Fish and epibenthic Fish and epibenthic assemblages in the Chukchi assemblages in the Chukchi

Sea: observations and Sea: observations and predictionspredictions

BA Bluhm, BL Norcross, K Iken, F Huettmann, BA Holladay (all University of Alaska Fairbanks), BI Sirenko (Zoological

Institute RAS)

Demersal fish and Demersal fish and epifaunaepifauna

• Plumb-staff beam trawl, 7 mm mesh (4 mm in cod end)

• 2-5 min hauls on bottom

• Sort, count, weight, identify

• 2004-2009, 165 fish st, 42 epifauna st

Why care?Why care?• Commitment to

Circum-polar Biodiversity Monitoring Program (Arctic Council)

•Climate signal integrators•Prey for subsistence species•Species of potential subsistence and commercial fisheries (snow crab)•Contribution to carbon cycling

Transform: Square root

Resemblance: S17 Bray Curtis similarity

SIMPRsqrt5%hijlgfbdceak

2D Stress: 0.22

Transform: Square rootResemblance: S17 Bray Curtis similarity

dhijcfegba

Similarity30

2D Stress: 0.22

NorthCoastal

Central

Northeast

East Siberian Sea

Herald Valley

Coastal

Central east

Southwest

Faunal Faunal similaritysimilarity

Fish

Fish-Epifauna

Chukotka

Alaska

East Siberian Sea

Wrangel Isl. Herald Canyon

Icy Cape

ClusterNo of stn

Used for prediction

67 north16 northeast44 central21 coastal64425

Observed fish Observed fish assemblagesassemblages

Clustering based on fish biomass, square-root transformed, Bray-Curtis similarity

Chukotka

Alaska

East Siberian Sea

Wrangel Isl. Herald Canyon

Icy Cape

ClusterNo of stn

Used for prediction

67 north16 northeast44 central21 coastal64425

Characteristic speciesCharacteristic species

Taxa contributing ≥10% to within cluster similarity

Observed fish-epifauna Observed fish-epifauna assemblagesassemblages

Kotzebue Sound

Bering Strait

Point HopeCluster No of stn Cluster name

9 East Siberian Sea5 Herald Valley5 central east5 southwest433 coastal3

Clustering based on fish and epifauna biomass, square-root transformed, Bray-Curtis similarity

Characteristic speciesCharacteristic species

Kotzebue Sound

Bering Strait

Point HopeCluster No of stn Cluster name

9 East Siberian Sea5 Herald Valley5 central east5 southwest433 coastal3

Taxa contributing ≥10% to within cluster similarity (fish species contributed ≤7%)Mean fish biomass per cluster 2-10% of total haul biomass

Environmental variables Environmental variables consideredconsidered

Variable Unit SourceDistance to mean summer ice edge

MetersU.S. National Ice Center

Bottom temperature

ºC

Compiled by S. Okkonen (Univ. of Alaska Fairbanks) for PacMARS project

Integrated chlorophyll a concentration

Mg chl a/m2

Matrai et al., integrated by C. Ashjian (WHOI) for PacMARS

Water depth Meters IBCAO

Grain size% phi 5 (silt)

J. Grebmeier, U Maryland, compiled for PacMARS

Sea surface Temp. (10 m)

