CSI Husky Lakes - an update on mercury transfer in food webs of a unique Arctic estuary, the Husky Lakes (NT).

Nikolaus Gantner 1, Jolie Gareis 2, Don Ross 2, Jennie Knopp 3, Ben Kissinger 4, Chris Furgal 3, Holger Hintelmann 1, Gary Anderson 4, Lois Harwood 6, Jim Reist 6 , Brian Liard 7 & experts 8 from the ISR

Poster layout by N. Gantner : ‘Cross-section’ of Husky Lakes including stylized Introduction 2011-13 Components, progress Results and discussion ice cover, salinity gradient, food web structure, and variable fish size. The Husky Lakes watershed (HLW) is a ‘true’ Arctic Ice-conditions and limnology watershed, located entirely North of 66 °. 1. Traditional Knowledge via semi-directed interviews .
Semi-directed interviews with 14 local experts on IK of HLW ecology. • HL ice thickness ranges from 0-8ft during the year. Lakes in the HLW region are important to the people of
24 hours audio recording of IK on ice conditions, lake ecosystem, • Ice thickness did vary among lakes and basins. Tuktoyaktuk and Inuvik. Popular for local fishermen are fish composition, fish health, fish habitat, and food webs. • Salinity ranged from 0.1-17ppt in Husky lakes Yaya Lake, Big Lake, Noell Lake and the Husky Lakes.
Mapping of local fishing locations and areas of significance to study • All lakes appeared mixed at time of sampling. (Fig. 1). A salinity gradient (of 0.0-1.8%) exists within the HLW food webs and ecosystem. •Analysis and comparison to earlier studies at HL. Yaya Big >1 % Lake Lake the HLW (Mills et al. 2008), as a result of marine
Qualitative analyses identified common & emerging themes in IK inputs from Liverpool Bay to the lake. shared by interviewees Mercury concentrations in Lake Trout Noell Lake Trout + 0 % salinity + CVC = [Hg]? • Lake Trout mean [THg] = 0.13 (±0.06) µg/g ww (Fig. 1A) in 2011-12.  Verification by interviewees to ensure IK was documented accurately <1 % • [Hg] in HL Lake Trout remain low over a 17-year period (1995-2012). and interpreted correctly. Lake trout is commonly harvested and known • Lake Trout from HL can be frequently consumed without exceeding the  Interview maps digitized into a GIS database for future use by to grow faster and larger in this marine- HgT guideline established by JECFA (Fig.1B) researchers and communities. 0 % influenced part of HLW (Mills et al. 2008). A 0.30 B Detailed information about the transfer of 2. Ice conditions, water chemistry, and water quality profiles [THg] in Husky Lakes Lake Trout Fig 1: Husky Lakes Watershed S of Tuk, NT. 0.25 1995 2002 2011+12 Red digits indicate the salinity of Husky Lakes mercury in HLW food web and determined to infer lake productivity. water. Asterisks identify additional study sites. concentrations in harvested fish is limited.
Abiotic data (Ice thickness and YSI) recorded Nov 11 – Sept 12. 0.20

Analysis pending [Hg] data. 0.15 Long term goal Identify the processes that drive mercury transfer and g/g ww, geomeans) ww, g/g that respond to cumulative impacts in the HLW. Husky Lake Trout + 1.8 % salinity + CVC = [Hg]? µ 0.10 3. Food web analysis using stable isotopes of N and C. ( [THg] n=50 n=10 n=62 Short term goals 1. Provide baseline information on the HLW 0.05
Littoral & benthic invert community sampled (Nov 11, May & Aug ’12). Eat up! cryosphere, food webs, and mercury concentrations, and their 0.00
Invert and selected fish freeze dried analysed for C + N. 1990 1995 2000 2005 2010 2015 2020 interactions. 2. Further work with existing Inuvialuit Knowledge (IK) on Fig 1. A) Unadjusted [THg] in Husky Lakes Lake Trout muscle from (1995-2012, Geomeans ±1xSD; B) Intake subsistence fishing and use of the Husky Lakes. 3. Combine both 4. Mercury concentrations in fish estimates of HgT from Husky Lakes Lake Trout. Dashed red line: Provisional tolerable weekly intake. Mercury ‘fingerprint’ in Lake Trout knowledge bases to help develop future strategic monitoring.
440 total fish collected in 2012 at all 4 study lakes. 6.00 6.00 Φ 5.03 Community involvement
108 Husky Lakes collected (Nov ’11+ May 12 + Aug 12). Noell vs Husky A B 4.00 Φ 1.78 Φ 2.11
Subset of fish analysed for [THg] using Tekran CVAFS system. 4.00 Yaya Lake LAT ? Hg Φ 1.06  Inuvik-based co-lead: Aurora Research Institute (ARI). Hg
[THg] Results compared to existing DFO data (1992, 2002). 199 2.00 199 Δ

