Fish Invertebrate Benthic Pelagic Surface
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Fish Invertebrate Benthic Pelagic Surface0
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Fish Invertebrate Benthic Pelagic Surface
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Fish Invertebrate Benthic Pelagic Surface0
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Fish Invertebrate Benthic Pelagic Surface
Morph 1
Morph Age-at-
maturity
(yrs)
Length-at-
maturity
(mm)
Immature
growth rate
Adult
growth rate
(K)
Reproduction
investment
Adult L∞
1 17.4 593.4 22.2 0.030 0.090 740.8
2 20.2 703.7 22.1 0.016 0.048 1371.9
3 18.6 581.7 22.3 0.028 0.086 773.7
4 20.2 640.9 22.0 0.027 0.081 809.6
Trout Life history - Biphasic model: results
Classical life-history trade-off
Comparable to piscivore life-history
Intermediate = Comparable to large benthic morph of Arctic Char?
Intermediate = surprising for the most specialized diet?
Chavarie et al. submitted (Journal of Great Lakes Research)
Morph Age-at-maturity Length-at-maturity Adult L∞
1 17.4 593.4 740.8
2 20.2 703.7 1371.9
3 18.6 581.7 773.7
4 20.2 640.9 809.6
South 7.3 454 647
North 10.4 439 647
Trout Life history - Biphasic model
McDermid et al., 2010 Chavarie et al. submitted (Journal of Great Lakes Research)
• narrower interorbital • longer trunk and dorsal • longer gill rakers • shorter lower arch • shorter caudal peduncle
• wider interorbital •shorter trunk and dorsal •shorter gill rakers • longer lower arch • longer caudal peduncle
• shorter, narrower caudal peduncle* • longer snout • shorter lumbar length • longer pectoral fins* • deeper body*
• longer, wider caudal peduncle • shorter snout • longer lumbar length • shorter pectoral fins • shallower body
DFA Axis 1 (68.7%)
-6 -4 -2 0 2 4 6 8
DFA
Axis
2 (2
7.5%
)
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Keith Arm - ShallowKeith Arm - DeepDease Arm - ShallowDease Arm - Deep
92.2% classification success
Wilks' Lambda = .039 Chi-square, p<0.0001
Cisco Morphometric Variation
Cisco diversity in diet
Supported by gut contents, fatty acids, stable isotopes
Shallow (<50 m)
Deep (50-100 m)
Mysis relicta
Copepods
Size at Age
Age
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Stan
dard
leng
th (m
m)
50
100
150
200
250
300
Keith Arm - ShallowKeith Arm - DeepDease Arm - ShallowDease Arm - Deep
Howland, K., C. Gallagher, D. Boguski, L. Chavarie, J. Reist, B. Rosenburg and S. Wiley. 2013. Variation in morphology, life history and ecology of cisco in Great Bear Lake, Northwest Territories, Canada. DFO Can. Sci. Advis. Sec. Res. Doc. 2013/106. v + 40 p. ; M. LeClaire, MSc.
