National Management Plan for the Genus Caulerpa Photo by R. Woodfield, Merkel and Associates Submitted to the Aquatic Nuisance Species Task Force Prepared by the Caulerpa Working Group October, 2005 Executive Summary A variety of surveys have confirmed at least twenty-one species and varieties of Caulerpa with populations in different regions of the United States (U.S.). Three species of Caulerpa are thought to be invasive due to their historic and ongoing invasions of U.S. and foreign waters; Caulerpa taxifolia (Aquarium or Mediterranean strain), Caulerpa brachypus and Caulerpa racemosa. In December 1999, the Aquatic Nuisance Species Task Force (ANSTF) established the Caulerpa taxifolia (Mediterranean strain) Prevention Committee. The Committee drafted the “Prevention Program for the Mediterranean strain of Caulerpa taxifolia” (Appendix A) which was an extension of the prior "Action plan to prevent the introduction and dispersal of the Mediterranean strain of Caulerpa taxifolia in U.S. waters”. In June 2000 divers detected C. taxifolia (Mediterranean strain) in Agua Hedionda Lagoon located in Carlsbad, CA and a second population in Huntington Harbor, CA. Divers first discovered non-native C. brachypus off the coast of southern Florida in 1999. Concerns have also been raised by scientists about C. racemosa, which has spread rapidly in the Mediterranean, but has not yet produced any problematic populations in U.S. waters. Documented impacts of invasive Caulerpa species include competition with marine plants and macroalgae, direct and indirect impacts on marine invertebrates, direct and indirect impacts on marine vertebrates and economic impacts due to control costs and costs associated with ecosystem alteration. To date, eradication efforts for C. taxifolia in California have cost over $3.7 million in direct control costs, and over $500,000 have been allocated to study the effects of C. brachypus in Florida. In 2002 the ANSTF recommended that a Caulerpa Working Group (CWG) be formed to provide input on the development of a National Management Plan (NMP) that addresses the genus Caulerpa. This NMP was developed with the input of the CWG and other Caulerpa experts to guide the ANSTF and other interested parties in managing Caulerpa species in U.S. waters. A petition to list Caulerpa taxifolia (whole species) and Caulerpa (whole genus) was submitted to the U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) on July 6, 2003. Currently the USDA APHIS is working on a pest risk assessment for the genus Caulerpa and will consider listing as Federal noxious weeds species of Caulerpa that are determined to pose a risk to the United States and that meet the International Plant Protection Convention definition of a quarantine pest. The goals of this National Management Plan for the genus Caulerpa are: 1) Prevent the introduction and spread of Caulerpa species to areas in U.S. waters where they are not native. 2) Early detect, rapidly respond to and monitor Caulerpa species in U.S. waters where they are not native. 3) Eradicate Caulerpa populations, in waters to which they are not native, where feasible. 4) Provide long-term adaptive management and mitigate impacts of populations of Caulerpa species in U.S. waters where they are not native and where eradication is not feasible. 5) Educate and inform the public, agencies and policymakers to advocate for preventing the introduction and spread of Caulerpa species. 6) Identify research needs and facilitate research to fill information gaps. 7) Review, assess progress and revise the management plan and continue developing information to meet national management plan goals. i Table of Contents Executive Summary ......................................................................................................................... i Figures............................................................................................................................................ iii Tables ............................................................................................................................................. iii 1. Purpose of this National Management Plan ............................................................................... 1 2. Introduction to the Genus Caulerpa........................................................................................... 3 2.1. Species of Caulerpa which are native to U.S. waters .......................................................... 5 2.2. Species of Caulerpa that may be introduced to U.S. waters to which they are not native... 7 2.2.1. Caulerpa taxifolia.......................................................................................................... 7 2.2.2. Caulerpa brachypus ...................................................................................................... 9 2.2.3. Caulerpa racemosa ..................................................................................................... 10 2.2.4. Other potentially invasive species of Caulerpa........................................................... 13 2.3. Assessment of historic Caulerpa introductions.................................................................. 18 2.3.1. History of Caulerpa taxifolia introduction in California............................................. 19 2.3.2. History of Caulerpa brachypus introduction in Florida.............................................. 19 2.3.3. History of Caulerpa taxifolia introductions in other regions ...................................... 19 2.3.4 Eradication and control efforts for Caulerpa taxifolia ................................................. 20 2.4. Regulation of Caulerpa species in the U.S......................................................................... 22 3. Impacts of Caulerpa Introductions........................................................................................... 23 3.1. Ecological Impacts of Caulerpa Introductions................................................................... 23 3.1.1. Direct and indirect impacts on marine plants .............................................................. 23 3.1.2. Direct impacts on marine herbivores........................................................................... 24 3.1.3. Indirect impacts on marine invertebrates..................................................................... 25 3.1.4. Indirect impacts on marine vertebrates........................................................................ 26 3.2. Economies that Could be Impacted by Caulerpa Infestations ........................................... 26 3.3. Actual costs of Caulerpa control in the U.S....................................................................... 28 3.3.1. Costs of eradication treatment in California................................................................ 28 3.3.2. Costs of control and educational outreach in Florida .................................................. 29 4. Implementation Action Items................................................................................................... 30 4.1. Primary Priorities for Implementation................................................................................ 31 4.2. Secondary Priorities for Implementation............................................................................ 43 4.4. Implementation Table for Action Items ............................................................................. 49 5. References Cited....................................................................................................................... 50 ii Figures Figure 1. Caulerpa taxifolia exhibits a habit typical of the genus: a creeping rhizome produces rhizoids downward and photosynthetic branches (in this case bearing leaf-like pinnules) upward..................................................................................................................................... 3 Figure 2. On the Pacific coast of North America indigenous populations of Caulerpa only exist as far north as Guadalupe Island. ............................................................................................ 5 Figure 3. Caulerpa taxifolia showed vigorous growth, prior to treatment in California................ 7 Figure 4. Caulerpa brachypus patches are growing on coral in FL. .............................................. 9 Figure 5. Caulerpa racemosa can grow rapidly in some environments....................................... 11 Figure 6. Caulerpa prolifera has shown characteristics that might be linked to invasiveness..... 13 Figure 7. Caulerpa cupressoides has been shown to exhibit very fast rates of growth................ 15 Figure 8. Caulerpa scalpelliformis can be considered potentially invasive in U.S. waters. ........ 16 Figure 9. Caulerpa mexicana can grow to 15m deep................................................................... 16 Figure 10. Caulerpa verticillata is another fast growing species of Caulerpa. ............................ 17 Figure 11. Caulerpa sertularioides has the potential to be invasive in coastal California........... 18 Figure 12. Commercial landings for Florida as reported by wholesale seafood buyers from 1988 to 2002 have steadily declined (data provided by NMFS 2004). .......................................... 27 Figure 13. Commercial landings for California, as reported by wholesale seafood buyers for 1988 to 2002 have been highly variable(data provided by NMFS 2004)......................................