Native and invasive crabs in the Gulf of Maine: are ...

What we need you to do:

1. Pick a rocky intertidal zone near you and plan a visit at low tide.
2. Print the Coastal Species Survey datasheet from the Gulf of Maine Research Institute's Vital Signs site (http://vitalsignsme.org/sites/default/files/content/level1_coastal.pdf). Because you will be documenting 5 species, you will need to print 3 extra copies of the last page of the datasheet.

3. Print these five species ID cards:
   • Asian shore crab (http://vitalsignsme.org/sites/default/files/content/ci_hemigrapsus_sanguineus_071012.pdf)
   • Green crab (http://vitalsignsme.org/sites/default/files/content/ci_carcinus_maenas_022814.pdf)
   • Chinese mitten crab (http://vitalsignsme.org/sites/default/files/content/fci_chinesemittencrab_113015_0.pdf)
   • Jonah crab (http://vitalsignsme.org/sites/default/files/content/cn_cancer_borealis_121115.pdf)
   • Rock crab (http://vitalsignsme.org/sites/default/files/content/cn_cancer_irroratus_022714.pdf)

4. Read through and print out a copy of the random quadrat sampling method protocol from here http://vitalsignsme.org/sites/default/files/content/method_quadrat_random_100109.pdf. You can use the random number generator NOW and write down the number you get on the protocol sheet.
5. Gather your gear. You will need a digital camera, at least one clean bucket, a pencil or pen, your data sheets, ID cards, the random quadrat sampling method protocol, a 20 meter rope or string with knots every meter, and a meter square quadrat (a second 4 m piece of string or rope with knots every 1 meter that you can use to make a square works beautifully)
6. At your intertidal site, follow the random quadrat sampling protocol to determine where to place your quadrat.
7. Search your quadrat for LIVE crabs. Check under rocks and seaweed where crabs like to hike. Put all the crabs you find into one bucket (with water in it). When you are confident that you have all the crabs from your quadrat, go on to the next step.
8. Use your crab identification skills and the species ID cards to sort the crabs in your bucket by species (it may be useful to sort each type into a separate bucket).
9. Once you have all your crabs sorted and identified, fill out a Vital Signs datasheet for each species. Record how many of each species you found, even if that number is zero. Make sure you take all the required pictures.

10. If time allows, collect and record additional information about the crabs, including size and sex. Record how many males and females of each species you found, and how big they were. Be careful not to count any crabs twice! Stay organized by sketching yourself a table with the following headers (or use ours at https://docs.google.com/spreadsheets/d/1gkgmK3y0p6nlRukCjv47WQbWrTl5mWTNw2jYDBZfo0w/edit?usp=sharing):
    • Specimen #
    • Crab species
    • Carapace size
    • sex

11. Once you've recorded all the data and checked your work, release all native crabs. NOTE: if you find a Chinese mitten crab, do NOT release it! Follow the instructions listed on the species ID card for this species. See the full teacher instructions for ideas on how to deal with green and Asian shore crabs.
12. If time allows, collect environmental data (water temperature, air temperature, salinity) from your quadrat and the area right around it.
13. Share your data here on iNaturalist. Our scientists will be alerted when you've posted your observation.

14. ALSO add your data to to this spreadsheet, https://docs.google.com/spreadsheets/d/1abQMiW2muyRoCPEaVE6-kxWgGq4CmoSfefgpGdWFNis/edit#gid=1412241173

    • Copy and paste rows 2-7 into a new tab
    • Label this new tab with your school’s/organization's name (or school and class if there will be more than one class contributing)
    • Go to your tab in the spreadsheet and enter your data
15. Revisit the project question – do you have an answer? How confident are you in your answer? What would make you more confident?
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