1. European Green Crab ID and Ecology 2. Is the Problem Increasing?
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European Green Crab on the Washington Coast Prepared by Alex Stote for the Olympic Coast National Marine Sanctuary Advisory Council July 23, 2020 Photo: Kelly Martin Alex Stote Emily Grason Crab Team Coastal Specialist Crab Team Project Coordinator Washington Sea Grant Washington Sea Grant European green crab (EGC) ID and habitat Historical context of EGC on the WA coast Are EGC increasing on the coast? What actions are being taken on the coast? How can you help? How to ID a European green crab 3 3 3 Native shore crabs Hemigrapsus spp. Not all European green crabs are green… Don’t rely on color to ID European green crabs! Stevens et al. (2014) And not all green crabs are European! Don’t rely on color to ID European green crabs! Hairy Shore Crab Purple Shore Crab (Hemigrapsus oregonensis) (Hemigrapsus nudus) What is the risk to Washington? What is the risk to Washington? Where do green crab live? Europe East South Western (native) North Africa North America America Outer Coast Hard substrate + + + 0 Soft substrate 0 0 0 0 Protected embayments Hard substrate ++ ++ ++ 0 Soft substrate ++ ++ ++ ++ Grosholz et al 1996 Biol Conservation What habitats are at risk? • “Pocket estuaries” • Lagoons • Channels • Artificial habitats (e.g. impounded tidal areas) Green crabs can survive a wide range of conditions Fresh Marine Warm Cool Intertidal Subtidal Low flow/energy High flow/energy Green crabs prefer protective structure EGC on the West Coast ● Periodically abundant on WA coastal estuaries ● Swept north on 1997/1998 ENSO ● Came from US east coast ● First confirmed in SF Bay in 1989 EGC on the West Coast 140 120 WA Boom-Bust 100 80 OR Boom-Bust* 60 40 20 StandardizedCatch* 0 1997 2007 2017 *Catch per unit effort = # Crabs per 100 trap- days Data courtesy of Sylvia Behrens Yamada (OSU) EGC on the West Coast Yamada, S.; Yednock, B.; Geierman, C.; Akmajian, A.; Prickett, J. (2018) Dataset for Status of the European Green Crab, Carcinus maenas, in Oregon and Washington coastal Estuaries in 2017. OSU Libraries. Dataset. https://doi.org/10.7267/N9VD6WM4 Are EGC becoming established on the WA coast? • Makah finding and rapid response in 2017 • Reported sightings from shellfish growers Photo: Adrianne Akmajian Photo: Brian Sheldon Are EGC becoming established on the WA coast? • Data observations from Washington State Yamada, S.; Yednock, B.; Geierman, C.; Akmajian, A.; Prickett, J. (2018) Dataset for Status of the European Green Crab, Carcinus maenas, in Oregon and Washington coastal Estuaries in 2017. OSU Libraries. Dataset. https://doi.org/10.7267/N9VD6WM4 What are we doing to address these changes? Sentinel Sites Assessment Sites + various coastal partners ● Trapping dedicated sites ● Intensive (high density of 1x/month from April – traps) and extensive (wide September scope) trapping effort over ● Molt hunt multiple days ● Detect habitat ● Assess size and scope of associations of EGC population (where are crabs, how many, infer dynamics, arrival) What are we doing to address these changes? Sentinel sites What are we doing to address these changes? Sentinel sites Assessment sites How can you help? How can you help? Eyes on the beach: Where to Look for European Green Crab • Muddy, soft sediment • Protected from the open water • Vegetation Thank you! Alex Stote [email protected] [email protected] wsg.washington.edu/crabteam Photo: Kelly Martin 1. Early detection 3. Eradication/Removal 1. Crab Team Network: 1x/mo, 3 day (2 night) trapping effort, Ongoing, opportunistic intensive Trapping, Molt, Transect intensive (high density of traps) effort to track and remove crabs. 2. Additional Prospecting by WDFW and extensive (wide scope). Trap and other partners only. ● Find new populations while ● Assess size and scope of ● Target hotspots and edges they are at low density population (where are crabs, how many, infer dynamics, ● Adaptive management, ● Assess changes caused by arrival) collect data on effort and EGC catch in real time, as well as ● Prioritize efficiency and standardized monitoring ● Detect habitat associations efficacy for EGC of EGC ● Prioritize efficiency and ● Agency/staff efficacy for EGC ● Volunteer retention, pocket estuary monitoring.