a lake nipissing partners in conservation case study correspondence address:

Summer 2010 collapse of the Lake Nipissing zooplankton community subsequent to the introduction of

the invasive zooplankter Bythotrephes longimanus

Jean-Marc Filion

A Lake Nipissing Partners in Conservation case study

Correspondence address:135 West Peninsula Rd, North Bay, ON P1B [email protected] April 4, 2012

2010 – Sampling Stations – Lake Nipissing

S3

S6

S5

S8

S4S2

S1

N GooseIs

ManitouIs

French River

South Bay

Sturgeon Falls

NorthBay

CallanderBay

5 km

Surface area 873 km2 Average depth 4.5m 5% of all Ontario angling

Horizontal strata sampling method

Direction of travel

Float

Weight

Net

Net being hauled horizontally150 m at a depth of 1 m

in this instance.

Depth data loggerinserted in net tomonitor depth of haul

Taking the animals out of the net, and washingthem into a large, white, plastic tub

Samples, once concentratedwith 80 micron filter

The Players

Young

Adult

Juvenile Tim

e

With each molt, an additional barb is added

Bythotrephes longimanus

barb

barbbarb

barbbarb

barb

Large transparentpredator – is out-competed byBythotrephes longimanus

Geotrichia Conochilus unicornis

Blue green algae Colonial rotifer

Lake herring (Cisco) (Coregonus artedi) - to 18 inches approximately

Yellow perch (Perca flavescens ) – to 12 inches approximately

Rainbow smelt (Osmerus mordax) – to 8 inches approximately

Yellow walleyeStizostedion vitreum

This fish waslive-released

S8 - Summer 2010 abundances of Bythotrephes longimanus

and its impact on zooplankton abundance

Results

2010 – Sampling Stations – Lake Nipissing

S3

S6

S5

S8

S4S2

S1

N GooseIs

ManitouIs

French River

South Bay

Sturgeon Falls

NorthBay

CallanderBay

5 km

30 May 7 Jun 13 Jun 20 Jun 27 Jun 6 Jul 11 Jul 19 Jul 31 Jul 10 Aug 20 Aug 20 Sep0

20

40

60

80

100

120

9

103

39

83

113

42

103

14

3

11 14

S8 - Bythotrephes longimanus average abundances

Populati

on expan

sion

Population crash

2010

an./m3

0

50

100

150

200

250

300

23

3 17

291

11

75

13

30

53

140

55

230

73

36

110

5 114

22

52 6 217 19

63 4 315 11 7

14 11 16

Bythotrephes longimanus abundances per stratum per date

30 May 7 Jun 13 Jun 20 Jun 27 Jun 6 July 11 July 19 July 31 July 10 Aug 20 Aug 20 Sept

Station 8 - Lake Nipissing, 2010

1m 5m 10m

an./m3

Popu

latio

n ex

pans

ion

Population crash

Bythotrephes eats zooplankton

So what is the zooplankton population doing during this time?

30 May 7 Jun 13 Jun 20 Jun 27 Jun 6 Jul 11 Jul 19 Jul 31 Jul 10 Aug 20 Aug 20 Sep0

1

2

3

4

5

6

1m 5m 10m

Zooplankton mostly at d > 5m(mainly Daphnia galeata mendotae)

Zooplankton recoverymostly at d > 5m

(mainly Copepods)

S8 - Zooplankton abundance per date per stratum

2010

Relativescale

30 May 7 Jun 13 Jun 20 Jun 27 Jun 6 Jul 11 Jul 19 Jul 31 Jul 10 Aug 20 Aug 20 Sep0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Relativescale

S8 - Zooplankton abundance (averaged over the strata )

Population crash due to Bythotrephes predation

2010

Partial recovery later in the summer

Large Daphnia galeata mendotae populationS8, May 30th, 2010 in the 5m stratum

Mostly daphnia

Mostly daphnia

100 Bythotrephes 3900 Bythotrephes 150 Bythotrephes


1900 Bythotrephes720 Bythotrephes 750 Bythotrephes

1000 Bythotrephes170 Bythotrephes

400 Bythotrephes

Fewer daphnia

Zooplankton depleted in all strata

June 13

June 20


By the end of June, the spiny water flea had pretty well eliminated most of the zooplankton in the water column

1500 60 150 Bythos

60 300 70 Bythos

By July 11, 2010, Bythotrephes itself had crashed to much lower abundances.Only small remnant zooplankton populations remain over much of the lake.