4) Understanding spatial variation in the aquatic ecology of Great Bear Lake:
• Build on existing time series for large-bodied fish
species to address questions regarding stock status & sustainable harvest levels
• Address knowledge gaps regarding the lake
ecosystems & the relationships of different ecosystem components to fisheries production
• Develop baseline from which to assess impacts of
climate change & other anthropogenic drivers on lake ecosystems & harvested fish
Methods - Ecosystem Sampling Design Inshore (0-2 m)
Littoral (3-20 m)
Pelagic-profundal (21-50 m)
Pelagic-profundal (51-100 m)
Pelagic-deep profundal (100-150 m)
Depth Zone
Water quality
Zooplankton (plankton net)
Benthic Inverts (Kick, Ponar grab)
Fish (gill nets)
0-2 m Seine only
3-20 m
21-50 m Lower/ Upper Lower/ Upper
51-100 m Lower/ Mid/ Upper Lower/ Mid/ Upper
100+ m Lower/ Mid/ Upper Lower/ Mid/ Upper
Composition, Abundance, Biomass
Composition, Abundance, Biomass
Composition, Abundance, Biomass, Demographics
Temp, Chla, DO, pH, Tubidity, Conductivity
Community-based monitoring sites
Off shore (60 m depth) temperature array; zooplankton; benthic invertebrates
Nearshore benthic/ terrestrial invertebrates
X Deline
Keith Arm
(Johnson 1975 JFRBC)
Development of thermocline in 2012 -14
Mctavish Arm 23-Jul-2014
Benthic invertebrate abundance Great Bear lake 2012
0
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1000
Red (0-2 m) Yellow (3-20 m) Green (21-50 m) Purple (51-100 m) Blue (100+ m)
Num
ber o
f aqu
atic
inve
rtebr
ates
in a
sam
ple
Sampling strata
Kick Net Ponar Grab
Local Fisheries- Traditional Ecological Knowledge Environment, human uses and related stressors
Stressor Great Bear Lk Great Slave Lk Climate change Major/
Change in Ice Free period (almost 3 weeks in 30 years) No direct major impact on fisheries yet
Major, Change in ice condition Habitat disturbance, Fish diseases, Change in migration Subsistence: Negative/dangerous in winter Commercial: Positive, longer season
Water level No Major, impact on catches (change in fishing locations, spawning, migration)
Pollution / Water quality No, Well Controlled Major, Fish diseases & contamination
Mining No now Major, water level change, contamination
Commercial fisheries No Minor, Cullage
Sport fisheries Minor (C&R) Minor, C&R mortality
Tourism No Little, Speed boats, Spawning grounds
Transport No Little, Spill
Janjua et al.
Other highlights: • New and updated information on species distribution patterns
and communities
Surface Mid-water Bottom
Lake Trout McTavish Arm 2014
Further work • Lab analyses in progress: zooplankton, benthic invertebrates, fish
• Examine patterns in distribution, abundance, demographics of fish, invertebrates
o relationship to each other, environmental variables,
o changes over time - historical data, reference approach (CHARS), coring
• Utilize data in ecosystem and population models as it becomes available (update Janjua et al. Aquatic Ecosystem Health & Management 2014, Can. Tec. Rep. Fish. Aquat. Sci., in press)
• Lake trout and cisco studies – ongoing; M.Sc. (M. Leclaire), Post-Doc (L. Chavarie)
• Write up TK workshop results (Y. Janjua and L. Chavarie)
• Years 1 – 3 completed in a 5 year cycle:
o Continue in Dease Arm (summer 2015) o Continue community-based monitoring close to Deline
Thank You! Mahsi Cho! • NWT Cumulative Impacts Monitoring Program • Sahtu Renewable Resources Board • Deline Renewable Resources Council • Deline Lands and Finance Corporation • GNWT Renewable Resources Deline • DFO Hay River, Yellowknife & Inuvik • Polar Continental Shelf Project • Natural Sciences and Engineering Research Council • Canadian Circumpolar Institute • Traditional Knowledge, Deline: Paul Modeste, Douglas Baton, John Tutcho, George
Kenny, Morrıs Modeste, Joseph Blondın, Jr., and Alfred Tanıton; community researchers Michael Neyelle &Mavis Baton
• Field Work 2012: Deline -Darren Kenny, Bobby Modeste, Allison Tatti, Gerald Tutcho, Archie Vitale; DFO Winnipeg - Dave Boguski, Kristin Hynes
• Field Work 2013: Deline –Chris Yukon, Archie Vitale, Allison Tatti, Morris Betsidea, Isodore Betsidea; DFO Winnipeg - Kristen Adair
• Field Work 2014: Deline –Chris Yukon, Archie Vitale, Morris Betsidea, George Menacho, Barbara Yukon ; DFO Winnipeg - Dave Boguski, Michel LeClaire
• Invertebrate analyses: Erica Smith, Lyla Witschi, Michelle Wetton, Sarah Semmler