ºC World Ocean Atlas

Bottom salinity PSUCompiled by S. Okkonen (UAF) for PacMARS

Variable Unit Source

Aspect Degrees IBCAODistance to run-off

Meters R-ArcticNet

Slope Degrees IBCAODistance to coast

MetersWorldcoastline webportal

Sea surface salinity

PSU World Ocean Atlas

Silicate conc.Mmol/m3 World Ocean Atlas

Phosphate concentration

Mmol/m3 World Ocean Atlas

Apparent O2 utilization

Mol O2/m3 World Ocean Atlas

Predicted Predicted assemblagassemblag

eses

north

coastal

central

northeast

Bering Sea

Bathymetry (m)0 - 25

26 - 50

51 - 75

76 - 150

151 - 1000

1001 - 4000

Chukotka

Alaska

East Siberian SeaWrangel Isl. Herald Canyon

Icy Cape

ClusterNo of

stnUsed for prediction

67 north16 northeast44 central21 coastal64425

EnvironmentEnvironmental niches for al niches for

fish fish assemblagesassemblages

North: near mean summer sea ice extent, low bottom temperature

Central : high chlorophyll a, near ice edge, muddy sediment, >40 m

Coastal: near coast, high surface and bottom temperatures, far from ice edge

Northeast: coarse sediment, <40 m, high(er) bottom temperature, rel. low chlorophyll

north

coastal

central northeast

Thanks!Thanks!• Funding through RUSALCA

(NOAA-CIFAR), PEW Environmental Group (US Arctic Program), CMI (Fish),

• Species identifications aided by Drs L Cole, K Coyle, D Fautin, A Gebruk, M Hoberg, P Kuklinski, C Mah, CW Mecklenburg, E Rodriguez, A Rogaecheva, I Smirnov, O Tendal

• Vessel support, Ship crews and trawl teams of Prof. Khromov, Oscar Dyson /AFSC/NOAA, Oshoru Maru / Hokkaido Univ.

Temporal comparison of Temporal comparison of epifauna and food web in epifauna and food web in the southern Chukchi Sea the southern Chukchi Sea (2004, 2009, 2012): First (2004, 2009, 2012): First

resultsresults

BA Bluhm, KB Iken, C Serratos (all University of Alaska Fairbanks), B Sirenko (Zoological Institute RAS)

Why care?Why care?Food web•Carbon flow•Food web length – carbon transfer efficiency•Pelagic-benthic coupling

Epifauna•Climate signal integrators (long-lived)•Prey for subsistence species•Species of potential subsistence and commercial fisheries (snow crab)•Contribution to carbon cycling•Commitment to Circum-polar Biodiversity Monitoring Program (Arctic Council)

• Plumb-staff beam trawl, 7 mm mesh (4 mm in cod end)

• 2-5 min hauls on bottom

• Sort, count, weight, identify

Time series stationsTime series stations

EC

AF

B

G

Chukchi Sea

D

Bering Sea

AW BSW

ACW

Freshwater inflow,gravel

Hard substrate

Biomass and Biomass and compositioncomposition

Caveat: No replicate trawl hauls

0

20000

40000

60000

80000

100000

120000

CL10

-04

CL10

-09

CL10

-12

CL8-

04CL

8-09

CL8-

12CL

6-04

CL6-

04CL

6-12

CS8-

04CS

8-09

CS8-

12CL

3-04

CL3-

09CL

3-12

CL1-

04CL

1-09

CL1-

12CS

17-0

4CS

17-0

9CS

17-1

2

Biom

ass (

gram

wet

wei

ght 1

000

m-2

)

Station and year

OtherAscidiaceaEchinodermataArthropodaMolluskaCnidaria

A BC G D

E F

Russian coast

Anadyr Water

Alaskan coast

Bering ShelfWater

Biomass trendBiomass trend

Snow crab: Snow crab:

abundant but abundant but

small in Chukchismall in Chukchi

0

10

20

30

40

50

60

20 30 40 50 60 70 80

Abso

lute

freq

uenc

y

Carapace width (mm)

Chukchi Sea males

0

2

4

6

8

10

12

14

16

18

20

18 38 58 78 98 118 138

Abso

lute

freq

uenc

y

Carapace width (mm)

Beaufort Sea males

SCI2 SCI3

Mean 69SD 29N=344

Mean 40SD 11N=2669

0

20

40

60

80

100

120

140

160

0 100 200 300 400 500

Cara

pace

wid

th (m

m)

Water depth (m)

Males

Mature females

Immature females

Transform: Fourth rootResemblance: S17 Bray Curtis similarity

StationABCDEFG

Similarity40

2004

2004

2004

20042004

2004

2004

2009

20092009

20092009

20092009

2012

2012

2012

2012

2012

2012 2012

2D Stress: 0.17

Community structure Community structure stablestable

Anadyr Water

Point Hope

Russian coast

Coastal Current

Food web – trophic Food web – trophic levelslevels

4

6

8

10

12

14

16

18 20092004

AW ACW AW ACW

δ15N

POMSurface deposit - bivalves

Neptunea sp.