S8 Results

Aug. 7, 2010 Kevin O'Grady captures a 35 cm walleye with only Bythotrephes in its stomach.

Aug. 13, 2010 Stéfane Filion captures a 30 cm walleye with only Bythotrephes in its stomach.

Come August some harvestablewalleye started consuming Bythotrephes

Food web implications

walleye

snails

minnows

insectlarvae

perch

copepods cladocera

herringsmelt

Energy flowBefore introduction of Bythotrephes

Food web implicationswalleye

snails

minnows

insectlarvae

perch

copepods Cladocera

herringsmelt

Energy flowAfter introduction of Bythotrephes

Bythotrephes

Lostto

sediments

Nutrientsmay recyclein early fall - wind /shallowdepths

Food web implications(before Bytho)

walleye 1 kgperch 10 kgzooplankton 100 kgphytoplankton 1000 kg

Food web implications(after Bytho – no collapse)

walleye 0.1 kgperch 1 kgBytho 10 kgzooplankton 100 kgphytoplankton 1000 kg

Food web implications(after Bytho – after collapse)Energy flow constricted

walleye 0.001 kg = 1 gperch 0.01 kgBytho 10 kg * 1/100 0.1 kgzooplankton 100 kgphytoplankton 1000 kg

Fisheries management implications(present system)

Healthy walleye pop + Healthy ecosystem Max. sustainable yield = 100,000 kg


Healthy walleye pop + Healthy ecosystem Max. sustainable yield = 100,000 kgStressed walleye pop

(harvest set at 2/3 of m.s.y.) = 66,000 kg


Healthy walleye pop + Healthy ecosystem Max. sustainable yield = 100,000 kgStressed walleye pop


NFN gets 2 fish for every 1 fish sport fisheryNFN harvest quota set at 44,000 kgSport fishery quota set at 22,000 kg

Fisheries management implications(Energy flow restricted)

Healthy walleye pop + Unhealthy ecosystem Max. sustainable yield = 50,000 kg (too high?)


Healthy walleye pop + Unhealthy ecosystem Max. sustainable yield = 50,000 kgStressed walleye population



NFN gets 2 fish for every 1 fish sport fisheryNFN harvest quota 22,000 kgSport fishery quota 11,000 kg

2011 harvest resultsNFN quota set at 40,000 kg or so

Caught 21,000 kg


Healthy walleye pop + Unhealthy ecosystem Max. sustainable yield = 50,000 kgVery stressed walleye population (large walleye?)

(harvest set at 1/3 of m.s.y.) = 17,000 kg ???


(Just one of many management options)

Fisheries management going forward

• We are at a critical point• Doing nothing is the worst option• We are out of time• Nobody wants the take the medicine• Need a plan and a way to sell it /implement it

Food web implicationsA number of problems may arise from the introduction of Bythotrephes.

“We demonstrated that increases in trophic position of the magnitude reported here can lead to substantial increases in fish contaminant concentrations.”

Bythotrephes invasion elevates trophic position of zooplankton and fish: implications for contaminant biomagnificationMichael D. Rennie • Angela L. Strecker • Michelle E. Palmer

Biol Invasions (2011) 13:2621–2634DOI 10.1007/s10530-011-0081-0

Nineteen lakes studied, focused primarily on lake herring (Coregonus artedi)

Food web implications of the addition of smelt to the ecosystem

“Rainbow smelt invasion may affect the accumulation of persistent lipophilic contaminants and heavy metals such as mercury in top predators.”

Ecosystem effects of Rainbow Smelt (Osmerus mordax) invasions in inland lakes: A literature reviewRebekah C. Rooney and Michael Paterson

Canadian Technical Report of Fisheriesand Aquatic Sciences 2845 (2009)

Children (to age 15) and women of child bearing age

Walleye in this range must be released

March 2011, MOE Guide to eating sport fish in Ontario. Consumption advice in the tables is based on an average meal size of 227 grams for an average size adult of 70 kilograms (154 pounds).

