ANEMOON Beach washup monitoring (SMP) data along the Dutch coastline collected through citizen science.

On transect locations, all washed-up marine organisms and remains are determined
and counted on a biweekly or monthly basis. The SMP-trajects vary in length from about
one to fout kilometer. Observers make sure they are at the starting point of the SMP
traject 30-60 minutes before low tide. Then the first half of the monitoring walk takes
place along the low-tide line. At the turning point of the traject the observers turn around
and walk back following the high tide line.
During the monitoring walk observations are being noted, special findings are
photographed and sometimes material is brought home for species determination.
Macroalgae, Cnidarians, Gastropods, Cephalopods, Bivalves, Crustaceans,
Echinoderms, Shark and Ray egg capsules and Bryozoans are noted at species level.
For each species the abundance class (0, 0-10, 11-100, 101-1000, 1001-10000, 10001 –
100000, >100000) and “decay category” are noted (Alive, Doublet, Single valve, Empty
snail shell, Flesh remains, Dead (whole specimen), Peel/skeleton, Fragment, without flesh, Exuvia, Subfossil, Fossil, Egg capsule, Egg).

For now there are nine transects along the Dutch coastline. This number is increased when new transects are born.

New observers always accompany experienced observers for some time before going
through the monitoring process on their own. The fact that observers walk in pairs at a
minimum makes consultation and discussion possible. When in doubt about an
identification, the collected material is examined by other experienced citizen scientists
or, or if necessary by ANEMOON affiliated experts. The species that are standardly found
in the SMP are regularly seen and are often not difficult to identify. When in doubt about
the species identity, observers are instructed to note down XX on the SMP fieldwork form
or in the SMP-webapp. The XX observations are included in the analysis as ”Missing
Values”.