Pagurus rathbuni

Leptasterias sp. Nephtys sp.

Hyas coarctatusChionoecetes opilioArgis larGymnocanthus tricuspisMyoxocephalus scorpiusLumpenus fabriciiBoreogadus saida

Strongylocentrotus droebach.

AW consumers depleted in δ15N compared to ACW in both yearsUse of fresher (=isotopically light) material through shorter food chains in AW

2012

Food web – carbon Food web – carbon sourcesource

-25

-24

-23

-22

-21

-20

-19

-18

-17

-16

-15

-14 20092004

AW ACW AW ACW

δ13C

POMSurface deposit - bivalves

Neptunea sp.

Pagurus rathbuni

Leptasterias sp. Nephtys sp.

Hyas coarctatusChionoecetes opilioArgis larGymnocanthus tricuspisMyoxocephalus scorpiusLumpenus fabriciiBoreogadus saida

Strongylocentrotus droebach.

Consumer δ13C depleted in ACW – possible freshwater signalDepleted δ13C POM in AW in 2009

– strong freshwater signal in 2009

2004 results: Iken K et al (2010) Deep-Sea Research II 57: 71-85

2012

Learned so far?Learned so far?Food web•Food web reflects water masses (tight pelagic-benthic coupling in AW)•Food web structure stable between 2004 and 2009•Food source signal variable at point measurement

Epifauna•Biomass variable between years•Individual species can drive tends (stock fluctuations in snow crab?•Community structure stable in area, different by substrate and water mass•Combination of metrics tell more than one metric

Thanks!Thanks!• Funding through NOAA-CIFAR

NA08OAR4320870, CIFAR IPY• Ship crews and trawl team of

Prof. Khromov, B. Holladay• Crab funding (CMI, BOEM), and

lab team• Stable isotope lab team• Species identifications aided by

Drs L Cole, K Coyle, D Fautin, A Gebruk, M Hoberg, P Kuklinski, C Mah, CW Mecklenburg, E Rodriguez, A Rogaecheva, I Smirnov, O Tendal

RUSALCA Synthesis - RUSALCA Synthesis - BioBio

Need from phys-chem-geo•Spatial and temporal patterns of environmental conditions on different scales (next slide) for water column and (near) bottom (latitude / longitude, depth, value)

•Joint interpretation!

•Mapping support across projects for special issue?

Bio: Have•Species distributions•Community distributions•Biomass / abundance distributions•Food web•Some fluxes•Some rates (benthic respiration, copepod egg production)•Variability / change over time (to varying degrees)

Life cycles provide Life cycles provide integration scalesintegration scales

Day month year decade century

µm mm cm dm m

Bacteria larvae zooplankton fishes benthos mammals

Possible papersPossible papers• One overarching highlights paper (or extended

editorial to special issue)• Regional highlight, system description as multi-

year composite: Herald Canyon area• Temporal variability highlight: focus on DBO 3

•All multidisciplinary, multi-author, multinational•Unique and complementary to other synthesis efforts•Need lead team (Russia/USA) or interdisciplinary post-doc based in both countries (Liza-Maria concept)

RUSALCA Synthesis - RUSALCA Synthesis - BioBio

Future Need next decade?•Continue time series (minimum DBO transect 3?)•Increased integration with phys-chem-geo•More rates: Current rates, e.g. grazing, growth, age•Future rates through experiments?•Thermal windows and physiological plasticity?•Link to sea ice?•Predictive capability?•Carbon flux model?

•Interdisciplinary post-docs with Russia-US advisory team, based in two countries?