Meals per month

Bow to the queen !

Want a copy of the full report?

Jean-Marc Filion

[email protected]

S3

S6

S5

S8

S4S2

S1

N GooseIs

ManitouIs

French River

South Bay

Sturgeon Falls

NorthBay

CallanderBay

5 km

Lake Nipissing Outlet – French River HeadwatersS4 - Zooplankton community structure

S4 – A biodiversity refugeS4 is located in an area of crucial importance to Lake Nipissing as it serves as both a fish and zooplankton refuge, thus helping to preserve biodiversity. It is near the outlet of Lake Nipissing, which drains in a southwesterly direction via the French River. The bathymetry of this area is unusual in that a cold water refuge is available due to the deeper waters available in this location. The maximum depth that we were able to find using our Hummingbird depth sounder was 54m.

In the summer this areabecomes a cold waterrefuge for the lakeherring (cisco) and thesmelt. Warmer waterson top and oxygen depletion at depth keepthe fish sandwichedin a definite band, as indicated by this picturetaken of our Hummingbirdsonar unit.

S4

0.5 kmDepths in metres

7,0

6,0

5,0

4,0

3,0

2,03,04,0

1,0

8,8

9,0

8,0 6,07,0

5

10

15

20

25

30

35

40

45

0

Depth (m)

S4 - French River - D.O.(mg/L) - 2001

July August

5

10

15

20

25

30

35

40

45

0

20

22

18

16

10

14

12

8

6

6

8

10

12

14

16

18

20

S4 - French River - Temp. (C) - 2001

Depth(m) July August

4 mm

New Players

Mysis relicta

Chaoborus

1 5 10 15 18 23 28 31 34 380

5

10

15

20

25

30

0

1

2

3

4

5

6

21.3

28.7

7.0

4.1 2.3

2.7 1.81.6

0.4 0.2

S4 –Bythotrephes and zooplankton abundances vs depth

Bythotrephes

Zooplankton

Zooplanktonabundance(Relative scale -max is 6)

Bythotrephesabundance(an/m3)

Depth (m)

July 10, 2010

Fish zone

Something interestingmay be going on atthese depths

Bythotrephes abundances correlate negatively with depth

1 5 10 15 18 23 28 31 34 380.0

5.0

10.0

15.0

20.0

25.0

30.0

Diaptomus Cyclops Epischura lacustris Senecella calanoides

S4 - Relative abundances of Copepod taxa vs depth

Depth (m)

Relative abundance

Copepod abundances correlate positively with depth

Something interestingmay be occurringat these depths

Fish zone

1 5 10 15 18 23 28 31 34 380.0

5.0

10.0

15.0

20.0

25.0

Daphnia Bosmina Eurycercus Latona setifera

S4 - Relative abundances of selected Cladocera taxa vs depth

Something interestingmay be occurring atthese depths

2000/2001 sampling indicatesthat a 9-spine sticklebackpopulation exists at depthat S4 – exactly at what depthis not known at this time.

Relative scale (max is 30)Mostly D. pulicaria

Fish zone

Diaphanasoma birgeionly collected in traceamounts and only in the 1m stratum

Depth (m)

1 5 10 15 18 23 28 31 34 380.0

2.0

4.0

6.0

8.0

10.0

12.0

Conochilus Geotrichia Ostracoda

June 10, 2010

S4 - Relative abundances of Conochilus,Geotrichia and Ostracoda taxa vs depth

Relative scale(max is 30)

Depth (m)

Callander Bay

S3

S6

S5

S8

S4S2

S1

N GooseIs

ManitouIs

French River

South Bay

Sturgeon Falls

NorthBay

CallanderBay

5 km

S1 - Zooplankton community structure

0.5 kmS1

Callander Bay

July 7 Aug 10.00

5.00

10.00

1.0

3.8

5.55.0

9.1

0.4

Bythotrephes abundance by date & by stratum

1m 5m 8m

S1 - Callander Bay

an./m3

Jul 7 Aug 10

5

10

15

20

25

30

0.4 0.40.60000000000000

1

S1 - Leptodora abundance1m5m8m

Relative scale

In 2000/2001 Leptodora was quite abundant reaching abundances ofover 100 an./m3 in mid-August. In2010, Leptodora is only present intrace amounts in early July, and is not collected Aug. 1st.

