fishes of the laguna de santa rosa then, now, andtomorrow? · then, now, and...tomorrow? teejay...

Fishes of the Laguna de Santa Rosa

Then, Now, and...Tomorrow?

Teejay O’Rear

Graduate Group in Ecology

Wildlife, Fish, and Conservation Biology

U.C. Davis

[email protected]

mailto:[email protected]


Outline

•Quick Laguna tour

•Then

•Now

•Tomorrow


Sebastopol

Rohnert Park

Santa RosaSanta Rosa Creek


Background

•Pond-like stream

Main Points?

•Very fertile

What fish are in there?


Then (1988)

•Only one known study of the Laguna’s aquatic community

•CH2MHill – 1988

•7 reaches

•Spring, summer, autumn

•Gillnets and seines

•Zooplankton, invertebrates, water quality


Then (1988)


Then (1988): Gillnets


Then (1988): Seines


Then (1988)

Main point? Fish community dominated by species that are tolerant of

•Low dissolved oxygen

•High water temperatures

•Still water


2008 Aquatic Community Survey

Purposes

•See if the fish community has changed since 1988

•Determine environmental factors affecting the fish community

•To provide baseline data for management activities


Now (2008)

Surveyed

•3 sites in 2 reaches

•On 2 days in August

Collected

•Water-quality data

•Invertebrates via net sweeps

•Fishes via gillnets and seines

•Fishes for gut-content analyses


Now (2008)

map


Now (2008): Gillnets


Now (2008): Seines


Then and Now: Gillnets

0

5

10

15

20

25

CARP SBF BC SS GSF BG

Species

20081988


Then and Now: Seines

0

50

100

150

200

250

300

MQF LEP LMB SBF SS SC ROA BC STBK BLB CYP FHM

Species

20081988 All Sites1988 ORP and SRLC


Now (2008): Gut Content Analyses

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fathead Minnow Sacramento BlackfishYOY

Mosquitofish Black Crappie Bluegill YOY Bluegill Age 1+

Species

Bosminidae Cyclopidae Daphniidae Chironomidae larvae Chironomidae pupaeCorixidae Talitridae Poeciliidae Other


Now (2008)

Main points?

•Fish community – changed little

•Like 1988, dominated by hardy fishes

•Low DO

•Warm, still water

•Spawn in/on vegetation

•Young/small fishes – feed on zooplankton

•Larger fishes – feed on aquatic insects


Now (2008)

Factors structuring fish community

•Low dissolved oxygen

•High water temperatures

•Lack of spawning riffles


Tomorrow?

•A little warmer?

•More Ludwigia BHM?

•No restoration?


Tomorrow?•A little warmer?

•Less Ludwigia?

•Better water quality?


Big-Time Thanks

Bill Cox Amber Manfree

Jason Moore

fishes of the laguna de santa rosa then, now, andtomorrow? · then, now, and...tomorrow? teejay...

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