 Consultation, public meetings, scoping sessions, and TK interviews.
Monte Carlo dietary intake model built using Crystal Ball (v11.1, 2.00 ΦΔ 0.00 Oracle) according to [Hg] in Lake trout caught in Husky Lakes. FW LAT M LAT FW LAW M LAW LAT FW  Regular updates to stakeholders in Tuktoyaktuk and Inuvik in public Fig 2. A) Hg SIRs in Lake Trout (LAT) collected from Noell
EPA+DHA [Hg] obtained from literature (Lake Superior Lake trout) LAT M meetings or presentations (FJMC, ARI, ILA, TCC, HTC’s). 0.00 Lake in 2009 (freshwater lake, n = 3) and Husky Lakes in
Estimated HgT exposure from Husky Lakes Lake trout if -2.00 -1.00 0.00 1.00 2.00 2011 (marine, n=3). B) Φ is calculated as the average MIF  Hiring and training of local people for field work ('50:50 rule'). δ202 Hg (∆199 Hg) offset from sediment (freshwater n=4, marine, n=3) to consumption ranged between 75 and 750 g/wk (uniform distribution). fish in freshwater lakes (LAT n=3, LAW n=3) and marine  Inuvialuit Knowledge (IK) is used to select sampling locations, timing 5. Mercury Stable Isotopes – ‘fingerprint’ Food web characteristics influenced lakes (LAT n=9, LAW n=6). Husky Lake food web (partial) -14 8 16 15 Gammarids and parameters within our scientific sampling efforts. • δ NLAT =14.8 ±0.5 ‰ -16 Gammarids 7
Variations of Hg SI ratios, a tool capable of indicating Hg processes 14 13 -18 • δ Cinvert ±3.0 ‰ 6 12 -20 N

13 C 5 (Yin et al. 2010) 15

N invert

and/or sources , determined in biota, water, & sediments. 10 • δ C ↓ in ↑ sal -22 δ 13 δ Relevance and benefits to the Inuvialuit Settlement Region 15 ~6‰ 4 δ 15 -24 ~2.5‰ 8 • δ Ninvert ±1.3 ‰
Selected samples extracted and analysed. 6 -26 3 Inverts 15 FW Increasing salinity • δ Ninvert ↑ in ↑ sal -28 Increasing salinity
Directly addresses research needs of the community. 4 FW 2 ~6‰ t l k
Reveal lake-specific Hg ‘fingerprint’ in fish. -30 e rth h 1 e P Is ili 3 p 4 5 t l ak o B ak d s n B am 2 • Baseline = ? ke rth th 1 ke P Is ilik 3 mp 4 5 l L N outHL 0L n h' in L c HLBHLB La o ou LB La nd 's nn B a LB LB el e S 0 o a Ig H n ll e N S H 0 o ah Igi HL n c H H o e 5 o 3 e oe k ke 50 m o 3 e N Lak k iam N / -28 -26 -24 -22 -20 -18 -16 N La a ia N 2/ ub a La D 2 2 rub Lake + Site a L 2 D 2 B Gr a 2 B B G
Highlight and preserve TK on ice and fish in the HLW. ay ya B LB L Lake + Site ay y L L Y a H H Y a LB H H 6. Fish ages and movement δ13 C Y HL Y H
Know the range of contaminants in fish from HLW.
Fish ages and otolith microchemistry will elucidate life history, growth Knowledge gain
Training and capacity building in relevant sampling methods. rates and movement of individual fish within the HLW, aiding the 1.Use existing IK to aid study design, field work and interpret measurements.
Pilot-project (2011-14) for community-based long term monitoring. interpretation of [Hg]. 2.Baseline information on mercury concentrations in harvested fish.
Otoliths extracted and analysed on laser-ablation ICP MS 3.Mercury ‘fingerprint’ in fish, reflecting either variable Hg sources or
HL Lake Trout movement data – see Kissinger et al. poster differences in Hg processes (e.g., light conditions) in the water column. 4.Elucidate HLW food web interactions with water conditions and mercury. 5.Life history and extent of lake trout movement within the Husky Lakes.

1Chemistry, Trent University, PTBO, ON, 2Aurora Research Institute (ARI) Inuvik, NWT, 3Environmental and Life Sciences, Trent U, PTBO, ON, 4Biological Sciences, U Funding: NSERC Banting Fellowship Program to NG; Northern Contaminants Program, Cumulative Impact Monitoring Program (both DAAND); Support: Polar Continental Manitoba, 6Freshwater Institute, Fisheries & Oceans Canada, Winnipeg, MB, 7U Waterloo, Waterloo, ON, 8Inuvialuit from Tuktoyaktuk and Inuvik, NT Shelf Project, Environment Canada, Tuk CC (J. Russel), ILA Tuk, Tuk HTC (board), Tuk Hamlet office; DFO Inuvik. Field support by S. McFadyen, C. Pokiak, C. Felix, R. Members: NG, JK, BK Contact: N. Gantner ([email protected] ); Info: Husky Lakes Research group Noksana, J. Tedjuk, J. Keevik, M. and L Kotokak (Tuk). G. Anaviak, D. Nasagaloak and all interviewees did a great job!! Also, thanks to all who patiently taught us how to play Snert more quickly. SNERT!! References: ACIA 2005; Mills et al. 2008 DFO CTRFAS 2778; Yin et al 2010 AG 25:1467-77; Roux et al 2013 20 th NCP Results workshop, Sept 24-25, Ottawa, ON