S1- Leptodora kindtii

S1 - 2010

140

14

1.4

0.14

an./m3

- mouth areaof 0.5 m2 – 300micron Nitex mesh.

S1 - 2001

Jul 7 Aug 10

5

10

15

20

25

30

0.1

12.5

0.3

7.5

0.600000000000001

6

S1 - Diaptomus abundance

1m 5m 8m

Relative scale

By the end of the 1st week of July Bythotrephes had driven Diaptomids at S1 to trace amounts. Historicaly abundances at this time were in the 15000 an./m3 range. By the 1st of August the Diaptomids are recovering somewhat.

S1- Diaptomids

S1 - 2010

Relative scale

By the end of the 1st week of July Bythotrephes had driven Cyclops at S1 to trace amounts. Historically abundances at this time were in the 20000 to 40000 an./m3 range. By the 1st of August the Cyclops are recovering somewhat.

S1- Cyclops

S1 - 2010

Jul 7 Aug 10

5

10

15

20

25

30

0.4

24

12.5

7.5

S1 - Cyclops abundance

1m 5m 8m

Relative scale

By the end of the 1st week of July Bythotrephes had driven Daphnia at S1 to trace amounts. Historically abundances at this time were variable but typically in the 5000 an./m3 range. In 2010, by the 1st of August Daphnia were very abundant at depth. In 2001 only D. retrocurva was collected at S1. In 2010 only one D. retrocurva individual was collected, the rest being Daphnia galeata mendotae.

S1- Daphnia

S1 - 2010

Jul 7 Aug 10

5

10

15

20

25

30

0.3

5

0.3

4.5

0.4

30

S1 - Daphnia abundance

1m5m8m

Jul 7 Aug 10

5

10

15

20

25

30

0.1

S1 - Bosmina abundance

1m 5m 8m

Relative scale

By the end of the first week of July 2010, Bythotrephes had pretty well eliminated the Bosmina sp. from Callander Bay. They remain absent from the collections on Aug. 1st. In 2000/2001 their average abundances come July were in the 5000 to 20000 an./m3 range. The ‘U’ shaped curve from 2001 may imply that Bosmina may serve as a food source for juvenile and larval fish who move on to other prey as they reach a larger size.

S1- Bosmina sp.

S1 - 2010

Historically Diaphanasoma at S1 was a highly variable species, sometimes attaining abundances as high as 40000 an./m3, only to almost disappear from the collections the week after. Collections in 2000/01 were made using vertical hauls. This may imply horizontal patchiness. Populations were usually small at the beginning of July, but then increased to an average of 10000 an./m3 come the first of August. In 2010, Diaphanasoma was not collected on July 7th, 2010 and showed little sign of becoming abundant on the 1st of August. It was absent from the collections at the 8m stratum. Bythotrephes may be keeping this species at low abundance levels at S1.

Jul 7 Aug 105

1015202530

2.5 1.5

S1 - Diaphanasoma abundance1m5m8m

Relative scale

S1- Diaphanasoma birgei

S1 - 2010

S1 was sampled July 7th and August 1st, 2010. Holopedium gibberum was onlycollected in trace amounts from the 5m stratum on July 7th. Historically,Holopedium had average abundances of around 100 an./m3 in early July and early August. It would seem that Holopedium disappears quicker and attains lowermaximum abundances since the introduction of Bythotrephes.

S1 – Holopedium gibberum

Jul 7 Aug 10

5

10

15

20

25

30

0.1

10

0.2

7.5

S1 - Conochilus unicornis abundance

1m5m8m

Jul 7 Aug 10

5

10

15

20

25

30

0.1

10

0.2

4.5

S1 - Geotrichia abundance

1m5m8m

Relative scale

Relative scale

Conochilus unicornis and Geotrichia, not collected in any important amount in 2000/01is now becoming common to moderately abundant as summer progresses at S1.

In the winter perch turn to eating snails and mayfly naiads. They could do the same in the summer.

a lake nipissing partners in conservation case study correspondence address:

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