slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Ecological Interactions in Lake Superior PowerPoint Presentation
Download Presentation
Ecological Interactions in Lake Superior

Loading in 2 Seconds...

play fullscreen
1 / 22

Ecological Interactions in Lake Superior - PowerPoint PPT Presentation


  • 185 Views
  • Uploaded on

Ecological Interactions in Lake Superior. Sean Cox, Chris Harvey, and Jim Kitchell Center for Limnology University of Wisconsin, Madison. Fish community objectives (FCOs). Self-sustaining forage fish populations Maintaining native fish community Self-sustaining lake trout populations

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Ecological Interactions in Lake Superior' - Sophia


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Ecological Interactions

in Lake Superior

Sean Cox, Chris Harvey, and Jim Kitchell

Center for Limnology

University of Wisconsin, Madison

slide2

Fish community objectives (FCOs)

  • Self-sustaining forage fish populations
  • Maintaining native fish community
  • Self-sustaining lake trout populations
  • Self-sustaining populations of salmon
outline
Outline
  • Lake Superior food web structure: Stable Isotopes
  • Simulating ecological and fishery interactions: 1929-1998
  • Recommendations
slide4

Siscowet

L.T.

Burbot

5

D. sculpin

Chub

Whitefish

S. sculpin

4

Herring

Mysis

3

Diporeia

Zooplankton

2

Detritus

Phytoplankton

Lake Superior

pelagic food web

(ancestral)

Trophic Level

slide5

5

4

3

2

Lake Superior

pelagic food web

(modern)

Sea lamprey

Steelhead

Siscowet

L.T.

Coho

Burbot

Chinook

Smelt

D. sculpin

Chub

Whitefish

S. sculpin

Trophic Level

Herring

Mysis

Diporeia

Zooplankton

Detritus

Phytoplankton

slide6

Trophic structure: Stable Isotopes

What are they?

  • Heavy to light isotope ratio in tissues
  • 15N/14N and 13C/12C
  • Fractionate predictably up food chain
slide7

Trophic structure: Stable Isotopes

What are they used for?

  • Tracers of long-term diet history
  • d15N indicates trophic level
  • d13C indicates production source
slide8

Top predator

10

Forage fish

7

Zooplankton

3

Phytoplankton

0

-30

-26

-18

-22

Trophic structure: Stable Isotopes

d15N (‰) Trophic level

d13C (‰) Production source

slide9

Trophic structure: Western L. Superior

12

Deep

Food Web

Siscowet

Burbot

Lean

10

Kiyi

Chinook

S. Sculpin

8

Bloater

Herring

d15N (‰) Trophic level

Coho

Dws

Mysis

6

Smelt

Cal. Copepods

Shallow

Food Web

4

Diporeia

Cycl.

Copepods

2

Seston

Cladocerans

0

-24

-32

-30

-28

-26

d13C (‰) Production source

slide11

16

Lake herring diet only

14

12

10

8

6

Transformers

4

Parasites

Spawners

2

0

0

100

200

300

400

Isotopes indicate diet changes

d15N (‰) Trophic level

Lamprey body mass (grams)

slide13

Fishery Catch

- Catch

- Effort

USGS Trawl Survey

- Biomass

- Recruitment

Exotic Invasion

- Smelt

- Sea lamprey

Food Web Structure

- Stable isotopes

- Food habits

Ecosystem Simulation Model

Species Interactions

- Competition

- Predation

Fishery Interactions

Simulating ecological interactions

Stock Assessment

- Biomass

- Recruitment

- Harvest rates

slide14

Changes in major species since 1930

Biomass / Biomass in 1930

slide15

Deep water food web

Chub

Biomass / Biomass 1930

Siscowet

slide16

Deep water food web

Biomass / Biomass 1930

slide17

Shallow water food web

Biomass / Biomass 1930

key ecological effects
Key Ecological Effects
  • System continues to respond to invasion and collapses that occurred more than 50yrs ago
  • Mysis and smelt facilitate energy transfer between deep and shallow food webs
  • Potentially important interaction between whitefish and herring
recommendations
Recommendations
  • Whitefish may be headed for moderate decline as they approach carrying capacity
  • Siscowet too, but magnitude is uncertain
  • Develop management plan aimed specifically
  • at recovery of lake herring
compensatory recruitment

3.0

2.5

2.0

1.5

1.0

0.5

0.0

0.0

0.5

1.0

1.5

Compensatory recruitment

Age-1 Recruitment

Spawning stock

lake herring recruitment 1929 1970
Lake herring recruitment, 1929-1970

Age-1 Recruitment

Spawning stock

depensatory recruitment

1971-1998

Depensatory recruitment

Age-1 Recruitment

Spawning stock