Mapping the Salish Sea Floor for Rockfish Habitat

H. Gary Greene

Tombolo, Orcas Island WA

Rockfish in the Salish Sea Workshop

Seattle, WA June 28, 2011

A Geologist

Multibeam Data Coverage 2000 to present

CSUMB

San Juan Island

Lopez Island

Orcas Island

After Mosher and Johnson, 2000

(Burmester, Blake, & Engebretson, 2000))

Geologic Setting

Numerous episodes of uplift & subsidence associated with tectonics and glacial cycles

End moraine

Geology - Glaciation

Side moraine or esker

Outwash banks

San Juan Archipelago

Tombolo MBES bathy relief map

VancouverIsland

volcano

Fraser R

.

Washington

BritishColumbia

120O

122O124O

124O

126O

126O

128O

128O

130O

130O

Strait ofGeorgia

Fraser Delta

Victoria

Maxim

um

ice extent

PugetSound

Strait ofJuan de Fuca

60

55

50

135 130 125 120 115

B.C.

ALTA.

WASH.

QueenCharlotte

Islands

Figure 1

Figure 2

Fault Fault

* Rockfish sketch provided by ADFG website

Geology = Habitat

Image courtesy of Alaska Fish & Game

Various unconsolidated features

75%

Sediment waves 9%

Bedrock 8%

Glacial features 6%

Sediment covered bedrock 2%

Mounds and depressions 1%

Anthropogenic <1%

Boulders / pinnacles <1%

San Juan Archipelago Habitats

Habitat Mapping - Ecosystem Management

Tombolo

Potential Rockfish Habita (Red areas)

Salish Sea Mapping Effort MBES Bathymetry (EM 3000 & 3002)

Foraging Habitats

Sandwave Field

N

San Juan Island

Shaw Island

Lopez Island

FHL

Abundance in Sandwave Field

• If avg. density = 84 fish/m2:

44,556,805 fish • If light density = 120 fish/m2:

63,742,733 fish

USGS eyeball Sediment camera

USGS Video Camera

San Juan Channel Sand Waves

~30 m

Eyeball drop - crest

Eyeball drop - trough

1.5 cm

Eyeball Drop - Crest

1.5 cm

Eyeball Drop - Trough

Eelgrass on Salmon Bank

Eelgrass

Conclusions

• Marine benthic habitat mapping in the San Juan Archipelago has progressed to the point where other thematic maps can be constructed

• Value added through focusing on rockfish and PSL sub-tidal habitats

• Shallow water mapping underway and “white zone” being addressed

• Eelgrass beds including abundances is being mapped