Status of the invasive alga Undaria pinnatifidain Monterey Harbor

Steve I. Lonhart

SIMoNSanctuary Integrated Monitoring Network

www.mbnms-simon.org

Collaborators• Elkhorn Slough National Estuarine Research Reserve

– Kerstin Wasson

• University of California Santa Cruz– Mark Carr, Craig Syms, Rich Walsh and Michelle Fuller

• Moss Landing Marine Laboratories– Michael Graham and Heather Kerkering

• California Department of Fish and Game– Bill Paznokas, Tim Olivas, David Osorio

• Monterey Harbor Master’s Office– Scott Pryor and Steve Scheiblauer

• City of Monterey Volunteer Services– Julie Dillemuth

Monterey Harbor Aug 2001

Santa Barbara HarborApril 2001

Channel Is. H.,Port HuenemeJune-Nov 2000

Santa Catalina Is.June 2001

LA and LB harbors,March-May2000

Spread of Undaria in CaliforniaFrom: Silva et al. (2002) in Biological Invasions

Using a framework for the control of marine invaders(From Bax et al. [2001] in Conservation Biology)

Step 1. Establish the nature and magnitude of the problemStep 2. Set clear objectivesStep 3. Consider full range of alternativesStep 4. Determine risks of control methodStep 5. Reduce riskStep 6. Assess cost-benefit of controlStep 7. Monitor and evaluate the program

Phenology of Undaria

• Japan: sporophytes begin rapid growth in winter, mature in late spring, die in summer

• France: two or more generations, spores released most of the year

• Monterey: tending towards overlapping cohorts

Oct and Nov 2002: stratified random sampling of floating docks

Undaria removed from Dec 02 to Feb 03

0

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<10 11-20 21-30 31-40 41-50 51-60 61-70 71-80

Size (cm)

Number removed

N=1282Mean=16.7 cmVar=174.25

Undaria removed from Apr to Oct 03

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<10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 81-90 91-100 101-110

111-120

>120

Size (cm)

Number removed

N=1111Mean=36.1 cmVar=1185.6

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Dec Jan Feb Apr May Jun Sep Oct

Number

Total

Damaged

Sporophyll

Mature

Undaria removed December 2002 - October 2003

What have we learned thus far?

• Eradication in Monterey Harbor is very unlikely• Undaria is not found on

– some shaded structures– pilings with heavy native algal cover

• Pugettia producta is the most common grazer• Sporophyte growth is variable in space and time• Undaria can recruit in fall• Boat and skiff hulls are fouled

• Coordination among agencies requires patience– Have MOUs in place for future invasions

What will we do next?

• Study survival of detached, pre-reproductive thalli• Look at effects of shading on recruitment, growth• Expand surveys beyond the harbor• Test Pugettia feeding preferences

Funding: none.Many thanks to the volunteers

from the City of Monterey