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You are here: Home / Manager's Tool Kit / Early Detection and Rapid Response / The Early Detectives / Elkhorn Slough Early Detection Program for "Least Wanted" Aquatic Species
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Early Detection and Rapid Response

The Early Detectives: How to Use Volunteers Against Invasive Species, Case Studies of Volunteer Early Detection Programs in the U.S.

Elkhorn Slough Early Detection Program for "Least Wanted" Aquatic Species

Contacts: Kerstin Wasson, Research Coordinator, Elkhorn Slough National Estuarine Research Reserve
E-mail: research@elkhornslough.org
Phone: (831) 728-5939


The Elkhorn Slough National Estuarine Research Reserve (ESNERR) (The Slough), in partnership with the Elkhorn Slough Foundation and the Monterey Bay National Marine Sanctuary, and with funding from California Sea Grant, has recently launched a volunteer early detection (VED) program for aquatic alien invaders. The goal of this new program is to detect new invasions of problematic non-native aquatic organisms early enough to allow for successful eradication. In order to find new invasions throughout the Elkhorn Slough and the Monterey Bay, ESNERR researchers have enlisted scores of Monterey Bay area citizens who are active in marine habitats. The success of this program depends on having as many pairs of eyes as possible on the lookout for new aliens. These eyes are primarily focused on identifying two-dozen least-wanted invaders identified by Slough researchers as posing a significant threat to the rich native coastal biodiversity of central California.


Though the early detection program at the Slough is still relatively new, it is already having success in terms of involving the public in detection efforts and employing rapid response to identified species invasions. Working with approximately 50 coastal organizations throughout Central California, Slough researchers prepared and distributed thousands of their "least wanted" species booklets. Since the booklet was distributed, an invasion of one "least wanted" species, Wakame (Undaria pinnatifida), was identified. Slough scientists are now engaged in rapid response efforts to control the invasion of this invasive brown kelp.

Program Design

The Slough designed its early detection programs to discover new invasives during the window of opportunity for eradication. To do this, the Slough began by assessing existing non-native species composition in the region to establish a baseline, and then chose "least wanted" invaders for the area. From a potential pool of hundreds of known aquatic invaders, Slough scientists chose a subset of two dozen species that: 1) were, at the time, not yet present in the Monterey Bay area, 2) have a high potential to be transported there (especially from nearby sources such as San Francisco Bay), 3) are relatively large and easy to identify, and 4) are likely to have a significant ecological impact if they invade. Each of the two-dozen "least wanted" species is described in the booklets that the Slough has prepared and published. The booklets provide information on diagnostic features for identification, and information on habitat, native origin, invaded areas, and ecological concerns. The booklets also contain instructions on what to do if an alleged invader is sighted: volunteers are directed to note their exact location, collect a single voucher specimen, and immediately make an "urgent invasive alert" to the ESNERR. Slough scientists will then confirm the identification and inform the appropriate agencies (which vary by species and habitat). The Slough will help to coordinate interagency efforts to plan the most appropriate response strategy, and will support rapid response efforts to contain or eradicate the new invasion, if appropriate.

The target areas for this early detection program are Elkhorn Slough and Monterey Bay, central California, because the coordinators of this program are based there, because the ESNERR has good baseline information for these areas and because there are many citizens active in aquatic habitats there. However, the Slough welcomes reports from as far south as Morro Bay to as far north as Moss Beach.

To enlist as many least-wanted species watchdogs as possible, the Slough is attempting to provide booklets to all citizens in the Monterey Bay area who frequent aquatic habitats and are likely to notice alien species. By holding a training workshop and providing free materials, the Slough has involved about 50 regional coastal organizations (kayaking, fishing, diving, conservation groups; harbormasters; government agencies; aquaria; universities and research organizations) in this effort, resulting in broad dissemination of nearly 4000 booklets to their constituents. By involving the community in this effort to look for and report new invasions of "least wanted" species, the Slough is increasing the likelihood of detecting new invasions early enough to take action. The slough hopes avid aquatic resource users will familiarize themselves with the unwanted aliens, and help the Slough protect the rich native coastal biodiversity of central California.

