Fisheries research and monitoring programs, gaps and priorities Ts - - PDF document

09/02/2016 1

Fisheries research and monitoring programs, gaps and priorities

Tsá Tué Biosphere Reserve Research and Monitoring Workshop February 9‐11, 2016

1) Monitoring of catch and biological indicators of harvested and non‐harvested larger bodied fish species in all areas of GBL:

• Ongoing since 2000 ‐ needs science review (DFO RAP) and

publishing through DFO Canadian Science Advisory Secretariat Future Work:

• Recommend continued monitoring:
• key in detecting changes with climate, harvest and

development particularly in harvested species of interest such as lake trout

• needed to model sustainable harvest levels

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2) Compare genetic relationships among fish from different arms of GBL to determine stock structure as it relates to current management zones within GBL:

Research conducted:

• Lake Trout – comparison of different harvested stocks, and among

different morphotypes

• Cisco ‐ comparison of depth associated morphotypes in two areas

(Keith and Dease Arms)

• Published in the primary literature (3 papers) and could also

feed into DFO RAP described in 1) Future research:

• Genetic relationships of cisco in other regions of GBL and

Whitefish

• Genomics ‐ multi species comparison to understand the process
• f intraspecific diversification, a major component of

biodiviersity in northern areas such as GBL.

3) Documentation of morphological variation and ecological roles of major fish species in GBL:

Research conducted:

• Lake Trout – documentation of multiple shallow water

morphotypes (2 papers) and inter‐morph comparison of diet (2 papers) and life history (1 paper); could feed into DFO RAP

• Cisco ‐ comparison of morphology, diet and life history in two

areas (Keith & Dease Arms; DFO Research Document). MSc. Mitch LeClaire (U of MB) expand to compare all arms

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3) Documentation of morphological variation and ecological roles of major fish species in GBL:

Future research:

• Analysis and write up of TEK regarding different lake trout types
• Deep water trout morphology – L. Chavarie post doc
• Lake trout ecology ‐ Juvenile diet (multi‐arm), reproductive cycles

(otoliths)

• Whitefish diversity complex – L. Chavarie
• GIS spatial analysis , morphology/habitat across multiple species ‐

process driving intraspecific diversification

• Biology/ecology of other fish species: walleye, pike, round

whitefish, grayling, stickleback, sculpin

• River fish connecting to GBL ‐ interaction between these

communities, especially when species use both environments

4) Understanding spatial variation in the aquatic ecology of Great Bear Lake:

Research conducted:

• Spatially extensive survey of the GBL aquatic ecosystem initiated

in 2012 (until 2017) to assess water quality, primary (chlorophyll a), and secondary production (zooplankton and forage fish) in addition of ongoing monitoring of large bodied fish.

• 6 fixed community based stations near Deline (more intensive

seasonal and annual monitoring)

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Future research:

• Characterize “reference condition” & identify key ecosystem

components that should be focus of future long‐term monitoring

• Recommend continued community‐based monitoring; coordination with

parks; need for replication

• Sampling off offshore and deeper (>150m) areas of GBL (not covered in

current study)

• Winter work – seasonal variation
• Carbon cycling – link between terrestrial and aquatic foodwebs
• Predation rates, phytoplankton production (limiting factors for lake

productivity), effects of increased inputs (due to climate warming, other sources of nutrients), nutrient cycling, survival, overwintering and vertical migration of zooplankton

4) Understanding spatial variation in the aquatic ecology of Great Bear Lake: 5) Food‐web studies and ecosystem modelling of GBL:

Research conducted:

• EcoSim modelling of trophic linkages and lake/fisheries status

utilizing historical data in combination with TEK (I paper, 1 DFO Tech Report)

• No funding to continue this work using updated data from the

DFO ecosystem survey Future research:

• Reanalysis of models with updated data
• Prediction of sustainable harvest, climate change impacts on

fishery

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7) Mercury in food web

Research Conducted:

• Analysis of mercury levels in fish from McVicar Arm sparked by

community concerns (samples from DFO ecosystem study, analysis by G. Stern)

• White fish have low mercury, but some of the trout and all the

Walleye are very high.

• Health Canada consumption guideline is 0.5 ug/g; some of the

Walleye are almost double this value. Future research

• Analysis of trout & walleye along gradient through McVicar Arm
• Study to try understand why this area gives rise to fish with such

high levels of mercury and how climate change may exacerbate

• r reduce the problem

6) Climate change

Future Research:

• Recent ecosystem studies on GBL suggest changes due to climate,

but don’t know when started (no long‐term data)

• Potential approaches for obtaining retrospective data:
• Lake bottom coring ‐ how productivity & mercury deposition

has changed over time (increased mercury deposition with warming has been noted in other water bodies)

• Dendrochronology/retrospective analysis of otoliths and/or

tree rings to track past regional changes in climate/productivity

• Changes in fish thermal habitats using otolith carbon isotopes
• Analysis of TEK information collected by Janjua/Chavarie on

local observations of climate change

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7) Movement patterns/critical habitat of migratory species:

Future work: Identify and characterize critical habitat – spawning, rearing,

• verwintering
• Could be done using satellite imagery, aerial photography,

lakebed classification, tagging studies

• Some of this addressed through Great Bear Lake

ecosystem study

• Use of information from previous TEK studies (Janjua,

Chavarie) to look at spawning areas and potential rearing areas (areas with vegetation)> help direct more specific studies of critical habitat.

• Great BearLake – some limited tagging studies done on

lake trout;

Future work: 8) Collection of harvest information for fish

– subsistence, lodge, itinerant anglers

9) Study to determine mortality rates of fish released by sport fishery

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Future Research: Studies of fish and aquatic ecosystems (e.g., harvest studies, monitoring of abundance, identification of critical habitat ) of other lakes/waterbodies in the GBL watershed

Many waterbodies and studies can be difficult/expensive (especially critical habitat) so need to be prioritized: – areas that are expected to receive development in the future – areas that are important to communities in the Sahtu Region – areas that drain into Great Bear lake, e.g., rivers to the east where there has been mining, or there are mining interests (exploaration) – prioritization could be based on information gained through literature review, harvest studies ( important fishing locations), interviews with community members