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
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