Program Statistics

The ESNERR employs 6 full-time staff research scientists. Kerstin Wasson is the staff researcher who led the design of the Slough's volunteer early detection program. The volunteer early detection program is carried out by ESNERR staff, other wildlife research scientists in the Monterey Bay area and thousands of civilian volunteers that spend time in aquatic habitats. Funding for the early detection program comes from the Elkhorn Slough Foundation, which raises money through public and private donations to fund the entire Elkhorn Slough Reserve. The early detection program does not have a specified budget. Funding is allocated as needed for rapid response efforts, but the actual early detection is done through volunteer efforts and is just part of the job for Slough employees. There are 24 species of the program's least wanted list, chosen for reasons previously mentioned. The area covered by the early detection program includes the following aquatic systems: the entire Monterey Bay, the Elkhorn Slough and other estuarine systems connected to the Monterey Bay.

Current Obstacles

The Slough is counting on the approximately 50 organizations that it has held workshops with and sent booklets to for keeping the momentum going in the "least-wanted" species early detection efforts. Slough employees do not have time to continuously train civilians in early detection. Training needs to spread virally. Experienced volunteers need to pass on their early detection knowledge to newbies. There also needs to be adequate follow up between participants and Slough researchers to positively identify invasions so rapid response can occur. Because early detection is voluntary, time is the most valuable resource to volunteers and staff with other obligations. When identifications happen, there needs to be an efficient system in place to go about rapid response. Currently this part of the program lacks consistency.

Program Designer's Reflections

Kerstin Wasson designed the early detection program for aquatic invasives of the Elkhorn Slough and the Monterey Bay. She designed the program knowing that alien species posed a serious threat to the rich native biodiversity of the slough and the bay, but did not know which invasives could successfully be eradicated by rapid response efforts. Wasson feels that such knowledge would have helped her focus the program better, but such knowledge was unavailable and is only now becoming known. Despite this, Wasson has been very satisfied with her program as an early detection tool and especially as a vehicle for education of the general public. The program has educated thousands of Monterey Bay recreational users on the importance of prevention and early detection of invasive species.

Designer Recommendations

The first thing someone designing a VED program should do is find out which invaders are already present. This is called a baseline survey. The VED program designer should then asses which species are most likely to: show up in the next ten years, establish tolerances (thermal, etc.), have big community or habitat impacts, and be noticed by the general public. When choosing least wanted species for a VED program, a designer should note that detection and success are made easier when a species can be easily identified and be eradicated if detected early. The most critical step is: filtering from hundreds of possible invaders those most relevant to include in an early detection program. A VED program will be successful if it can have a measurable impact. It is a waste of time going after species that are impossible to find, or may be impossible to get rid of.

Quick Facts

Staffing: 6 (ESNERR research staff: Early Detection is one of their many responsibilities)

Operating Budget: The ED program is volunteer; the ESNERR has its own budget

Species Targeted: 24 "least wanted" invaders (www.elkhornslough.org)

Caulerpa (Caulerpa taxifolia)
Wakame (Undaria pinnatifida)
Smooth Cordgrass (Spartina alterniflora)
Black Sea Jellyfish (Maeotias inexspectata)
Spotted Jellyfish (Phyllorhiza punctata)
Striped Barnacle (Balanus amphitrite)
Red Swamp Crayfish (Procambarus clarkii)
American Lobster (Homarus americanus)
Chinese Mitten Crab (Eriocheir sinensis)
Harris Mud Crab (Rhithropanopeus harrisii)
Eastern Mud Snail (Ilyanassa obsoleta)
Channeled Whelk (Busycotypus canaliculatus)
Veined Rapa Whelk (Rapana venosa)
Atlantic Ribbed Mussel (Ischadium demissum)
Green Mussel (Perna spp.)
Northern Quahog (Mercenaria mercenaria)
False Angelwing (Petricolaria pholadiformis)
Winged Oyster (Pteria sterna)
Asian Clam (Potamocorbula amurensis)
Northern Pacific Seastar (Asterias amurensis)
Spaghetti Bryozoan (Zoobotryon verticillatum)
Mediterranean Fan Worm (Sabella spallanzanii)
Chameleon Goby (Tridentiger trigonocephalus)
Diamondback Terrapin (Malaclemys terrapin)

Location: USA, Elkhorn Slough and Monterey Bay, Central California.

Report prepared by: Lucas Nagy

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Last Modified: May 18, 2016
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