Status of the invasive alga Undaria pinnatifida in Monterey Harbor Steve I. Lonhart SIMoN Sanctuary Integrated Monitoring Network

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 Harbor April 2001 Channel Is. H., Port Hueneme June-Nov 2000 Santa Catalina Is. June 2001 LA and LB harbors, March-May 2000 Spread of Undaria in California From: 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 problem Step 2. Set clear objectives Step 3. Consider full range of alternatives Step 4. Determine risks of control method Step 5. Reduce risk Step 6. Assess cost-benefit of control Step 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 December 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